The paradoxical phenomenon of the coexistence of overweight and underweight individuals in the same household, referred to as the “dual burden of malnutrition”, is a growing nutrition dilemma in low- and middle-income countries (LMICs).The objectives of this study were (i) to examine the extent of the dual burden of malnutrition across different provinces in Indonesia and (ii) to determine how gender, community social capital, place of residency and other socio-economic factors affect the prevalence of the dual burden of malnutrition.The current study utilized data from the fourth wave of the Indonesian Family Life Survey (IFLS) conducted between November 2007 and April 2008. The dataset contains information from 12,048 households and 45,306 individuals of all ages. This study focused on households with individuals over two years old. To account for the multilevel nature of the data, a multilevel multiple logistic regression was conducted.Approximately one-fifth of all households in Indonesia exhibited the dual burden of malnutrition, which was more prevalent among male-headed households, households with a high Socio-economic status (SES), and households in urban areas. Minimal variation in the dual burden of malnutrition was explained by the community level differences (<4%). Living in households with a higher SES resulted in higher odds of the dual burden of malnutrition but not among female-headed households and communities with the highest social capital.To improve household health and reduce the inequality across different SES groups, this study emphasizes the inclusion of women's empowerment and community social capital into intervention programs addressing the dual burden of malnutrition. As the gross national product (GNP) of low- and middle-income countries (LMICs) increases, the overweight burden shifts to the populations with a low socio-economic status (SES), among whom the underweight burden still remains high The global burden of overweight mothers and stunted children demonstrates a critical situation in middle-income countries. The highest prevalences of this phenomenon were observed in Guatemala (Latin America), Egypt (Africa), and Uzbekistan (Asia). These results consistently confirm a higher prevalence of a dual burden of malnutrition in rural areas compared with urban areas The dual burden of malnutrition has been associated with economic factors such as higher SES, household wealth, income, and GDP and socio-demographic characteristics such as family size, age difference between the underweight and overweight members, maternal support, and urban residency In Indonesia, women play a minor role in policy and government decision-making processes the ability of actors to secure benefits by virtues of memberships in networks and other social structures” social networks, the reciprocity that arise from them, and the value of these for achieving mutual goals” Numerous studies have reported a potential link between social capital and health outcomes, including non-communicable diseases (NCDs) The objectives of this study were (i) to explore the extent of the dual burden of malnutrition in Indonesia across different provinces and (ii) to determine how gender, community social capital, place of residency and other socio-economic factors affect the dual burden of malnutrition.Indonesia is an archipelago in Southeast Asia with a population of 247 million living in its 34 provinces. Approximately half of the Indonesians live on Java Island. Sixty-nine percent of the population live in rural areas. Muslims form the largest religious group, which accounts for 89% of the population (http://www.rand.org/labor/FLS/IFLS.html). The survey was conducted by the RAND Corporation and consists of four waves that were conducted in 1993, 1997, 2000, and 2007–2008. Thirteen out of 27 provinces, which contain 83% of the population, were selected. Enumeration areas (EAs), the primary sampling unit, were randomly selected within each of the provinces. In total, 321 EAs were selected. We used the term “community” to refer to EAs in this study. Households were randomly selected within the EAs. Although the IFLS is a longitudinal survey, weights were constructed both at the individual and household level treating the IFLS as a cross-sectional survey. Therefore, the IFLS was representative of the Indonesian population living in the 13 IFLS provinces in each wave This study utilized the IFLS dataset, which is the only large-scale longitudinal survey available for Indonesia 2 to categorize individuals as underweight, normal weight, and overweight/obese 1/LM(1+L×S×z). Where z is the z score corresponding to the required centile and the values of L, M, and S vary with age and sex. The reverse process, of converting a child's BMI to a z score, involves the equation: L−1)/(L×S)z = ((BMI/M). The values of L, M, and S are for the child's age and sex.Children less than two years old and pregnant women were excluded. As a result, 12,037 households and 42,749 individuals remained in the study . Two traA household with a dual burden of malnutrition was identified if there was at least one underweight and one overweight member in the household. Households with only one member and households without BMI data or only one available BMI measurement were excluded. Finally, 9,743 households consisting of 38,237 individuals were included in the analysis .Households were classified into four distinct groups, including (i) “underweight households” with at least one underweight member and no overweight member (28%), (ii) “normal households” without underweight or overweight members (21%), (iii) “overweight households” with at least one overweight and no underweight member (32%), and (iv) “dual burden households” with at least one underweight and one overweight member (19%). In this study, we focus on comparing the “dual burden households” with the other types of households combined.Households were classified as male- and female-headed households based on the sex of the household's head reported in the survey. Statistics Indonesia (BPS) defined a head of the household as (i) the person who is actually responsible for the daily needs of a household or (ii) the person who is considered the head of the household The education level of the household head is based on their highest education level and was categorized into “no schooling”, “elementary”, “secondary”, and “university/college”.We used asset and housing variables to create SES quintiles (1 = poorest and 5 = richest) using a Principal Component Analysis (PCA) We controlled for the influence of age in the analysis by accounting for the proportion of household members less than 15 years old and greater than 60 years old.In this study, the collective feature of social capital was measured based on the existence of programs and activities in the community, such as village cooperatives, neighborhood watch programs, village improvements, child development, teen development, elderly programs, youth and family groups, village loans, and health funds in the communities. The responses to each of these indicators were used and summarized with a PCA and the resulting index was divided into tertiles, including lowest, middle, and highest community social capital.In addition, households were categorized based on living in urban or rural areas to control for the effect of residency on the analysis.To account for the multistage/cluster sampling design, we used the individual and household weights in all the analyses of individual and household level data, respectively. This was performed using the svyset and svy commands in Stata Version 12.1 . The individual level data were used to calculate the prevalence of underweight and overweight individuals. The data were further collapsed into household level data for subsequent analyses on the dual burden of malnutrition. The results of the descriptive analysis were presented as numbers and weighted percentages with their 95% confidence interval (CI). Prevalences were presented for each province and provinces were ranked based on their 2008 Human Development Index (HDI) A total of 45,306 individuals within 12,048 household participated in the IFLS4 with a female/male ratio of 0.96. In this study, complete data were obtained from 38,237 individuals within 9,743 households.The prevalence of underweight and overweight were significantly different among provinces (p<0.001). Underweight was more common in rural areas  and in provinces with a lower HDI. In contrast, overweight was more prevalent in provinces with a higher HDI and in urban areas  . AdditioThe percentage of households with a dual burden of malnutrition in Indonesia was 19% and significantly different among provinces (p<0.01). Jakarta (25%), South Sulawesi (23%), and Lampung (22%) had the highest prevalences. North Sumatra (15%), Central Java (17%), and Yogyakarta (17%) had the three lowest percentages of households with a dual burden of malnutrition .The differences in the prevalence of the dual burden of malnutrition across provinces were more prominent among female-headed households compared with male-headed households  and in uThe univariate logistic regression revealed that the dual burden of malnutrition was more prevalent (i) among male-headed households than female-headed households, with prevalences of 20% and 16%, respectively, (ii) among households for which head had a higher education level, and (iii) among households with a high socio-economic status. There was no significant difference between households with less than 50% and more than 50% less than 15- and greater than 60-year-old members. When we analyzed community level characteristics, the prevalence was higher in urban areas compared with rural areas, 23% and 17%, respectively. Although the prevalence was slightly higher in communities with the highest social capital compared with communities with lowest social capital, 20% and 18%, respectively, the difference was not statistically significant .The multilevel multiple logistic regression (only fixed-effect) analysis revealed that being in a female-headed household and living in a rural area was significantly associated and had a protective effect. The odds of having a dual burden of malnutrition were higher in households with a higher SES. Community social capital was not significantly associated with the dual burden of malnutrition in any of the regression analyses .The results from the random-effect portion of the multilevel multiple logistic regression models indicated that (i) a small amount of the variation in the prevalence of the dual burden of malnutrition (VPC 2%) was explained by the community level differences and the place of residency, (ii) the proportional change in variance (PCV) was 34%, (iii) the median odds ratio (MOI) was 1.26, (iv) the interval odds ratio (IOR) was 0.49–1.20, and (v) the sorting out index was 22%. Additionally the differences in province level were controlled for in this model, but no significant change was observed.After stratifying the multilevel multiple logistic regression analyses by household head, community social capital, and place of residency, the results from the fixed-effect portion of The random-effect portion of The main findings of this study include the following: (i) approximately one-fifth of all households in Indonesia exhibit a dual burden of malnutrition with significant differences in the prevalence across provinces; (ii) only a small amount of the variation in the dual burden of malnutrition could be explained by the community level differences (<4%), while the remaining 96% could be explained by differences between households; and (iii) the main determinants of the dual burden of malnutrition are having a male head of the household, living in households with a higher SES, and living in an urban area. Moreover, the level of community social capital is not significantly associated with the prevalence of the dual burden of malnutrition, and households with higher SES levels are positively associated with a dual burden of malnutrition regardless of whether the household is located in an urban or a rural area. However, these associations are only significant in male-headed households and households in communities with the lowest social capital.The prevalence of a dual burden of malnutrition has nearly doubled during the last fifteen years according to data from another conducted study in Indonesia using the 1993 IFLS data, which had reported a prevalence of 11% In agreement with our findings, several other studies have reported the association between a higher SES, income or GDP and urban residency with a dual burden of malnutrition in LMICs To our knowledge, no study has investigated the societal aspect of dual burden of malnutrition such as female-headed households and community social capital as well as applying related theories in explaining the statistical significances. In this study, we identify the inequality in the distribution of double burden of malnutrition across different provinces in Indonesia, and the prevalence ranges from 15% in North Sumatera province to 25% in Jakarta province. We also use multilevel approach and identify that only 4% of the variation in dual burden of malnutrition could be attributed to the unobserved factors at community level. These are novice knowledge that has not been addressed in previous research. A recently published article, however, examined the association between intra-household inequalities and dual burden of malnutrition in Indonesia using longitudinal IFLS data Several studies emphasize the positive influence on children's health and condition when women are empowered in the households. Additionally, underweight children contribute significantly to the dual burden phenomenon; thus, if empowerment of women improves children's health, this empowerment will also, in turn, protect households against the dual burden of malnutrition. This hypothesis may explain the protective effect of the female-headed households on the dual burden of malnutrition reported in the present study even after controlling for the head's education and household SES. Taken together, it is “gendered power relations” within the households that affect household health when women take the position that is typically a male role Additionally, this study presents the effects of different household SES on the dual burden of malnutrition at the household level compared with the household head gender and the level of community social capital where the households were located. Household SES does not significantly affect the dual burden of malnutrition in households with a female head and situated in communities with a high social capital. These results suggest that empowering women and improving community social capital could reduce inequalities across different SES groups. These findings are supported by studies in Indonesia The current study has several strengths, including a large sample size, a low percentage of missing data and a high response rate, which provide sufficient statistical power to make robust inferences of the extent of the dual burden of malnutrition in Indonesia. Therefore, the probability of bias in estimating the odds ratios is reduced. Conducting a multilevel analysis at the country level on a novel research topic, such as the dual burden of malnutrition, is an additional strength of the present study. Considering the role of gender and community social capital with other household and community level factors provides an opportunity to examine the dual burden of malnutrition from different societal angles and to identify niches for potential interventions from a social perspective.Some limitations of this study need to be considered when interpreting the results. Drawing conclusions about causality was not possible because of the cross-sectional study design. Dual burden of malnutrition was not separately compared with other types of households such as overweight, underweight, and normal weight. Even though, such comparisons were not within the scope of the current study, further detailed analyses could better help understanding the determinants of the dual burden of malnutrition. For instance, in the study by Roemling and Qaim, fewer significant effects were observed when they compared dual burden households with overweight households, separately. This indicates that dual burden households are more similar to overweight households compared to normal weight households The dual burden of malnutrition in Indonesia doubled between 1993 and 2008 and is unequally distributed. Inequalities in the dual burden of malnutrition in Indonesia exist across populations with different economic developments. However, these gaps are decreased in populations with access to community social capital. Furthermore, the sex of household's head as a proxy for gender relations plays a significant role in influencing the existing problem at the household level. Therefore, to address the dual burden of malnutrition in Indonesia, this study emphasizes the importance of women's empowerment and improvement of community social capital in community intervention programs.


