We report on research on individual-difference measures that could be used to assess the validity of eyewitness identification decisions.The predictive utility of face recognition tasks for eyewitness identification has received some attention from psychologists, but the previous research focused primarily on witnesses’ likelihood of correctly choosing the culprit when present in a lineup. Far less discussed has been individual differences in witnesses’ proclivity to choose from a lineup that does not contain the culprit. We designed a two-alternative non-forced-choice face recognition task  to predict witnesses’ proclivity to choose for a set of culprit-absent lineups associated with earlier-viewed crime videos.r values averaging .43. The likelihood of choosing correctly on old/new pairs (a measure of face recognition skill) was only weakly predictive of correct identifications in culprit-present lineups (mean r of .22).In two studies involving a total of 402 participants, proclivity to choose on new/new pairs predicted mistaken identifications on culprit-absent lineups, with Our findings could be the basis for further research aimed at developing a standardized measure of proclivity to choose that could be used, along with other measures, to weigh eyewitnesses’ lineup identification decisions.The online version of this article (10.1186/s41235-018-0150-3) contains supplementary material, which is available to authorized users. Hundreds of former prison inmates have been exonerated following mistaken criminal convictions partly based on incorrect eyewitness identification evidence. Many published papers have shown that jurors and judges are surprisingly poor at assessing the quality of a witness’s memory, usually placing too much faith in testimony that is error-laden and subject to predictable biases. We present studies conducted as part of an effort to develop a test of the likelihood that a particular witness will make a correct decision when judging a police lineup. We developed the Lineup Skills Test (LST) of both (a) a person’s ability to discriminate previously seen from new faces presented in pairs and (b) a person’s proclivity to mistakenly choose from pairs of new faces. Our results indicate that witnesses’ scores on this skills test are correlated with their responses on full-sized lineups for the culprits of earlier-viewed crime videos. Our test was better at predicting mistaken identifications on culprit-absent (CA) lineups than it was at predicting accurate identifications on culprit-present (CP) lineups.On the Witness Stand at the beginning of the twentieth century: “The courts will have to learn, sooner or later, that the individual differences of [people] can be tested to-day by the methods of experimental psychology far beyond anything which common sense and social experience suggest”. Our aim in the current project is to contribute to the development of useful measures of an eyewitness’s lineup identification skill, both in terms of their ability to identify the culprit when present in a lineup (sensitivity) and their ability to reject a lineup when the culprit is not present (proclivity to choose).Individual differences may predispose some people to be more likely than others to make accurate eyewitness identification decisions. Indeed, such differences have been in the hive mind of psychologists since Munsterberg  first published Psychologists have reported many studies of suspect identification in which witnessing conditions, delay, and/or testing conditions were systematically manipulated  = .61 (see Table The literature on the Cambridge Face Memory Test (CFMT), which was developed to diagnose prosopagnosia by Duchaine and Nakayama , provider = .6) could serve as the basis for a measure useful for real-world policing in assessing the quality of eyewitness IDs. In the current work, we test the importance of knowing an individual’s proclivity to choose for such a measure.Scores on the CFMT have been thoroughly examined for correlation with related measures, as shown in Table r = .4. In the following we briefly summarize all the published studies of which we are aware that explored the relationship between sensitivity or response bias on tests of face recognition and performance in CP or CA lineup identification tasks. The sample sizes in many of the individual studies were small, but they collectively encourage optimism regarding the prospect of developing face recognition tests that usefully inform assessments of individual witnesses’ accuracy on lineups.Individual differences in face recognition ability have been used as a predictor of lineup identification accuracy with some success, though few researchers have found relationships stronger than r values, sample sizes, and 95% confidence intervals [CIs] around r.) This correlation varied around r = .45 across three small-N studies with slightly different procedures, but two other studies using the BFRT did not produce correlations larger than r = .05. Using two new samples, Hosch tested the relationship between accuracy on the same lineup task and measures of sensitivity and response bias on a yes/no face recognition task. The number of trials in the face task was not reported, but the first sample yielded no correlation between sensitivity and ID accuracy and a significant correlation between response bias and ID accuracy. Also, participants who produced a correct selection on a CP lineup were more conservative in their face recognition decisions (B″ mean = .59) than those who produced a false alarm on a CA lineup (B″ mean = −.1). A second study weakly replicated these findings . Follow-up analyses demonstrated that participants who produced false positive IDs drove the effect, as this group tended to make fewer true positive responses and more false negatives in the Weschler test (p’s between .1 and .05). That false positives drove Morgan et al.’s effects provide evidence that proclivity to choose on a lineup is a predictable individual difference.Morgan et al.  providedData from Kantner and Lindsay , 2014 ind = .71, our calculated 95% CI ; see Table d = .93, 95% CI ). In a second experiment, participants who made a correct lineup response (either choosing or rejecting) tended to have higher correct rejection rates on the modified Bruce task . That an individual witness’s proclivity to choose  on a lineup was predicted by their proclivity to choose in the modified version of the Bruce task makes sense because the latter is much like a 10-person lineup. However, that a witness’s tendency to choose correctly from a CP lineup was also predicted by their proclivity to choose in the Bruce task  in which 50% of the trials contained a studied face and an unstudied face and the other 50% contained two unstudied faces.In Experiment 1, we tested the extent to which accuracy and proclivity to choose on the LST predict accuracy and proclivity to choose on CA and CP lineups. Participants first viewed a series of crime videos, completed the LST, and then judged a lineup pertaining to each of the videos viewed earlier. To gain more stable estimates of individual decision tendencies on lineups while not including so many lineups that participants would confuse which lineups were associated with which crime videos, we presented five videos during the initial phase of the experiment and the five corresponding lineups at the end. To maximize the number of observations of each type of lineup for a given participant, the presence of the culprit was manipulated between subjects. Thus, half of participants viewed five CA lineups (CA condition), while the other half viewed five CP lineups (CP condition).N = 122, CA condition N = 143) for $0.60. Following exclusionary criteria established before data collection began, participants who confessed to major distractions or to skipping portions of the procedure were removed before we analyzed the data , as were participants who did not stay on the video pages long enough to watch them . Participants who recognized an actor from the video clip were also removed from the CA condition (N = 2). Data from the remaining 185 participants were used for analysis.Participants were recruited online via Amazon’s Mechanical Turk , the average reported age was 35 years, with a range from 20 to 66. The sample included 60 women, 69 native English-speakers, 44 who reported having earned at least a bachelor’s degree, and 46 who reported having taken no university courses in psychology. In the CP condition (N = 94), the average reported age was 34 years, with a range from 21 to 70. The sample included 54 women, 73 native English-speakers, 67 who reported having earned at least a bachelor’s degree, and 45 who reported having taken no university courses in psychology.Participants self-reported their demographics. For the CA condition (https://osf.io/euchx/ for more information about the videos). Clips ranged from 47 to 83 s in length and were presented with the original sound tracks. The lineups each contained six individual photos about 250 × 350 pixels in size. Figure The five crime videos were clipped from British television crime dramas and depicted middle-aged Caucasian male culprits committing crimes . The data are left in their raw form in graphs for readability.We converted individual accuracy rates on both the LST and the lineups themselves to r(89) = .45, p < .001, 95% CI ). There was also a significant correlation between the old/new pair rejection rate