The JND for frequency-band increments was 2.8 dB excluding the 0.25-kHz low-pass band, for which the JND was 4.5 dB. The JND for broadband increments was 1.5 dB. Participants’ median frequency-band and broadband JNDs were positively correlated. JNDs were mostly independent of age, pure-tone thresholds, and cognitive score. In consideration of self-fitting adjustments in noisier conditions, JNDs were additionally estimated at a more sensitive d’ of 2. These JNDs were 6 dB for bands below 1 kHz, and 5 dB for bands at and above 1 kHz. Overall, the results suggest noticeable fine-tuning adjustments of 3 dB and self-fitting adjustments of 5 dB.Frequency-dependent gain adjustments are routine in hearing-aid fittings, whether in matching to real-ear targets or fine-tuning to patient feedback. Patient feedback may be unreliable and fittings inefficient if adjustments are not discriminable. To examine what gain adjustments are discriminable, we measured the just-noticeable differences (JNDs) for level increments in speech-shaped noises processed with prescription gains. JNDs were measured in the better ears of 38 participants with hearing impairment using a fixed-level, same-different task. JNDs were measured for increments at six individual frequency-bands: a 0.25-kHz low-pass band; octave-wide bands at 0.5, 1, 2, and 4 kHz; and a 6-kHz high-pass band. JNDs for broadband increments were also measured. JNDs were estimated at  Frequency-dependent gain is the hearing-aid parameter fundamental to restoring audibility to listeners with hearing loss. This parameter, which we will refer to as the frequency-gain response (FGR), is most commonly set by the application of a prescription formula to pure-tone thresholds. The FGR is then verified by real-ear measurements (REMs) which assess the gains delivered to the tympanic membrane, allowing the clinician to account for ear canal resonance properties and fitting software errors. While presenting speech-shaped noises (SSNs) or recorded speech, gains at frequency bands are adjusted to prescribed targets via hearing-aid fitting software. FGR curves based on fitting software commonly deviate from real-ear gains, and REMs help ensure that prescription targets are met .This procedure does not guarantee objective benefit nor patient satisfaction. Pure-tone thresholds do not provide a comprehensive measure of hearing status; FGR curves which maximize objective benefit may depend on abilities such as suprathreshold loudness perception, frequency resolution, and even cognitive capacity . PrescriFine-tuning is the patient-centered practice of adjusting parameters following the initial-fit or REM, and is largely focused on the FGR . NaturalThere are no guidelines on the scale of adjustments that should be made when fitting the FGR. Clinical practice varies widely and hearing-aid fitting software permits gain adjustments at levels of 1 dB (or less) at a range of manipulable frequency handles. Fine-tuning could be unreliable and inefficient if patients are unable to discriminate FGR adjustments (frequency-specific or broadband changes in output). It is unlikely that an FGR adjustment of a magnitude less than what is discriminable will elicit authentic patient feedback. This problem could be particularly apposite for paired comparison fittings and self-fitting technologies, in which empirically different parameter alternatives could be perceptually indiscriminable, particularly when in acoustically noisy environments. If adjustments improve audibility, but are not noticeable, then self-reported outcome measures will unlikely reflect an improvement. Further, a patient may expect adjustments to be immediately noticeable, which may lead to dissatisfaction and nonuse if they are not .Even with REM adjustments, discrepancies occur between the real-ear and target gain ; currentDiscrimination of spectral peaks in complex stimuli is most germane to discrimination of FGR adjustments. Profile analysis is an experimental paradigm which tests the ability to discriminate variations in spectral shape, typically an increment of a single pure-tone component relative to background components . Roving There has been previous research into the broadband FGR adjustments required to elicit a differing percept. Previous psychophysical evidence on the ability to discriminate narrowband (⅓-½ octave) adjustments in a broadband stimulus varies from 2 dB for trained listeners with normal hearing  to 4 to In the current study, we measured the JNDs for frequency-band increments to verify REM tolerances and ascertain discriminable step-sizes for adjusting the FGR. We also measured the JNDs for broadband increments, analogous to traditional level discrimination. Participants were either hearing-aid candidates, or users. We presented SSNs, a common test signal for REMs , and empWe additionally examined age and cognitive ability as mediators of discrimination . WorkingIn total, 38 participants  were recruited from local audiology clinics. The median age of participants was 63.5 years, ranging from 37 to 74 years. Participants had varying degrees of hearing loss. Unmasked pure-tone thresholds were measured immediately prior to the experiment . The medThis study was approved by the West of Scotland research ethics service (WoS REC(4) 09/S0704/12). Informed written consent was obtained from all participants prior to the experiment.All stimuli were SSNs with gains independently digitally generated in MATLAB  with a sampling rate of 44.1 kHz and sampling depth of 16 bits. Stimuli were presented monaurally via circumaural headphones  to better (BE4FA) ears at 60 dB SPL prior to the application of gain.L) of 3, 6, 9, or 12 dB in one of six frequency bands, which were the same bands to which the gains were applied. Alternate spectra for the broadband condition were SSNs plus prescribed gains plus a ΔL of 1, 2, 3, or 4 dB applied across all six frequency bands. To generate stimuli, standard and alternate spectra were first multiplied with the complex spectra of independently generated Gaussian noise in the frequency domain, and then converted into the time domain using an inverse Fourier transform.Standard spectra were SSNs plus prescribed gains. The speech spectra were based on averaged male and female speech from 12 languages . Gains wLs. Audibility was subjectively checked with participants after practice trials. The duration of each stimulus was 500 ms (including 20 ms raised cosine onset and offset ramps), separated by silent interstimulus intervals (ISIs) of 375 ms. Presentation level was roved across trials by a randomized amount chosen from a flat distribution of ± 3 dB.Standard stimuli were calibrated  so that the overall A-weighted presentation level was 60 dB SPL prior to the application of gain. Alternate stimuli were calibrated to confirm the ΔThere were four possible stimulus combinations for each trial: two same  and two different . Stimulus combinations were counterbalanced and presented randomly.The experiment was conducted in a single, one-and-a-half–hour session. A screening questionnaire of basic patient details including hearing-aid status was completed, and unmasked pure-tone thresholds were measured. Cognitive ability was estimated after pure-tone audiometry. Following this, participants started the experimental task of discriminating frequency-band and broadband increments in SSNs. Participants were seated in a sound-proof audiometric booth, and stimuli were presented monaurally to their better-hearing ear. Participants completed two blocks of trials with a break between, each lasting approximately 15 to 20 minutes. Twenty practice trials were embedded into the start of each block.A fixed-level, same-different task was utilized. Participants were asked to listen to each presentation and decide “Were the sounds the same or different?” Participants responded by choosing the appropriate button (“same” or “different”) on a touch screen monitor. Visual feedback (“correct” or “incorrect”) was provided following each response.Ls were presented: four ΔLs  for each of the six  frequency-band conditions, and four ΔLs (1–4 dB) for the single broadband condition. Coupled with four stimulus combinations  repeated twice, there were 224 trials , presented in randomized order, per block. Each participant completed two blocks, resulting in 64 trials per psychometric function per participant for each of the seven conditions.Twenty-eight ΔIn a pilot study, we measured increment and decrement JNDs—negative adjustments to the prescription FGR—of 26 participants using a one-up, three-down adaptive, three-interval, 3AFC task. Decrement JNDs were difficult to measure; 21% of the total were excluded because of ceiling effects, poor adaptive tracks , and failed adaptive tracks which terminated without a threshold estimate. While it is possible that this difficulty was influenced by the procedure, previous research has also reported difficulties in measuring decrement discrimination, which is suggested to be poorer than increment discrimination because of coding differences . TherefoVisual letter monitoring (VLM) and visual digit monitoring (VDM) tasks were used to estimate cognitive ability. Both tasks incorporate working memory, attention, reaction time, and continuous performance processes, and have been used previously in auditory research .d’ values. A single d’ score was aggregated across test types and speeds for each participant. Five participants—who were either dyslexic or nonnative English speakers—did not complete the tasks.In the VLM task, single consonants and vowels were presented alternately on a touch screen monitor, and participants identified three-letter consonant–vowel–consonant words. In the VDM task, single digits were presented, and participants identified even–odd–even sequences. Participants completed two runs for each task with ISIs of 1,000 and 2,000 ms, respectively. Participants completed a practice run with a 2,000-ms ISI prior to the formal runs. The task order was randomized across participants, although a 2,000-ms ISI run was always tested first. Correct hits and false alarms were measured and cognitive scores were expressed with d’ values for each ΔL. d’ is a measure of sensitivity approximately linearly associated with signal strength, which increases with hit rate and decreases with false alarm rate , corresponding to 76% correct in a 2AFC task  and broadband (across frequencies) increment JNDs. JNDs were determined by fitting logistic functions to d’ data, with a JND corresponding