To describe the underlay tympanoplasty technique using an acellular dermal graft(AlloDerm) for tympanic membrane (TM) reconstruction in a guinea pig model and to demonstrate the feasibility of the technique using AlloDerm tissue harvested from the prepuce as a source of tissue for future grafting in human TM reconstruction.The prepuce was divided during circumcision and the acellular dermis was prepared using a number of standard processes. Two groups of guinea pigs were prepared. In the case group (20 guinea pigs and 40 ears) removal of TM was performed with tympanoplasty using AlloDerm, and in the control group (eight guinea pigs and 16 ears), removal of TM was performed without tympanoplasty. In each group, the TM was completely removed in one ear and partially removed on the other side, and the integrity of the TMs was re-evaluated after 8 weeks.In the case group, the healing rates in the completely and partially removed TMs were 83.3% and 94.4%, respectively. The difference in healing rate  was statistically significant (P<0.05).The use of AlloDerm is safe and effective in the repair of TM perforations in a guinea pig model. Acceptable results of AlloDerm tympanoplasty in a guinea pig model may pave the way for the effective use of this material in human TM reconstructions. Tympanic membrane (TM) perforations are a common otologic problem . TemporaTissue engineering is an emerging multidisciplinary field in which researchers are striving to replace or regenerate damaged or lost tissues. The principle common to tissue engineering is to produce new tissues by seeding cells onto a suitable three-dimensional scaffold in an appropriate growth environment. According to this principle, AlloDerm can be regarded as a natural acellular scaffold to facilitate TM healing . It is dThe objective of this study was to demonstrate the feasibility of using AlloDerm tissue harvested from the prepuce as a source of tissue for future grafting in human TM reconstruction through use of a guinea pig model.This experimental study was performed in the Imam Khomeini hospital complex of Tehran University of Medical Sciences with the cooperation of the Pediatric Urology Research Center.AlloDerm was supplied by the above center, and prepuce was selected as an available, cheap and easily transportable source of AlloDerm preparation. The prepuce was divided during circumcision under sterile conditions and was maintained in Roswell Park Memorial Institute (RPMI) solution containing penicillin and streptomycin at 4 °C. Then the prepuce (on the ice) was transferred under a laminar hood and its mucus was divided, before being placed on a dish containing saline solution and put into the incubator at 38 °C for 48 hours. After this time, the prepuce was transferred under the laminar hood again for de-epidermization, and its epidermis was collected and picked up gently. Then, the de-epidermization solution was aspirated, and 20 ml of Hanex solution was added to the bottle before the bottle was rotated three times at 60 revolutions per minute (rpm) for 5 minutes. In the next stage, the prepuce was added to 1% sodium dodecyl sulfate (SDS) solution for 90 minutes and was transferred to the rotator revolving at 60 rpm. The SDS solution was substituted every 30 minutes. Then the prepuce was put into Hanex solution on a rotator revolving at 60 rpm for 20 minutes thrice, and then added to 1% Trigon solution X-100 for 20 minutes. After this stage, the prepuce was processed with 0.5% trypsin and 2% ethylenediaminetetraacetic acid (EDTA) at 37 °C for 30 minutes. Then the acellular prepuce was washed in phosphate buffered saline (PBS) solution for 30 minutes thrice and was maintained in the PBS solution containing penicillin and streptomycin until cell culturing.In this study, 28 guinea pigs were divided into a case and a control group . Twenty guinea pigs were selected as a case group. The integrity of the TMs and middle ears of these guinea pigs were confirmed by inspection under a microscope and then using tympanometry in the audiology service. Then under general anesthesia (intramuscular injection of 10 mg/kg ketamine and 50 mg/kg xylocaine) and under sterile conditions and with the aid of a microscope and routine microsurgery instruments for the ear, the TM of one side of each guinea pig was completely removed with the tympanic ring  and underlay tympanoplasty was performed with a cellular dermis and without trauma to the ossicular chain, with endaural incision. On the other site, the TM was partially removed  in anteroinferior and posteroinferior quadrants (the tympanic ring was maintained) and tympanoplasty was performed in the same manner as previously described. After surgery, 40 mg/kg trimethoprim and 20 mg/ml sulfadiazine were intramuscularly injected for prophylaxis of infection. The integrity of the TMs of both sides was evaluated by otomicroscopy and tympanometry 8 weeks after surgery and the success rate of tympanoplasty was assessed.Eight guinea pigs were selected as the control group. Removal of TM was performed in the manner described for the case group, but tympanoplasty was not performed and the TMs were left for possible spontaneous healing . Also in the control group, for evaluation of possible undesirable immunologic reactions, a piece of AlloDerm was implanted subdermally in the forearm of each guinea pig. The amount of AlloDerm was similar to that required for bilateral tympanoplasty (to ensure approximately similar antigenic load with the case group). Again, both ears of the guinea pigs were evaluated 8 weeks after surgery in the same manner as the case group, and subdermally implanted AlloDerms were removed and sent to the pathology service for evaluation of inflammatory changes.After data collection, all statistical analysis was performed using SPSS software . Statistical values were determined using the Fisher exact test. P≥0.05 was considered to be statistically significant. From 28 guinea pigs, four (two in each case and control group) were deceased by the end of the study. Eighteen guinea pigs remained in the case group. Among the ears with complete TM removal , three grafts (16.7%) failed and 15 grafts (83.3%) healed. In the other ear of the guinea pigs in this group , one graft (5.6%) failed and 17 grafts (94.4%) healed. In the control group, six out of eight guinea pigs survived. Among the ears with complete TM removal , none (0%) healed spontaneously. In the other ear , four TMs (66.7%) healed spontaneously and intact TMs were confirmed in these cases. In two cases (33.3%), TMs had a perforation . Rate ofPathologic assessment of subdermally implanted AlloDerm in the control group indicated slight chronic and nonspecific inflammatory changes without necrosis or foreign-body reactions.Temporalis fascia remains the most commonly used material for TM reconstruction. It has a very high success rate and offers several advantages . RevisioAlloDerm is an acellular dermal graft that is processed from banked cadaver skin. The cellular elements are removed in the processing of the allograft but the native collagen and elastin matrix and the basement membrane complex (BMC) are preserved. It is also treated with agents that prevent any viral transmission when implanted. Because the tissue is acellular, it does not produce an antigenic inflammatory response after implantation . OriginaSeveral studies illustrate the use of AlloDerm in tympanoplasty. Fayad et al. studied 24 patients undergoing tympanoplasty for chronic otitis media. Successful perforation closure was achieved in 87.5% of cases . A studyIn this study we used AlloDerm for tympanoplasty in guinea pigs. Because of legal and ethical considerations, it is desirable to demonstrate safety and effectiveness of this technique in animal models before it is used in human tympanoplasty. According to similar animal model studies in otologic surgeries we followed-up the cases for 8 weeks and demonstrated that use of AlloDerm is safe and effective in the repair of TM perforations in a guinea pig model. Furthermore, we did not see any adverse inflammatory reaction against AlloDerm. In general, this technique was successful in guinea pig models, and for better evaluation we recommend comparison of the results of AlloDerm tympanoplasty with other available materials such as the fascia, vein, and perichondrium in future animal studies. The use of AlloDerm is safe and effective in the repair of TM perforations in a guinea pig model. Acceptable results of AlloDerm tympanoplasty in a guinea pig model may pave the way for the effective use of this material in human TM reconstructions.


