It has been proposed that hearing loss may result in improved visuospatial abilities. The evidence for this assertion is inconsistent, and limited to studies in congenitally deaf children, despite older adults with age-related hearing loss constituting the vast majority of the hearing impaired population. We assessed visuospatial  ability in older adult hearing aid users with and without clinically significant cognitive impairment. The primary aim of the study was to determine the effect of hearing loss on visuospatial abilities.Seventy-five adult hearing aid users (HA) aged over 65 were recruited, out of whom 30 had normal cognition (NC-HA), 30 had mild cognitive impairment (MCI-HA), and 15 had dementia (D-HA). The Rey Osterrieth Complex figure test (ROCFT) copy, 3 min recall and 30 min recall tests were performed to evaluate the visuoconstructional and visuospatial memory abilities of the participants.p < 0.005). Compared with previously published normative data, the NC-HA performed significantly better in the ROCFT copy (p < 0.001), immediate recall (p < 0.001), and delay recall (p = 0.001), while the MCI-HA performed similarly to the expected norms derived from population , and the D-HA performed below this norm.There were significant differences between the ROCFT copy, 3 min recall, and 30 min recall among the three cohorts (Though visuospatial abilities tend to decline when the global cognitive functioning declines, we found suggestive evidence for positive effects of age-related hearing loss on visuospatial cognitive ability. Participants with mild cognitive impairment and hearing loss, who would have been expected to perform worse than normative data, were in fact performing as well as cognitively healthy subjects without hearing loss. Visuospatial ability could be targeted when providing rehabilitation for the older adults with hearing loss. Hearing impairment especially age-related hearing impairment was found to be associated with many health conditions such as physical and cognitive frailty , mild coThe most concerning health consequences of hearing impairment would be cognitive decline. It has been suggested that hearing impairment can cause cognitive deterioration through various pathways such as auditory deprivation, through depression and social isolation . HoweverThe visuospatial ability of the hearing-impaired population has been studied extensively due to a belief that this population had better visuospatial ability as a compensatory mechanism for their hearing loss. For a congenital profoundly deaf population, who may rely on sign language and lipreading, visual vigilance is needed . StudiesThe majority of hearing impairment among older adults is not congenital but results from age-related hearing loss that affects up to 1 in 3 of older adults age over 65 . There iWe assessed visuospatial  ability on older adult hearing aid users with and without clinically significant cognitive impairment. The primary aim of the study was to determine whether older people with hearing impairment with and without global cognitive impairment may perform differently than would be expected from normative data.We recruited a convenience sample of seventy-five adult hearing aid users (HA) aged over 65, out of whom 30 had normal cognition (NC-HA), 30 had mild cognitive impairment (MCI-HA), and 15 had dementia (D-HA).The NC-HI were recruited via recruitment flyers and posters distributed in the hearing aid center at the Royal National Throat, Nose and Ear Hospital (RNTNEH), London, United Kingdom. To ensure normal cognition, only those with a General Practitioner’s Assessment of Cognition GPCOG;  score = The MCI-HI and the D-HI were recruited via clinician referral and research registry in the memory clinics at Camden and Islington NHS Foundation Trust, London, United Kingdom. The diagnosis were made according to ICD-10 diagnostic criteria. Inclusion criteria in addition to their cognitive diagnosis were audiogram pure-tone average in the speech frequency range  of 30 dB HL or more in the better hearing ear.Rey Osterrieth Complex figure test is a standard neuropsychological assessment commonly used to assess visuoconstructive and visual recall abilities . The insThe ROCFT can be divided into two subtasks, which are the ROCFT copy and ROCFT recall tests.This test evaluates the visuoconstructive cognitive ability to copy an abstract figure as accurately as possible within a time limit . The tesThis test evaluates episodic non-verbal visual memory by recalling the complex figure previously copied as described above . The parThe recall had two stages. After 3 min from the ROCFT copy, the participant was asked to draw the figure again. The researcher took away the drawing and continued to have a conversation with the participant about their hearing problems. At 30 min, the participant was asked to draw the figure again from memory.Montreal Cognitive Assessment is a commonly used cognitive screening test in general clinical settings. Previous research has shown that using MoCA among the hearing impaired population may result in lower score by up to −1.66 points . This maTherefore, we opted for the visually based MoCA to accurately assess the cognitive abilities of the hearing impaired participants. The detailed description of the test instruction and materials can be found in our previously published paper .The Rey Osterrieth Complex figure test (ROCFT) copy, 3 min recall and 30 min recall tests were performed to evaluate the participants’ visuoconstructional and visuospatial memory abilities. The total performance scores of each test were calculated. Due to the floor and ceiling effects of the performance scores in selected cohorts, the data did not conform with normal distribution. Therefore, non-parametric statistical analysis was used. The comparison of total performance scores for each cohort was done with independent-samples Kruskal–Wallis test.t-test.The scores were also compared to the norms for these tests, obtained from samples with normal cognition and hearing previously published for different age groups . The comThe baseline characteristic of the three cohorts was shown in p < 0.005). For the ROCFT copy, the NC-HA scored 35.33 (SD = 0.24), the MCI-HA scored 31.01 (SD = 1.35), the D-HA scored 20.89 (SD = 3.24) as demonstrated in There were significant differences between the ROCFT copy, 3 min recall, and 30 min recall among the three cohorts , the MCI-HA scored 12.22 (SD = 1.09), the D-HA scored 3.50 (SD = 1.14) as demonstrated in For the ROCFT 30 min recall; the NC-HA scored 19.63 (SD = 0.95), the MCI-HA scored 11.91 (SD = 1.07), the D-HA scored 3.46 (SD = 1.16) as demonstrated in t-test showed the NC-HA performed significantly better in the ROCFT copy (p < 0.001), immediate recall (p < 0.001), and delay recall (p = 0.001), while the MCI-HA performed similarly to the expected norms derived from the population , and the D-HA performed significantly below this norm as illustrated in The previously published age-appropriate normative data  were alspulation  (p = 0.4We found that cognitively healthy participants with hearing loss had significantly better visuospatial performance than expected relative to normative data from people without hearing impairment. Participants with mild cognitive impairment and hearing loss, who would have been expected to perform worse than normative data, appeared to be performing at a similar level to cognitively healthy subjects without hearing loss. Our findings suggest that age-related hearing loss/hearing aid wearers may result in improved visuospatial abilities.However, the suggestion that visuospatial abilities outperform the global cognitive functioning is highly dependent on whether the normative data are applicable for the tested persons. Therefore, we selected the age matched published data set for this comparison. However, ideally like in many other studies on cognitive functioning, we should have built a data set of control participants within our own research and environment setting. This would be the most suitable way to clearly demonstrate the intended results.The ability to copy a complex pattern such as the ROCFT reflects the participants executive functions especially planning and organizing  and visuSince we targeted hearing aid wearers, this improved visuospatial may also be a result of hearing aid use. Previous UK Biobank research showed that hearing aid acted as a protective factor against visuospatial working memory error despite decreasing overall working memory of the hearing-impaired population .For the MCI-HI, the ROCFT copy ability, though decreased from the N-HI, still performed comparably to the norms. Although memory is the first function affected in most individuals with a MCI diagnosis, their executive functions are also commonly impaired . Still, Several studies have shown that older adults with hearing loss may have worse episodic memory of target words than their normal-hearing peers even after accounting for cognitive status . HoweverVisually based assessments were previously found to measure the hearing impairment population’s cognitive abilities more accurately than verbal assessment . The ROCFor the MCI population, memory ability, as assessed in ROCFT recall is usually impaired early in the disease progression . HoweverWe found a relatively larger mean difference score in the ROCFT recall task, which reflects the memory domain, than in the mean difference in the ROCFT copy tasks among the three cohorts. This may be because the memory impairment starts earlier with a larger effect in the course of MCI and dementia disease progression. The ROCFT recall tasks were significantly worse among D-HI and MCI-HI compared with the NC-HI group in both in the 3 min recall and the 30 min recall tasks.Previous research showed similar trends that individuals who needed to utilize lipreading and sign language, i.e., the early onset or the profound hearing impairment population, may have better visuospatial abilities than their normal-hearing peers . NeuroimCurrently, several United Kingdom local support groups for hearing aid users provide various kinds of support, including manipulating the hearing devices, psychological support, and lipreading and facial cue interpretation lessons. Several participants in our cohorts were also active participants in these other supporting activities. Therefore, this may be another potential explanation for their superior visuospatial abilities.Lipreading is generally used for communication purposes by hearing-impaired individuals. Even without hearing aids, the speech recognition scores of hearing-impaired individuals improve with lipreading . It is eOur research also indicates that the cross-modal plasticity may not only present in the congenital deaf population. It may also