to the ΔL dB estimated at line fits to d’ = 1. Two types of JNDs were estimated: increment JNDs in six frequency bands , as well for broadband JNDs . We therefore report median JNDs and nonparametric inferential statistical analyses for JND comparisons. Twenty-three JNDs  were excluded because of poor fits resulting in extreme values. These were identified by visualizing fits and assessing their associated root-mean-square error values.The Shapiro–Wilk test  indicated’ = 2, which corresponds to greater sensitivity for discrimination in noisier conditions, both acoustically and experimentally. We assume that JNDs at d’ = 1 measured in noisy conditions would be greater (poorer) than the current JNDs at d’ = 1. Considering this, we additionally report JNDs estimated at a more sensitive d’ = 2, given the greater sensitivity required to discriminate in noisier conditions relative to the sensitivity required to discriminate in optimal conditions. This was done considering the increasing availability of technologies which allow for self-adjustments to highly complex stimuli in highly variable environments . Thirteen JNDs at d’ = 2  were excluded because of poor fits resulting in extreme values.We additionally estimated JNDs as above at ronments . For a fd’ = 1. A LP and 1 kHz JNDs . Because of this difference, the 0.25 kHzLP JND is reported separately from the “frequency-band JND” grouping. Across all participants, all octave bands (0.5–4 kHz) and the 6 kHzHP band, the median JND was 2.8 dB, 95% CI . For the 0.25 kHzLP band, the median JND was 4.5 dB, 95% CI . The median broadband JND was 1.5 dB, 95% CI . Frequency-band JNDs were significantly greater than broadband JNDs .LP band) and broadband JNDs . Frequency-band JNDs were not correlated with each other when adjusting for multiple comparisons . There was only one significant correlation between frequency-band JNDs and pure-tone thresholds at the corresponding frequency when adjusting for correlations between thresholds and age: a positive correlation between participants’ 6-kHz threshold and their 6-kHzHP JND . The 6 kHzHP JNDs increased  with increasing pure-tone threshold. There were no significant correlations between either BE4FA or age and individual JNDs (frequency-band or broadband) when adjusted for the correlation between BE4FA and age . A Wilcoxon rank-sum test revealed no significant differences between hearing-aid users’ and non–hearing-aid users’ median frequency-band and broadband JNDs (p > .05). There was no significant correlation between the proportion of life with a hearing-aid and median frequency-band or broadband JND (p > .05 for both).Pearson correlation coefficients revealed a positive correlation between participants’ median frequency-band , as was BE4FA . We calculated standard coefficients as opposed to partial coefficients as neither age nor BE4FA correlated with JNDs. Frequency-band JNDs were not correlated with cognitive score . Broadband JNDs were negatively correlated with cognitive score . Across 33 participants (median age of 62 ± 8.0 standard deviation years), the average cognitive score was 1.9 out of a total of 3.6. Age was negatively correlated with cognitive score . In this dataset, the 0.5-kHz and 1-kHz JNDs were also significantly different . The remaining JNDs comparisons were not significantly different. Across all participants, the median JND for higher frequency bands (1–4 kHz octave and 6 kHzHP) was 4.8 dB, 95% CI . The median JND for lower frequency bands (0.25 kHzLP and 0.5 kHz octave) was 5.4 dB, 95% CI . The median broadband JND was 2.6 dB, 95% CI . Frequency-band JNDs were significantly greater than broadband JNDs .LP band. We identified a positive correlation between participants’ median frequency-band and broadband JNDs, suggesting some consistency between the discrimination of frequency-band and broadband increments.We measured increment discrimination in six individual frequency-bands of SSNs. Participants had varying degrees of hearing impairment, and stimuli were presented at a baseline of 60 dB SPL plus individually prescribed gains. The frequency-band JND was 2.8 dB, and 4.5 dB for the 0.25 kHzd’ = 0.77), d’ = 1.52), d’ = 2.These results are congruent with previous literature. Using a 2AFC task with a one-up, two-down adaptive procedure , The median broadband JND was 1.5 dB. Presenting stationary SSNs in a 2AFC one-up, three-down adaptive procedure  have reported little difference between level-based discrimination measured with and without compression . In addiThere was a fair amount of variance across participants, similar to previous research examining the detection and discrimination abilities of listeners with hearing-impairment . The vard’ = 1 were mostly independent of centre frequency; the median frequency-band JND was 2.8 dB, and the 0.25 kHzLP JND was 4.5 dB. The broadband JND was 1.5 dB. JNDs were also mostly independent of pure-tone threshold. Although frequency-band JNDs were greater than broadband JNDs, correlations suggest some relationship between frequency-band and broadband discrimination. While frequency-band JNDs were not correlated with cognitive score, broadband JNDs were. JNDs at d’ = 1 suggest initial frequency-band gain adjustments of 3 dB to be noticeable in a quiet clinic. JNDs at d’ = 2 suggest initial frequency-band gain adjustments of 6 dB for frequencies below 1 kHz, and 5 dB for frequencies at and above 1 kHz in noisier environments.We measured frequency-band and broadband JNDs for gain increments in SSNs. Participants had varying degrees of hearing loss and were provided with prescribed amplification. Frequency-band JNDs at


Literature regarding the different degrees of hearing loss in patients with Cornelia de Lange syndrome (CDLS) reports that half of the affected patients exhibit severe to profound sensorineural hearing loss. We present the first pre-school child with CDLS who underwent cochlear implantation for congenital profound sensorineural hearing loss.A 3-year-old boy with CDLS underwent unilateral cochlear implantation for bilateral profound sensorineural hearing loss. He had characteristic facial features, bushy eyebrows and synophrys, limb anomalies, growth and mental retardation. Based on the results of postoperative speech perception and production tests, his gain in language skills and expressive vocabulary was modest. However, a cochlear implantation had a significant effect on auditory development, in terms of making him aware of sound localization and the different types of environmental sound.Criteria for cochlear implantation are expanding and now include children with disabilities in addition to deafness, such as those with CDLS. Profoundly hearing-impaired children affected by borderline mental retardation should be considered as potential candidates for cochlear implantation. Cornelia de Lange syndrome (CDLS), which is characterized by mental retardation and a characteristic appearance, was first described in 1933 by the Dutch pediatrician Cornelia de Lange. The features of this syndrome include low-set hairline front and back, low-set ears, long eyelashes, bushy eyebrows and synophrys (joined eyebrows). Other clinical symptoms are a short upturned nose, thin lips, a crescent-shaped mouth, low birth weight, developmental delay, microcephaly, excessive body hair, small hands and feet, vision abnormalities, seizures, cleft palate, gastrointestinal and heart disorders. The syndrome occurs in approximately 0.5–1 of every 10,000 live births. Most cases are sporadic and result from autosomal dominant mutation in the NIPBL and SMC3 genes , and was considered to have border mental retardation. A computed tomography (CT) scan of the temporal bone showed normal patency of the basal turn on both sides .Three months after his assessment, the child successfully underwent cochlear implantation of the right ear with Med-el Sonata implant. After typical mastoidectomy and posterior tympanotomy, a Med-el standard electrode was totally inserted via cochleostomy. The postoperative period was uneventful. An X-ray confirmed the intracochlear position of the electrode array . No compIn order to measure the child’s auditory-speech perception and speech intelligibility, we used internationally reliable instruments: i) Listening Progress Profile (LiP) to assess his auditory-speech perception; ii) Capacity of Auditory Performance (CAP), which comprised a nonlinear hierarchical scale of auditory receptive abilities, ranging from 0 to 7; and iii) Speech Intelligibility Rating (SIR), a 5-point rating scale that quantifies the speech production abilities of the child . PreoperTwo weeks postoperatively, the LiP score of the child had progressed slightly to 12% and his CAP score had increased from 1 to 2 ; however, his SIR score remained at 1. At his latest follow up, 3 years postoperatively  exhibit severe-to-profound sensorineural hearing loss, cochlear implantation could be considered in this group. The first and only report, by Pulec and Saadat in 1993 . ChildreNevertheless, cochlear implantation combined with auditory training in this the 3-year-old boy with CDLS had a significant effect on the auditory development in terms of making him aware of sound localization and the different types of environmental sound. We believe that by improving the hearing of a child with this syndrome and multiple congenital deficits, we can alleviate his symptoms and enhance the child’s general function; conversely, untreated deafness can increase disproportionately the symptoms of mental retardation, affecting the development of receptive and expressive skills. The speech perception and production improvement in such children should be carefully monitored over the long term, as improvement can be detected after long-term speech therapy.Typical temporal bone CT findings have been described in CDLS, such as external auditory canal stenosis, soft tissue opacification of the tympanomastoid cavity, a relatively large malleus head and incus body, hypoplastic cochlea and dilated vestibule . In the The beneficial effect of cochlear implantation on communication in children with additional disabilities, such as in CDLS, is promising. Even though speech perception and production skills remain below average for the child’s calendar age, cochlear implantation can result in improved audiological and quality of life outcomes. The criteria of cochlear implantation are continually expanding to include even individuals with additional disabilities and borderline mental retardation.