and the CA lineup rejection rate (r(89) = .58, p < .001, 95% CI ). Figure r(92) = .22, p = .027, 95% CI ).7Figure 95% CI .4, .70). FAs predicted, participants who falsely chose more often on new/new pairs in the LST also tended to choose falsely more often on later CA lineups than participants who correctly rejected more new/new pairs. The correlation for this proclivity to choose was of a reasonable size for effects of this type, but it fell short of the larger correlation coefficients of some of the CFMT studies in Table Having found evidence that the LST can predict performance on lineup ID tasks, we next sought to increase the real-world utility of the test. The police often cannot conduct a lineup on the same day as a crime, as was done in Experiment 1, and the police probably would not want to expose witnesses to many new faces before showing them a lineup. With this in mind, we designed Experiment 2 to include a 2-day delay between exposure to the crime videos and the ID task, and to have participants complete the lineup skills test after, rather than before, the lineups.The purpose of Experiment 2 was to test for relationships between face recognition skill and proclivity to choose with a 2-day delay between the viewing of the crime and the administration of the lineup to make the process more realistic. In addition, we addressed two limitations of the first experiment. First, all the faces were re-randomized into a new set for each participant, thereby controlling for the possibility of effects based purely on our pre-randomized sets. Second, MTurk workers have widely varying internet connection speeds and are sometimes distracted, which may have added error variance to Experiment 1. We conducted Experiment 2 in the lab with undergraduates using E-Prime 2.0.10.242 .N = 221) were recruited via the University of Victoria’s psychology participation pool. They were compensated with extra credit in a psychology course.Participants (N = 115) and the other half viewed all CP lineups (N = 106). Immediately after the last lineup, the LST was introduced. The faces in the LST were re-randomized anew for each participant.The stimuli were the same as in Experiment 1 except that assignment of faces to condition was randomized anew for each participant. Participants were tested in groups of from 2 to 25. They viewed the five crime videos on a data projector screen. The order of the videos was varied across groups such that each crime was in each position for approximately 1/5 of participants. After the fifth crime video was shown, the participants were dismissed with instructions to return in 2 days. At the beginning of the second session, the lineups were presented with the same title and in the same order as the videos had been presented. Approximately half of the participants viewed all CA lineups (r(113) = .42, p < .001, 95% CI ). Figure r(104) = .21, p = .031, 95% CI ).Figure r = .43. The results of Experiment 2 indicate that the predictive utility of the LST is robust to longer delays between viewing a crime and attending a lineup as well as to a procedural change that placed the lineup administration before the LST. These findings provide support for the potential utility of a test of proclivity to choose in applied settings.Experiment 2 replicated the major findings from Experiment 1. The relationship between new/new pair correct rejection rates and CA lineup correction rejection rates was replicated and similar in strength to that of Experiment 1. The correlation between CP lineup accuracy and old/new pair accuracy also proved robust to a 2-day delay and to the presentation of lineups before the LST. The consistency of the test of the proclivity to choose across Experiments 1 and 2 suggests that its predictive utility for lineups is around r(347) = .43, 95% CI  and the strength of the face recognition skill correlation was r(200) = .27, 95% CI . The robustness of the correlation with proclivity to choose across the four samples suggests it has prospective utility to predict lineup decisions in the real world. The correlation between old/new rejection rates and CA lineup rejection rates in several samples is also a reflection of the strength of proclivity to choose as a stable individual difference and further supports the findings of Kantner and Lindsay  useful for CP lineups. Having predictors on both sides of being good at faces is desirable, given the uncertainty of the culprit’s presence in the real world. If this new measure proves to be reliable, a score for a witness could be used to weigh ID evidence. A lineup rejection should be considered more exonerating if the witness has a high proclivity to choose, while an ID from a witness with a low proclivity to choose would constitute strong evidentiary support that the suspect was the culprit.Unlike real witnesses, our subjects watched several unrelated crime videos and attended a lineup for each video. While the use of multiple lineups was intended to increase the stability of our estimates of individuals’ lineup decision tendencies, most real-world witnesses attend a single lineup. To determine whether our use of multiple lineups affected the basic pattern of results relative to the use of only a single lineup, we calculated the correlation between the LST and performance on the very first lineup for each subject. In doing so, we combined data from the two experiments reported here and the two pilot studies reported in Additional File These initial data from our LST should be considered a preliminary step towards an eyewitness prediction measure of an individual’s response bias. We utilized standard laboratory procedures and emphasized the experimental control at this initial stage, but increased ecological validity in future work will be essential for establishing the usefulness of a test such as the LST in applied settings. Therefore, an important direction for future research is to conduct studies of the LST in more realistic conditions. In addition, changes to the materials or the procedure of the LST could alter (and perhaps strengthen) the relationship between proclivity to choose in a lineup and proclivity to choose in the LST. For example, the stimulus set we used in the LST contained more male than female faces, while test trials often contained one male and one female face. Gender biases may have added noise to our measurements of individuals’ choosing behavior, and future research could eliminate this possibility by using items with only one gender. On the other hand, the use of a more racially diverse face set would make the test more applicable for police precincts with diverse citizenship. In addition, while the facial expressions in the LST differed between study and test, they were homogeneous along many other dimensions. Faces that differ more markedly between presentation at study and at test  would better emulate the differences between the first and second exposures to a face in eyewitness situations and may increase the correspondence between decisions on the two tasks.Performance on the LST was generally poor. Although it matched the average level of performance on the lineup task, it is an open question for how an LST yielding higher discrimination might correlate with lineup decisions. For example, accuracy on the LST was a weak predictor of lineup performance in the current experiments, but the relationship might be stronger if LST sensitivity was farther above chance.Information about an individual witness’s likelihood of identifying innocent and guilty suspects could be combined with other measures of the witness’s performance, such as confidence or response latency. A complete model for weighing eyewitness ID decisions would also account for characteristics of the lineup , witnessing conditions , and the delay between the witnessed event and the lineup, along with the prior odds that the suspect is the culprit (based on other aspects of crime-relevant evidence).Finally, we know of no previously published study that presented both two-person mini-lineups and full-sized lineups to the same group of participants. That mini-lineups account for some variance in lineup scores but leave a substantial portion of the variance unaccounted for suggests researchers using mini-lineups as placeholders for real lineups should exercise caution when interpreting their results. Mini-lineups based on study phases with many trials are still useful, however, because it is critical to show a research participant many lineups to account for more of the variance in individual memory abilities.How individual differences work in eyewitness ID must receive more attention from researchers. We developed a two-alternative non-forced-choice face recognition test that reliably predicted an individual’s proclivity to choose in a series of lineups. Proclivity to choose may be an important facet of lineup decisions and could be of use to the police as part of a package of person- and situation-based predictors that jointly provide important information for weighing eyewitness evidence of the guilt or innocence of a suspect.Additional file 1:The importance of decision bias for predicting eyewitness lineup choices: Toward a Lineup Skills Test. (DOCX 20 kb)Additional file 2:Figure S1. Proclivity to choose correlation for Pilot Experiment 1 with linear trendline, both axes jittered. (PNG 229 kb)Additional file 3:Figure S2. Proclivity to choose correlation for Pilot Experiment 2 with linear trendline, both axes jittered. (PNG 241 kb)Additional file 4:Figure S3. Proclivity to choose correlation for all four experiments combined with linear trendlines, both axes jittered. (PNG 495 kb)Additional file 5:Figure S4. Face recognition skill correlation for Experiments 1 and 2 combined with linear trendlines, both axes jittered. (PNG 344 kb)