There is no doubt that good bimanual performance is very important for skilled handball playing. The control of the non-dominant hand is especially demanding since efficient catching and throwing needs both hands.We investigated training-induced structural neuroplasticity in professional handball players using several structural neuroimaging techniques and analytic approaches and also provide a review of the literature about sport-induced structural neuroplastic alterations. Structural brain adaptations were expected in regions relevant for motor and somatosensory processing such as the grey matter (GM) of the primary/secondary motor  and somatosensory cortex (SI/SII), basal ganglia, thalamus, and cerebellum and in the white matter (WM) of the corticospinal tract (CST) and corpus callosum, stronger in brain regions controlling the non-dominant left hand.Increased GM volume in handball players compared with control subjects were found in the right MI/SI, bilateral SMA/cingulate motor area, and left intraparietal sulcus. Fractional anisotropy (FA) and axial diffusivity were increased within the right CST in handball players compared with control women. Age of handball training commencement correlated inversely with GM volume in the right and left MI/SI and years of handball training experience correlated inversely with radial diffusivity in the right CST. Subcortical structures tended to be larger in handball players. The anatomical measures of the brain regions associated with handball playing were positively correlated in handball players, but not interrelated in control women.Training-induced structural alterations were found in the somatosensory-motor network of handball players, more pronounced in the right hemisphere controlling the non-dominant left hand. Correlations between handball training-related measures and anatomical differences suggest neuroplastic adaptations rather than a genetic predisposition for a ball playing affinity. Investigations of neuroplasticity specifically in sportsmen might help to understand the neural mechanisms of expertise in general. Neuroplasticity, the capacity of the central nervous system to modify its structural and functional organization, involves highly complex, multistep processes that include numerous time-dependent (and maybe less time-dependent) events that occur at different levels such as the molecular, synaptic, cellular, electrophysiological, and structural organization level . The scoThe sum of the above-mentioned microscopic and mesoscopic brain alterations, whether functional or structural in nature, can be measured in vivo by using a variety of magnetic resonance imaging (MRI) techniques . T1-weigIndeed, there is strong evidence from cross-sectional structural MRI studies that sensory, motor, and cognitive training modulates brain morphology ,8,13–15.In two previous studies of our group, the morphometric features of brain areas relevant for motor and sensory control were investigated in professional female ballet dancers  and in pThe reviewed studies based on T1- and diffusion-weighted MRI data combined with voxel-based (VBM) or surface-based morphometry (SBM), manual volumetry (tracing), voxel-wise analyses of diffusion parameters, or fibre tractography combined with graph-theoretical (network) analyses. In summary, the review shows that local GM and WM morphology is altered in sportsmen compared with laymen in the somatosensory-motor network including the MI and primary and secondary somatosensory cortex , premotor cortex, SMA, basal ganglia, thalamus, cerebellum, CST, and corpus callosum ,17,19–33Although it is well established that finger/hand/arm performance (a.k.a. handedness) is related to motor cortex morphology , there iAlthough there is preliminary evidence for structural alterations in the hand representations of judo wrestlers  and worlIn the present study, we investigated structural brain alterations associated with long-term, intensive and extensive handball training and experience and focused on the motor and somatosensory aspect of handball playing, although efficient processing of visuospatial information and its transformations into executive motor programs are also vital for excellent handball playing. Long-term structural brain adaptations were expected to be evident in the somatosensory-motor network including MI, SMA, premotor cortex, SI, SII, basal ganglia, thalamus, and cerebellum in the case of GM and in the CST and corpus callosum in the case of WM.The research reported in the present study was conducted according to the principles expressed in the Declaration of Helsinki. The local ethics committee of the canton Zurich, Switzerland, approved the study and it’s protocols and written informed consent was obtained from all participants prior to study enrolment. The subjects were paid for participation in the study.Twenty-five women with a mean age of 24.4 years  participated in the study. Thirteen participants were professional handball players, who played in the highest national league and some of them were members of the Swiss national female handball team, and 12 were control women matched with respect to handedness and age, who never trained handball or any related ball game such as basketball or volleyball. Except for the regular flute lessons at school, none of the handball players and control women had a formal musical education or learnt to play any musical instrument at an advanced level. Two handball players had to be excluded; one due to a loss of the diffusion-weighted as well as functional brain data (the latter of which however are not part of the present study) and one due to a severe imaging artefact in her T1-weighted scan. Hence, the group of handball players consisted of 11 players with a mean age of 23.6 years (SD = 2.9 years), who were compared against 12 control women with a mean age of 25.5 years (SD = 2.9 years) who were matched with respect to handedness and age. All participants were consistent right-handers as assessed by the hand dominance test ,38. PartMRI scans were acquired on a 3.0 Tesla Philips Intera whole body scanner  equipped with a transmit-receive body coil and a commercial eight-element head coil array that is capable of sensitivity encoding (SENSE).3  and reconstructed to a resolution of 0.86 × 0.86 × 0.75 mm3 . Further imaging parameters were: Field of view (FOV) = 220 × 220 mm2, echo-time (TE) = 2.3 ms, repetition-time (TR) = 20 ms, flip-angle α = 20°, SENSE factor R = 2.0. Total acquisition time was about 4.24 minutes.A volumetric 3D T1-weighted gradient echo sequence (turbo field echo) image was measured with a spatial resolution of 1 × 1 × 1.5 mm3  and a reconstructed spatial resolution of 1.72 × 1.72 × 2.50 mm3 . Further imaging parameters were: FOV = 220 x 220 mm2; TE = 50.0 ms; TR = 11,300 ms; α = 90°; SENSE factor R = 2.1; b-value b = 1,000 s/mm2; and number of averages = 2. Diffusion was measured in 15 non-collinear directions preceded by a non-diffusion-weighted volume (reference volume). Total acquisition time was about 17.7 minutes.A diffusion-weighted spin echo, echo-planar imaging sequence was used to obtain diffusion-weighted scans with a measured spatial resolution of 2.29 × 2.34 × 2.50 mmhttp://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FSLVBM), an optimised VBM protocol [www.fmrib.ox.ac.uk/fsl). First, structural images were brain-extracted and GM-segmented before being registered to the Montreal neurological institute (MNI) 152 standard space using non-linear registration [http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FSLVBM/UserGuide) revealed that the effects of the VBM group comparison (n = 23) are most sensitive with sigma = 5, whereas the effects of the VBM correlation (n = 11) are most sensitive with sigma = 3. We therefore decided to apply an isotropic Gaussian kernel with sigma = 5 (corresponding to 11.5 mm FWHM) for the group analysis and a sigma = 3 (corresponding to 6.9 mm FWHM) for the correlational analysis. It is important to note that this procedure, which however might be regarded by others as an issue of “cherry picking”, is scientifically valid and in accordance with the theory behind smoothing. These maps were then subjected to statistical analyses (see below).Between-group differences in GM volume were evaluated by using VBM ,40. T1-wprotocol  that is protocol  (www.fmrstration . The reshttps://www.jubrain.fz-juelich.de/apps/cytoviewer/cytoviewer-main.php) or from the Harvard-Oxford cortical and subcortical structural atlas (http://www.cma.mgh.harvard.edu/fsl_atlas.html) both implemented in FSL. Following probability maps were used from the Juelich histological atlas: Primary motor cortex, MI  [To restrict the statistical analysis to the cortical regions of interest (ROIs) that are part of the somatosensory-motor network, we used probability maps derived from the Juelich histological atlas (nd BA4p) , primarynd BA4p) , premotond BA4p) . The SMAnd BA4p) –51 becauAs a negative control condition, we also investigated a brain area for which we did not expect any difference between groups. The primary and secondary visual cortex (BA17 and BA18) served as control regions and its probability masks  have beewww.fmrib.ox.ac.uk/fsl). In a first step, non-brain tissue was automatically removed [Diffusion tensor imaging (DTI) data pre-processing and tract-based spatial statistical (TBSS) analysis were performed with FSL version 5.0.3  , we used the probability maps of the left and right CST and that of the corpus callosum derived from the Juelich histological atlas ,57 impleAs a negative control condition, we also investigated a tract for which we did not expect any difference between groups. The cingulum served as a control tract and its probability masks  have been derived from the JHU (John Hopkins University) WM tractography atlas  implemenThe FreeSurfer image analysis suite (see above) has also a fully automated subcortical segmentation procedure that provides, with high accuracy, the volumes of the subcortical structures such as the basal ganglia, thalamus, cerebellum, and corpus callosum. The volumetric segmentation procedure is described in more detail elsewhere –61. We iSurface-based morphometry (SBM) has been applied in addition to the VBM analysis for two reasons: First, we applied SBM to replicate the volumetric findings of the VBM approach by using a surface-based morphometric data pre-processing stream that is different from the pre-processing stream applied in the common VBM approach. Second, SBM was used to track down whether differences in volume  are driven by differences in cortical thickness or cortical surface area. The full procedure applied in the SBM analysis of cortical thickness, cortical surface area, and cortical volume is described in the For the between groups comparison of demographic and global brain measures t-tests for independent samples were applied using IBM SPSS statistics version 22 . Error probability was set at p < 0.05 (two-tailed) uncorrected for multiple comparisons.For the VBM and DTI data, group comparisons as well as correlations have been performed. Voxel-wise general linear models were applied using permutation-based non-parametric testing that also corrects for multiple comparisons across space (FSL’s randomise tool). The threshold free cluster enhancement technique was used in addition . Error pWe also correlated age of handball training commencement and years of handball training experience with the VBM and DTI parameters within the group of handball players. For these two correlations, data have to be demeaned using the—D option in randomise.As described above, we restricted the statistical analyses of the VBM data to the regions of interest, i.e., to areas that are part of the somatosensory-motor network, and those of the DTI data to the CST and corpus callosum.For the between-groups comparisons of the volumetric subcortical segmentations  analysis of covariance models were applied using IBM SPSS statistics version 22. In all these comparisons, total GM volume was used as a covariate of no interest in order to correct for global brain size differences. Error probability was set at p < 0.05 (two-tailed) uncorrected for multiple comparisons.Associations between the VBM and DTI findings, subcortical, callosal, and