GST) genetic polymorphisms (GSTT1 rs1049055 and GSTM1 rs10712361) and susceptibility to Noise-induced hearing loss.It has been proposed that Noise-induced hearing loss is a complex disease that is combination of environmental and genetic factors. There are inconsistent results concerning the association between variation in glutathione S-transferase (GST gene polymorphism and Noise-induced hearing loss among noise-exposed workers. Methods: In a case-control study, male workers from tile and ceramic factories were selected randomly. Subjects were classified into two groups according to the result of audiometry: 73 subjects showed Noise-induced hearing loss which was considered in the case group and 87 subjects without hearing loss was enrolled in the control group. The GSTT1 and GSTM1 polymorphism of both groups were assessed by multiplex polymerase chain reaction.This study was designed to assess the association between GSTT1 and GSTM1 genotypes were more frequent in case group but no significant statistical difference was seen in case and control groups. No significant link between GSTT1 and GSTM1 genotypes was found.Null GSTT1 and GSTM1 has no effect on susceptibility to noise induced hearing loss.This study suggests that the genetic variability of  Several NIHL susceptibility genes have been suggested, such as, genes encoding for the antioxidant systems, potassium ion channels, heat shock proteins, and the signaling function of the immune system 105/I1e105 might be more susceptible to the effects of noise There are limited and inconsistent results about association between variation in GST genes and susceptibility to NIHL. Rabinowitz et al. showed that among 58 noise-exposed American workers, GSTM1 null individuals had lower amplitudes of high frequency otoacustic emissions compared to individuals possessing the gene. However their finding lacked sufficient power and this may be a spurious finding 2.This case-control study was performed in accordance with the guidelines in the Declaration of Helsinki and with approval from the medical ethics committee of Shahid Sadoughi University of medical sciences, Iran. An informed consent was obtained from all study subjects.2.1.The present study was conducted on male workers from 7 tile and ceramic factories in Yazd, a center province of Iran. Factories which had high stability of the workforce and had periodic noise level measurements were selected by simple random sampling from all tile and ceramic factories in Yazd (n = 30). In each factory subjects who had been employed for at least 3 years and exposed to hazardous noise (≥ 85 dBA) were selected by simple random sampling Those with previous history of acoustic trauma, congenital or familial hearing loss, and ototoxic drug consumption, positive medical history of diabetes mellitus, hypertension, head trauma, head surgery, chronic otitis media, conductive hearing loss in pure-tone audiometry, previous exposure to organic solvents or loud noise in previous or second job or in non-occupational form, and family history of deafness were excluded from the study.A questionnaire including age, duration of employment in current job, smoking and alcohol consumption and medical history was filled for each subject.After usual otoscopic examination, pure-tone audiometry  was performed for the subjects in an acoustic chamber meeting the requirements of the American National Standards Institution (ANSI) 2004 by an expert audiologist (blinded to the study) After considering inclusion and exclusion criteria, according to the result of audiometry, subjects were classified into two groups: from 80 NIHL subjects, 73 individuals with audiograms suggestive NIHL as a case group  and from total 90 subjects, 87 normal hearing individuals enrolled in the study as controls 2.2.Venous blood samples for DNA extraction were also collected in EDTA tubes at the workplace and placed immediately container and then transported on dry ice to the laboratory. This extraction was carried out under sterile conditions and under the laminar hood. DNA extraction from blood was performed using a DNA extraction kit called Bio Flux . The next step was DNA extraction for use in the polymerase chain reaction. The purpose of the multiplex PCR was to amplify the genomic DNA regions containing GSTT1 , and GSTM1  in addition to the B-globin gene as control. At this stage, 15 µl Master Mix 2x  (which itself contains 2mM MgCl2), was made up of a total volume of 30 µl: containing 100 ng of genomic DNA and 12.5 pM each of the forward and reverse GSTT1, GSTM1, and B-globin primers.The PCR reaction was carried out in 3 steps, one cycle of 94 °C for 5 minutes followed by 30 cycles of 94 °C for 1 min, 62 °C for 1 min, and 72 °C for 1 min and the final step was 72 degrees for 5 minutes. The PCR product was run in 2% (w/v) agarose gel and the bands were visualized with UV light.Three bands should be observed: The B-globin band to be observed in all wells is 268 bp, GSTT band is 480 bp and GSTM band is 219 bp. Both GSTM and GSTT bands may exist or have been deleted, creating four different patterns: T+ M+, T+ M−, T− M+ or T− M−.2.3.t-test and Mann-Whitney test were used to compare continuous variables between groups. The frequency of polymorphism was compared between groups by chi-square test and Fisher's exact test and odds ratios with corresponding 95% confidence intervals (95% CI) were calculated with Mantel-Haenszel method. P-value ≤ 0.05 was considered statistically significant.Data was analyzed by SPSS version 18 . One-Sample Kolmogorov-Smirnov test was applied to test normality of study variables. Independent Student's 3.A total of 160 male subjects that comprised 73 individuals with audiograms suggestive NIHL as a case group and 87 normal hearing individuals as a controls participated in this study. Null GSTT1 and null GSTM1 were found in 33 persons (20.6%) and 54 individuals (33.8%) of the study population, respectively. The frequency of null GSTT1 and GSTM1 genotypes and interaction between these genes as well as the comparison of the results among NIHL and control groups are shown on No significant interaction between GSTT1 and GSTM1 genotypes was found  .4The aim of this study was to assess that genetic variability of GSTT1 and GSTM1 is associated with susceptibility to NIHL in Iranian population.It seems that many factors play a role in NIHL including genetic and environmental factors. Subjects who developing NIHL after exposure to noise are often exposed to many other risk factors that interact with each other and/or with genetic factors This study did not detect that the genetic variability of GSTT1 and GSTM1 affect on susceptibility to noise induced hearing loss. There are many controversial studies on association variations in oxidative stress genes and susceptibility to NIHL. Carlsson et al. analyzed genetic polymorphism in the 10% most susceptible and 10% most resistant extremes of 1200 Swedish noise-exposed workers to investigate whether genetic variation is associated with susceptibility to NIHL. In their study no significant differences were found between 103 noise-susceptible and 114 noise-resistant Swedish workers from the point of view of GSTM1 and GSTT1 polymorphism The findings of study on Brazilian subjects  suggest effects of GSTT1 and GSTM1 polymorphism on the risk of NIHL Several studies showed that antioxidant system is activated after noise exposure. It seems that noise exposure levels are important in activation of this system. So, it is possible in studies that did not find association of GST gene and NIHL, like our study, the noise exposure levels to which the majority of study workers have been exposed over the years did not reach the critical level needed to activate the antioxidant system, and therefore differences in their antioxidant systems are unlikely to show up in their findings. However, it is possible that difference exists when subgroups  be evaluated separately Our results showed that the observed frequency of null GSTT1 and null GSTM1 were 20.6% and 33.8%, respectively. The 20.6% frequency of null GSTT1 is on the low end of the range of 19–58% reported in some Asian populations also the 33.8%, frequency of null GST M1 is of the range of 28–63% reported in some Asian populations Our study has several limitations. First of all, it was a cross-sectional study, and may therefore distort the association due to the healthy worker effect, and does not allow demonstration of a causal relationship. Secondly, this study lacks sufficient power due to small sample size. NIHL has complex nature that is influenced by interaction of environmental and genetic factors Due to the impact of ethnic differences on the gene level, the associations can only be valid when they have been replicated in an independent population, therefore, this study was conducted for the first time on the Iranian population.5.We did not detect that the genetic variability of GSTT1 and GSTM1 effect on susceptibility to noise induced hearing loss in Iranian population. Further studies should include workers with different noise exposure patterns. Combination of genes variation with other risk factors should also be analyzed.(1). Noise-induced hearing loss is a complex disease affected by both genetic and environmental factors.(2). Several Noise-induced hearing loss susceptibility genes has been suggested but oxidative stress genes are obvious candidate genes. One of important antioxidant enzymes in the cochlea are glutathione S-transferase (GST).(3). This study investigates the association between GST gene polymorphism and noise induced hearing loss among Iranian noise-exposed workers.(4). Further studies should include different population with different noise exposure patterns such as noise exposure levels, noise exposure times.