occur later in life in older adults with age-related hearing loss who usually start developing hearing impairment in middle age . With crMany studies among older adults who underwent auditory interventions with cochlear implantations also showed improvement in overall global cognition indicating positive cortical plasticity despite their older ages . HoweverThis superior visuospatial ability could be of benefit even in the presence of global deterioration of overall cognitive function in hearing impaired individuals. Further rehabilitation program may utilize lipreading techniques and use of other visuospatial clues such as facial expression, etc. By emphasizing the communication techniques that are most accessible to them, these individuals would have better communication and would potentially preserve longer their cognition. A previous systematic review also showed the importance of communication strategies and techniques in addition to hearing amplification for this group of older adults with hearing impairments .Another potential explanation is the sampling issue. We did not have a control group where the participants did not have hearing impairment. We had to compare the data to the previously published norm. The general health and education levels of our participants may differ from those in the norm samples. We did not have the information about the norms overall cognitive functioning data such as IQ, etc. Therefore, there is a possibility that our NC-HI cohorts may had higher overall functioning than the normative data set, also reflected in the superior ROCFT scores. Further study to compare these cohorts with normal hearing controls, matched for IQ may be needed to investigate this aspect in more detail.The main limitation of our study is that we had to compare the data to the normative data study that was conducted in 1995 as we did not have a control group with normal hearing. Moreover, the age and education years were slightly different among the cognitively normal and cognitively impaired cohorts. This discrepancy and its implications of it were discussed and explored more in our previous published work .With a relatively small sample size, the lack of difference of ROCFT scores for the MCI-HI and the D-HI compared with norms could also be due to inadequate statistical power. Further studies with larger cohorts of cognitively impaired older adults hearing aid users may be useful to explore their ability in more detail.We found suggestive evidence for the positive effects of age-related hearing loss on visuospatial cognitive ability. The visuospatial ability could be targeted when providing rehabilitation for the older adult with hearing loss, for example, with lipreading training, to support their communication.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.NU, D-EB, JS, and SC contributed to the conception and design of the study. NU organized the data collection and database, performed the statistical analysis, and wrote the first draft of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.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.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


H syndrome is an autosomal recessive disorder caused by mutations in SLC29A3. Hyperpigmentation, hypertrichosis, hyperglycemia, and hearing loss are some characteristics of this disorder, and it has a prevalence of < 1/1000. The aim of this report is to spread awareness among otologists, audiologists, and pediatricians about this syndrome and its audiological features.An 8-year-old male with a diagnosed H syndrome registered to our clinic with a complaint of hearing loss. The patient was diagnosed with hearing loss in a different clinic using only the air-conducted click auditory brainstem response test which showed wave V at 60 dB nHL for the right ear and at 80 dB nHL for the left ear. The initially performed pure tone audiometry (PTA) test in our clinic revealed a bilateral asymmetric hearing loss with a moderate sensorineural hearing loss in the right ear and a profound mixed hearing loss in the left ear. The performed air conducted click auditory brainstem response (ABR) result showed wave V at 55 dB nHL for the right ear and at 70 dB nHL for the left ear. Then, the repeated PTA test revealed a mild-severe sensorineural sloping hearing loss in the right ear and a severe sensorineural hearing loss in the left ear.Although hearing thresholds in H syndrome could be within normal limits in some patients, sensorineural hearing loss is an important characteristic feature for this syndrome. Sensorineural hearing loss could be progressive or of sudden onset and ranges from mild to profound. Thus, it must be taken into consideration to apply the audiological follow-up regularly and paying attention to the patient’s complaints; also, a regular follow-up for language development of children with H syndrome and for the hearing aids is advised. H syndrome is an autosomal recessive disorder, which its name came from the major clinical and laboratory findings of cutaneous hyperpigmentation and hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, low height, and hyperglycemia , 10. H sHere, we describe the audiological findings of a Syrian boy who was diagnosed with H syndrome.Our patient is 8 years old first child of first-cousin consanguinity Syrian healthy parents. He has two smaller siblings without any complaint. According to the reports, a homozygous pathogenic variant in exon 6 of the SLC29A3 gene was detected. The child has heart anomalies (aortic stenosis), hyperpigmentation and hypertrichosis Fig. , type 1 At age of 3, the child started complaining about his hearing by saying that he is not hearing well and there is a strange sound in his ears. Getting older, he complained about ringing in his ears that wake him up sometimes. Also, his mother noticed his complaint about dizziness and imbalance which disappear after eating something. Unfortunately, through this period no audiological evaluation was done due to the available services and financial issues in the country where he was living. On September 23, 2019, at age of 8 years, the air-conducted click ABR test which was performed in a different clinic showed wave V at 60 dB nHL for the right ear and at 80 dB nHL for the left ear , transient evoked otoacoustic emissions (TEOAEs), and PTA tests were performed on the same day Tables . The perOn January 10, 2020, the air conducted click ABR test was performed in our clinic and showed wave V at 55 dB nHL for the right ear and at 70 dB nHL for the left ear Fig. . The difOn February 10, 2020, oculomotor assessment and balance tests also were performed. The patient was asked to follow the clinician’s finger with his eyes without head movement, and the assessments of gaze holding, pursuit, saccades, and vergence were performed. Oculomotor test results were normal and no nystagmus was revealed. Romberg’s test was negative. No refixation saccades were revealed with head movements to the right and left sides on head impulse test. The patient was asked to stand on a firm surface with the eyes open, and then closed. Postural sway was observed and could not stand with eyes closed. Lastly, the patient’s Gait was slow with a widened base.The results of temporal bone magnetic resonance imaging and high resolution computed tomography revealed a bilateral normal temporal bone.Hearing aids usage was recommended to improve the child’s hearing thresholds. The child was referred by us to a hearing aid center for earmold impression; then, hearing aid trying was done by another audiologist in our clinic, but unfortunately as his family could not afford the hearing aids’ price, they had registered in non-governmental organizations to help, but starting of COVID-19 pandemic delayed the process.Necessary permissions were taken from the parents, and the informed consent form was signed by the father of the child.A mutation in the SLC29A3 gene that encodes the human equilibrative nucleoside transporter hENT3 is the cause of the H syndrome . SensoriMolho-Pessach et al.  investigEven though the H syndrome is rare as it has a prevalence of < 1/1000, in Molho-Pessach et al. , the majMitochondrial cytopathies are several diseases caused by a disturbance in one or more of the mitochondrial metabolic pathways, either by an unclear mutation in the DNA or by maternally inherited mitochondrial genome mutation . One of Indeed, hENT3 is recognized as playing a major role in transferring the nucleosides into the mitochondria, thereby helping in mitochondrial DNA synthesis/ repair . MitochoFor our patient, the existed difference between the initial and latterly repeated PTA test results for the left ear is thought to be due to the tiredness our patient felt during the test, as he had more than one appointment in different policlinics on the same day. The audiological evaluation for our patient revealed a mild-severe sensorineural sloping hearing loss in the right ear and severe sensorineural hearing loss in the left ear, with bilateral normal tympanometry and absent TEOAEs, and a preserved ASR in the right ear. The reason of preserved ipsilateral ASR in the right ear and its absent in the left ear is thought to be due to Metz recruitment, as hearing loss of cochlear origin results in ASR thresholds within normal limits for levels of hearing loss up to 60 dB HL and to 70 dB HL in some cases .These results support the necessity of supporting the subjective hearing tests with objective tests such as ABR in children with additional problems like our patient and also the necessity of regular audiological follow-up due to the risk of progressive hearing loss.We had several limitations with this case; the family is living 12 h far away from our hospital, which forced them to plan all the needed appointments for the same day. This problem limited us to repeat the tests within a short period. Furthermore, the detailed vestibular assessment with laboratory tests  was planned to be done, but because of the COVID-19 pandemic, it was postponed. Unfortunately, the patient passed away in July 2020.Hearing loss characteristics in H syndrome patients vary between mild to severe sensorineural hearing loss, and it could be of progressive or sudden onset. Although the H syndrome is rare, it has a higher prevalence in some countries than others, especially in the Middle East countries. This report aimed to spread awareness about the audiological findings in H syndrome especially among otologists, audiologists, and pediatricians who work in the Middle East countries. Regular audiological and language development follow-up and using objective and subjective tests during audiological evaluation is highly recommended; also, a regular hearing aids checking is recommended as the hearing loss could be progressive.