cerebellar volumes were investigated using Pearson’s correlation implemented in IBM SPSS statistics version 22. Error probabilities was set at p < 0.05 uncorrected for multiple comparisons.2 in size. Correlations between handball training-related measures and SBM-derived parameters were not conducted.For the SBM data, a vertex-wise general linear model based on parametric statistics was applied within FreeSurfer (MRI_GLMFIT tool) without using the threshold free cluster enhancement technique. Although the SBM data reported in the present study, the results of which are reported in the Demographic, behavioural, and global brain measures of the subjects under investigation are summarised in In what follows, we first describe the results of the VBM and those of the DTI analysis. We then report the findings of the subcortical  volume analysis, those of the analysis of regional corpus callosum volumes based on T1-weighted MRI scans, and the findings of the cerebellar GM and WM volume analysis. Next, associations between the above-mentioned findings are described. Last, we briefly report what have been found in the SBM analysis, the results of which are only presented in the Supplementary Information online.In addition to the results reported here, which all are statistically significant at a corrected alpha error probability, we also present findings derived from an explorative approach using a more liberal statistical threshold . All theses explorative findings, however, are not part of the main manuscript and can be found in the The analysis of probabilistic cortical GM volume derived from the VBM data within the a priori defined regions revealed three clusters with increased cortical volume in handball players compared with control women . The larAfter correction for multiple comparisons, there were no clusters with decreased probabilistic GM volume in handball players compared with control women. No significant differences between the groups were found within the primary and secondary visual cortex (BA17 and BA18), which served as a negative control region.When applying a whole brain group comparison no additional, statistically significant clusters were found. We then extracted the mean GM probabilistic volume within the three clusters revealed by the group comparison , Table 3However, within the group of handball players, we correlated age of handball training commencement and years of handball training experience with local GM volume also in voxel-wise analyses within the regions of interest , we nevertheless report it because no (arbitrary) cluster extent threshold has to be applied when using the threshold-free cluster enhancement technique . The anaThere was no significant cluster that showed decreased mean diffusivity in handball players. After correction for multiple comparisons, there were neither clusters with increased FA or axial diffusivity nor clusters with decreased mean or radial diffusivity in control women compared with handball players.With respect to the corpus callosum and after correction for multiple comparisons, there was no significant cluster that showed differences between groups in FA, mean, axial, or radial diffusivity. No significant differences between the groups were found in any of the diffusivity parameters within the cingulum, which served as a negative control tract.We then extracted the mean FA within the three clusters revealed by the FA group comparison Figs  and meanHowever, within the group of handball players, we correlated age of handball training commencement and years of handball training experience with local FA, mean, axial and radial diffusivity also in voxel-wise analyses within the regions of interest, i.e. within the left and right CST. Years of handball training experience were inversely associated with radial diffusivity in a cluster located in the right CST on the height of the corpus callosum . Age of  = 5.88; p = 0.003; ƞp2 = 0.78). Subsequent post hoc univariate analyses of covariance (ANCOVA) were statistically not significant . There was no significant correlation between years of handball training or age of training commencement and the volumes of the eight subcortical structures.Subcortical brain volumes of the handball players and control women are summarised  = 1.01; p = 0.44; ƞp2 = 0.24). Subsequent post hoc ANCOVAs corrected for total GM volume revealed no statistically significant results. There was no significant correlation between age of training commencement or years of handball training and the volume of the five callosal subregions and the sum of them.A MANCOVA also corrected for total GM volume revealed no significant volume differences of all five corpus callosum regional volumes together  = 7.65; p = 0.012; ƞp2 = 0.28; right hemisphere: F = 5.14; p = 0.035; ƞp2 = 0.20)  .There were no significant correlations between age of training commencement or years of handball training and the left or right cerebellar GM or WM volume.We also investigated whether associations exist among the neuromorphometric features of different regions of interest. For that purpose, we first extracted mean GM probability of the clusters revealed in the VBM analysis and mean FA and axial diffusivity of the clusters revealed in the DTI analysis and then correlated these measures with each other as well as with subcortical, callosal, and cerebellar volumes, the latter of which are also correlated with each other. Due to the fact that the two groups differ in most of these measures (as shown above), one cannot investigate the associations of these neuroplastic alterations across both groups because this would be an issue of “double dipping” and would result in inflated correlation coefficients . To avoiOf the 28 correlations conducted within the group of control women only 4 correlations reached statistical significance, two of which were a prior expected and declared as not interesting, i.e. the correlation between FA and axial diffusivity as well as the correlation between left and right subcortical volumes. In contrast, 10 out of 28 correlations conducted within the group of professional handball players reached statistical significance. Mean FA of the clusters found in CST with the DTI analysis is positively correlated with corpus callosum white matter volume derived from the T1-weighted image. The left and in part the right subcortical volumes derived from the T1-weighted image positively correlated with axial diffusivity in the CST, cerebellar GM and WM volume and corpus callosum volume, the former measure derived from the DTI analysis and the latter measures derived from the T1-weighted image. None of the negative associations reported in As already mentioned, the surface-based analysis served as a replication and validation approach and its results are summarised in In the present study, we investigated specific anatomical features of the brain of professional female handball players compared with control women without a history of any ball-related sport experience and/or activity. By using two different MRI modalities (T1- and diffusion-weighted) combined with different computational, neuromorphometric analysis tools  we were able to explore in greater detail the neural correlates of training-induced neuroplastic adaptations in handball players. In the case of GM morphology, we focused on the hand representations in MI and SI, but other GM regions of the somatosensory-motor network such as the SMA, basal ganglia, thalamus, and cerebellum were investigated in addition. In the case of WM morphology, we focused on the diffusion properties of the CST and corpus callosum in our analyses based on DTI data, while callosal and cerebellar WM volumes based on T1-weighted images were investigated as well.As predicted, we found differences in GM and WM morphology between handball players and control subjects in brain regions associated with the motor and somatosensory control of both hands (and arms). Main results are increased GM volume in handball players in the right MI/SI hand representation, in the SMA / cingulate motor area (this cluster extends across both hemispheres) and in the left intraparietal sulcus as well as increased FA and axial diffusivity in the right CST, which is involved in the motor control of the left hand and arm. Age of handball training commencement is inversely related to GM volume in the right and left MI/SI hand representation, whereas years of handball training experience positively correlates with mean FA within the right CST. Alterations in GM morphology are associated with alterations in white matter morphology.Most of the studies listed in our review of the literature see  investigHowever, the core value of the present study is its more holistic and complementary approach that is characterized by (I) the investigation of almost all brain structures associated with the somatosensorimotor network, (II) the application of different MRI modalities to investigate GM and WM anatomy simultaneously, (III) the combination of different computational neuromorphometric tools and analyses, (IV) the direct association of the GM and WM results as well as (V) the fact that the study also provides a review of the literature about structural brain correlates associated with other forms of sport. The main findings of the present study are discussed in greater detail below.When comparing our results with those reported by other structural imaging studies that also investigated sportsmen see , convergAlthough we did not find statistically significant GM differences in the premotor cortex when correcting for multiple comparisons in the VBM analysis, we found evidence for neuroplastic alterations of the premotor cortex in handball players using our surface-based morphometric approach. Cortical volume and cortical surface area were increased in the right premotor cortex  Figs, whHandball playing is very similar to basketball playing, but unfortunately the three studies listed in Morphological alterations in the handballer’s brain are not restricted to the GM morphology. The WM morphology is altered as well. Two clusters with increased FA and axial diffusivity within the handballer’s right CST were found. When comparing our results with those reported by other structural imaging studies of sportsmen based on DTI data see , convergrd Annual Meeting of the Society for Neuroscience, San Diego, CA, USA, November 09–13, 2013) showed that left and right ventral striatal volumes are enlarged in two internationally known top track and field athletes, a male javelin thrower and a male long jumper [The findings of the analysis of the subcortical volumes should be interpreted with caution because they only reach statistical significance when analysed in a multivariate way, i.e. both thalami and all bilateral basal ganglia substructures together. Although all structures tended to be larger in handball players , only thg jumper . These ag jumper  rather tThe sum of all five corpus callosum regional volumes tended to be larger in handball players than in control women . UnfortuWith respect to the cerebellum, handball players showed larger cerebellar GM volumes, but only on a trend level, whereas their cerebellar WM volumes were statistically significantly reduced compared with control women . Using mThe analysis of the associations between the various measures investigated in the present study aimed at highlighting whether the alterations observed were independent from each other or whether alterations in one brain region are related to alterations in other brain regions. The statistically significant associations found between the different morphological measures were all positive see . These cUse-dependent neuroplastic changes more often lead to increases than to decreases in tissue and can therefore be denoted progressively in its nature and might be regarded as a “mirror finding” of what have been reported in another study that investigated the effects of short-term upper limb immobilization on brain plasticity and these changes can be denoted regressively (deprivation-related) neuroplastic alterations . In thatWhen comparing the results derived from the VBM analysis with those derived from the SBM analysis mainly convergent findings emerged. For example, the cluster with increased probabilistic