Helicobacter pylori association is presented as an illustration of these considerations, followed by a delineation of unresolved questions and avenues for future research.The ubiquity of horizontal gene transfer in the living world, especially among prokaryotes, raises interesting and important scientific questions regarding its effects on the human holobiont i.e., the human and its resident bacterial communities considered together as a unit of selection. Specifically, it would be interesting to determine how particular gene transfer events have influenced holobiont phenotypes in particular ecological niches and, conversely, how specific holobiont phenotypes have influenced gene transfer events. In this synthetic review, we list some notable and recent discoveries of horizontal gene transfer among the prokaryotic component of the human microbiota, and analyze their potential impact on the holobiont from an ecological-evolutionary viewpoint. Finally, the human- Noah and his family were saved -- if that could be called an advantage. I throw in the ‘if’ for the reason that there has never been an intelligent person of the age of sixty who would consent to live his life over again. His or anyone else’s. The Family were saved, yes, but they were not comfortable, for they were full of microbes. Full to the eyebrows; fat with them, obese with them, distended like balloons. It was a disagreeable condition, but it could not be helped, because enough microbes had to be saved to supply the future races of men with desolating diseases, and there were but eight persons on board to serve as hotels for them. The microbes were by far the most important part of the Ark’s cargo, and the part the Creator was most anxious about and most infatuated with. They had to have good nourishment and pleasant accommodations. There were typhoid germs, and cholera germs, and hydrophobia germs, and lockjaw germs, and consumption germs, and black-plague germs, and some hundreds of other aristocrats, specially precious creations, golden bearers of God’s love to man, blessed gifts of the infatuated Father to his children -- all of which had to be sumptuously housed and richly entertained; these were located in the choicest places the interiors of the Family could furnish: in the lungs, in the heart, in the brain, in the kidneys, in the blood, in the guts. In the guts particularly. The great intestine was the favorite resort. There they gathered, by countless billions, and worked, and fed, and squirmed, and sang hymns of praise and thanksgiving; and at night when it was quiet you could hear the soft murmur of it. The large intestine was in effect their heaven. They stuffed it solid; they made it as rigid as a coil of gaspipe. They took pride in this. Their principal hymn made gratified reference to it:"Constipation, O Constipation,The Joyful sound proclaimTill man's remotest entrailShall praise its Maker’s name."– Mark Twain, Letters from the Earth (1909)The human (or other multicellular host) with its symbiotic microbiota is termed the ‘holobiont’—a term coined by Lynn Margulis . The tenHydra vulgaris (Phylum Coelenterata) [H. vulgaris involve host modulation by anti-microbial peptides (AMPs) resulting in the eventual stabilization of the assembled microbial communities over the lifetime of the host [gyrB gene, rather than the more slowly evolving 16S rRNA gene, has uncovered evidence of co-speciation of gut microbiota within hominid lineages—humans, chimpanzees, gorillas and bonobos. Specific clades of Bacteroidaceae and Bifidobacteriaceae identified by gyrB sequences have been maintained within these four hominid lineages over the order of ~ 105 generations [In the evolutionary context, natural selection acts directly on phenotypes and only indirectly on genotypes . Selectinterata) . The fluthe host . Recent erations . HoweverAlgoriphagus machipongonensis can induce the formation of a ‘multicellular’ rosette, an aggregate of individual cells, in the free-living, unicellular choanoflagellate Salpingoeca rosetta [In trying to understand how these assemblages developed, diversified and persisted over evolutionary time, we face a problem that Darwin faced in his own time: The paucity, or perhaps our own lack of recognition, of ‘transitional forms’ that could provide us a window into evolutionary innovations and ecological conditions that resulted in the relatively stable holobionts of today. In this context, we highlight the unprecedented observation that a sulfonolipid termed ‘rosette-inducing factor’ (RIF-1) produced by the aquatic bacterium  rosetta . This ob rosetta . Given t rosetta , 37, it Pseudomonas syringae, gene gain by HGT had occurred at a rate equivalent to 20% of the rate of point mutation [Horizontal gene transfer  among prokaryotes accelerates phenotypic diversification by enabling the exchange and acquisition of genetic material , thereby bypassing the need for repeated evolution and retention of genes through vertical  transmission , 39. Invmutation . Studiesmutation –56. HGT mutation . At the mutation  identifimutation  analyzedHelicobacter pylori with humans are re-evaluated within the holobiontic framework. However, we do not discuss general aspects of HGT within the microbiota, HGT between the host and the microbiota or between eukaryotic and prokaryotic microbiota within the human host [In this synthetic review, we recount some notable discoveries and analyses of HGT within the prokaryotic component of the human microbiota that are potentially relevant to the holobiontic context. Though both prokaryotes and eukaryotes constitute the human microbiota, this article focuses on the prokaryotic component that is far better studied, significantly more numerous  and possman host ). Finallman host –64. The man host .One line of future inquiry that would add weight to the holobiont view would be to determine how the host or the microbiota (or particular members thereof) influence the rate tempo of prokaE. coli (Ec77 and Ec56) found that conjugation efficiency (8.46 × 10−5 transconjugants/donor) decreased by a little less than twofold (4.51 × 10−5transconjugants/donor) when the E. coli strains were co-cultured with a human colorectal adenocarcinoma cell line (Caco-2), as compared to controls [Evidence for specific host effectors influencing microbial HGT is so far scanty, but there are tantalizing glimpses of possible effectors and mechanisms. A cell culture-based study of conjugation efficiency between two clinical isolates of controls . More inE. coli HB101 transformation (a frequency of 1 × 10−7/cfu) with plasmid pBR322 DNA in the absence of calcium chloride [The resident microbiota are under constant selection by host innate immune system that produces cationic anti-microbial peptides (CAMP) or cationic host defense peptides  that are capable of destabilizing bacterial membranes –71. We schloride . HoweverSalmonella enterica serovar Typhimurium (STm), it resulted in an increase in the abundance of resident E. coli (mostly phylogenetic group ECOR B2) amounting to > 80% of the total intestinal bacteria. This promoted conjugal transfer of plasmid 2 (p2) from STm to E. coli at very high efficiencies. Thus, the apparent influence of inflammation on HGT may be coincidental, in that inflammation-associated dysbiosis in the microbiota could fortuitously lead to greater opportunities for HGT for a subset of microbes that proliferate in large numbers.Some data in the literature suggest that inflammation of host tissues could influence prokaryotic HGT. A study by Stecher et al. highlights a connection between inflammation and HGT among Enterobacteriaceae in the mammalian (murine) gut . The autPseudomonas aeruginosa, usually a harmless commensal of humans, produces a matrix containing extracellular DNA (eDNA) during growth in biofilms. eDNA has been found to induce human neutrophils in vitro to produce pro-inflammatory cytokines (IL-8 and IL-1β) [Salmonella enterica serovar Typhimurium and E. coli, Peterson et al. demonstrated a threefold increased efficiency of transfer (~ 1.5 × 10−6 versus ~ 5 × 10−7 transconjugants/donor) of a conjugative plasmid from the former to the latter in vitro at physiologically relevant concentrations of norepinephrine (5 μM).It is interesting to note that the opportunistic pathogen d IL-1β) . A studyd IL-1β) . These fd IL-1β) ). So fard IL-1β) . Workingdownregulating the inflammatory response [Another mechanism potentially coupling host inflammation to HGT among the microbiota could be via the production of CHDPs as a result of infection-induced inflammation . CHDPs response , while tSalmonella enterica serovar Typhimurium-induced inflammation indicates that inflammation caused by pathogens can promote HGT among different Salmonella strains via activation of prophages. Prophage activation results from the triggering of the bacterial SOS response in response to the DNA damage caused by free radicals released by host immune cells (e.g. neutrophils) during inflammation [Streptococcus pneumoniae lacks the LexA repressor and the SOS response. Instead, its response to DNA-damaging agents such as mitomycin C and fluoroquinolones includes the induction of competence [S. pneumoniae but also among members of the resident microbiota. However, it is salutary to note that the relation between HGT and the SOS response/DNA damage is also species-dependent. For example, in Streptococcus thermophilus, a lactic acid bacterium used in the dairy industry, the SOS response antagonizes rather than promotes the development of competence [Recent work on ammation . As freempetence . It is tmpetence .P. aeruginosa (discussed above) could play the role of a keystone pathogen in terms of inducing inflammation that might, in turn, modulate HGT within the microbial community.Thus, the inflammatory state that influences HGT between members of the microbiota may be a consequence of pro-inflammatory states induced in the host by a component(s) of the microbiota itself. Stated differently, the induction (or suppression) of the host inflammatory response potentially couples microbial HGT to interactions between the constituents of the holobiont. This leads to an interesting question of what comes first: Does inflammation lead to dysbiosis or does dysbiosis promote inflammation? More importantly, how resilient is the holobiont to such states, and how and when is the ‘tipping point’ reached? Can perturbations arise due to random drift, as well as during long-term environmental and physiological alterations e.g. change in diet or exercise respectively? In this context, we point out the ‘keystone pathogen hypothesis’ that suggests that certain pathogens, themselves not very numerous, could exert a disproportionate influence on both dysbiosis and inflammation . The terZobellia galactanivorans) to Bacteroides plebeius within the Japanese gut microbiota [B. plebeius to exploit a reliable resource. A subsequent study indicated that HGT via an integrative and conjugative element (ICE) resulted in the horizontal acquisition by the gut bacteria B. thetaiotaomicron and B. uniformis of a polysaccharide utilization locus (PUL) that enabled these bacteria to utilize agar and carrageenan  [Understandably, the human gut microbiota is subjected to environmental selection based on food sources, especially in omnivorous humans. HGT events under environmental selection can result in the preservation of gene sequences from transiting species, especially if there is a strong and persistent selection pressure . This scenario was spectacularly borne out by the analysis of carbohydrate-active enzyme (CAZyme) genes in the gut microbiota of Japanese individuals. CAZyme genes encoding enzymes specific for marine algal carbohydrates (porphyranases and agarases) had been transferred from a seaweed-dwelling saprotroph  . Interese algae) . Interese algae) , 88. It aga1) in the soil bacterium Paenibacillus sp. SSG-1 that was found to be highly similar to genes found in human oral and gut bacteria—Paenibacillus sp. D14 and Clostridium sp. D5 respectively [aga1 were found in other members of the two genera. The closest match was with the marine bacterium Rhodopirellula sallentina SM41, indicating HGT from a marine bacterium to the human microbiota due to seaweed consumption. As Paenibacillus sp. SSG-1 was isolated from soil at a site distant from a marine environment, Song et al. surmised that this was likely due to spitting or the usage of human waste as fertilizer.In 2016, Song et al. characterized a β-agarase gene  is retained without disruption Fig. . The preStreptococcus mutans, a member of the human dental plaque biofilm, competence development is coupled to the secretion of bacteriocins, to which it is itself immune. Under these conditions, S. mutants was also found to be capable of taking up plasmids released by S. gordonii in co-culture. [S. salivarius couples bacteriocin production to genetic competence [S. salivarius genomes are found to contain multiple ICEs, including those encoding bacteriocins [Vibrio cholerae [The reciprocal relationship between the host and its microbiota highlighted in the preceding section does not preclude evolutionary conflicts between and within the individual members of the microbiota. The members of the microbiota also produce membrane-destabilizing agents that could potentially promote HGT in a manner analogous to CHDPs mentioned earlier. Bacteriocin production by the members of the human microbiota has been inferred by bioinformatics analyses –94 and aculture. . Likewismpetence . S. salieriocins . Thus, teriocins . Organischolerae . All thecholerae . This ischolerae .Prokaryotes encode a variety of mobile genetic elements, collectively termed the mobilome, that participate in HGT. Additionally, bacteriophages  are also significant contributors to HGT within the prokaryotic component of the human microbiota . The moAggregatibacter actinomycetemcomitans links CRISPR-Cas to bacterial transformability [cas genes compared to competent strains. Accordingly, Jorth and Whiteley suggest that rapidly changing environments would favor dynamic genomes and, therefore, competent strains, whereas stable environments would favor non-competent strains. This also means that non-competent strains that lack functional cas genes are vulnerable to phage infections, which could again select for competent strains. While being careful to avoid teleology, we observe that one barrier to HGT (non-competence) has concomitantly compromised another barrier that could enable HGT through phage-mediated transduction. It would be of interest to determine whether similar mechanisms that affect competence in concert with enhancing or suppressing barriers to HGT are operative among the members of the resident human microbiota.Specific prokaryotic barriers to HGT are of two major types: the CRISPR-Cas and restriction-modification (R-M) systems. The CRISPR-Cas system in bacteria and archaea is analogous to an adaptive immune system in that it can prevent future productive infections by phages that have been encountered earlier. An interesting observation by Jorth and Whiteley (2012) in the case of the human periodontal pathogen mability . The bacRestriction-modification (R-M) systems are ubiquitous in both Bacteria and Archaea, as borne out by the continuously expanding database of restriction enzymes . The preHelicobacter pylori, an ancient [H. pylori carriers are asymptomatic. Infected individuals present with varying degrees of gastric inflammation, and a progressively decreasing minority of hosts develop peptic/duodenal ulcers or gastric cancer or lymphoma of mucosa-associated lymphoid tissue.Our view of host-microbe interactions has historically evolved in the background of what has been termed a ‘dualistic framework’ of ‘good’ versus ‘evil’ . Briefly ancient  and a pr ancient , 126 is  ancient ; howeverH. pylori with its human host, the chronicity of its infection and the variable nature of the clinical outcomes for the host indicate that co-evolution of H. pylori and humans is an ongoing process and perhaps reflects a ‘transitional form’ of holobiont evolution alluded to in the introduction. It has been suggested that the view of H. pylori as a human pathogen is due to its discovery in a pathogenic context and that this association may be viewed as the result of a trade-off between costs and benefits for the human holobiont [H. pylori has a protective effect against childhood diarrheal diseases [H. pylori infection enhances the gastric immune response against the cholera vaccine [H. pylori infection is also positively correlated with enhanced protection against tuberculosis [H. pylori infection is offset in evolutionary terms, by the increase in the likelihood of the human host attaining reproductive age [The co-existence of olobiont . Indeed,diseases . Gastric vaccine . H. pylorculosis , 132. Thtive age .H. pylori infection, especially the development of gastric cancer due to chronic inflammation later in life is strongly correlated with the presence of a pathogenicity island (PAI) designated cag (cytotoxin-associated gene) that encodes a type IV secretion system (T4SS) and has probably been acquired by some strains via HGT [cagPAI encodes the oncogenic CagA protein that can be translocated via the T4SS into host cells with which H. pylori comes into close contact. This has the effect of tilting the balance in favor of increased inflammation and gastric cancer risk, but it is not known whether increased and chronic inflammation due to H. pylori infection influences HGT in H. pylori and/or other members of the human microbiota. A subset of H. pylori strains also encodes one or more T4SSs that can transfer DNA to other strains as well as related species like Campylobacter jejuni in vitro [H. pylori inhabiting the stomach and C. jejuni the small intestine—this raises the possibility of HGT between transiting and resident bacterial species, ensuring the dissemination of genes from one ecological niche to another. Rohrer et al. determined that the comB T4SS  was necessary for plasmid uptake in recipient H. pylori cells by both transformation and conjugation [H. pylori strains contain “plasticity zones” harboring transposons that encode, among other elements, the tfs3 [tfs4 [The spectrum of clinical outcomes upon  via HGT , 135. Thin vitro . Given tjugation . The genthe tfs3 , 139 ands3 [tfs4  type IV s3 [tfs4 .H. pylori is naturally competent [https://tinyurl.com/y9pntzw3). It exhibits considerable strain diversity across geographical locations [H. pylori in the role of DNA donor, rather than an acceptor, as was seen with the case of C. jejuni (above). Even among H. pylori strains, we might expect that the success of HGT might depend on the extent of genetic relatedness (i.e. sharing the same R-M complement). Incidentally, the plasmid transfer experiments of Rohrer et al. [H. pylori suggest that the numerous R-M systems are not insuperable barriers to DNA transfer in H. pylori. Bubendorfer et al. (2016) carried out a detailed analysis of inter-strain transfer of genomic DNA fragments and their patterns of integration into the recipient genome via homologous recombination using carefully chosen H. pylori strains in an attempt to address this issue [While ompetent , 142, itocations  and evenocations . Given tr et al.  involvinis issue . Their sThe role of intra-prokaryotic HGT in the overall survival and propagation of the human (and other) holobionts is barely beginning to be understood, not least because of the immense technical, logistic and ethical challenges involved. HGT could potentially ensure the wider dissemination (and preservation) of genes derived from rare or transient/extraneous members of the microbial community and restore functions that would be otherwise compromised as a result of gene/species loss. Moreover, human cultural evolution may also have already impacted HGT in unforeseen methods. The invention of sewage networks that concentrate unprecedented quantities of human and animal waste before eventual disposal (with or without treatment) into water bodies has presented microorganisms with a nutrient-rich environment on a vast scale that was absent for most of human history and may have affected microbial HGT in unknown ways –148. TheThe holobiontic perspective has the signal merit of bringing into sharp focus the value of functional studies of the microbiota as a necessary and informative complement to studies based on 16S rRNA gene-based diversity analysis. Functional information integrated with other available ‘omics’ technology platforms, especially proteomics and metabolomics, could be more informative in identifying interactions that cooperate to produce the holobiont phenotype. Metagenomic sequencing of microbial communities can, in principle, enable identification of HGT events within the population under scrutiny using computational methods. However, a limiting factor in detecting HGT in these communities is our ability to assign a source organism for the short sequence reads typical of metagenomic samples. Recent work assembling genomes entirely from metagenomic data demonstrates that such a reconstruction is indeed possible –154. Micdetecting HGT events post facto, estimating their rate presents additional problems. The mechanisms of HGT and their frequency of occurrence are dependent on the species under consideration as well the environmental conditions (biotic and abiotic) prevailing at a given time. In order to determine changes in rates above a ‘background’ as a result of a particular intervention, it would be necessary to monitor HGT between donors and recipients before and after the said intervention. Clearly, at the present time, such studies can be conducted with individual organisms (depending on our ability to culture them), but not with entire communities. Additionally, quantitative assessments made based on particular species may not be applicable to others. Selection pressures themselves vary in terms of kind, degree and duration, probably resulting in a wide variation of transfer rates throughout the holobiont’s lifetime. The influence of second-order effects i.e., changes that alter HGT rates, is also difficult to quantify across the board for a highly diverse and still insufficiently characterized, dynamic microbial community. For example, it has been discovered that Roseburia hominis, a firmicute symbiont of the human gut, exhibits an upregulation of the transcription of genes related to plasmid mobilization/conjugation 14 days after being administered to germ-free mice [As noted in the first section, some estimates of the extent of HGT in individual microbes as well as microbial communities are available. However, compared to ree mice . Therefosumptuous housing’ for the microbes but also receive significant ecosystem services in return. And more importantly, ‘germs’ causing ‘desolating diseases’ are by no means representative of the salient contributions of a vast number of microbes either. However, precisely because research efforts have focused intensely on ‘germs’ for more than a century, much information is available that could be leveraged to better understand the role of HGT in maintaining holobiont homeostasis. As the case of H. pylori indicates, some of the implications of this information may be underappreciated due to its focus on pathogenesis. Thus, we cannot help but appreciate Mark Twain’s prescience in discerning that the microbes (harmful or not) were indeed ‘the most important part of the Ark’s cargo,’ and affirm that rapidly accumulating knowledge of the many functions of the microbiota in diverse multicellular organisms provides ‘man’s remotest entrail’ with sufficiently weighty reasons ‘to praise its Creator’s name.’Microbiological research has afforded us unparalleled glimpses of the hidden lives led by DNA in prokaryotic communities comprised of billions of individuals, not only in its journey down lines of lineal descent but also across phylogenetic groups. Both microbiology and medicine have come a long way since Mark Twain wrote his corrosive satire quoted in the beginning. It is increasingly clear that humans do not merely provide ‘To reiterate, positive or negative selective pressures can impact the holobiont simultaneously and at multiple levels of complexity. The choice of the holobiont as a unit of selection does not exclude other units of selection at lower levels of complexity—human, microbial, genomic or genetic. In this article, we have purposely highlighted only those instances of HGT modulation that couple the human host and members of the microbiota, thereby supporting the current usage of the term ‘holobiont’ , 160. Un


The percentage of older adults with hearing loss who stop using their hearing aids and the variables associated with this phenomenon have not been systematically investigated in South America. This problem is relevant to the region since countries such as Colombia, Brazil and Chile have public programmes that provide hearing aids to older adults. The aims of this study were to determine the percentage of older adults fitted with a hearing aid at a public hospital in Chile who subsequently stop using it and the auditory and socio-demographic variables associated with the hazard of discontinuing hearing aid use.A group that included 355 older adults who had been fitted with a hearing aid was studied retrospectively. In a structured interview, participants were asked about socio-demographic variables and answered part of the Chilean National Survey on Health, evaluating self-perceived hearing loss and responding to questions about discontinuation of hearing aid use and their satisfaction with the device. Survival models were applied to determine the hazard of stopping hearing aid use in relation to the variables of interest.The rate of discontinuation of hearing aid use reached 21.7%. Older adults stopped using their hearing aids mainly during the first 5–6 months post-fitting, and then this number steadily increased. The income fifth quintile was 2.56 times less likely to stop using the hearing aid compared to the first. Those who self-reported that they could not hear correctly without the hearing aid were 2.62 times less likely to stop using it compared to those who reported normal hearing. The group that was very dissatisfied with the hearing aid was 20.86 times more likely to discontinue use than those who reported satisfaction with the device.Socio-demographic variables such as economic income and auditory factors such as self-perceived hearing loss and satisfaction with the device were significantly associated with the hazard of stopping hearing aid use. Self-perceived hearing loss should be considered part of the candidacy criteria for hearing aids in older adults in Chile and other (developing) countries. It has been reported that between 1 and 40% of older adults from developed countries stop wearing their hearing aids post-fitting  identifiDespite the large number of studies of factors associated with hearing aid use and/or discontinuation