Although the effect of hearing loss on years lived with disability (YLD) is quite substantial, occupational hearing loss among migrant workers is significantly under-studied. In Kuwait, where nearly two-thirds of the population are migrant workers, the burden of occupational noise-induced hearing loss (ONIHL) is unknown. The objective of the study was to assess the prevalence of ONIHL among migrant workers in Kuwait and explore workplace and individual risk factors that are associated with ONIHL. We obtained data of annual physical exams for the year 2018 conducted by the Shuaiba Industrial Medical Center (SIMC) for all industrial workers in the area. We applied univariate and multivariate logistic regression models to estimate the effects of individual and occupational characteristics on ONIHL. A total of 3474 industrial workers visited the SIMC for an annual exam. The vast majority were men (99%) and non-Kuwaitis (98%) with a median age of 38 years. A total of 710 workers were diagnosed with ONIHL with a prevalence of 20.4%. Age, years of experience, and self-reported exposure to noise were associated with statistically significant higher odds of ONIHL. When adjusted for age, years of experience, and other individual level factors, type of industry was not a statistically significant predictor of ONIHL. The study uncovers the significant burden of hearing loss among the migrant worker subpopulation in Kuwait, an area of occupational health that is often underestimated or unrecognized. Although laws and regulations are in place to prevent and control noise in the workplace, the onus is on local authorities to ensure the necessary training and controls aimed to reduce noise exposure. Noise in the environment ranges from tolerable to hazardous levels. According to the International Labour Organization (ILO), noise is linked to workplace environmental pollution which may lead to adverse health effects and burden the economy . ContinuHearing loss is a significant public health problem that denotes social and economic burdens . AlthougThe prevalence of occupational hearing loss in developing countries at 23% is more problematic compared with developed countries at 16% . For exaONIHL among migrant workers is an overlooked public health problem in Kuwait, which necessitates urgent policy and regulatory implementation. To bridge the research gap, the current study aims to investigate the prevalence of ONIHL among migrant workers in Kuwait and explore workplace and individual risk factors that are associated with ONIHL.This cross-sectional study is retrospective in nature and utilizes data from annual medical examinations conducted by the Shuaiba Industrial Medical Center (SIMC) at the Department of Occupational Health of the Ministry of Health. The SIMC is located in the Al Shuaiba industrial area and provides services to migrant workers from various industrial factories and corporations located in the Al Ahmadi governorate . The SIMAll audiometric tests were conducted by two experienced, well-trained nurses in a testing facility fulfilling ISO 8253-11989) criteria. All subjects were examined by otoscopy to exclude external and middle ear medical disorders such as ear wax, otitis externa, and otitis media, followed by Pure-tone audiometric tests (air and bone conduction) that were conducted to determine the hearing thresholds across the conventional frequencies 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz for both ears of each subject, using a Madsen-Orbiter 922: Diagnostic Audiometer, with TDH-50P earphones. The audiometer met ANSIS3.26-1981 standards and was calibrated. Measurements were taken using 5 dB increments. Audiometric tests were only made at least 18 h after the last exposure to noise to allow recovery from any temporary hearing threshold shifts. Noise-induced hearing loss is a “sensorineural hearing deficit that begins at the higher frequencies (3000 to 6000 Hz) and develops gradually as a result of chronic exposure to excessive sound levels” 89 criter. Only whMost of the workers on average worked 72 h per week . However, official daily working hours per day were 8, and the extra hours were considered as overtime earning additional income. Moreover, SIMC conducted a survey on self-reported noise exposure (yes/no), which was completed by the participants. The questionnaire also collected data on age, gender, years of experience, noise exposure, nationality, job type, and industry type.p < 0.05 was used for all tests. Statistical procedures were performed using SPSS version 26 .Continuous variables were expressed as mean and standard deviations or median and interquartile ranges. Categorical variables, such as age group, gender, years of experience , noise exposure (yes/no), nationality, job type, and industry type were presented as numbers and percentages. To examine the independent factors associated with ONIHL, the study employed univariate and multivariate logistic regressions and reported odds ratios with confidence intervals for each factor. Univariate analyses were conducted to investigate the relationship between the ONIHL and other predictors, one at a time. Multivariate logistic regression was performed to elucidate the relationship between the outcome and variables after adjusting for other predictors. A significance level of After adjustment, the odds of ONIHL among age groups remained statistically significantly higher than the reference group, although the effect estimates were attenuated after adjustment. Workers aged >61 years were 30.5 times more likely to have ONIHL than young workers. A trend is clearly observed: the odds of ONIHL increase for every 10 years increase in the categories of age. The coefficient for gender is no longer statistically significant in the multivariate regression after adjusting for the other variables. A work experience of >30 years exhibits twice the adjusted odds of ONIHL compared to a work experience of ≤15 years. Similarly, self-reported exposure to noise is associated with an adjusted odds ratio of 2.0 (1.7–2.4). Furthermore, the results for Filipinos (OR: 1.5: 95% CI: 1.0–2.2) and Pakistanis  remain significant compared with Indians (reference group). Finally, job and industry type became non-significant, except for job type crafts and related trade works .To the best of our knowledge, this study is the first in Kuwait and the Gulf Region to assess the prevalence and predictors of ONIHL among migrant workers. We leveraged routinely collected secondary data from the SIMC to enable the investigation of ONIHL. The study uncovers the significant burden of hearing loss among the migrant worker subpopulations. This area of occupational health is often underestimated or unrecognized among marginalized subpopulations, which renders it an important public health topic .Unwarranted exposure to noise can result in cochlear trauma which leads to hearing loss and tinnitus. Occupational workers are at most risk of noise-induced hearing loss. Noise-induced hearing loss is a term used to describe the effects of long term and continuous exposure to noise. As an exposure, magnitude of noise can be correlated to cochlear damage. Acoustic trauma is another term used to describe sudden hearing loss typically caused by single or repeated noise exposure. NIHL can be characterized by being either temporary, where the individual can regain their hearing within 48 h, known as temporary threshold shift (TTS), or it can result in permanent threshold shift (PTS). Some individuals might experience hidden hearing loss, where a pure-tone threshold shift is absent. The pathophysiology of permanent threshold shift is as follows: loss of the outer hair cells with evidence suggesting that this might cause the degeneration of the auditory nerve  . In a siThe evidence at hand shows that migrant workers in Kuwait suffer from ONIHL with a prevalence of 20.4%, which is in line with the results of  at 21.5%The age pattern observed in the study is similar to those of ,40. InteMigrant workers worldwide suffer from significant issues that compromise their physical health and mental wellbeing. In addition, they are at risk of having occupational diseases and injuries due to many stressors that arise from individual, occupational, environmental, and community domains . MigrantThe Kuwait Environmental Public Authority (KEPA) regulates noise control in industrial settings, namely, Articles (19), (54), and (55) from the Environmental Protection Law 42/2014 Amended by 99/2015 and Decision No. (210/2001). Furthermore, the Ministry of Social Affairs and Manpower have a Ministerial resolution No. (208/2011) regarding the safety levels and standards of noise in workplaces and areas. The legal text of each regulation is mentioned in Although laws and regulations are in place to prevent and control noise in Kuwait, the results indicate a possible problem in the implementation of such rules and regulations. An overall prevalence of 20.4% in a slightly younger workforce indicates that industrial institutions and workers in Kuwait have a lot more to do. Thus, it is recommended that each company should provide a periodic report of its noise levels to KEPA, which should establish a robust monitoring system for industrial companies and a disciplinary fine system for