Neurodegeneration is associated with changes in basal cellular function due to the dysregulation of autophagy. A recent study introduced the involvement of autophagy during spinal nerve ligation (SNL). Nefopam has shown potential for reducing neuropathic pain, but the underlying mechanisms are unknown. Here, we investigated the effects of nefopam on neuropathic pain development following SNL, focusing on the involvement of autophagy.The functional role of nefopam in capsaicin-induced autophagy was assessed by human glioblastoma M059 K cells. The neuropathic pain model was used to determine whether the effect of nefopam on pain control was mediated through autophagy control. Neuropathic pain was induced by L5 and L6 SNL in male rats randomized into three groups: Group S (sham-operated), Group C , and Group E (received nefopam). A behavioral test using a von Frey was examined. Expression changes of autophagy in response to nefopam was analyzed in spinal cord tissues (L4-L6) by immunoblotting and immunohistochemistry.The paw withdrawal threshold examined on days 3, 5, 7, and 14 post-SNL was significantly higher in Group E than in Group C. SNL increased the levels of microtubule-associated protein 1 light chain 3B (LC3B-1), with concomitant reduction of sequestosome 1 (SQTSM1/p62), compared with Group S, indicating that SNL induced autophagy. These effects were reversed by nefopam injection, and the results were confirmed by immunohistochemistry for LC3-I/II. Furthermore, SNL-mediated JNK activation was markedly decreased following nefopam injection. Hematoxylin and eosin staining on Day 14 post-SNL revealed that SNL caused lymphocyte infiltration and oligodendrocyte localization in the substantia gelatinosa of the dorsal gray horn, which were reduced by nefopam injection.Collectively, the mode of action of nefopam on neuropathic pain appears to be associated with downregulation of phospho-JNK and autophagy, as well as modulation of the immune response. Neuropathic pain was previously thought to be the consequence of changes in the activity of neuronal systems, immune cells, and immune cell-derived inflammatory cytokines . HoweverAccording to Berliocchi et al. , completNefopam is a centrally acting analgesic that has similar action to triple neurotransmitter reuptake inhibitors and anticonvulsants. Recently, nefopam has been suggested for the treatment of neuropathic pain because it has analgesic properties –13. Prop® CRL-2365™) were maintained in DMEM  supplemented with heat-inactivated 10% fetal bovine serum, 50 μg/ml penicillin, and 50 μg/ml streptomycin at 37 °C in a 5% CO2–95% air humidified incubator. Capsaicin, SP600125, and thapsigargin were obtained from Sigma  and Calbiochem , respectively. Other chemicals used were of the purest grade available from Sigma .Human glioblastoma M059 K cells  and followed the International Association for the Study of Pain guidelines on ethical standards for the investigation of experimental pain in animals [n = 36, n = 12 in each group) according to the random numbers generated by a computer. Rats in the sham group (group S) underwent a sham operation without SNL. While, rats in the control and experimental groups (groups C and E) received SNL for the induction of neuropathic pain Groups and induction of neuropathic pain [Rats were randomized into three groups  intraperitoneally for 3 days immediately following the SNL procedure [Those in group S had just sham operation. Rats in the group C were administered normal saline for 7 days following the SNL procedure. Those in group E were administered 30 mg/kg of nefopam hydrochloride . Cell lysates was quantified for protein content, and separated by SDS-PAGE in 12–15% acrylamide gels, transferred to polyvinylidene difluoride membranes , and then immunoblotted with corresponding antibodies. Phospho-JNK (#9251), JNK (#9258), mammalian target of rapamycin , and phospho-mTor (#2971) were obtained from Cell Signaling . Anti-rabbit polyclonal atg8/LC3 antibody (#3868) was obtained from Cell Signaling . TNF-α  and β-actin  were purchased from Santa Cruz Biotechnology . The bands were visualized using chemiluminescence Western Blotting Detection Reagents (Millipore), and quantified with ImageJ densitometry software .2O2. Immunohistochemistry procedures were performed using the Polink-2 AP broad detection kit according to the supplier’s protocol . The slides were counterstained with hematoxylin and mounted with an immunohistomounting medium . Histological changes in spinal cord tissues were observed under a microscope .After conventional dewaxing and microwave antigen retrieval in 10 mM sodium citrate buffer (pH 6) for 10 min, sections were incubated with microtubule-associated protein 1 light chain (LC3) antibody (1:50) (#3868) overnight at 4 °C. A negative control without primary antibody was performed for each specimen. Endogenous peroxidase activity was prevented by incubating the sections for 15 min in 0.3% HSpinal cord tissues were cut into approximately 0.5 cm length pieces vertically in the center of L5 and were fixed in neutral buffered formalin, dehydrated, embedded in paraffin, and sectioned. The sections were deparaffinized in xylene, rehydrated in an ethanol gradient, and stained with hematoxylin and eosin (H & E). Pathological changes in spinal cord tissues were observed under an optical microscope .Mechanical allodynia was assessed by paw withdrawal threshold (PWT) measured with von Frey filaments . After acclimation in the laboratory environment for 30 min, mechanical stimulation was applied to the plantar surface of the hind paw vertically for 5 s with a series of eight von Frey filaments . Abrupt withdrawal or flinching of the hind paw were regarded as a positive response and PWT was calculated by the up and down method . The cutp-values < 0.05 were considered statistically significant. A two tailed t test was performed for comparisons of densitometry between the groups.Data were expressed as the mean ± standard error of the mean. The results of the behavioral experiments were analyzed by a repeated measures one-way analysis of variance and Scheffe’s post-hoc test. The differences between groups were analyzed by t-test. Non-parametric data were analyzed by the Kruskal-Wallis test followed by Scheffe’s post-hoc test. Results with Capsaicin, the pungent ingredient in hot chili peppers, is a selective agonist of transient receptor potential cation channel subfamily V member 1 (TRPV1), which is involved in pain sensation . Capsaicn = 12). The PWT was significantly reduced in rats from Groups C and E compared with those in Group S. The PWT of rats from Group E was higher than that of rats from Group C during the observation period (n = 12 for each group). However, significant differences were recorded on Day 5 post-SNL  and Group E (received nefopam) 3 days after the SNL procedure. Rats from Group S (sham-operated) showed no mechanical allodynia  localized in the dorsal gray matter  increased the withdrawal threshold and downregulated activation of JNK and autophagy. Immunohistochemistry for LC3-I/II, an autophagy marker, revealed that SNL-induced LC3-I/II immunoreactivity decreased following nefopam injection. Strong positive staining was localized in the cell body of the neurons, indicating that the action of nefopam might occur via affecting on function of neuron. Furthermore, a change in the immunoreactivity of LC3-I/II was revealed in the dorsal horn of the gray matter, indicating that autophagy may affect sensory neurons rather than motor neurons. However, our hypothesis requires further clarification. Western blot analysis of spinal cord tissue lysates revealed that SNL activated JNK and autophagy, which were mitigated by nefopam. Therefore, our in vitro results are consistent with previous reports showing that SNL-mediated JNK activation was inhibited by nefopam , 6.Glial cells including oligodendrocytes, astrocytes, and microglia, are known to play important roles in the pathology of neuroinflammation and neuropathic pain . In the Although, autophagic responses are known to help cells avoid death by offering an alternative cell-death pathway as a stress adaptation , the rolBased on our in vitro and in vivo studies, we speculate that the inhibitory effect of nefopam on neuropathic pain following SNL might be associated with regulation of the JNK-mediated autophagy signaling by nefopam. Although our present results show a relationship between autophagy and the effects of nefopam, however, it need to be improved the precise mechanisms of nefopam molecular regulation on autophagic processes and proinflammatory cytokines to ensure our hypothesis on the causal relationship between nefopam and autophagy.In conclusion, SNL increased autophagy and JNK activation, and also increased lymphocyte infiltration into the dorsal gray matter. Consequently, PWT significantly increased and neuropathic pain developed. However, nefopam injection markedly decreased autophagy and JNK activation. Nefopam increased PWT after SNL, and its mode of action appeared to be associated with the downregulation of phospho-JNK and autophagy.