of their use in older adults from developed countries –8, very Specifically in Chile, since 2007, adults aged 65 and older who require hearing aids are provided with one device  either for free or with a maximum co-payment of 20% of the device price . The latDespite the fact that the programme that provides hearing aids for older adults in Chile began more than 10 years ago, both the percentage of those who have stopped using them –over the course of time– after the initial fitting and the variables associated with discontinuation are unknown. Although prior studies in South America , 16 haveThe sample was comprised of 355 older adults, hearing aid users aged between 65 and 85 years. All participants were monaurally fitted with a hearing aid at La Florida Public Hospital in Santiago, Chile.The sample size was calculated by determining the effect size based on the data reported by a previous study about discontinuation of hearing aid use in a sample of South Korean adults . The meaIn order to reach statistical power for the multivariate survival analyses, which included several covariates, a larger sample size than the above was required. In this study, we explored the association between discontinuation of hearing aid use and 11 variables: gender, age, education level, income level, own health perception, auditory disability, three factors relating to own perception of hearing level, pure-tone average  in the fitted ear and satisfaction with the hearing aid. Simulation studies have established that for regression models for the analysis of survival data, it is recommended to include one predictor variable per 10 events in the sample –19. TakiThe research protocol was approved prior to the commencement of the study by La Florida Hospital’s Ethics Committee and by the Scientific Ethics Committee of the Pontifical Catholic University of Chile. All participants signed an informed consent form previously cleared by the boards of the aforementioned institutions.La Florida Hospital commenced providing hearing aids to older adults under the government programme in 2015. At the time of this research, 823 older adults had been fitted with a hearing aid for the first time at least one year before the study began and thus were considered prospective participants for this research. The list containing this number of participants with their contact details was provided by the hospital authorities. Prospective participants were initially selected at random and then contacted by telephone with the aim to explain the study and invite them to take part in it. Those who agreed to participate and gave consent for the research team to review their medical files were then preselected. Subsequently, their medical records were accessed to determine the possible presence of either external or middle-ear problems not associated with age-related hearing loss. Participants presenting with such problems were excluded. This is because in the presence of such disorders, the hearing aid fitting procedure has to be adapted accordingly . ParticiThe home visit began with a shortened version of the Mini-Mental State Examination (MMSE) that was previously adapted and validated in Chile . In addiIn total, as far as your income is concerned, how much money do you receive on average in a normal month? The question about self-perceived state of health  had five possible answers in a Likert-type format, ranging from excellent health (1 point) to bad health (5 points).Next, part of the Chilean National Survey on Dependency in Older Adults (ENADEAM in Spanish)  questionIf you use a hearing aid, answer the following questions, thinking about your hearing without wearing a hearing aid. Do you think you hear normally in both ears? Two other questions with a binary response (yes/no) were also asked: Are you capable of watching a television programme at a volume that is acceptable to other people? and Are you capable of following a conversation involving three or more people?Afterwards, a question from the Chilean National Health Survey (ENS)  was usedAuditory disability was evaluated using the Spanish version of the Amsterdam Inventory for Auditory Disability and Handicap (S-AIADH) . This inAuditory thresholds were obtained using information from the older adults’ medical records. Audiologists at the hospital carried out air conduction pure-tone audiometry from 250 to 8000 Hz in a double-wall, sound-proofed booth according to ISO norm 8253–1. The air conduction pure-tone threshold average  of the ear fitted with the hearing aid was calculated.Do you use your hearing aid? The response options – considering use in days per week – included not at all, every day, most days (at least 5 days per week), some days (1–4 days per week) and only occasionally. Among those who selected the ‘not at all’ option, the time that passed before they stopped using the hearing aid was determined by asking the question, When did you stop using the hearing aid? To diminish memory bias, the interviewer referred to important biographical facts  and bank holidays . In addition, a multiple-choice question was included from the questionnaire used by Bertoli et al. ) at the first month of follow-up; 0.85 (95% CI [0.81–0.88]) at 12 months; and 0.73 (95% CI [0.67–0.78]) at 24 months . In the univariate model, a significant association between worse self-reported state of health and discontinuing hearing aid use was observed. However, when controlling for covariates, such an association was no longer significant  were not associated with discontinuing the use of the hearing aid (see Table p = 0.106). The same was true when considering the overall effect of the variable (p = 0.069).Differences were observed according to years of education and when this variable was divided into quintiles Table . HoweverIn the univariate model, the fourth income quintile was significantly different than the other quintiles. Participants in this quintile were 2.50 times less likely to stop using the hearing aid compared to those in the first quintile (lower income). However, in the multivariate model, it was observed that participants in the fifth quintile (higher income) were 2.56 times less likely to discontinue hearing aid use as compared to participants in the first quintile see Fig. .Fig. 3SWald – X2 = 2.57; p = 0.46). When separating the 25th percentile with the greatest difficulties, fewer older adults tended to stop using their hearing aid .No significant association between the hazard of discontinuing hearing aid use and self-reported auditory disability  was significantly associated with discontinued use of the hearing aid  in both the univariate and multivariate models . Participants who indicated that they could hear normally in both ears were 2.6 times more likely to stop using their hearing aid than those who reported that their hearing was not normal. In Fig. The perceived hearing problem (determined using the question 95% CI 1.4–4.78). Do you think you hear normally in both ears?) is positively associated  with auditory disability (S-AIADH). In other words, participants who do not recognise that they have a hearing problem have lesser auditory disability (with a higher score on the S-AIADH for lesser disability). In the case of audiometric thresholds, these are negatively related to scores on the S-AIADH  and to not recognising the hearing problem . The higher the audiometric threshold, the more likely the self-perception of not hearing normally and having a greater auditory disability in daily life are observed.It is notable that not recognising a hearing problem (Participants who reported other hearing problems (i.e. hearing problems in everyday situations in the ENS questionnaire) were not more likely to stop using the hearing aid compared to those who did not self-report hearing problems in daily life . In Fig. Finally, the lower the satisfaction with the hearing aid, the greater the hazard of discontinuing the use of the device  of the older adults attended none or only one of such follow-up sessions. We hypothesise that mobility problems or difficulties travelling to the hospital may be the main reason for participants not attending follow-up sessions. Other possible reasons that may be associated with discontinuing hearing aid use may relate to age-related manual dexterity and sight problems. Also, we hypothesise that participants were not aware that the hearing aid can be replaced free of charge if it does not work properly. This should be addressed in one of the follow-up sessions that participants who experienced a malfunctioning hearing aid probably did not attend.Gianopoulos et al.  in the UThe rate of discontinuation of hearing aid use in this study is higher than that reported in Switzerland (3%) using the same instrument but in a different language . Three aRegarding the time frame when the discontinuation of hearing aid use occurs, the only prior study is from South Korea , where hThe second aim was to determine the effect of self-perceived hearing problems, the audiometric threshold, auditory disability, hearing aid satisfaction and socio-demographic variables on the hazard of discontinuing hearing aid use in Chilean older adults. Differences were detected according to income quintile, with the fifth quintile (with higher income) being almost three times less likely to stop using their hearing aid compared to the first. This is in agreement with some studies carried out in developed countries. In the United States, Garstecki and Erler  observedDespite the fact that 100% of this study sample had hearing loss based on the audiogram, 14.4% reported that they heard normally in both ears without a hearing aid. It was observed that those who were unaware of their hearing problems were almost three times more likely to stop using their hearing aid than those who were. The survival curve of this last group shows that the discontinuation of hearing aid use increases progressively from the time the hearing aid is fitted. Similarly, Garstecki and Erler  found anThe fact that a percentage who did not perceive they had hearing problems received a hearing aid anyway is explained by the way in which the Chilean public healthcare system works. Although the clinical practice guidelines generated by the Chilean Ministry of Health recommend using the Shortened Hearing Handicap Inventory for the Elderly questionnaire (HHIE-S) as well as pure-tone audiometry, in practice only the pure-tone average criterion is used . Therefore, an older adult who presents with bilateral moderate hearing loss, no matter what he or she self-reports, is still fitted with a hearing aid. Stephens et al.  recommenp < 0.001) than the score obtained by the S-AIADH validation study . Given that a higher score in this instrument means less disability, this sample involves fewer people with hearing disabilities than those in the validation report. In this study, an association between auditory disability in daily life and satisfaction with the hearing aid was observed. Participants with lower self-perceived auditory disability seemed less satisfied with their hearing aids. This agrees with prior studies conducted in developed countries that found the greater the auditory difficulties, the greater the use of and satisfaction achieved with the hearing aid [The average score on the S-AIADH was significantly higher . In addition, due to the fact that some prospective candidates refused to take part in the study (n = 35) and that the sample included only participants aged between 65 and 85 fitted with a hearing aid at a specific clinic, extrapolating the results for the total population of older adults who are fitted with hearing aids in the Chilean public healthcare system may not be adequate. However, the sample of older adults investigated in this research comes from a community of older adults who live in a district (i.e. La Florida) of the city of Santiago that has similar characteristics to the general older Chilean elderly population. For example, 90% of older adults in this district are users of the public healthcare system. This percentage is similar to the overall population of older adults in Chile who utilise this system. In addition, information about only gender and age for older adults who did not choose to participate in the study and participants who were excluded due to the exclusion criteria was available. It should be noted that these variables were not associated with discontinuation of hearing aid use in this study. Therefore, this lack of information did not allow us to compare the variables associated with discontinued use between included and excluded participants. A posteriori analysis of the sensitivity of the estimations was not possible for the same reason.Another limitation is that satisfaction was measured using a unique question. Although there are questionnaires for this (the Satisfaction with Amplification in Daily Life, or SALD , for exaThe levels of discontinuation of hearing aid use reached 21.7% in a maximum of 30 months of retrospective follow-up. The greatest number of people who stopped using the hearing aid did so in the first 5–6 months, with the effect becoming more gradual after that. Socio-demographic variables such as economic income, self-perceived hearing loss and satisfaction with the hearing aid were significantly associated with discontinued use of the device. Self-perception of hearing loss should be considered when choosing candidates for free programmes providing hearing aids for older adults in South America.