violators. Moreover, each industrial company should provide employees with hearing conservation programs, which are intended to serve workers exposed to occupational noise. In general, a hearing conservation program should include noise exposure monitoring, hearing protection, and hearing testing, training, and record-keeping . InternaThe study has its limitations. First, the sample was extracted from data provided by the SIMC; thus, the sample may not be representative of all industrial workers in Kuwait. However, the results are comparable to studies utilizing random samples. Second, noise exposure information was self-reported. Such exposure assessment is prone to recall bias and therefore should be interpreted with caution. Similarly, it was not possible to separate noise exposure from work and from outside work. The current study used one audiogram per employee in estimating a snapshot prevalence. Follow-up studies based on a baseline audiogram and a repeated measure of periodic audiogram per worker will be critical to establish temporality. The stratification of subgroups may have resulted in smaller sample sizes and therefore the readers must be cautioned when interpreting the results. We therefore did not examine the severity of any hearing loss in this cohort. Moreover, the study was short of data on education level and behavioral aspects, such as the use of headphones for phone calls or listening to music, which may have influenced the results. Future research should focus on a representative sample and collect additional specific data on hearing thresholds and covariates to render the results generalizable. Finally, future studies in Kuwait must also investigate the economic and social burdens of ONIHL, which could be significant to public health.In conclusion, the study provided evidence that one-fifth of migrant industrial workers in Kuwait suffer from hearing loss likely from occupational exposure. The prevalence of ONIHL calls for prevention using available measures, such as the existing use of hearing protection devices and hearing conservation programs. The results point to several recommendations. In Kuwait, companies must adhere to the permissible noise levels following the local laws as well as international standards such as the recommendations of the U.S. Occupational Safety and Health Administration (OSHA). In addition, the implementation of laws must be more assertive as KEPA continues its monitoring of the industrial sector. Preventing hearing loss can reduce significant social and health burdens on individuals and the population.


Leishmania spp. The improvement of existing treatments and the discovery of new drugs remain ones of the major goals in control and eradication of this disease. From the parasite genome, we have identified the homologue of the human oncogene PES1 in Leishmania major (LmjPES). It has been demonstrated that PES1 is involved in several processes such as ribosome biogenesis, cell proliferation and genetic transcription. Our phylogenetic studies showed that LmjPES encodes a highly conserved protein containing three main domains: PES N-terminus , BRCT (found in proteins related to DNA repair processes) and MAEBL-type domain . This gene showed its highest expression level in metacyclic promastigotes, the infective forms; by fluorescence microscopy assay, we demonstrated the nuclear localization of LmjPES protein. After generating mutant parasites overexpressing LmjPES, we observed that these clones displayed a dramatic increase in the ratio of cell infection within macrophages. Furthermore, BALB/c mice infected with these transgenic parasites exhibited higher footpad inflammation compared to those inoculated with non-overexpressing parasites.Leishmaniasis is a neglected tropical disease caused by  Leishmania genus. Over 90 sandfly species are known to transmit Leishmania parasites. Clinical manifestations range from self-healing cutaneous lesions to visceral forms which can cause death if untreated. According to the Global Health Observatory, out of 200 territories reporting to WHO in 2020, 98 were endemic for leishmaniasis: 71 countries are endemic for both visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL), 8 for VL only, and 19 countries are endemic for CL only [Leishmania has allowed the identification of the Pescadillo (PES) homologue. This oncogene is conserved among eukaryotes and has been mainly related to ribosomal biogenesis as part of the PeBoW complex [PES have been detected in several tumours such as colon, breast, or prostate cancer [PES homologue detected in the fungal pathogen Candida albicans was demonstrated to be an essential switch for the yeast-inducing stage, which is responsible for fungal spread throughout the body [Plasmodium falciparum, exhibiting a protein expression level dependent on parasite stage [Leishmania spp. are heteroxenous parasites, they display several development stages and morphological changes, regulated by differential gene expression, in response to the different stress environments present in each host [PES in Leishmania major, and we also attempted to shed some light on its involvement in parasite biology and its role as a therapeutic target against pathogenic protozoan.Estimates suggest that approximately one tenth of the world’s population lives in extreme poverty USD <1.90/day), mostly affected by Neglected Tropical Diseases (NTDs) .90/day, . Some NT CL only . The tre CL only . First-l CL only . Current complex ,11,12. B complex ,14, embr complex  and gene complex . In addie cancer ,18,19,20the body . In relate stage . Therefote stage ,24. Somete stage . The strte stage . Since Lach host ,28. For ach host . Our worLmjPES (LmjF.04.0810) sequence was retrieved from gene DB as a protein-coding gene in Leishmania major. This gene is located on chromosome 4 in all the Leishmania species and is highly conserved in trypanosomatids. It is found on chromosome 9 and 8 in T. brucei and T. cruzi, respectively [L. major gene-sequence identity was higher than 85% and 63% when compared to L. mexicana or L. braziliensis, and L. donovani or L. infantum, respectively. In addition, such an identity was also higher than 60% when compared to Trypanosoma spp. genes. LmjPES encodes a protein of 671 amino acids with an estimated molecular mass of 77.29 kDa and a theoretical pI of 9.69. This protein was predicted to contain two main conserved domains: an N-terminal pescadillo-like protein (NPLP) domain and a BRCT domain  were used to reconstruct the PES phylogram  to perform further experiments.ectively ,31. On tT domain A as foun species . These a species B, since  domains A. On the domains A. A diso domains A. Gene Ohylogram B. Consis cluster B. Based Leishmania predicted the presence of NLS, and therefore, a nuclear location. To validate such a prediction, the plasmid pXG-mCherry34-LmjPES  expression was quantified in both procyclic and metacyclic promastigotes. As shown in LmjPES metacyclic forms selected by PNA method exhibited the highest expression levels of this gene, more than eight times higher (8.14 ± 0.11) than those observed in procyclic ones. The promastigotes negative-selected by PNA method corresponded to the parasite stage, which is able to infect immune cells. Therefore, LmjPES expression might be related to infectivity.Having described the presence of the LmjPES reached its highest gene expression level in the metacyclic stage, we decided to elucidate the role of this gene in the parasites’ acquisition of infectivity and in the progression of the disease by evaluating cells harbouring episomally overexpressed LmjPES. The episomal expression vector pXG-HygR-LmjPES was constructed by the strategy previously described  which exhibited similar rates of overexpression  (LmjPES-overexpressing parasites displayed a growth curve and cell cycle profile similar to control parasites (data not shown). Since escribed A, and usarasites B. The qPctively) C. GrowthLmjPES-overexpressing metacyclic promastigotes at a 20:1 (promastigotes:macrophage) ratio. Three hours post-infection, significant differences were observed in the percentage of infected cells (20.86 ± 3.42 for control vs. 34.16 ± 3.81 in clone 1 and 39.47 ± 5.67 in clone 2) (LmjPES2), which showed the highest level of LmjPES gene expression. Six hours post-infection, the percentage of infected macrophages as well as the number of intracellular amastigotes remained higher in LmjPES-overexpressing strain infections   and clone 2) A and in clone 2) B. In facctively) A,B. FiguLmjPES in virulence in vivo, the integrative plasmid pLEXSY-HygR was used to overexpress the PES homologue in L. major parasites. LmjPES sequence was obtained from L. major cDNA with both primers, LmjPESpLEXSYFw and LmjPESpLEXSYRv, and then inserted into pLEXSY-HygR plasmid  locus (LmjPES gene expression levels were measured by qPCR. One clone overexpressing ten times more (10.36 ± 0.06) than control (cells harbouring pLEXSY-HygR plasmid) was selected for in vivo infections  locus A and thefections C. LmjPES would induce an increase in lesion size (>0.60 mm), we carried out an additional study. Lesions were allowed to grow until day 35 (five weeks) after the last inoculation. It was observed that the percentage of animals displaying a significant lesion size (>0.60 mm) was 0%, 