N = 119 intervention and N = 241 control across two health-care systems). The trial aims to evaluate the effectiveness of a suite of videos to improve advance care planning (ACP) for nursing home patients. This report uses mixed methods to explore the optimal and suboptimal conditions necessary for implementation fidelity within pRCTs in nursing homes.The Pragmatic Trial of Video Education in Nursing Homes (PROVEN) is one of the first large pragmatic randomized clinical trials (pRCTs) to be conducted in U.S. nursing homes . Qualitative interviews held after 15 months with champions were purposively sampled from facilities within the highest and lowest adherence rates . Two researchers analyzed interview data thematically using a deductive approach based upon six domains of the revised Conceptual Framework for Implementation Fidelity (CFIF). Matrices were developed to compare coded narratives by domain across facility adherence status.In total, 28 interviews involving 33 champions were analyzed. Different patterns were observed across high- versus low-adherence facilities for five CFIF domains. In low-adherence nursing homes, (1) there were limited implementation resources (Context), (2) there was often a perceived negative patient or family responsiveness to the program (Participant Responsiveness), and (3) champions were reticent in offering the videos (Recruitment). In high-adherence nursing homes, (1) there was more perceived patient and family willingness to engage in the program (Participant Responsiveness), (2) champions supplemented the video with ACP conversations , (3) there were strategic approaches to recruitment (Recruitment), and (4) champions appreciated external facilitation (Strategies to Facilitate Implementation).Critical lessons for implementing pRCTs in nursing homes emerged from this report: (1) flexible fidelity is important , (2) reciprocal facilitation is vital , and (3) organizational and champion readiness should be formally assessed early and throughout implementation to facilitate remediation.NCT02612688. Registered on 19 November 2015.ClinicalTrials.gov,  Pragmatic randomized clinical trials (pRCTs) are increasingly employed to maximize the translation of evidence-based interventions into practice. These trials differ from explanatory  RCTs in design and intent. As conceptualized by the Pragmatic Explanatory Continuum Indicator Summary version 2 (PRECIS-2) framework , trials Implementation fidelity is important for accurately interpreting findings of both efficacy and effectiveness trials, but are a particular concern for pRCTs, in which, by design, adherence to the intervention is less tightly controlled by the research team. The importance of fidelity in traditional RCTs has long been recognized, and the National Institutes of Health Behavior Change Consortium has recommended practices for ensuring and assessing fidelity within this context . While tMixed-methods study designs are a valuable approach in deciphering the why and how of success or failure in achieving fidelity within pRCTs . A qualiThis report aims to use mixed methods to further our understanding of factors influencing fidelity to a trial protocol within the context of pRCTs by leveraging data from the Pragmatic Trial of Video Education in Nursing Homes (PROVEN), which is one of the largest pRCTs to be conducted in nursing homes. PROVEN implements an advance care planning (ACP) video education program in intervention facilities. ACP, the process by which clinicians determine patients’ and families’ preferred treatment decisions prior to treatment needs, most appropriately results in advance directives . Nursing homes are required to engage in this process; however, evidence reveals deficiencies in meeting this mandate –17. VideBrown University’s Institutional Review Board gave approval to PROVEN and determined that the nursing home providers were not engaged in research using human subjects. Extensive detail on the trial design can be found elsewhere .N = 360 nursing home facilities; health-care system 1: N = 98 intervention, N = 199 control; health-care system 2: N = 21 intervention, N = 42 control). The trial began in March 2016 and was completed in May 2019. The intervention included a suite of five videos (~ 6–10 min in length) to aid in health-care decision-making: (1) General Goals of Care, (2) Goals of Care for Advanced Dementia, (3) Hospice, (4) Hospitalization, and (5) Advance Care Planning for Healthy Patients. These videos were loaded onto tablet devices, and two tablets were provided to each intervention facility. Family members could also access the videos online on their own devices through a password-protected internet link.In brief, PROVEN was conducted in two large nursing home health-care systems in the U.S.  offering the video to patients and families and 2) doing so within specified time parameters. At each intervention facility, one or two ACP champions  were designated as the individuals responsible for delivering the intervention. As per the implementation protocol, they were instructed to offer a video to all newly admitted or readmitted patients (or their family members) within 7 days of admission and to all long-stay patients (length of stay > 100 days) every 6 months or upon change in status over an 18-month implementation period. Consistent with a pragmatic trial, other elements of the program were customizable to real-world demands . We enclose the mplementation guides for champions , and if shown, which video was shown and to whom. The research team was able to link the video status reports to the Minimum Data Set data to determine the proportion of new admissions and long-stay residents who had a completed video status report, implying a video was offered, as per the protocol. During the implementation period, the health-care system leadership gave the champions monthly feedback reports, which included their facility’s adherence or video offer rate. These reports were reviewed at regular telephone group and individual conference calls with health-care system leadership or research team members.To be consistent with PROVEN’s focus on long-stay patients within its primary trial outcome, adherence in this report was measured using the cumulative completion rates of video status reports for long-stay patients only (to the exclusion of rates for short-stay patients). This rate was calculated across each facility in the health-care systems that had consistently collected interview data. Nursing homes were categorized into quintiles based on the distribution. Nursing homes in the top quintile were considered high-adherence facilities and those in the bottom, low-adherence facilities.An experienced research assistant conducted semi-structured telephone interviews with champions from all intervention facilities to gather their perceptions of the implementation at 4 months, 9 months, and 15 months into the implementation. Qualitative data for this report were derived from the 15-month interviews  that moderate the relationship between program implementation and adherence: (1) Intervention Complexity, (2) Participant Responsiveness, (3) Quality of Delivery, and (4) Strategies to Facilitate Implementation . It is pThe modified version of CFIF, which guides this report, adopts these four moderating constructs and proposes two additional ones: Recruitment and Context . RecruitThis mixed-methods report followed a sequential explanatory design and integrated PROVEN’s quantitative and qualitative data at the methods level. This was done by connecting the two datasets through the sampling framework . Sites wWithin each health-care system, nursing homes in the top (high-adherence) and bottom (low-adherence) quintiles of adherence rates were identified based on the video status reports. Facilities with an adherence rate of zero were excluded; these facilities were disengaged from the program for a wide variety of reasons  to the extent that feedback from their champions would not have been informative. Only interviews from these high- and low-adherence nursing homes were analyzed. The analysis was done deductively across the two facility classifications to identify differential factors influencing fidelity as established by the six modified CFIF constructs . Two resA total of 28 facilities from each of the two health-care systems were sampled from the top and bottom quintiles of adherence rates Table . In healN = 2) or nursing roles (N = 2).A total of 33 champion interviews were conducted and analyzed from among these 28 facilities (5 facilities had two champions). The champions were female (33/33) and mostly social workers (29/33). The professions of the four additional champions fell within administrative roles  emerged regarding PROVEN’s patients’, family members’, and champions’ reactions and attitudes towards the intervention. Patients’ and family members’ responsiveness, as perceived by the champions, tended to differ by facility adherence status, representing a paired-divergent theme. Champions in high-adherence facilities frequently described an openness on the part of patients and families to participate in the ACP Video Program. For example, one high-adherence facility’s champion noted:It makes [the ACP conversation] harder, to be honest with you... After a while, the conversation becomes negative because you’re getting so much pushback from the family or from the resident that don’t want to use it. They don’t want to watch it.