The number of older adults with vision and/or hearing loss is growing world-wide, including in China, whose population is aging rapidly. Sensory loss impacts on older people's ability to participate in their communities and their quality of life. This study investigates the prevalence of vision loss, hearing loss, and dual sensory loss (combined vision and hearing loss) in an older adult Chinese population and describes the relationships between these sensory losses and demographic factors, use of glasses and hearing aids, unmet needs, and impacts on social participation. The China Health and Retirement Longitudinal Study is a population-based longitudinal survey conducted since 2011. The 2013 dataset for people aged 60 and over was used in this study. Items analyzed included demographic data , self-reported ratings of vision , hearing (excellent-poor hearing and the use of hearing aids), dual sensory loss (both poor/fair vision and hearing), and social participation. Of the sample, 80.2% reported poor/fair vision, 64.9% reported poor/fair hearing, and 57.2% had poor/fair vision and hearing. Few respondents (10%) wore glasses regularly and 20.1% wore glasses from time to time. Only 0.8% of respondents wore hearing aids although the proportion with hearing loss was high (64.9%). The proportion of unmet needs for glasses and hearing aids was 54.9 and 63.9%, respectively. Low socio-economic status (SES), poor education, and rurality were significantly associated with the prevalence of poor/fair vision and hearing, the use of glasses and hearing aids and the unmet needs of glasses/hearing aids. Poor/fair vision and/or hearing, and the unmet needs for glasses/hearing aids were significantly and negatively associated with social participation. Sensory loss is a significant health issue for older Chinese people that impacts on their social participation. Training primary care health professionals in identification and rehabilitation approaches is needed as well as increasing the numbers of vision and hearing specialists working in the field. Providing information on sensory loss and the use of aids to older adults will also help improve older adult's quality of life. As adults age, they experience a range of physical changes, including changes in vision and hearing acuity. According to the WHO , 253 milIn China, few population–based studies have explored the prevalence and impact of the co-occurrence of vision and hearing loss, known as Dual Sensory Loss (DSL). Dual Sensory Loss (DSL) is defined as “the acquired loss, in various degrees of severity of both vision and hearing acuity, associated with aging and prevalent in older adults”  (p. 1). Population-based studies of vision loss in China have shown the extent of the problem especially in older age groups. Zhao et al.  analyzedHearing impairment is also a prevalent condition in China that increases with age. A 1998 study conducted in Shanghai, China found that out of 2,044 people aged 65–74 years, 486 people (23.8%) rated their hearing as poor, whilst out of 1,050 people aged 75 years and over, 415 people (39.5%) rated their hearing as poor  used earPrevalence estimates of DSL  vary greLimited prevalence data is available on DSL in the Chinese population. In a study of 2,003 older residents (aged 60 years and over) in Hong Kong, Chou and Chi  found thSensory loss impacts on older peoples' abilities to communicate and participate in society and can contribute to decreased productivity and quality of life , 18.Communication difficulty is significantly impacted by sensory loss and consequently often leads to decreased social interaction and participation. In particular, people with vision loss have difficulty perceiving visual cues such as visual detail, distance perception, illumination and facial acuity of the communication partner . People Visual aids are not always helpful for people with severe vision loss and many older adults with hearing loss or DSL do not successfully use amplification or other assistive listening devices successfully to improve their hearing . In ChinSensory loss in older people in China is thus a major chronic health issue that has the potential to impact on the social participation and the quality of life of older Chinese. The availability and use of sensory aids are important components in assisting older people with sensory loss to function at their full potential.There are few population-based studies that examine in detail vision, hearing and dual sensory loss in China. The China Health and Retirement Longitudinal Study (CHARLS) used in this study is a national representative population-based longitudinal survey of people aged 45 years and over, that includes a number of items on sensory loss and aid use as well as social participation.The aims of this study are to:estimate the prevalence of self-rated vision and hearing and DSL in the older adult cohort (60 years and over) of the CHARLS study;evaluate the relationship between the prevalence and severity of self-reported sensory loss and age, gender, socioeconomic status, and rurality;evaluate the relationship between the prevalence of self-reported sensory losses and the uptake of visual aids (glasses) and auditory aids (hearing aids) to assess unmet needs; and,evaluate the relationship between self-reported sensory loss, visual aids (glasses) and auditory aids (hearing aids) use and social participation.The CHARLS is the first nationally representative and longitudinal survey of people aged 45 years or above on aging and health in China. It was designed by following the protocols of the Health and Retirement Survey (HRS) in the US and conducted by the China Center for Economic Research at Peking University . Face-toIn the first wave of CHARLS in 2011, 17,596 respondents aged 45 years and over were surveyed. In the second wave in 2013, the sample size increased to a total of 18,246 respondents, in which 14,988 were from Wave 1.n = 8,268). There are some missing data or non-response for each of our study variables. For instance, 7,401 have reported information on vision capacity, 7,396 on vision capacity for long distance, 7,398 on near vision capacity, 8,193 on wearing glasses or not, 7,430 on using hearing aid or not, and 7,431 on social activities.For our investigation of hearing and vision loss, which are most prevalent in older people, we only included older adults (those aged 60 years and over) in the analyses  (relative living standard and quintile of household expenditure) were calculated followed by Spearman correlations between the prevalence rates of vision and hearing status, unmet needs and social participation. Finally, a multivariate regression analysis was performed to examine the conditional associations of poor/fair vision/hearing, DSL and the unmet needs for glasses or hearing aids with social participation by controlling for age group and gender. The ordered logit model was run for the number of types of social activities, while the logit model was run for whether respondents participated in any, leisure, helping others or learning social activities. The multivariate regression models used in this study are simple without controlling for other important factors, such as disability, deafness, blindness, or psychological problems. However, the modeling approach serves the broad purpose of the paper to investigate the conditional associations between social participation, vision/hearing loss, and the use of sensory aids.The statistical software we have used for the analysis is STATA/SE 15.1. Individual weights denoting the inverse of the probability that the observation are included because the sampling design with household and individual non-response adjustments, are used for our analysis.In CHARLS 2013, there are three questions asking respondents about their vision: (1) Do you usually wear glasses or corrective lenses ? (2) How good is your vision for seeing things at a distance, like recognizing a friend from across the street ? (3) How good is your near vision, like reading ordinary newspaper print ? The two questions for hearing are, “Do you ever wear a hearing aid (1 = yes or 2 = no)?” “Is your hearing excellent, very good, good, fair, poor, or very poor ?”In the current literature, vision/hearing loss has been defined either objectively passing certain thresholds in medical examination/testing, e.g., Kuang et al.  or subjeBased on these responses, we created five different variables to measure vision or hearing loss: (1) having poor/fair vision (for either long distance or near vision); (2) having poor/fair vision for long distance; (3) having poor/fair near vision; (4) having poor/fair hearing; (5) dual sensory loss (having poor/fair vision and hearing). In addition, we included self-reported blindness.Since wearing glasses or using hearing aids could be influenced by both affordability and services needs, a variable was derived to measure the unmet needs for glasses and for hearing aid/s use as follows: (1) Unmet needs for glasses = a vision loss was reported but glasses were not used; (2) unmet needs for hearing aid/s = if a hearing loss was reported but hearing aid/s were not used. The counterpart of unmet needs includes those without vision/hearing loss who do not need sensory aids, and those with vision/hearing loss who use glasses/hearing aid/s regularly or from time to time.Socioeconomic status (SES) is an economic and sociological combined total measure of a person's work experience and of an individual's or family's economic and social position in relation to others, based on their income, education, and occupation . There aEducational attainment was categorized into three groups: (1) primary or under schooling; (2) secondary schooling; (3) college or above degrees. The urban and rural areas were defined according to the most recently published statistical standard by the National Bureau of Statistics of China (NBS) , where uTo measure social participation in the CHARLS 2013 dataset, respondents were asked “Have you done any of these activities in the last month (multiple options)? (1) Interacted with friends, (2) Played Ma-jong, played chess, played cards, or went to community club, (3) Provided help to family, friends, or neighbors who do not live with you, and who did not pay you for the help, (4) Went to a sport, social, or other kind of club, (5) Took part in a community-related organization, (6) Done voluntary or charity work, (7) Cared for a sick or disabled adult who does not live with you and who did not pay you for the help, (8) Attended an educational or training course, (9) Stock investment, (10) Used the Internet, (11) Other (12) None of these. Options 1, 2, 4, and 5 are defined as leisure activities, options 3, 6, and 7 as social activities helping others out and options 8, 9, 10, and 11 as learning activities for new knowledge.Five variables were generated to define social activities based on the