47.62%, and 65.63%, for the uninfected, positive controls (pLEXSY-HygR), and pLEXSY-HygR-LmjPES infected mice, respectively (LmjPES group (*** p < 0.001), as assessed by log-rank (Mantel–Cox) analysis , whereas such lesion sizes in the uninfected and pLEXSY-HygR groups remained almost unchanged (lesion size was <0.60 mm in more than 60% of mice after five weeks)  E. Thus, LmjPES-overexpressing parasites compared to those inoculated with pLEXSY-HygR-harboring Leishmania   B.Leishmania genus comprises heteroxenous parasites which acquire the capability to infect vertebrates through morphological and molecular changes. In the present work, the pescadillo homolog from Leishmania parasites has been firstly characterized and related with parasite in vitro and in vivo infective processes.The Pescadillo (PES) gene was first discovered as a site of a retrovirus-insertion mutation that caused severe defects during embryogenesis in Zebrafish [PES product is a well-conserved protein. Moreover, its homologues have been identified and functionally well characterized in the human (PES1), yeast , and mouse (Pes1) proteomes [Leishmania parasites. The genome availability of several Leishmania species allowed us to detect the presence of PES homolog in L. major (LmjPES). Due to its high conservation and the importance of the cellular processes in which PES protein is involved, we aimed to study its role in Leishmania parasites. The sequence analysis of the conserved motifs and prediction based on alignments showed that LmjPES protein has an evolutionary highly conserved N-terminal domain of pescadillo-like proteins (NPLP-domain) composed of 260 amino acids. These domains have traditionally been related to proteins involved in ribosome biogenesis [The ebrafish . This geebrafish ,33,34,35roteomes ,37. Howeogenesis ,39. In fogenesis ,39. The ogenesis . It is cLeishmania. Further research will be needed to determine if the LmjPES MAEBL domain performs a similar function, or if it is just an evolutionary footprint from non-conserved domains. Since this domain belongs to proteins involved in host cell adhesion, and the adhesion process is critical during infectivity, the presence of the aforementioned domain in LmjPES could show that this protein plays a role in the infectivity process within Leishmania biology. NPLP-domain within LmjPES is followed by a BRCT fragment, which belongs to a complex group of protein domains first described in the tumour-suppressor protein BRCA1. BRCT domains are DNA/protein binding modules mostly implicated in cell processes such as DNA Damage Response (DDR), DNA repair, and/or cell cycle control  in a widThe nuclear localization of LmjPES was initially predicted by the presence of Nuclear Location Signals (NLS) in the sequence of the protein, specifically located in the C-terminal region. We further demonstrated that LmjPES is a nucleus-located protein, supporting previous results showing the nuclear location of PES homologues. Leishmania major. LmjPES gene expression in metacyclic parasites was significantly higher when compared to its level in procyclics. Thus, it might be involved in Leishmania infectivity, since it is mainly expressed in the infective forms. Similarly, previous research demonstrated the implication of a PES homolog from Candida albicans in both in vitro and in vivo virulence [Plasmodium falciparum a PES ortholog (PfPES) has been identified during the characterization of the first dual phosphatase as a protein, showing significantly increased levels from ring to trophozoite [Leishmania infectivity. When murine peritoneal macrophages were infected with LmjPES overexpressing parasites, we observed increased infectivity ratios in correlation with higher LmjPES expression levels after the infection. Our data suggested that this gene might be implicated in the infectious capability of the parasites. In vivo analyses showed similar evidences. To induce such overexpression, L. major parasites were transfected with a constitutive expression vector harboring LmjPES sequence. pLEXSY-HygR-LmjPES infected mice showed significantly higher footpad thickness than that of pLEXSY-HygR infected mice. Accordingly, hematoxylin–eosin staining presented a higher infiltration area in footpads from LmjPES-overexpressing infected mice relative to control footpads. An increase of the susceptibility to L. major generally occurred after the sub-cutaneous (s.c.) inoculation of a relatively high number of parasites into BALB/c mice, and therefore the induction of the early T helper 2 (Th2) response [Leishmania has been previously detected [It is well known that ribosomal proteins can exhibit extra ribosomal functions . We therirulence ,34. On tphozoite . Althougresponse ,48. Consresponse ; the spldetected ,50,51,52detected ,54,55,56Leishmania parasites have been described as antigens detected by the host immune system [Leishmania ribosomal proteins combined with CpG oligodeoxynucleotides have demonstrated effectiveness as vaccination against primary [Leishmania parasites by the production of reactive oxygen species (ROS). In fact, the increased tissue expression of iNOS has been closely associated with resistance to L. major [LmjPES-infected mice five weeks after the last inoculation. This might be due to the putative antigenic nature of PES homologue, since some parasite antigens are conserved intracellular proteins like heat shock proteins, histones or ribosomal proteins [Certain ribosomal proteins from e system ,58. In a primary  and seco primary . The acq primary . IFNγ an primary , which wL. major . In our proteins . PES1 expression was suppressed in confluent Hela cells, associated with a reduced proliferation, while early passage Hela cells exhibited higher expression levels of PES1 [PES1 [Furthermore, as part of PebOW complex, PES has been related to cell proliferation through its involvement in the cell cycle . It has  of PES1 . Ribosom of PES1 . Moreove of PES1 , and thi of PES1 ,66. InteS1 [PES1  as a mecPES and the PES protein orthologous sequences were obtained from TriTrypDB [L. major protein sequence (XP_888589.1) was used as the query sequence for BLAST searches. Multiple sequences alignments were performed using the BLOSUM62 matrix implemented in CLUSTALW program.Nucleotide and genomic sequence data from the kinetoplastid homologs of riTrypDB . Other kThe secondary structure overview from LmjPES was predicted using Quick2D, implemented in MPI Bioinformatics Toolkit . LmjPES Plasmodium falciparum. Evolutionary analyses were conducted in MEGA X [Protein–protein Basic Local Alignment Search Tool (BLASTP) was used to retrieve the ortholog sequences of LmjPES XP_888589.1) protein. Multiple sequence alignment was performed using MUSCLE v3.8.31 ,82, as i89.1 protL. major parasites (Lv39c5) were maintained as previously described [escribed . For infescribed . Animal LmjPES was amplified by PCR from L. major genomic DNA with the primers LmjPESmCherry-Fw and LmjPESmCherry-Rv, LmjPESpXG-Fw and LmjPESpXG-Rv, and LmjPESpLEXSY-Fw and LmjPESpLEXSY-Rv  cloning vector. Plasmids were digested with the following restriction enzymes: NotI-HF  for the pXG-LmjPES-mCherry34 construct, BamHI  for the pXG-HygR-LmjPES construct, and NcoI  and KpnI  for the pLEXSY-HygR-LmjPES construct. These digestions were gel purified using QIAquick® Gel Extraction Kit (Qiagen™) following the manufacturer’s protocol, and then ligated using T4 Ligase (Invitrogen™). LmjPES sequences and orientation within pXG-LmjPES-mCherry34 and pXG-HygR-LmjPES were confirmed by PCR and sequencing. pLEXSY-HygR-LmjPES plasmid was linearized by digestion with SwaI  before electroporation [LmjPES integration in the 18S rRNA locus.The plasmids pXG-mCherry 34, pXG-HygR and pLEXSY-HygR were used in this study. Plasmid pXG-mCherry34 was assembled as reported . The codLEXSY-Rv , for insporation . pLEXSY-7 log-phase pXG-mCherry34-LmjPES L. major promastigotes were fixed using a 1% paraformaldehyde/phosphate-buffered saline  solution. Then, cells were stained with a 1 mg/mL DAPI  solution (30 min at 4 °C) and washed twice with PBS. Images from the slides were acquired in a PerkinElmer ultraVIEW confocal microscope.A total number of 2 × 104 cells per well in Roswell Park Memorial Institute (RPMI) medium and allowed to adhere overnight at 37 °C in a 5% CO2 incubator. Metacyclic L. major promastigotes harbouring pXG-HygR or pXG-HygR-LmjPES plasmids and isolated by the peanut agglutinin (PNA) method [2 atmosphere. Chamber slides were washed with PBS, fixed with methanol three and six hours post-infection, and finally stained with Giemsa. The number of amastigotes per macrophage was evaluated by light microscopy . Murine peritoneal macrophages extracted as previously described  were see) method  were useLmjPES overexpressing parasites (pLEXSY-HygR-LmjPES) and control parasites (pLEXSY-HygR), respectively. The animals were subcutaneously inoculated as reported [w/v) formaldehyde  and then formalin-fixed.BALB/c mice were distributed in three groups; mice from one group were PBS inoculated, and two groups were infected with reported . FootpadLmjPES and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) housekeeping gene [Leishmania parasites (ct(GAPDH)-ct(gene) method [A stationary phase culture was used to select metacyclic parasites by PNA