[Participant 4]In contrast, champions from low-adherence facilities often described patients and families as reluctant to view the videos. A low-adherence facility champion described this phenomenon:Despite this contrast in responsiveness, champions from both high- and low-adherence facilities felt that patients and family members who did watch the video ended up reacting positively to it. In this paired-convergent theme, both types of facilities had champions who reported that a video sometimes motivated a change in advance directives, e.g., from full code to comfort care.It’s a great program. It’s a great resource to have. I think everybody should have the resource, but more so as an option, not necessarily a requirement… Let us use it as a resource as needed or as we feel it fit. [Participant 5]Champions’ own responsiveness to the ACP video program varied by facility adherence status. Facilities with low adherence tended to consider the intervention as needed on a conditional basis, an unpaired theme. One low-adherence facility champion stated:When I read [the principal investigator’s] book and looking at this process, it fills my heart with joy that he has taken this under his wing… It’s not only had a professional impact, but a personal impact. [Participant 6]On a few occasions, champions from high-adherence facilities portrayed a personal investment in ACP, which informed their positivity to the ACP video program, another unpaired theme. One such champion explained:Just by showing, presenting it to the patient as what it can do, what’s in it for them. With all sales, you know, we’re kind of selling this video, and with any sales, people want to know what’s in it for them. [Participant 7]A Recruitment paired-divergent theme related to how PROVEN’s champions solicited patients and family members to watch a video. High- versus low-adherence facilities differed in the comfort level or attitude with which they approached this task. High-adherence facilities had some champions who approached recruitment of nursing home residents and family members as a strategic effort, as one such champion explained:It’s hard to walk up and say: “Well, it’s your time. You have to see this video again.” We don’t say that, obviously, but that’s how I feel about it. “Oh shoot. I’ve got to call this family in.” Or I’ve got to go approach them and say watch this thing again. [Participant 8]Some champions from low-adherence facilities approached recruitment with a more tentative stance, as expressed in the following quote:I usually try to have a discussion after it’s over and ask them if they have any questions and then within two days call them back after they’ve seen it to see if there was any questions, how they’re feeling, you know just to make sure that everything’s on an even kilter. [Participant 9]One unpaired theme reflected the intent of PROVEN’s ACP video program to be an adjunct to general ACP discussions between champions and patients and families. High-adherence facility champions tended to use this dovetailed approach. A high-adherence facility champion referred to this tendency:. This was epitomized by a low-adherence facility champion’s statement:It’s no challenge as far as showing the video, but it’s hard for me because originally they sent four of us up there to train and it’s been pretty much me that’s been having to do that and being a social worker, I have a lot of duties and I just have to make the time for it and so I really need some help or maybe to get maybe our new unit managers on board if we could get them some training. [Participant 10]CFIF’s Context construct emerged as three unpaired emergent themes that highlighted how intervention facilities’ characteristics and concurrent events  differed by adherence status. Resource challenges in low-adherence facilities were cited by championsLike I said, we are part of a big push anyway with our feed hospital as far as POLSTs and advance care planning as it is. We really deferred a lot mostly to the POLST form, have [the patients and families] review it, the docs going over it with them, and there just isn’t usually that need for the video. [Participant 5]Champions from low-adherence facilities also described less of a need for the ACP video program given the co-occurring ACP interventions locally. A champion from this type of facility explained:It’s definitely case by case… If the facility is having a lot of challenges with conversations with families and not having advance directives in place and things just kind of hanging out there, I think [the ACP video program] would be really great. [Participant 11]In a few high-adherence facilities, champions felt that new staff or facilities having a hard time with ACP would benefit the most from the ACP video program. When asked if she would recommend the ACP video program to other skilled nursing facilities, a high-adherence facility’s champion responded:Well, we got on with our little meetings we have with the doctor, Dr. X [a PROVEN principal investigator]… He would kinda give us insight how we could pursue, you know even the difficult families, you know, what maybe we could go this route, instead of that way. Maybe go around instead of forward…and it kinda gave us a little insight on where we are lacking, try to include everyone in the mix, instead of just the few that we see all the time. [Participant 12]Two key themes emerged (one unpaired and one paired-divergent) related to the research efforts by the team, corporate leaders, and champions to optimize implementation. High-adherence facility champions often commented on the positive impact the collaborative team leadership had on their ability to maintain fidelity. For example, as one high-adherence facility champion mentioned:So, I mean, I’m trying to put a lot of little processes in place to actually implement better. It’s just, you know, it’s baby steps. [Participant 1]In a few instances, champions’ own efforts to facilitate implementation could be characterized as qualitatively different across facility adherence status. A high-adherence facility champion explained her own approach, which reflected ongoing purposeful efforts at implementation despite challenges:I told [a health-care system leader] that we had had a lot of changeover and it was nobody but me and that I needed some help and so, but, I don’t, nothing’s happened yet. So, I don’t know what I need to do on my end. [Participant 10]In contrast, a low-adherence facility champion related her own sense of uncertainty about how to address implementation challenges she faced:This mixed-methods analysis of the PROVEN trial data provides insights into the implementation experiences in a large nursing home-based pRCT evaluating an ACP video program. Only one of the CFIF domains, Intervention Complexity, did not yield divergent or unpaired themes by facility adherence status, while the remaining five domains did . In terms of Intervention Complexity, both types of sites seemed to find the intervention simply designed. Of the most notable contrasts by facility types, low-adherence facilities were characterized by: (1) perceived negative patient and family responsiveness to the ACP video program (Participant Responsiveness), (2) tentative champion recruitment efforts (Recruitment), and (3) limited organizational resources (Context), while high-adherence facilities were characterized by: (1) perceived greater patient and family willingness to engage in the ACP video program (Participant Responsiveness), (2) strategic approaches to recruitment (Recruitment), (3) champions’ use of the video to bolster ACP conversations , and (4) champions’ appreciation of facilitation by the research and leadership team (Strategies to Facilitate Implementation). Three key lessons regarding fidelity efforts in pRCTs can be gleaned from these findings: the importance of flexible fidelity, reciprocal facilitation, and organizational readiness. As modified CFIF domains  supported these three lessons in an overlapping manner, domain-specific findings will be embedded throughout the following discussion of each lesson.This work underscores the importance of embracing flexible fidelity when conducting pRCTs. Flexible fidelity recognizes the need to deliver core elements of an intervention while allowing for the purposeful adaptation of non-essential intervention features  , 30. SucThe need for such adaptability at the individual and organizational levels is apparent from our and others’ findings, especially those findings related to Participant Responsiveness and Context. PROVEN’s champion interviews underscored how individual stakeholder needs  should be factored into implementation efforts. Such an approach could foster positive Participant Responsiveness in these stakeholders, which was at times lacking in PROVEN’s low-adherence facilities. Other trials  have suggested this same need to adjust interventions mid-stream. Potential factors that influence fidelity include the emerging needs of both patients  of champion implementation efforts through continuous qualitative feedback and coaching. The more negative Participant Responsiveness to the intervention by PROVEN participants in low-adherence facilities may highlight the need for engaging all stakeholders from the initial planning stages of pRCTs onward. Such a strategy could enhance stakeholder buy-in to the intervention, as other studies have found. A quantitative analysis of PROVEN discovered that a characteristic of facilities associated with adherence was champion engagement  . An RCT Facilitation in the opposing direction, from leadership team to champion, can also play a critical role in fidelity for pRCTs by addressing issues relating to Participant Responsiveness, Recruitment, and Strategies to Facilitate Implementation. We found that in PROVEN’s high-adherence facilities, champions perceived that facilitation driven by the leadership team  was beneficial. These leadership team-driven activities, promoted by other studies of palliative care interventions –38, may In line with other studies, PROVEN’s findings  highlight another lesson about fidelity in pRCTs: the need to assess organizational and champion readiness and to adapt accordingly. Tools such as the Organizational Readiness for Change Assessment (ORCA) and the Organizational Readiness for Implementing Change measure can assess the potential that an organization has for implementation success , 42. ConThe limitations of this work should be noted. First, conducting qualitative interviews with patients and family members, in addition to champions, could have provided valuable triangulation of our findings. This was beyond the scope of this study, however. Second, we combined the two health-care systems’ data in the analysis despite their differing sizes and cultures. Third, our classification of some qualitative themes as unpaired could be misleading. One may not be able to draw inferences about the absence of a theme in one adherence type  that was present in the other adherence type  given that a number of issues could lead to this finding . We tried to counter this limitation by developing a detailed interview guide accompanied by interviewer-initiated prompts as needed. Finally, our findings may not be transferable to other long-term care settings, including nonprofit facilities.Findings from this large pRCT of a simple intervention suggest that flexible fidelity may be an important overarching principle for realizing optimal implementation in pRCTs. In this vein, reciprocal facilitation, i.e., champions aiding the leadership team in pRCT design and, conversely, the leadership team aiding champions with implementation, may dynamically enhance implementation fidelity. Facilities deemed at-risk of implementing pRCTs without fidelity could be identified by formally measuring organizational readiness early and throughout the implementation. Such facilities could then benefit from targeted remediation support.Additional file 1. Champion Implementation Guide.Additional file 2. Intervention Facility Implementation Guide.Additional file 3. Interview guide 15 months post-implementation.Additional file 4. Structured Analytic Codebook