respondents' responses to this question and are as follows: (1) the number of types of social activities as described above; (2) any of these social activities; (3) any of the leisure activities; (4) any of the activities helping others out; and (5) any learning activities for new knowledge.Table In the 2013 CHARLS sample, there were 8,268 respondents aged 60 years and over, of which, 49.5% were men whilst 50.5% were women. More specifically, there were 32.4% of respondents aged 60–64 years, 26.6% of respondents aged 64–69 years, 18.6% of respondents aged 70–74 years, and 22.4% of respondents aged 75 years and over. Sixty percent of respondents were from rural areas whilst 40.0% were from urban areas.The educational attainment was very low in this sample. Of all the respondents aged 60 years and over, only 1.9% had a college or above degree, 40.4% had secondary schooling, and 57.7% had primary or under primary schooling. About 3.1% of all respondents reported having a better living standard than the average in their cities or counties, 20.3% reported about the same and 50.2% reported a worse living standard than the average in their cities or counties. About 26.1% of respondents were located in the lowest quintile of household expenditure, while 14.4% were in the highest quintile of household expenditure .Amongst all respondents aged 60 years and over, the following information was evident: (1) 81.0% reported poor or fair vision capacity for either long or near distance, <1% of respondents across the age groups reported blindness, 65.6% reported poor or fair hearing capacity, and 58.3% reported Dual Sensory Loss (DSL); (2) 19.0% of respondents reported good vision with no need for glasses, 26.2% wore glasses and 54.82% reported having no glasses even though they reported poor or fair vision; (3) 34.5% of respondents reported good hearing without the need for hearing aids, very few respondents (0.6%) used hearing aids and 65.0% of respondents reported having a hearing loss, yet did not use hearing aids.Of the 7,431 respondents (89.9% of the full sample) who reported information about their social activities, 54.4% of respondents reported having any social activities in last month, 50.2% reported participating in leisure activities, 10.8% reported helping others and 3.3% participated in learning activities.The prevalence rates of self-reported vision loss, hearing loss and DSL, the use of aids (glasses and hearing aid/s), and social participation were obtained and analyzed by age, gender, education, urban/rural residence, and SES .Table Men in the 70–74 year age range consistently had the highest prevalence of self-rated poor/fair short or long vision, poor/fair hearing and DSL although the respondents 75 years and over were the highest group to regularly use glasses or wear hearing aids. The pattern for women is different. Women in the 60–64 age group reported the highest prevalence of short or long poor/fair vision while women in the 70–74 age group reported the highest prevalence of wearing glasses regularly. For women, the 75 years and over age group reported the highest prevalence of poor/fair hearing and DSL. The youngest age group (those 60–64 years) had the highest prevalence for wearing hearing aids.In summary the prevalence rates for short or long poor/fair vision, poor/fair hearing, and DSL are high in this older sample. However, it should be noted that the prevalence range across the age groups is small. Overall, in comparison to the prevalence of poor/fair vision, poor/fair hearing and DSL, only a small proportion used glasses (10.0% regularly and 20.1% from time to time) or wore hearing aid/s (0.8%). Glasses and hearing aid use were much lower than the proportion of respondent's reporting poor/fair vision (80.2%) or poor/fair hearing (64.9%) demonstrating an unmet need.Table Distribution Table  and SpeaThe Spearman correlations shown in Table Since vision and hearing capacities were strongly correlated with age, multivariate binominal logit or ordered logit models were conducted to examine the conditional associations between DSL and social activities by controlling for age group, gender, poor/fair vision/hearing, DSL, and the unmet needs for glasses or hearing aids into the regression models. The regression results are presented in Table From Table R-square value within 0.2 to 0.4 represents excellent fit. The Pseudo R-square in our final model is 0.01–0.04, less than the level of excellent fit, but we argue that it serves our purpose to investigate the conditional associations between social participation, vision/hearing loss, and the use of sensory aids. The low level of model fit could due to other factors, which are not included in this study, but have influence on later life social participation, such as severe disabilities and health conditions , which were beyond the scope of this study.It must be noted however that the sample size of people wearing hearing aids was very small in this survey hence its related results need to be treated cautiously. In general, a Pseudo Results of the current study are that self-assessed sensory loss  are highly prevalent conditions experienced by older adults in China. Vision loss was more prevalent (80.2%) than hearing loss (64.9%) and DSL was experienced by over half of the cohort (57.2%).The prevalence rates of sensory loss in the present study are higher in comparison to the prevalence of vision and hearing loss in older people in Western countries. For example, in Australia, the prevalence of vision loss in Australia ranges from 4.37 to 46.15%  for indiOther population-based studies of vision and hearing loss in China found similar results to the present study. Based on 4 datasets collected in 2012 , Bai et al.  found a According to a survey of 6,984 older adults, Gong et al.  found thThis differences in the prevalence of vision loss, hearing, and DSL between the current study to those conducted in Western countries is not surprising since there are country disparities in the general health status of populations, exposures to environmental and occupational hazards, identification of sensory loss , access to healthcare and service delivery design for those with sensory losses. The Global Aging Watch Index  indicateComparison between the Household, Income, and Labor Dynamics in Australia (HILDA) Survey  and CHARGender differences for the prevalence of poor/fair vision and hearing impairment in this study were evident but not large. Whilst there were slightly more women reporting vision loss than men, the opposite occurred for hearing loss. This is consistent with previous research that supports these gender differences. According to Courtright and Lewallen , more woEducation, financial security and rurality impacted negatively on self-reported vision and hearing. Those people with less education or who lived rurally or had a poorer living standard or earned less, had a higher prevalence of self-reported poor/fair vision or hearing. This is not surprising since it is common for people who have financial constraints or live rurally to have less access to healthcare  as well as experience poorer health outcomes compared to their metropolitan counterparts . There iThere was a low uptake of glasses and hearing aids in this study although self-reported poor/fair vision were in comparison, large. This is not surprising and has been confirmed in previous research. According to Kuang et al. , in ChinIn the current study, although the prevalence of hearing loss was large, the use of hearing aids was small, leading to a high rate of unmet needs. This was especially so for those with low education, poorer SES and in those who lived rurally. Again, this is not surprising since in China, there is overall a smaller than expected uptake of hearing aids or assistive devices. In a review of the literature, Ji et al.  reportedSocial participation is particularly important for general health and well-being and older people are encouraged to participate in social activities even if they have health difficulties . Social In this paper we have provided strong evidence that the prevalence of sensory loss is a significant health issue for older Chinese that impacts on their ability to engage in social and work activities. However, unmet needs for sensory aids are high in China.Regular vision and hearing screening for older Chinese is recommended and increasing the uptake of sensory aids is an important goal to reduce disability in those with sensory loss. The health system in China predominantly relies on doctors and nurses to deliver health care, mainly in tertiary hospital settings . The 20. While tThe availability of audiologists or doctors and nurses with audiology training is low in China and thus identification of hearing loss and access to audiological services is uncommon especially for older people with low financial resources. To increase the use of sensory aids in older people with sensory loss, reduced financial barriers to both screening and the cost of aids is needed.We recommend that further training in sensory loss and rehabilitation be made available to primary care health professionals, particularly those who have high older patient caseloads. There is also a need for the training of hearing specialists in hearing care. Some multinational private hearing care companies are now setting up hearing training centers in China but public facilities are limited . FinallyCHARLS is an excellent longitudinal survey on China's health but our findings should be interpreted with some caution as there are limitations which should be noted. Firstly, we have only examined the cross-sectional associations between sensory loss and social participation without aiming to understand the underlying causality. Secondly, CHARLS is a representative community sample in urban and rural areas but it does not cover the ~1% older people living in an institution. Thirdly, CHARLS uses self-reported measures of sensory loss which has great ecological validity and reflective of sensory disability, yet might be subject to reporting bias and prone to cultural difference in conceptualisations of sensory loss, thus potentially limiting comparisons of our findings with similar studies in western developed countries. Future research could further explore the casual relationships between DSL and social participation and well-being using longitudinal data when more waves of CHARLS survey data become available.The original CHARLS survey data was approved by the Ethical Review Committee of Peking University, and all participants signed informed consent at the time of participation. There is no need for ethics approval for second hand data users.CH and CB conceptualized the paper. CG conducted all the statistical analyses. CH drafted the paper and CG and CB revised the paper. All authors have final approval of the published article and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.