GM volume found in the SMA/CMA region in the VBM analysis  and might therefore diminish the reliability to detect between group differences. Although this might be a major limitation of the present study  it is clear that strong effects identified with small samples will also be identified in larger samples. When using corrected statistical tests as have been applied in our present study the alpha error is small, but the beta error becomes large. Thus, meaningful moderate or small effects will only be detected with larger samples . HoweverAs predicted, we found differences in GM and WM morphology between handball players and control women in brain regions associated with the motor and somatosensory control of the hands. Main results are increased GM volume in handball players in the right and left MI/SI hand representation, more extended and with a higher effect size in the right than left hemisphere, in the SMA/cingulate motor area (the cluster extends across both hemispheres) as well as increased FA and axial diffusivity in the right CST. Brain structures seem to be altered in handball players as a consequence of the intensive handball playing training rather than a consequence of a genetic predisposition for a particular neural trait because handball playing-related measures such as age of handball training commencement correlated negatively with GM volume in the right and left MI/SI and years of handball training experience correlated positively with FA in the right CST. However, longitudinal studies are needed in order to unequivocally track down whether the observed structural alterations are driven by nurture (trainings-induced neuroplasticity) or by nature (genetic predisposition) or potentially driven by both. Investigations of neuroplasticity specifically in sportsmen help to understand the neural mechanisms of expertise in general and might contribute to improvements in the field of neurorehabilitation as has been recently shown by other studies .S1 FigRegions of interest used in the surface-based morphometric analysis.(DOCX)Click here for additional data file.S2 Fig2. The left column shows the left hemisphere and the right column shows the right hemisphere. The first row represents lateral views of mean inflated surface models derived from the subjects under investigation and rotated by 30° in order to have a better view into the central sulcus. The second row represents the medial views. More detailed information of the clusters presented can be found in The surface-based morphometric approach also revealed increased cortical volume in professional handball players compared with control participants in identical, similar and other regions as found in the voxel-based morphometric analysis. The statistical parametric maps were height-thresholded at p < 0.05 (uncorrected for multiple comparisons) as well as cluster extent-thresholded by considering only clusters larger than 25 mm(DOCX)Click here for additional data file.S3 FigStatistical maps were thresholded with p < 0.05 (uncorrected for multiple comparison). The left column shows the left hemisphere and the right column shows the right hemisphere. The first row represents lateral views of mean inflated surface models derived from the subjects under investigation and rotated by 30° in order to have a better view into the central sulcus. The second row represents the medial views. More detailed information of the clusters presented can be found in (DOCX)Click here for additional data file.S4 Fig2. A) Left hemisphere and B) right right hemisphere. The first row represents lateral views of mean inflated surface models derived from the subjects under investigation and rotated by 30° in order to have a better view into the central sulcus. The second row represents the medial views. The inset in A) represent the PMC cluster rotated down by 60° to reveal that this is one connected cluster. The inset in B) represent the SII cluster rotated up by 60° to reveal the whole extent of this cluster. More detailed information of the clusters presented can be found in The statistical parametric maps were height-thresholded at p < 0.05 (uncorrected for multiple comparisons) as well as cluster extent thresholded by considering only clusters larger than 25 mm(DOCX)Click here for additional data file.S1 MethodsThe clusters found in the voxel-based morphometric analysis are located within these regions of interest (ROIs). The exact boundaries of these ROIs can be found elsewhere (see supplementary reference #13 in S1 Methods). The left column shows the left hemisphere and the right column shows the right hemisphere. The first row represents lateral views of mean inflated surface models derived from the subjects under investigation and rotated by 30° in order to have a better view into the central sulcus. The second row represents the medial views. The functional brain areas located within these ROIs are reported in brackets. Abbreviations: CMA, cingulate motor area; MI, primary motor cortex; PMC, premotor cortex; SI, primary somatosensory cortex; SII, secondary somatosensory cortex; SMA, supplementary motor area.(DOCX)Click here for additional data file.S1 ResultsAdditional findings that were statistically not significant, but showed a trend toward significance (0.05 < p < 0.10).(DOCX)Click here for additional data file.S1 Table2 in size. Clusters indicated by the paragraph sign (§) survived error correction for multiple comparisons by using Monte Carlo simulations on the cluster size using 5000 permutations. The ampersand sign (&) highlights clusters with cortical differences in handball players compared with controls as found by both the voxel-based as well as the surface-based morphometric analysis. (A) to (H) indicate corresponding clusters across cortical measures. Abbreviations: BA, Brodmann area; CMA; cingulate motor area; MI, primary motor area; MNI, Montreal neurological institute (space); PMC, premotor cortex; SI, primary somatosensory cortex; SII, secondary somatosensory cortex; SMA, supplementary motor area.Clusters within the different measures are ordered by decreasing statistical significance. Bold printed clusters represent cluster within the predicted regions of interest (ROIs). The ROIs also contain parts of the brain for which we did not pose any hypothesis because these ROIs were chosen from a predefined atlas. However, the clusters found outside of the predicted regions but inside the ROIs are presented for completeness. (HABA > CON) indicates clusters that showed increased values in handball players compared with control women. (CON>HABA) indicates clusters that showed decreased values in handball players compared with control women. The statistical parametric maps reported here were height-thresholded at p < 0.05 (uncorrected for multiple comparisons) as well as cluster extent thresholded by considering only clusters larger than 25 mm(DOCX)Click here for additional data file.S2 Table*, corpus callosum volume was computed based on a mid-sagittal slice of 5 mm thickness.(DOCX)Click here for additional data file.


Background: Providing patients with a video recording of their visit with a medical professional is a common-sense method for improving patient-provider communication.Objective: To describe the patient and provider experiences to video recording clinical medical encounters and providing the patient with a copy of the video for informational purposes.Methods: Since 2009, over 2,800 patients of eight different neurosurgeons chose to be video recorded during their encounter with the doctor and were provided access to the recording to watch over again as a way to recall what the doctor had said. The video system was set up as a handheld video camera, and video files were downloaded and made accessible to patients via a secure Internet patient portal. Between 2012 and 2014, patients who participated were surveyed regarding their use of the video and what was recorded on the video. The experience of the providers from a clinical and medico-legal standpoint was also reviewed.Results: Three hundred and thirty-three responses to the survey were received (39.2% response rate). More than half of patients  watched their video more than once, and over two-thirds  shared their video with a family member, friend, or another physician. Patients self-reported improved memory after watching their videos  and 50.2% responded that having the video made them feel more “at ease” with their medical problem (N=299). Overall, 88.0% of respondents indicated that their video had been helpful to them, and 98.5% would recommend having future visits video recorded. No patient made a comment that the video was intrusive or had prevented them from being open with their doctor. Finally, in the high-risk specialty of neurosurgery, none of the 2,807 patients who have been recorded since 2009 have used a video in a medico-legal action.Conclusions: Patient responses to the recording system and having a copy of their video were very positive. Most respondents indicated that they had improved memory as well as decreased anxiety about their neurosurgical problem. There have been no legal challenges to date from giving patients access to the video recording. Our results indicate that the benefits to patients for expanding the use of video in medicine may outweigh perceived risks to providers. Good provider-patient communication is important to help all patients understand complex medical information and to become active participants in their own medical care. This is especially important when providing informed consent for procedures when providers must explain the diagnosis, treatment options and alternatives, risks and benefits, medications and their uses, follow-up, and long-term goals. Many prior studies have shown that patients’ abilities to recall medical information are often inhibited by a number of factors. Certain interventions for improving comprehension and recall of medical information have been successful. These include written materials, audio recordings, and generic video recordings about medical conditions, treatments, and discharge instructions. Despite the pervasiveness of video both within and outside of medical offices, few studies have attempted to assess the impact that video recording has had from the patient’s perspective. In the present study, we examine the results of a satisfaction survey given to patients who were filmed using a personalized video recording system known as The Medical Memory (TMM). Since 2009, more than 2,850 patient consultations and follow-up visits have been recorded using this system by the authors. Additionally, we discuss the experiences of the providers using the video recording system and the implications of expanding the use of video recording in medicine from a clinical and medico-legal standpoint.It is well-established in the literature that patients’ memory for medical information extends to just a few topics. Patients typically forget most of what their doctors would deem “key” information within hours or days of their consultation visit . In one Recall tends to decrease when influenced by stressful or anxiety-inducing situations, such as discussion of cancer, the prospect of major surgery, or for certain types of information on which patients may place greater importance , 6-8. MaThese factors have implications for the quality of the decisions that patients are making in collaborative medicine and the ability of patients to understand what medical procedures they are consenting for. In 2007, the American Medical Association produced the Health Literacy Program video “Health literacy and patient safety: Help patients understand,” in which one patient described as a film producer had not been able to read the informed consent materials and recall the information discussed in a preoperative consult . The patIn this paper, we present the self-reported experience of patients who received a video recording of their visit with a neurosurgical provider at a major institution. Additionally, we report on the experiences of the neurosurgeons who used the video recording system within their clinics from the perspective of whether or not video recording in this manner is intrusive, causes medico-legal problems, and/or whether personalized videos provide a greater benefit than audio alone or generic non-personalized informational videos.Two different methods of video recording patients were used, as the technology that was being used by the third-party video recording company changed in early October 2014. Prior to that date, video recordings were made using standard Sony HMX-QF20BN handheld video cameras mounted on tripods and fitted with 32 GB standard SD cards. Videos were recorded by the office staff setting up the cameras for each clinic day, then returning the SD cards and cameras each night. Each patient was required to sign a paper copy of a HIPAA waiver allowing recording of the visit and a copy of the video recording company's terms and conditions before recording began.  