We found no significant differences between faecal VOC patterns of HC and RCD. Based on faecal VOCs, CD could be discriminated from RCD and HC. This implies that faecal VOC analysis may hold potential as a novel non-invasive biomarker for RCD. Future studies should encompass a larger cohort to further investigate and validate this prior to application in clinical practice.Currently, the gold standard for diagnosis of coeliac disease (CD) is based on serology and gastroduodenoscopy with histology of duodenal mucosal biopsies. The aim of this study was to evaluate the potential of faecal volatile organic compounds (VOCs) analysis as a novel, non-invasive tool to discriminate between CD in remission in patients on a gluten-free diet (GFD), refractory coeliac disease (RCD) and controls without CD. Patients with an established diagnosis of CD on a GFD, RCD and healthy controls (HC) were instructed to collect a faecal sample. All subjects completed questionnaires on clinical symptoms, lifestyle and dietary information. Faecal VOCs were measured using gas chromatography-ion mobility spectrometry. A total of 13 CD, 7 RCD and 10 HC were included. A significant difference in VOC profiles between CD and RCD patients (area under the curve (AUC) ± 95% CI: 0.91 (0.79–1)  Coeliac disease (CD) is a chronic, immune-mediated enteropathy triggered by the ingestion of gluten in genetically predisposed individuals, with an estimated prevalence of 1% in Europe ,3. Only The current gold standard to diagnose CD consists of serological screening for circulating transglutaminase 2 antibodies (TGA2) . ConfirmAnalysis of volatile organic compounds (VOCs) is an emerging technique in metabolomics. These carbon compounds are organic chemicals with a high vapour pressure, detectable in faeces, urine, breath, skin and saliva . In the In this explorative case-control study, patients were recruited from the Coeliac Centre Amsterdam . Patients who underwent a gastroduodenoscopy between October 2015 and November 2017 were eligible to participate. We included three groups; CD, RCD type II, and a non-coeliac control group that also underwent a gastroduodenoscopy. Inclusion criteria for all groups were adulthood ≥18 years), signed informed consent and comprehension of the Dutch language. Patients were eligible for the CD group if they had a positive tTGA titre (>7.0 U/mL) combined with a Marsh classification >2 of the duodenal biopsies upon diagnosis and if they had followed a strict GFD for ≥2 years  years, s,31.Patient demographics, medication, gastroduodenoscopy and biopsy reports were obtained from electronic patient records. Information on dietary intake, weight and height, stool consistency based on the Bristol stool chart, smoking status and medication use were collected through a questionnaire.Patients included in this study were asked to collect a faecal sample  prior to their scheduled visit. Participants kept the sample in the freezer at home within one hour following collection, and transported this sample to the hospital in a cooled condition using ice packs and/or ice cubes on the day of their visit.From the original sample, a subsample of 500 mg was weighted using a calibrated scale , transferred into a glass vial  and re-stored directly in a −24 °C freezer until further handling. This amount of sample was chosen to provide an optimum ratio of VOCs to the sample headspace, as validated in a previous sampling method study for pattern-recognition analysis on faecal VOCs using field asymmetric ion mobility spectrometry . For the®, G.A.S., Dortmund, Germany) [Faecal samples were analysed using gas chromatography (GC) coupled to an ion mobility spectrometer (IMS)  , which wGermany) .® version 22. Ion mobility spectrometry data was first pre-processed prior to the statistical analyses. Areas that contained chemical information were cropped and a threshold was applied to remove background noise. The data was corrected for instrumental disturbances by baseline realignment. Classification was then undertaken using a 10-fold cross-validated approach, where the data was split into a 90% training set and a 10% test set. Within a fold, the Wilcoxon rank-sum test was used to find the 100 most discriminatory features and these features were then used to train five different classifiers . These models were then applied to the test set. This process was repeated until every sample had been classified as a test sample and from the resultant classification probabilities, statistical results were calculated.Demographics of each group  were compared using the non-parametric Kruskal–Wallis H test with the addition of the Wilcoxon rank-sum test for continuous data. The Fisher–Freeman—Halton exact test was performed for dichotomous data and Fisher’s exact test for dichotomous data in subanalyses. The statistical tests were performed using IBM SPSSThis study was approved by the local medical ethics committee (METc) of Amsterdam UMC location Vrije Universiteit medical centre (file number 15.368). Written informed consent was obtained from all study participants.p = 0.022) and none from the HC (p = 0.003) group. Anti-inflammatory therapy in RCD included budesonide in all five, whereas the two CD patients were treated with thiopurines for microscopic colitis. All CD and RCD patients reported adherence to a strict GFD. All HC self-reportedly followed a gluten-containing diet, one HC reported a restricted lactose intake.A total of 30 patients were included; 13 CD, 7 RCD II, 10 HC. Key symptoms leading to gastroduodenoscopy in the HC group were: retrosternal pain (30%), globus (30%), idiopathic iron deficiency anaemia (20%), reflux (10%) or change in bowel habits (10%). No macroscopic mucosal abnormalities were found in 70% of the cases, and 30% displayed mild forms of gastritis. Baseline characteristics are depicted in For every comparison, the outcomes of the support vector machine classifier are presented. The results of all five classifiers are presented in p = 0.000). Moderate accuracy was found for the differentiation between CD and HC (AUC ± 95% CI: 0.71 (0.51–0.91), p= 0.024). There were no significant differences between the faecal VOC patterns of RCD patients and HC (AUC ± 95% CI: 0.57 (0.29–0.86), p = 0.310). Receiver operator characteristic (ROC) curves for the comparisons are depicted in Using faecal VOC patterns, CD and RCD patients could be discriminated with high accuracy (AUC ± 95% CI: 0.91 (0.79–1), p = 0.000) [This pilot study was the first study to explore the potential of faecal VOCs as a non-invasive biomarker that can discriminate RCD from CD in patients on a GFD. We observed a significant difference in VOC profiles between CD and RCD patients and between CD and HC. We found no significant differences between faecal VOC samples of HC and RCD patients. Di Cagno and colleagues investigated the faecal microbiota and faecal VOCs of children with untreated CD, treated CD and controls, using gas chromatography-mass spectrometry solid-phase micro extraction analysis of VOCs. Not only did they observe differences in microbiome diversity and VOCs between CD and controls, a difference in VOCs was also observed in treated versus untreated CD . In othe= 0.000) . In colo= 0.000) . These rp = 0.003). This could have been of influence on the VOC profile. Based on VOC pattern recognition RCD was discriminated from CD with a sensitivity of 0.85 and a specificity of 0.86. These results hold great promise for the future and require validation in a larger cohort. We hypothesize that a larger sample size will temper the effect of personal bias on the heterogeneity, enabling machine learning to reduce this background noise.Since this study was a pilot study, the number of patients included was limited. We hypothesize that the inability to discriminate RCD from HC might have been attributable to the small sample size. The heterogeneity of VOC profiles of both groups is indirectly demonstrated by the length of the boxplots in Currently, a (repeat) gastroduodenoscopy with the histological examination of duodenal biopsies and flow cytometric analysis of freshly isolated duodenal lymphocytes are necessary to confirm RCD . The proFuture research focusing on faecal VOC profiles as novel non-invasive biomarker for RCD detection and monitoring may use chemical analytical platforms as gas chromatography–mass spectrometry (GC-MS) or pattern-recognition techniques like GC-IMS. While the first analytical platform has the potential to identify the specific metabolites differentiating between groups of interest, it is an expensive and time-consuming method that requires specialized personnel. The use of pattern recognition is favourable for clinical use, as it allows for fast, relatively low-cost and high-throughput analysis. Ideally, should differences in faecal VOC profiles of CD, RCD and HC be validated in a larger cohort, a disease specific faecal VOC print may be calculated, making VOC analysis a practical and cost-effective method for the evaluation of the discrimination between RCD and normal CD.In conclusion, we observed significant differences in faecal VOC profiles between CD and RCD patients using GC-IMS, and to a lesser extent between CD and HC, but not between RCD and HC. Our study outcomes imply that faecal VOC analysis may hold potential as a non-invasive biomarker for the discrimination between CD and RCD patients. Future research should focus on the validation of these findings in a larger cohort. The calculation of a specific faecal VOC print could make VOC analysis feasible as a more patient friendly and cost-effective diagnostic marker for RCD.