method as previously described . Total Ring gene , respectarasites . The rel) method .Immunohistochemistry studies were performed as previously described , using tp values were two-tailed and considered significant if p < 0.05. Data were represented as mean ± SD. Experimental differences between groups were studied by one-way ANOVA . Lesion sizes were compared by the log-rank (Mantel–Cox) test. The median time to develop a significant lesion (size > 0.6 mm) was estimated with Kaplan–Meier analysis. p-values were considered significant when * p < 0.05, ** p < 0.01, *** p < 0.001 and **** p < 0.0001.Statistical studies were executed with GraphPad Prism v7. The analyses were performed using the non-parametric Kruskal–Wallis and Mann–Whitney U tests. All Leishmania parasites with infectivity capability in vitro and virulence in vivo. On the one hand, transgenic parasites overexpressing LmjPES were able to infect a higher percentage of macrophages during in vitro infection. On the other hand, LmjPES expression in L. major parasites produced an increase in cell recruitment at the inoculation site during in vivo studies in BALB/c mice. Further studies are needed to better understand the role of this newly discovered gene in leishmaniasis outcomes. However, due to its relevant implications for parasite virulence, LmjPES might be considered a promising target for new drug design against leishmaniasis.In conclusion, the present work shows the relation between the newly discovered homologue of PES in


Hearing loss increases the risk of poor outcomes across a range of life domains. Where hearing loss is severe or profound, audiological interventions and rehabilitation have limited impact. Hearing dogs offer an alternative, or additional, intervention. They live permanently with recipients, providing sound support and companionship.A single-centre, randomised controlled trial (RCT) evaluated the impacts of a hearing dog on mental well-being, anxiety, depression, problems associated with hearing loss , and perceived dependency on others. Participants were applicants to the UK charity ‘Hearing Dogs for Deaf People’. Eligibility criteria were as follows: first-time applicant; applying for a hearing dog (as opposed to other support provided by the charity). Participants were randomised 1:1 to the following: receive a hearing dog sooner than usual [HD], or within the usual application timeframe (wait-list [WL] comparator). The primary outcome was mental well-being  6 months (T1) after HD received a hearing dog. The cost-effectiveness analysis took a health and social care perspective.n = 83, WL n = 82). A total of 112 (67.9%) were included in the primary analysis . At T1, mental well-being was significantly higher in the HD arm . Significant improvements in anxiety, depression, functioning, fearfulness/social isolation, and perceived dependency, favouring the HD arm, were also observed. On average, HD participants had used fewer statutory health and social care resources. In a scenario whereby costs of provision were borne by the public sector, hearing dogs do not appear to be value for money. If the public sector made a partial contribution, it is possible that hearing dogs would be cost-effective from a public sector perspective.In total, 165 participants were randomised , hearing dogs are cost-effective from the public sector perspective. Whilst it would not be cost-effective to fully fund the provision of hearing dogs by the public sector, a partial contribution could be explored.ISRCTN36452009.The trial was retrospectively registered with the International Standard Randomised Controlled Trial Number (ISRCTN) registry on 28.1.2019: The online version contains supplementary material available at 10.1186/s13063-021-05607-9. One in twenty of the world’s population currently live with a hearing loss which impacts their everyday lives. This figure is projected to double by 2050 as the world population ages . PrevaleFor those with severe or profound hearing loss, hearing aids offer little benefit . CochleaA further, or alternative, type of rehabilitative intervention is to acquire a hearing dog. Hearing dogs are animals specifically trained to provide ‘sound support’; that is, the ability to respond to common ‘daily living’ sounds  and to use different behaviours to alert and identify the sound to the deaf individual. Similar to other assistance dogs (e.g. guide dogs), there are accredited charities providing hearing dogs in many European countries, North America, Australia and New Zealand. Accredited hearing dog providers adhere to international standards for the assistance dog industry related to dog training and assessment, supporting the ‘hearing dog partnership’, and dog welfare . Whilst n = 3) with hearing dogs were not included in the effectiveness study ) hosted on the Qualtrics© survey 7 (platform). Participants received a £20 shopping voucher as a ‘thank you’ for returning their baseline questionnaire.Sooner than usual (hearing dog (HD) arm); orWithin HDfDPs usual timeframe (wait-list (WL) comparator arm)As soon as the profiles of two participants with the same HDfDP need categorisation were completed, pairwise randomisation was used to allocate one each to receive a hearing dog:Participants were blinded to their group allocation.Randomisation was carried out by a trial statistician at York Trials Unit using an allocation schedule generated in Stata v15. Study team members who were actively involved in the administration of the trial were not blinded.After randomisation, HD profiles were immediately made available to HDfDP trainers to identity a suitable hearing dog ‘match’. WL profiles were not made available until 6 months after HD received their dog or, to fulfil HDfDP’s commitment to receive a hearing dog within 2.5 to 3 years of applying, 16 months after randomisation, whichever came first.The study adhered to HDfDP protocols regarding cessation of a hearing dog partnership. Cessation may be instigated by the recipient , the organisation (e.g. concerns about dog welfare) or where recipient and the organisation jointly decide that the match has not proved successful .Pre-randomisation, participants who withdrew their application for a hearing dog or had their application closed by HDfDP (due to evidence emerging during the assessment process that the participant did not meet HDfDP acceptance criteria) were no longer eligible for participation in the trial. Post-randomisation, all participants, regardless of their application or partnership status remained within the trial unless they withdrew consent. Where a HD participant withdrew their application post-randomisation, the research team created a dummy partnership date from which to trigger T1 data collection. If HDfDP closed an application post-randomisation or removed the hearing dog, they had the option to request that the participant was removed from the study.The first follow-up data collection (T1) for each randomised pair took place 6 months after the HD participant received a hearing dog, at which point the WL counterpart was not expected to have received their dog. This was the primary time point. The decision to use 6 months after receipt of hearing dog as the primary time point was informed by two main considerations: (i) advice from HDfDP that, by that time, the settling in and adjustment period has typically passed and the partnership between individual and hearing dog well-established; (ii) ensuring HDfDP would maintain its commitment that all applicants (including those in the WL group) receive a hearing dog within 2.5–3 years of their application.Follow-up data collection was administered by the research team via post or email (containing link to electronic versions (English or BSL) of study questionnaire) according to participants’ preferences. Email/post and text reminders, and ‘thank you’ shopping vouchers (£20) supported retention.The selection of outcome measures was informed by the existing literature and in consultation with Hearing Dogs for Deaf People and hearing dog recipients.Short Warwick-Edinburgh Mental Well-being Scale (SWEMWBS) [a = 0.90.Self-reported mental well-being was measured using the 7-item SWEMWBS) . This isSWEMWBS) . InternaWork and Social Adjustment Scale (WSAS) [a = 0.84.e (WSAS)  measuresGeneralised Anxiety Disorder Assessment (GAD-7) [a = 0.93. (GAD-7)  is a sevPatient Health Questionnaire (PHQ-9) [a = 0.91. (PHQ-9)  is a ninHearing Loss Questionnaire (HLQ) comprises two sub-scales (HLQ-Sound (6 items), HLQ-Social (5 items)) which capture frequency of exposure to problems deaf people report experiencing in everyday life using a five-point rating scale . HLQ-Sound is scored 6–30 and concerns problems with sound detection/identification. HLQ-Social is scored 5–25 and concerns problems with feeling safe, dependence on others and social avoidance. The HLQ was derived from a checklist developed by a previous hearing dog evaluation [a = .82, HLQ-Social a = .85) indicated it was appropriate to use subscale scores. Split-half and test-retest reliability were also acceptable. (Further information available from authors).aluation  and whicaluation . Tests oPerceived dependency is a single question assessed perceived dependency on others: In a typical week, on how many days do you need family or