The lead author (A.M.) was responsible for downloading each video and creating a patient account through an administrator portal page, then sending a username and password to each patient through the secure messaging system. Patients received an email telling them their video was ready to be watched, typically within 24 hours of their doctor’s visit, including instructions on how to access and watch the video.After October 2014, the video company switched out the handheld cameras and tripods for Nexus 7 tablet computers loaded with a proprietary mobile app. This app allowed patients to input their own username and password (thereby improving the security of the system), increased the video upload and patient account creation time (from 24 hours to less than one hour), and created an electronic consent process for video recording (thereby eliminating the need for paper forms). Patients entered their email address and date of birth on the tablet, created a secure personal identification number (PIN) to be used as a unique first password, and then electronically signed the consent forms before the recording proceeded. After the visit, the video was encrypted, uploaded wirelessly to a cloud server, and the patient was sent a confirmation email for their account. Patients signed in with their PIN and then created a longer permanent password before having access to the video to watch as many times as they would like. Importantly, protected health information (PHI) is erased from the tablet itself after a successful upload so security and privacy are maintained in the event a device is stolen or lost.Beginning in December 2012, satisfaction surveys were sent out to patient users of the video recording system. Using an online survey collection tool, patients who had used the service were contacted by email and asked to fill out a 15-question survey developed by author A.J.M one week following a visit with a neurosurgeon at which they had been video recorded, and responses were received between 0 and 14 days after sending the survey (mean 2.1 days). This patient opinion survey was originally conceived as a tool to improve the video recording system and for customer service purposes, and as such, it has not been tested for validity; therefore, causality for our outcomes cannot be scientifically substantiated.The survey questions asked patients to describe what had been shown on their video, their opinions about video recording in general, whether or not they had shared the video with others , and about the quality of the technical aspects of the recording . In addition, four questions asked patients to self-report whether or not they remembered more information from their doctor’s visit, were more “at ease”, were less anxious about their treatment plan or diagnosis, and were more satisfied with the doctor after watching the video. Table As of December 2014, 333 surveys had been collected from 850 surveys sent, producing a response rate of 39.2%. Thirty-four respondents stated that they had watched the video zero times and were excluded from further analysis. The reasons given for not watching the video included not receiving a password to access the video online, a problem understanding how to get to the website to log in, the patient waited too long and the video access expired, the video was not needed by the patient, and bad internet connection affecting playability of the video. The remaining 299 surveys were included in the review. One hundred and eighty-three respondents (61.2%) were female and 116 (38.8%) were male. This proportion closely reflects the demographic makeup of all TMM users, where approximately 64% are female and 36% are male. Of the respondents, 131 (43.8%) watched their video exactly one time before taking the survey, and 168 (56.2%) watched their video more than one time, with six of these patients indicating that they had watched their video more than five times . Two hundred and five respondents (68.6%) shared their video with a family member, 41 (13.7%) shared the video with a non-relative friend, and 13 patients (4.3%) shared their video with another physician, while 80 patients (26.8%) indicated that they did not show the video to anyone else  and some kind of anatomical model in 90 videos (30.1%). Multinomial logistic regression analysis was performed to compare use of imaging in the video with overall satisfaction, and showed that respondents whose videos contained imaging or models were significantly more likely to feel “more at ease” (question 7), “less anxious” (question 8), “remember more” (question 9), rate the video as “helpful” to them (question 10), and answer "yes" to recommending the video to others (question 14) than respondents who did not indicate that imaging or models were shown (p<.001 for each question). One hundred percent of the patients who had been shown imaging on their video rated this as “helpful” to them, reflected in comments made about this aspect:“I have [an issue] that the doctor found on my CT/MRI that I had no idea I had. I was seeing him for a different health issue. It’s been great to be able to show the video to family of my CT and MRI.”“Seeing the MRI results let me see exactly where the problem area is and understand more of what the doctor was talking about.”Overall, 263 patients (88.0%) indicated the video was helpful to them in some way, and 259 of these respondents (98.5%) indicated they would also recommend the video service to other patients. Four respondents who answered that the video was helpful to them stated that although they felt that the video had been helpful to them, they would not recommend the use of video to others, though their comments did not expound on why they felt this way.Many patients self-reported that having a video recording of their consultation to refer back to had allowed them remember what the doctor had told them better. Two hundred twenty respondents (73.6%) said they remembered more after viewing their video and 68 respondents 22.7%) remembered about the same amount, with no patient stating that they remembered less  were in reference to the patient being able to remember something they had forgotten that the doctor had said or able to use the video to review the information. Some of the specific comments echoed quotes from other reference sources about medical information and recall: “Even though I researched my condition, I was caught off guard by the doctor’s response. There’s no way I would have remembered everything since we discussed several other possibilities.”“The entire episode with the tumor was a blur to me… [on the video], information was revealed that I was unaware of because of my fogginess.”“The conversation with the doctor brought out a point I would not have remembered if it were not mentioned on the video.”Three comments (0.18%) made the complaint that the video was unnecessary because the patient had been able to remember everything in the visit without a video:“Really, the video was not needed. My situation was not complicated at all, so there was nothing mentioned that was difficult to remember. However, the video would be extremely helpful if the situation were more complicated.”Some patients also commented that having the video available saved them phone calls to the doctor’s office, which may help to reduce demands on staff or on the doctor themselves:“Allowed me to review what was said during the meeting and saved a phone call to the doctor.”“[I most liked] being able to go back and watch it, and when I had questions, they were in the video and I didn’t have to call the office.”One hundred and fifty respondents (50.2%) indicated that having the video recording made them feel “more at ease” with their medical problem than before they saw their doctor compared with 16 (5.4%) who felt less at ease and 122 (40.8%) who felt about the same Figure .One hundred and eight respondents (36.1%) reported they felt less anxious about their problem compared with 23 (7.7%) who felt more anxious and 157 (52.5%) who felt about the same. Many of the comments received described experiences about how the video had helped the patient to become more comfortable with their diagnosis.“The video helped me feel better about understanding my issue and [showed me] another way to solve my medical problem.”“I was able to go over the info again at my own time when I was a little bit more at ease.”“We get anxiety in new surroundings. [The video was helpful] so I could know exactly what was said and contemplate it later with no anxiety.”Despite the fact that 23 respondents self-reported higher anxiety after watching the video, only two comments from the total 1,712 mentioned feelings of unease or discomfort:“I really noticed how the doctor didn’t seem to listen to [me]…. I felt rushed in the exam room and watching it again didn’t help.”“The resident told me surgery wouldn’t help me, but [the doctor] decided I need surgery. I’m not sure what to think. The video just stressed me out even more, I think.”While the majority of users indicated that they had no problems, 39 respondents did encounter some sort of issue and made a total of 103 comments about the problems they had encountered. These problems were coded into four categories: technical audio or video (problems involving the technology itself), password retrieval problems, camera user errors, and patient computer literacy issues. There was a total of 32 technical issues relating to extraordinarily long load times or audio/video sync issues (where the audio either lagged behind or was ahead of the video).“The video freezing was VERY frustrating while watching it.”“The audio and video were not in sync. The person I forwarded [the video to] experienced the same problem.”These technical problems were mostly determined to be due to poor internet connections with the exception of one, where a patient had multiple videos which began automatically playing in sync with one another. This error was corrected with a software patch to the video playback system.Eleven respondents had not received their password via secure email and had to call the office for assistance. Ten other respondents experienced a computer literacy problem, where they indicated it was difficult for them to figure out how to get to the video, even without any technical problems being present. In all of the following cases, the video was found to be loaded and working appropriately when the patient made contact to complain:“I am computer handicapped. I had my son bring up and load to the computer.”“My computer was not set up to view the program and I am very computer illiterate but finally got with the program!”The largest number of issues involved errors being made by the doctors, resident, or medical assistants operating the video camera within the examination room. A total of 50 comments received from 37 of the 39 respondents who indicated a problem mentioned improper positioning of the camera, forgetting to turn the camera on or off at appropriate times, or the provider or medical assistant not positioning him- or herself in front of the camera appropriately. Prior to starting to video record patients, medical staff are given training by TMM personnel in proper setup and positioning of the cameras so as to capture the doctor-patient conversation appropriately, and a TMM support person is available to help with any questions which may arise during the first week of clinic for that office. Physicians are also asked to maintain some level of camera awareness when in the exam room, so that they can notice if they have moved out of frame during the course of an examination and adjust the equipment accordingly. Despite these attempts, not all videos have been perfect:“The first 10 minutes was audio only; the video showed a blank white wall.”"The doctor forgot to turn the camera on and had to repeat the visit.”