Within an Internet of Multimedia Things, the risk of disclosing streamed video content, such as that arising from video surveillance, is of heightened concern. This leads to the encryption of that content. To reduce the overhead and the lack of flexibility arising from full encryption of the content, a good number of selective-encryption algorithms have been proposed in the last decade. Some of them have limitations, in terms of: significant delay due to computational cost, or excess memory utilization, or, despite being energy efficient, not providing a satisfactory level of confidentiality, due to their simplicity. To address such limitations, this paper presents a lightweight selective encryption scheme, in which encoder syntax elements are encrypted with the innovative EXPer (extended permutation with exclusive OR). The selected syntax elements are taken from the final stage of video encoding that is during the entropy coding stage. As a diagnostic tool, the Encryption Space Ratio measures encoding complexity of the video relative to the level of encryption so as to judge the success of the encryption process, according to entropy coder. A detailed comparative analysis of EXPer with other state-of-the-art encryption algorithms confirms that EXPer provides significant confidentiality with a small computational cost and a negligible encryption bitrate overhead. Thus, the results demonstrate that the proposed security scheme is a suitable choice for constrained devices in an Internet of Multimedia Things environment. An Internet of Things (IoT) is a networked architecture , of whicThis paper assumes that: confidentiality for video sensor networks  is integQ1. Are those encryption schemes computationally efficient enough (in terms of execution/encoding time) to employ in an IoMT communication environment?Q2. Is the analyzed ESR effective enough to apply SE to visually secure the videos encoded with one or other of the two common entropy coders in common codec use, that is, context adaptive variable length coding (CAVLC) and context adaptive binary arithmetic coding (CABAC) see ?To judge the protection afforded by EXPer, the encryption space ratio (ESR) is calculated as the ratio of the encrypted bits to all the bits of a compressed video bitstream. The ESR has previously been used as one way to judge the effectiveness of SE. In a variable bitrate (VBR) stream, the bitrate is dependent on the various configuration factors but if these are held constant across a number of test videos then both the spatial and temporal coding complexity change according to the content. For example, the presence of high spatial frequencies or textures within objects increases the coding complexity and likewise rapidly moving objects across video frames increases the temporal complexity. The quantization parameter (QP) also affects the bits allocated, with a low QP implying a higher compressed bitrate. The SE bitrate depends on the syntax elements that are selected for encryption. These syntax element bits may be fully encrypted, typically by a block cipher such as the advanced encryption standard (AES)  operatinThe focus of this paper is to answer those questions by experimentation. In the case of full (sometimes known as) naïve encryption, the complete video is encrypted. Therefore, the encryption overhead and the space ratio are at a maximum, which causes a bitrate overhead too. Herein, such weaknesses are addressed by proposing a complete lightweight security scheme for IoMT applications on a standardized H.264/advanced video coding (AVC) encoder for constrained surveillance devices. Notice that HEVC is currently too resource intensive to be used in an IoMT environment, see . In the SE already has a potential role in consumer electronics applications  and alsoEntropy coders are a feature of standardized hybrid video encoders . H.264/ADesign of a joint crypto-compression scheme acting upon selected video syntax elements output by the entropy engine of an H.264/AVC encoder. SE is applied, keeping in mind the requirements of IoMT devices.Ensuring that those selected syntax elements do not, once encrypted, have the potential to crash a decoder at the receiver. In other words, ensuring that they are format compatible with the H.264/AVC standard, even when encrypted.Application of ESR to the output from two entropy coders, CAVLC and CABAC. ESR is used as a diagnostic tool to obtain efficient SE. ESR was applied to ten test or benchmark video sequences. (The same procedure has been applied to video clips captured by constrained RasPi cameras.)Finding that the ESR estimate for CABAC is less than CAVLC, which implies that the CABAC entropy coder is suitable for IoMT cameras.Introducing an innovative, single-round, lightweight cipher EXPer  cipher and bit-level permutation).Performing a series of experiments with EXPer upon the output of an H.264/AVC encoder, comparing that cipher to simple XOR and the industry-standard advanced encryption standard (AES) . TherefoPerforming cryptanalysis that EXPer is secure against a variety of attacks, including key guessing, perceptual, known-plaintext attacks as well as statistical and inference attacks.The H.264/AVC codec is selected for implementation of lightweight encryption because, in both the CCTV industry and for smart monitoring in an IoT, surveillance devices (cameras) mostly operate on microprocessors, especially the RasPi, which only supports video compression in the H.264/AVC format . In an IThe remainder of this paper is organized as follows. In The heterogeneity of the communication technologies across an IoMT, deriving from the assortment of devices, sensors, and protocols, is a cause of security concern. Messages that are transmitted from smart objects will usually be stored and forwarded through several nodes  to reach their endpoint . An endpTo ensure confidential communication of information in an IoT, many schemes have been proposed, schemes which employ existing state-of-art encryption algorithms ,35,36,37In addition encryption, researchers have also proposed authentication schemes for IoT with existing standardized algorithms. Lee et al.  proposedAlthough, the encryption schemes given in Likewise, to avoid extra computational overhead and bitrate control, chaos theory is also utilized to implement the encryption process for IoMT systems ,50. ChaoSelection of syntax elements for two entropy engines, such as, CAVLC and CABAC.EXPer, an innovative lightweight cipher based on a combination of XOR and bit-level permutation rounds, with three different 128-bit keys.ESR is calculated according to the selected syntax elements of CAVLC and CABAC, as a way of diagnosing the effective visual protection .SE is applied by utilizing EXPer, according to the guidance given by ESR .This section explains the approach of the proposed security scheme for devices in IoMT environment. The security scheme is comprised of four components: There are two forms of entropy engines for efficient compression in H.264/AVC video encoder, CAVLC  and CABAIn this paper, for the convenience of implementation the focus is not on a newly proposed SE encoder technique. Therefore, we have employed our previous SE schemes for example as reported in , with onBins in the subsequent sections of this paper. A block diagram of the proposed security scheme is given in It is also worth mentioning here that these mentioned three types of parameters are produced only from residual information, as presented to the final entropy coding stage of a hybrid encoder and are proven to be format compliant in experiments. Textural residuals are taken from both homogeneous and heterogeneous areas within a video. For motion encryption, the arithmetic signs of motion vector difference (MVD) are encrypted while textural syntax elements are different for both CAVLC and CABAC  is computationally intensive, so it is not included in the proposed cipher. Moreover, the different forms of XOR are also not computed over videos, because their adoption can be effective for a computation over single image rather than a whole video with large quantity of surveillance frames. Although permutation is applied on bit-level within selected byte to effectively secure the camera captured videos. (k_1), and the bit-wise permutation by the shift operation. Permutation is performed with two randomly selected offsets, v_1, 2, ranging in value from 1 to 8. Additionally, permutation is performed on the output from the previous stage to provide significant statistical randomness with a reduced computational complexity. The permutation is applied as the bit-level, by re-ordering the bits within each byte. The impact of this permutation is not easily compensated for by an attacker, given that large volumes of video data are involved EXPer encryption consists of five steps/stages with a single iteration over those steps. In each step, XOR is performed using a secret key k_1), sub_key1 (k_2), sub_key2 (k_2) are dynamically generated at run-time for each input bitstream, by using a pseudo-random function (PRF). To keep the procedure simple, three dynamic keys are generated per video sequence and stored in a registry. Key security can be enhanced by using any standardized key management scheme [100 is considered resilient to key guessing or brute force attacks over keys [The symmetric secret keys: secret key  of the CABAC entropy coder. Then, X is XORed with the secret key, k_1. In other words, each 128-bit block of the stream of selected syntax elements, extracted from the original compressed