friends to help you overcome any difficulties caused by hearing loss?Validated BSL versions of the SWEMWBS, GAD-7, PHQ-9 and WSAS were already available , 44. TheHDfDP retained the right to allocate a hearing dog to a WL participant before T1 should the applicant’s unusual/complex needs significantly reduce the number of hearing dogs with the required specific aptitudes/skills likely to become available within the 3 years HDfDP commits to applicants receiving a hearing dog. Instances were recorded by the study team.n = 162) and at least 128 (80% of these) would be retained at T1. This would result in 80% power to detect an effect size of 0.5 of a standard deviation in our primary outcome measure .Recruitment was scheduled for a 12-month period during which we estimated that 200 individuals would be approached to take part and 180 would be eligible for recruitment to the study. We assumed that approximately 90% would opt to join the trial . Data were entered into SPSS Version 26 by staff not involved in data analysis. A random sample of 10% was double entered to assess data quality. A 5% threshold for the error rate was set to trigger further investigation but the error rate did not exceed this. Management of missing data followed guidance from scale developers where available. For the HLQ, we replaced up to one missing item in each subscale with the subscale mean.Baseline data were summarised descriptively by trial arm as randomised and as included in the primary analysis. Analysis was conducted using two-sided statistical tests at the 5% significance level using available case intention-to-treat.The primary analysis estimated the difference in SWEMWBS scores at T1 between HD and WL using linear regression adjusting for the baseline score and the individual’s HDfDP need categorisation. Secondary outcomes  were analysed in the same way.Standardised effect sizes were calculated by dividing the adjusted mean difference by the standard deviation of the analysed sample at baseline. An effect size of 0.2 was described as a small effect size, 0.5 a medium effect size and > 0.8 a large effect size .Secondary analyses included a series of ordinal logistic regressions, adjusting for HDfDP needs categorisation and baseline scores, which compared differences between arms at T1 in distribution across severity classifications of the SWEMWBS, GAD7, PHQ-9 and WSAS.A Complier Average Causal Effect (CACE) analysis  was condHealth-related quality of life, measured using the EuroQol 5 Dimensions A questionnaire developed specifically for the study, and reflecting the specific needs of the population, collected data on The following was collected at baseline, randomisation and T1:The costs of providing hearing dogs is borne by the charity (the current situation)The public sector funds the cost of providing hearing dogs.The cost-effectiveness analysis took a health and social care perspective which asked, compared to usual care, does providing hearing dogs provide value for money for the National Health Service (NHS) and local authorities (LA)? Or, in other words, does investing public sector resources in hearing dogs generate more benefit than could be generated by alternative spending? The main analysis considered two separate scenarios:Based on findings from the main analysis, a subsequent analysis considered how much the public sector could contribute towards the cost of hearing dogs with the expenditure representing value for money.Health and social care services used by study participants were costed The ii.The active intervention period (receipt of hearing dog to T1)For each scenario, we conducted two analyses:Table excluding the cost of the hearing dog was estimated using GLM with log-link and gamma distribution. The difference in costs in the scenario including the cost of the hearing dog was estimated using OLS. QALY and cost regressions included the EQ-5D-5L score and health and social care costs in natural units at baseline, respectively, in order to adjust for baseline differences across participants. All regressions included three dummies indicating the HDfPD’s ‘needs categorisation’ (the reference category: no remarkable/particular needs). For each time point, missing data were imputed using multiple imputation chain equation with predictive mean matching [Model selection was carried out using Akaike and Bayesian information criterion (AIC and BIC). In the whole trial period analysis, the difference in QALYs and costs between the two arms of the trial were estimated by ordinary least square (OLS). In the active intervention period analysis, the difference in QALYs was estimated using generalised linear model (GLM) with the log-link and normal distribution. The difference in costs in the scenario matching .Cost-effectiveness was calculated using the incremental cost-effectiveness ratio (ICER), which reports the incremental cost per QALY gained of one intervention compared to another. The incremental net health benefit (NHB) for hearing dogs compared to standard care was also estimated which captures the overall health gain from one individual receiving a hearing dog. This measure reflects any health benefits to that individual, and the impacts on other people’s health from any change in resource requirements. If hearing dogs are cost saving, those resources (or funds) can be used to generate additional health for other individuals, resulting in further health gain. In contrast, if they increase costs those resources are not available for others, resulting in health losses. Incremental net health benefit was estimated using three different cost-effectiveness thresholds: £15,000 , £20,000n = 83, 50%; WL n = 82, 50%). A total of 112 randomised participants (68%) were included in the primary analysis; 51  were not followed up at T1 as this was not triggered within the study timeframe (dictated by funding envelope), and two did not provide valid SWEMWBS at baseline. Of those followed up at T1 , 87% of HD arm participants had received a hearing dog and 91% of WL arm participants were still waiting to receive a hearing dog. Where T1 data collection was attempted, the response rate was 93%.Figure n = 123) and the average age was 48 years .There was evidence of a difference in SWEMWBS score at T1 Table  favourinWith respect to the secondary outcome measures, with the exception of the HLQ-Sound, there was evidence of a difference between the two groups at T1 favouring HD Table . Effect p < 0.001) times those of WL. Similar patterns were observed for the GAD-7 and PHQ-9, but not the WSAS .Within the analysed sample, 87% (48/55) of HD arm participants had a hearing dog and 91% (52/57) of WL arm participants had not received a hearing dog at T1  comprised n = 83 (HD arm) and 82 (WL arm). Table As for the effectiveness analysis, the analysed sample n = 16 compriseQALY) was 0.012 (ns). In the scenario where the cost of a hearing dog is borne entirely by the charity, the estimated differential cost (δCOST) was − £260, indicating that public sector care costs were lower for the HD arm. This difference was not statistically significant but, on average, it was driven by 0.6 fewer other outpatient visits  and 0.2 fewer day cases  in the HD arm. When the cost of the hearing dog  was included, δCOST was £2954 and was statistically significant, that is total costs were, on average, higher in the HD arm. Discounting QALYs and costs in the second year (from month 13 to 21) at 3.5%, in line with NICE guidance [For the whole trial period, on average, QALYs for the HD arm were higher than for the WL arm (1.300 vs 1.256). The estimated differential QALY  of 0.014, and marginally higher cost savings (δCOST) of £291, indicating that public sector care costs were lower for the HD arm. When the cost of the hearing dog was included, δCOST was £2954 and was statistically significant. That is, total costs were, on average, higher in the HD arm.Results for the active intervention period were similar with a marginally higher estimated differential QALY . The probability that the hearing dog was cost-effective was over 94% for all health opportunity cost thresholds considered.In contrast, in the scenario where the cost of a hearing dog is fully borne by the public sector, the ICER was £242,912 per QALY for the whole trial analysis period and £203,959 per QALY for the active intervention period. These values are considerably higher than the highest threshold of £30,000 per QALY and indicate that under this scenario, hearing dogs are not cost-effective. This is confirmed by a probability of cost-effectiveness equal to 0% and a negative NHB for all three thresholds. Figure 4  which have evaluated the impact of hearing dogs. Guest’s before and after study  also repIt is important to note that hearing dog recipients are individuals who have actively pursued receiving a hearing dog. Thus findings cannot be applied to all those with this level of hearing loss. Indeed, it is likely that some of this population would not consider such an option due to personal preferences, living situation or cultural background . In addiOur cost-effectiveness analysis implies that, given the current model of provision in the UK whereby the costs of hearing dogs are borne by the charitable sector (HDfDP), this intervention is a worthwhile investment when