“There was a gap of a few minutes when the doctor had left the room to review my files. It would have been nice if he had turned the camera off during that time.”In the present study, no patient made a comment that the video was intrusive or that they felt the video had made them feel uneasy or unable to discuss something with their doctor. Some comments mentioned that being on video actually helped them open up about their issue and make better medical decisions:“Having the video allowed me to change my decision and change my surgery to include all three levels… per [my doctor’s] observations that I watched on the video.”“Each time I re-watch the video I discover additional things. No way I could remember all this critical information without this video.”A major movement in the healthcare industry in 2014 focused on the concept of health literacy and making information conveyed by providers to patients more understandable by a larger proportion of the adult population, which may be responsible in part for improving patient recall of information. The typical focus of the health literacy movement is on designing new interventional methods of educating patients using written information  or technologies, such as standardized or personalized audio recorded information and standardized or personalized video-recorded information. Improvements for recall and/or anxiety are shown throughout these different interventions from standardized audio-recorded information (net negative improvement) to standardized video education (low positive improvement) to personalized audio-recorded information (high positive improvement).The use of standardized audiotaped information has not been closely studied, perhaps in part because it is inefficient to create standardized tapes when tape recording the consultation is just as convenient and provides information more appropriate to the patient’s specific issue. However, during our literature review, the authors found one study examining the effects of standardized audiotapes. Dunn, et al. found a linear increase in satisfaction scores between no tape (lowest), standardized audiotape information, and personalized consultation audiotaped information (highest) . Dunn alThe use of standardized videotaped educational programs is a different intervention which has been shown to have positive effects, more so for recall and comprehension than anxiety. In a 2010 study by Armstrong, et al., the use of a video education program for informed consent and wound care information significantly increased intragroup knowledge scores as opposed to the control group, although no significant between-group knowledge score differences were found . Atzema,Informed consent is an aspect of medicine which necessitates strong participant recall and comprehension of information. Norris and Phillips (1990) conducted a study using video-recorded standardized informed consent information and found evidence that strongly supported the efficacy of a video for the informed consent process . One hunIn opposition to these findings, some studies have reported no significant differences in recall scores between groups using video education. Johnson, et al. found no differences between standard written information, standard information plus video, and standard information and video, plus formal nurse-taught education . Bakker,Several studies have examined the use of consultation audio recordings to supplement recall or help reduce anxiety. Many studies agree that recall can be improved and anxiety can be reduced using audiotapes when patients are able to review them in a more comfortable setting or with a more comprehensive support structure of family or friends than is practical in a clinical office setting , 22-29.Ong, et al. found audiotapes improved recall of information (p<.01), but that patients were also more satisfied with the information provided to them when they had access to the tape than without (p<.05) and 98% of patients believed that the audiotapes positively impacted their care . SimilarBruera, et al. found that when personalized audiotapes were utilized in combination with written communications, recall of information significantly increased over the control group  . AdditioIn 2004, Flory and Emanuel conducted a systematic review of interventions to improve recall for informed consent. They found that of twelve trials, which included video-recorded information, five trials documented improvements in either comprehension or recall of information, although they note, “that potential has usually not been realized in practice…. If this result were further verified, video technology might be a useful tool for improving retention of information” . SchenkeThe authors’ experiences with the initial reaction of a physician to offering audio or video recordings to their own patients has suggested that they think that the video camera may be intrusive or that the patient or the doctor would be unable to discuss the patient’s medical issues as fully as if they were not being recorded.However, the literature on this subject seems to suggest the opposite. Martin and Martin determined that the majority of patients (50%) approved of videotaping in their consultation for teaching purposes, compared with just 11% who had reservations and 11% who disapproved . SimilarAnother way the video recording may be intrusive for providers is that it may slow down the clinical visit with patients. In an analysis of 339 videotaped consultations, half where the doctor was aware of being recorded and half where the doctor was unaware, Pringle, et al. discovered no significant differences between lengths of consults or the length of time taken on 26 of 27 common doctor and/or patient activities within the consultation; the one difference that was found to be significant was the time taken by the doctor to explore the patient’s problems . KnowingIn our study, no patient made a comment that the video was intrusive or that they felt the video had made them feel uneasy or unable to discuss something with their doctor. Some comments mentioned that being on video actually helped them open up about their issue and make better medical decisions. In our experience, the video camera has not been intrusive for our physicians. When the doctor enters the consultation room, he pushes a single button to start the recording and then conducts his visit as normal. If using models or showing the patient their images, the doctor can choose to bring the camera with them to record that explanation, then replaces the camera back in the room. When finished, the doctor simply pushes the same button to stop the recording as he exits the room. While this represents a departure for doctors to their normal clinical routine when starting to incorporate video recording in their clinics for the first time, we have observed that they become adept at using the cameras within one to two weeks.The fact that so many of our patients freely chose to have their visit video recorded and uploaded to the Internet, even paying a fee to use the service, speaks to the desire from the patient’s perspective that medical professionals begin to incorporate video recording technology into their practices. Video recording could be used as an adjunct to other patient empowerment and educational projects, such as OpenNotes  and multifunctional patient portal systems through practices’ existing electronic health record systems.Another criticism of video systems is that audio recording is enough to capture the information that the doctor tells a patient. Indeed, sites like the Oliver Center in Texas are experimenting with providing audio recordings of individualized discharge instructions to patients for postoperative care . However“I would have preferred [the doctor] thought to bring the video camera to the x-ray when he gave an explanation, but it was too late to have it repeated or captured.”“Having a discussion of my [problem] using the MRI and X-rays would have been helpful.”“I would have liked to have [my doctor] demonstrate via a model or review of my x-rays taken prior to the appointment.”“[I wish there was] more description using MRI and X-rays to help me get a better visual than just the doctor’s words.”With the recent changes to the medico-legal infrastructure to tighten security for patient protected health information (PHI) through the Health Insurance Portability and Accountability Act (HIPAA) and the Health Information Technology for Economic and Clinical Health Act (HITECH Act), concerns have to be raised about the security of recording, uploading, and downloading recordings that contain PHI. Krackow, et al. queried six attorneys who perceived no increased risk of malpractice with the use of personalized audiotapes and suggested that there was no medico-legal basis for concern . KrackowThe authors contacted local malpractice carriers in Arizona to determine the medico-legal impact of providing patients with video recordings, one of whom stated that personalized video recording had the potential to be “the best evidence of the actual communication [between physician and patient]…. My guess is videotapes would be helpful to the defense in many instances on informed consent discussions, etc.” .Another concern with video recording is whether the video is a part of the patient’s medical record. In the authors’ home state of Arizona, a medical record is defined as “all communications related to a patient’s physical or mental health or condition that are recorded in any form or medium and that are maintained for purposes of patient diagnosis or treatment” . An inteThe authors made their office the test site to evaluate a hypothesis that the use of personalized video recordings would not increase the legal risk in a high-risk specialty such as neurosurgery. Eleven physicians have provided almost 2,100 video recordings to patients since August 2012, and author R.W.P. has provided more than 1,500 of these videos since 2009 without a single legal challenge from a patient relating to or involving the video recording.Our survey showed that many patients self-reported increased ability to remember their doctors’ instructions and advice, and when they did not, many patients indicated that they knew that they could go back to the video recording to find information. Patients also self-reported decreased anxiety and a feeling that they were more “at ease” with their medical problem after reviewing the video, though it is unclear whether or not this is due to watching the video itself or to knowing that the information is readily available to them when needed. The majority of patients were pleased that videos were offered to them and would recommend having doctors’ visits recorded to other people. Despite having recorded more than 2,700 videos in a high-risk medical specialty, no medico-legal issues have ever occurred from either producing the video recording or from providing the video to a patient. It seems apparent from the results of our survey that patients not only want better, more easily understandable records of their doctor’s visits, but that the benefits of video recording seem to outweigh some of the legal risks that practitioners have cited in the past as a reason for not pursuing video records.The authors recognize that there are limitations to the present study that may affect the ability of the data to be generalizable. First, we use custom-designed and non-validated surveys rather than peer-reviewed and validated outcome measures to assess anxiety, recall, and feelings about each patient’s experience with video recording their office visit. Second, this data describes patients in a single neurosurgical clinic only, and the authors expect to find different rates of video acceptance and outcomes in different types of practices and specialties. Future research may be warranted to determine how the uses of personalized video visits for other subspecialties or general practice differ from our experiences.