bitstream, is encrypted and then in encrypted form is placed back into the output bitstream:X contains the syntax elements (or bins) selected from any input bitstream, and X’ contains the resulting encrypted syntax elements, grouped in blocks of 128-bits.Step 2: In the second step, a permutation is applied to the encrypted output X’ of (1). Thus, the selected and encrypted syntax elements are re-ordered through the permutation. Specifically, the elements of X’, on a byte-by-byte basis, are cyclically permutated by offset value v_1 using a circular right-shift operator. The shift operation in general is represented in (2), in which the input bytes are transformed, byte-by-byte, into the encrypted and permuted output, as shown in (2) for an offset value one, and in general in (3) by the value of v_1↦ is a transformation symbol and >>> is a circular shift operator that signifies transforming X’ into the X’’ bitstream, through a circular right-shift of the bits of each byte of X’. v_1 denotes an offset value.Step 3: In the next step, the resulting output of the previous step, which is X’’, is again transformed by an XOR operation with the 128-bit sub-key k_2, as:k_2 is derived by means of a PRF.As already mentioned in Step 4: In the fourth step, the previously encrypted output X’’’ is permutated once again with offset value ,v_2 again by a circular right-shift operator, applied on a per byte basis:Step 5: In the final step, the resulting bitstream, X’’’’, is XORed with the 128-bit sub_key2 (k_3), to produce encrypted bitstream outputE:outputE are re-merged with the compressed video bitstream. In that way, a decoder receives a format compatible bitstream, according to the format of the H.264/AVC standard.Subsequently, the bits of encrypted bitstream The five steps of the proposed algorithm are discussed in more detail below:The proposed algorithm is simple and, thus, convenient to implement even on videos directly taken from RaspPi cameras. The pseudo-code and flowchart in In order to evaluate the performance, experiments were performed on ten well-known  test vidBefore applying SE with EXPer on test videos, the focus of this paper is to analyze the ESR of two entropy coders over which the SE is applied. ESR is basically the amount of data within each video  over which the SE produces acceptable visual protection results see also . The tesTaking the ESR percentages for CAVLC first in Compared with SE of CABAC syntax elements in For the evaluation of results with EXPer, the experiments were performed on several test video sequences with the selected parameters such as those based on motion, texture, delta QP, and together with their combinations. The SE is applied with CABAC on all tested videos because CABAC is more compression efficient  or delta QP combined with texture (12.80% for mobile video and 4.15% for ICE video) is also less as compared to the encryption ratio with combined motion and texture (13.22% for mobile video and 4.21% for ICE video). The important point to note here is that the SE on the absolute values of dQP is not possible with complex cipher algorithms, because the number of rounds in complex ciphers makes these values out of range which destroys the format compliance and compression efficiency of the bitstream, and consequently crashes the decoder .However, in this paper, visual results in To analyze the performance of the EXPer, the absolute encryption time in seconds was measured for CIF videos. The results obtained from various experiments in this Section validate the robustness of EXPer.Perceptual quality is considered an important check on the strength of encryption algorithms. An encryption algorithm is considered robust if it succeeds in distorting a video sequence in such a way that an observer visually fails to detect any useful information from the encrypted bitstream. Clearly, the term ‘useful’ is dependent on the purpose that the video is to be put to, which, herein, is assumed to be IoMT purposes. The visual results of m and n are the width and height of the video frame under consideration, while X and Y represent the pixel’s intensity values of the two frames being compared. For a video sequence, the PSNRs of the frames are averaged across the sequence. A lower value of PSNR indicates less similarity between an original video sequence and the video sequence reconstructed from a compressed and encrypted bitstream. PSNR  measuresr ranges from 1 to −1. When two frames are the same, the correlation index is at a maximum, which is 1. Therefore, a lower value of correlation coefficient indicates higher distortion as a result of encryption. Another statistical method to compute the similarity between the original and encrypted pixels of the video frame is cross-correlation. The cross-correlation coefficient, r, is calculated as:N = 6000 pairs of adjacent pixels from the original and selectively encrypted test video frames.The correlation between adjacent pixels within video frames in the different directions  for plaintext and encrypted mobile video are shown in The SSIM index  is a metTo confirm the value of EXPer, a comparison with the most commonly used encryption algorithms XOR and AES was performed. XOR can be considered the most suitable encryption algorithm for IoT applications due to its simplicity and lower computational complexity. However, baseline XOR provides limited confidentiality for images, due to potentially high cross-correlations, and, therefore, AES can be utilized to provide greater confidentiality. Though AES is robust against known-plaintext, brute force, and statistical attacks, it incurs a higher encoding and decoding overhead, which is expensive for resource-constrained IoMT devices. Results were taken with both state-of-the-art ciphers to compare their performance with EXPer. Comparative visual results with XOR, AES-CFB , and EXPFor video quality analysis of these three ciphers, PSNR and SSIM results were also taken. The SSIM of the encrypted video with combined motion and texture parameters is illustrated in In addition to visual content protection, the efficiency of an encryption algorithm for real-time processing is dependent on the execution/encoding time. Therefore, to evaluate the efficiency of EXPer, a comparison with the encoding time of standard algorithms XOR and AES-CFB has been performed. The comparative results of For the security analysis of EXPer, a comparison with the correlation coefficient of standard algorithms XOR and AES-CFB has been performed. f is the gray-level value and p(f) is the probability of f. Entropy defines the uncertainty or the chaos level within video frames. It measures the amount of the gray level and the probability corresponding to the total information inside all other pixels and determines which pixels carry most of the information. It is calculated as: This section contains a cryptanalysis of relevant attacks upon the SE method of this paper. A prior cryptanalysis of the SE method also appeared in the leading journal paper , revieweIn this type of attack, the attacker tries to guess the keys and sub-keys by investigation of the encrypted bitstream streams. However, the proposed algorithm is sensitive to any changes in the plaintext bitstream or in the secret keys or the offset value. Bit-level chaining dependency exists between the permutation and XOR sequential steps in EXPer, which makes it challenging to apply differential attacks. Hence the proposed algorithm produces a different encrypted output bitstream for the same plaintext input bitstream if any change in the secret key takes place. Thus, whenever an attacker tries to insert random keys through a brute force attack in order to recover the original bitstream, they find more distorted bitstream rather on any clues about the encrypted bitstream and the sub-keys, as demonstrated in EXPer is implemented on video syntax elements rather than on a single image. All tested videos of file size 43.5  are compThe entropy analysis performed in A comparison of two recently proposed lightweight ciphers with EXPer appears in Various classes of IoMT devices are utilized for multiple services such as stored video streaming , live video streaming in the cases of video conferencing, online gaming, and other real-time applications, with the most confidential being interactive video streaming in the form of surveillance applications. It is crucial to modern IoMT nodes to provide data confidentiality in the form of data encryption. The most reliable cipher is AES with 128/192/256 bit keys. However, AES is still not an optimal choice for low-powered surveillance devices with simple hardware. In this paper, by keeping in view current security needs, we propose an ESR-validated security scheme for IoMT devices. Within a security scheme, the contribution of the paper is to examine two alternative entropy coders available for the H.264/AVC codec, such as AVLC and CABAC in detail and determine the ESR when applying SE with the proposed cipher to encrypt the selected syntax elements. As identified herein, using the CABAC entropy coder see  can consFuture work based on taking measurements of ESR in this paper can provide a way to more precisely model the trade-offs between computational complexity, and memory access in terms of energy consumption within a video sensor device. Both entropy coders have a content dependency, which increases the effect of bit errors. This implies that error resiliency or channel coding should be built into transmission over an IoMT network along with proper key management solution in future.