I4/mmm→Cmma→P21/m at 180 and 250 GPa, respectively, and all of these structures are metallic. The superconducting critical temperature Tc values of I4/mmm, Cmma, and P21/m are 47–193 mK, 5.99–8.16 K and 10.62–12.8 K at 1 atm, 180 and 260 GPa, respectively. Furthermore, the bonding nature of HfH2 is investigated with the help of the electron localization function, the difference charge density and Bader charge analyses, which show that HfH2 is classified as a ionic crystal with the charges transferring from Hf atom to H.The crystal structures and properties of hafnium hydride under pressure are explored using the first-principles calculations based on density function theory. The material undergoes pressure-induced structural phase transition  Tc superconductor at high pressures12Tc at lower pressure. For example, high Tc with 190 K in the sulfur hydrides at 200 GPa has been found by both of theoretical predicted and experimental observation56Up to now, hydrogen, the simplest and most abundant element of universe is still fascinating to physics community. The studies about hydrogen are mainly reflected in two aspects. One is the metallic and superconducting of hydrogen. The other is considered as the most promising clean energy sources with the capability of replacing fossil fuels. The former is going back to the early 1930: hydrogen was predicted to be a potential high 2, YH3, TiH2, ZrH2, HfH2, etc8910Tc, which is correlate with the important parameters of the Bardeen–Cooper–Schrieffer theory about superconductivityTc of Th4H15 is 8 K at ambient conditions2 can form CaF2 (Fm–3m space group) crystal structure. And in this structure, the metal atoms form a face-centered-cubic sublattice while the hydrogen atoms occupy the tetrahedral lattice sites. However, the group IVB dihydrides TiH2, ZrH2, and HfH2 show a basically face-centered-tetragonal (fct) cell structure (I4/mmm space group). And these dihydrides  are applied in various fields. For instances, TiH2 can be served as the catalyst in polymerization reaction, which is interesting in the new quenchable phases152 is widely used as a neutron moderator in nuclear reactor1718Hydrogen can also react with transition metal elements formed metal hydrides under certain conditions and they can keep stable under ambient conditions, such as YH2 at high pressure had a structural transformations I4/mmm→P4/nmm→P21/m and the calculated pressure of phase transition were 63 and 294 GPa, respectively2 were also investigated in experiment under high pressure22.The high-pressure development has become a vibrant area of research. Not only does pressure provide a different route to the synthesis of new compounds, but also enables many known materials to exhibit novel phenomena that cannot be found at normal conditions. Lately, theoretical study revealed that TiH2 system at zero temperature by using the newly developed ab initio evolutionary algorithm. Moreover, we employ a first-principles method to calculate their dynamical stability and electronic band structures. Our calculated results show that HfH2 adopts the I4/mmm structure at low pressures. On compression, Cmma phase possesses the lowest enthalpy, then at higher pressures P21/m becomes energetically favorable. Band structures and density of states indicate that these structures are metallic. The estimated Tc are 47–193 mK at 1 atm, 5.99–8.16 K at 180 GPa and 10.62–12.8 K at 260 GPa, for I4/mmm, Cmma and P21/m, respectively. The electron localization function (ELF), the difference charge density and Bader charge analysis show that HfH2 is an ionic crystal with the charge transferring from Hf to H atom. Our present study attempts to provide a better understanding of the pressure-induced phase transformations and properties of HfH2 under pressure.In this paper, we examine in detail the optimum static structures of HfH2 formula units (f.u.) at 1 atm, 50, 80, 100, 150, 200, 250 and 300 GPa. Analysis of the predicted structures gave us a shortlist of candidate structures with space groups Fm–3m, I4/mmm, P4/nmm, Cmma, P21/m and C2/m. 2 under high pressure. At 1 atm, we obtain two structures: a CaF2 type structure with space group Fm–3m (4 f.u./cell) and a centered tetragonal structure with space group I4/mmm (2 f.u./cell) (2 structure), where metal atoms form a face-centered cubic lattice, and the centers of tetrahedrons are occupied by H atoms. Note that in I4/mmm structure, Hf atoms form a body-centered tetragonal (bct) sublattice with its coordination number is 8, while the H atoms are located on the planes and present a one dimensional chain. Then we observed the most stable structure which possess simple tetragonal P4/nmm (4 f.u./cell) orthogonal Cmma (4 f.u./cell) at 200 GPa. In the above two phases, the metal atoms form a bct and fcc cell for P4/nmm and Cmma, respectively. For Cmma, the coordination number of Hf becomes 9. Finally, at 300 GPa, the monoclinic P21/m phase (4 f.u. /cell) becomes the preferred one  . At ambirred one . And in 2 under pressure has been investigated systematically. Enthalpy differences as a function of pressure for these competitive solid structures together relative to Fm–3m in the pressure range from 0 to 300 GPa are plotted in I4/mmm phase has lower enthalpies than all other candidates, which indicate it is the thermodynamic ground state. Above 180 GPa, Cmma (P4/nmm) becomes the most stable structure and remains up to 250 GPa. Then under higher pressures, a monoclinic P21/m becomes more favored. In these two transitions, the coordination number of Hf increased from 8 to 9, 9 to 12, respectively. Surprisingly, we found that Cmma and P4/nmm are energetically nearly degenerated in the range of 0–300 GPa, and enthalpy difference is less than 1 meV/f.u.. If I4/mmm, P4/nmm and P21/m phases satisfied the stability conditions of mechanics and dynamics, the phase transition sequence of HfH2 is similar to the TiH2P4/nmm is not stable both in dynamical and mechanical properties (see the later discussions). The calculated equations of state (EOS) depicted in I4/mmm→Cmma and Cmma→P21/m phase transitions are discontinuous changes in volume at the transition point with volume collapses of 0.9% and 7.6%, suggesting the two phase transitions are the first-order nature.The phase stability of HfHI4/mmm, Cmma, P4/nmm and P21/m phases in the studied pressure range are presented in I4/mmm, Cmma and P21/m structures are dynamically stable regardless of the applied pressure. By contrast, there are imaginary phonon frequencies for P4/nmm phase  of the mm phase  which inI4/mmm, Cmma, P21/m and P4/nmm structures were calculated at different pressures, as shown in ij meet the Born-Huang stability criteriaI4/mmm, Cmma and P21/m meet the mechanical stability criteria, suggesting that the three structures are mechanically stable in our studied pressure range. However, elastic constants of P4/nmm phase cannot satisfy the stability conditions of mechanics for tetragonal crystal system owing to C66 < 0, which means it is mechanically unstable.Mechanical property of the crystalline structure is one of the basic requirement when considering the phase stability. The elastic constants of I4/mmm, Cmma and P21/m phases at different pressures, as presented in 2  for ted in 2 , we see 2, the electron localization function (ELF) of I4/mmm, Cmma and P21/m at 100 GPa, 200 GPa and 250 GPa, are plotted in I4/mmm (100 GPa), Cmma (200 GPa) and P21/m (250 GPa), as shown in I4/mmm and Cmma phases in P21/m phase in e site  for the above three phases is different. The δ depended on pressure in Cmma is smaller than that in I4/mmm. While turning to P21/m, it exists two forms due to two inequitable Hf sites. The change of charge transfer may be related to the structural evolution. Overall, the ELF, the difference charge density and Bader analysis results reveal that the ionic bonds were formed between Hf and H, and HfH2 was classified as a ionic cyrstal with the charge transferring from Hf to H atom.In order to explore the bonding and analyze the ionic or covalent character of HfHn e site . To gainlog, and the electronic DOS at the Fermi level N(Ef) for I4/mmm, Cmma and P21/m. The Tc was estimated by using the Allen-Dynes modified McMillan equationμ* = 0.1–0.13 are adopted for HfH2. According to our calculations, the λ are 0.33, 0.64 and 0.87 for I4/mmm (at 1 atm), Cmma (at 180 GPa) and P21/m (at 260 GPa). The estimated Tc of I4/mmm, Cmma and P21/m, are 47–193 mK at 1 atm, 5.99–8.16 K at 180 GPa and 10.62–12.8 K at 260 GPa, respectively. We note that I4/mmm has a lower Tc value relative to the other two structures. For the I4/mmm (at 1 atm), the EPC parameter λ is 0.33, which indicate the electron-phonon interaction is fairly weak. In addition, the electronic DOS at the Fermi level N(Ef) for the phase I4/mmm is relatively small (3.978 states/spin/Ry/Unit cell). So the weak electron phonon coupling λ and small N(Ef) are the main factors, which lead to the low Tc. To study the pressure dependence of the superconducting critical temperature Tc of I4/mmm, Cmma and P21/m, the λ, ωlog and N(Ef) were calculated as summarized in log is increased in I4/mmm, while it is diminished in Cmma and P21/m. For N(Ef) and λ parameters, they both decrease as pressure increased, which mainly lead to the decrease of the Tc values for the above three structures.We calculated the electron phonon coupling (EPC) parameter λ, the logarithmic average phonon frequency ω2 at high pressures up to 300 GPa through ab initio evolutionary simulations. Three structures I4/mmm, Cmma and P21/m are predicted, and all of them are energetically much superior to others phases. The electronic structures are characterized as conductors with band overlap for I4/mmm, Cmma and P21/m phases. The measured superconducting transition temperature Tc values for I4/mmm, Cmma, and P21/m are 47–193 mK (at 1 atm), 5.99–8.16 K (at 180 GPa) and 10.62–12.8 K (260 GPa). Further analysis of the bonding nature shows that charges transfer from the hafnium to hydrogen with ionic bonds in HfH2. The current study has great implications for researching other transition metal hydrides.In summary, we have extensively investigated structures and examined the structural stability of HfH2 system at zero temperature. In the evolutionary structural predictions, the first generation of structures was always created randomly and its population size is 20–60 structures, increasing with system size. Every subsequent generation is produced from the best 60% of the previous generation. Moreover, the lowest-enthalpy structures always survived into the next generation. New structures are produced by variation operator heredity (60%), permutation (10%), and lattice mutation (30%). The energetic calculations and electronic structure calculations presented here are performed within density functional theory, carried out within the Vienna ab initio simulation package (VASP)d26 s2 and 1 s1 and cutoff radii of 2.5 and 0.8 a.u. for Hf and H atoms, respectively. The electronic wave functions were expanded in a plane-wave basis set with a cutoff energy of 800 eV and appropriate Monkhorst-Pack meshes were chosen for all structures to ensure that enthalpy calculations are well converged to better than 1 meV/atom. In the geometrical optimization, all forces on atoms were converged to less than 0.005 eV/Å. We used the Bader charge analysis3233I4/mmm, Cmma and P21/m, respectively.We have used the evolutionary algorithm USPEX code 2627mutation %. The enHow to cite this article: Liu, Y. et al. First-principles study on the structural and electronic properties of metallic HfH2 under pressure. Sci. Rep.5, 11381; doi: 10.1038/srep11381 (2015).