seen from a public sector perspective. Compared to usual care, hearing dogs reduced use and costs of public sector health and social care services, and improved QALY-based outcomes. Whilst it was not cost-effective for the full cost of hearing dogs to be borne by the health and social care sector, a partial contribution by the public sector of between £442 and £726 , over the initial 6-month period of the hearing dog partnership could represent value for money . If the benefits and impacts on health observed in this study persisted over the duration of the hearing dog partnership (11 years on average), a contribution by the public sector of between £8,236 and £13,538  would represent value for money. As with other charities addressing health and social care needs, it would appear that the NHS and LAs benefit from the service provided by HDfDP. However, given its dependency on charitable donation, the extent to which HDfDP can exceed current rates of provision – and thus further benefit the public sector - is unclear.Finally, we note that the trial evaluated the impacts of hearing dogs provided by Hearing Dogs for Deaf People. Assistance Dogs International (ADI) accredited hearing dog providers in other countries may differ with regard to training, assessment, matching and support processes. Findings may therefore not be applicable to hearing dogs provided by other ADI accredited organisations or other types of hearing dog providers.Whilst the trial design and cost-effectiveness methods used are robust, there are a number of limitations. A hearing dog partnership typically lasts around 11 years. However, this trial only investigated the first six months into the partnership.  It is unlikely, however, that a trial design could be used to investigate longer-term outcomes.Several HD arm participants did not receive a hearing dog within the data collection period. Consequently, we fell short of our target sample size n = 128) at T1 meaning non-significant findings could be due to a lack of statistical power, rather than the absence of a true difference. The study only used self-report measures. Future studies could consider independent assessment of some outcomes . The nature of the intervention, and the way it is provided, inherently introduce limitations that are not possible to remediate. Individuals in the WL arm had already been accepted for a hearing dog and had undergone HDfDP’s assessment process, thus they were not a true ‘no intervention’ comparator. However, we note that any impacts of this appear negligible . This reflects how much benefit could be derived from alternative use of resources. At present, however, there is no empirical threshold value available for the health and social care sector combined. In the absence of this, we drew on widely used estimates of the health opportunity cost for the health care sector, which may not be representative of the social care sector. Finally, we note our estimates of the potential public sector contribution are subject to structural uncertainty because they assume effects on health observed during the trial period persist for the entire period of the hearing dog partnership. Whether this is the case is yet to be established.Findings indicate that, hearing dogs (provided by an organisation adhering to ADI standards) positively impact recipients’ mental well-being as well as daily functioning, mental health, experiences of fearfulness and social isolation and perceived dependency on others, at least in the short term. They suggest that hearing dogs are good value for money for the public sector but only if it does not bear the full cost of providing them. The study is an example of successful delivery of a trial in a third sector organisation with no previous experience of integrating a trial into its application, assessment and delivery processes. It also breaks new ground within the wider field of assistance dog evaluations.Additional file 1. CONSORT checklist.Additional file 2. Health and social care unit costs.Additional file 3. Cost-effectiveness analysis, supplementary tables : Table 6: Health care resource use at each time point. Table 7: Social care resource use at each time point. Table 8: EQ-5D-5L index score, health and social care costs at each time point. Table 9: Missing data at each time point.Additional file 4. Cost-effectiveness analysis, supplementary figure. . Figure 2: Cost effectiveness plane and acceptability curve.Additional file 5. Cost-effectiveness analysis, supplementary table . Table 10: Cost-effectiveness analysis based on SC-QALYs: descriptive statistics and results.Additional file 6. Cost-effectiveness analysis, supplementary figure . Figure 3: Cost effectiveness plane and acceptability curve .


Frailty is associated with poor health outcomes in later life. Recent studies suggested that hearing loss may be a potentially modifiable risk factor associated with frailty.This systematic review and meta-analysis aimed to investigate the association between hearing loss and frailty in observational studies of adults aged 50 years or over. We included observational studies with participants ≥ 50 years old that have clear descriptions of hearing and frailty measurement methods. Meta-analyses were conducted using measurement of risk and 95 % confidence interval of each individual study. Quality assessment, risk of bias, heterogeneity and sensitivity analyses were also conducted. Our study followed PRISMA guidelines.Our search identified 4508 manuscripts published in English between 1 and 2000 and 9 February 2021. Sixteen articles reported acceptable measurements of both hearing loss and frailty. Two papers were not suitable for meta-analysis. Twelve sets of cross-sectional data involving 12,313 participants, and three sets of longitudinal data involving 3042 participants were used in the meta-analysis. Hearing loss was associated with an 87 % increase in the risk of frailty among cross-sectional studies  and 56 % among longitudinal studies . There was considerable heterogeneity among studies, but their quality rating, sample size or approach used to assess hearing loss did not change the results substantially.The findings of this systematic review and meta-analysis of observational studies suggest that hearing loss increases the risk of frailty in later life. Whether this relationship is causal remains to be determined.The online version contains supplementary material available at 10.1186/s12877-021-02274-y. Frailty is a common clinical syndrome in older adults that is associated with adverse health outcomes and increased mortality over time . There iRecent research findings have shown that frailty is not a static syndrome, and many of its signs and symptoms can be reversed, at least partly, with appropriate interventions, such as physical activity, diet and review of medications –10. ThesThere are a number of potential pathways linking hearing loss to frailty . HearingGiven the negative health outcomes associated with frailty and the high prevalence of hearing loss in this age-group, it seems important to determine if this association is likely to be causal. An initial step in this process would be to determine if there is an association between hearing loss and frailty by reviewing currently available studies investigating this. Thus, this systematic review and meta-analysis aimed to examine the association between hearing loss and frailty in later life. Specifically, we wanted to determine if in older adults aged 50 years or older, does hearing loss increase the risk of frailty compared with normal hearing? We hypothesised that hearing loss would increase the risk of frailty in older adults aged 50 years or over.This review focused on observational studies and was limited to papers published in English. We searched cross-sectional, cohort and case-control studies investigating the association between hearing loss and frailty. Studies were included if: (1) the subjects of the study were aged 50 years or above; (2) hearing loss was self-reported or measured by audiology tests; (3) the presence of frailty was ascertained through the use of a valid measure. Studies were excluded if: (1) the type or cause of individuals’ hearing loss was reported and the hearing loss may not be permanent, for example, it was conductive or caused by other health issues such as tumour or injury; (2) the study did not offer a clear description of hearing and frailty assessment.We conducted a comprehensive literature search of Medline, PsychINFO, Embase, and the Cochrane Collaboration databases from 2000 to February 2021. This time limit was set because studies on frailty emerged prominently after 2000 according to previous review articles , 5, 24. Identified citations from the electronic and manual searches were screened for eligibility by RT and full text documents of potentially eligible articles were retrieved. These articles were further assessed for final eligibility by all authors.Data extracted from the final articles included: authors, sample characteristics, study characteristics, measurement and criteria of hearing loss and frailty, and quantitative data for the purpose of meta-analysis. Authors were contacted when necessary if study information or data were not reported in the published articles.The quality of the articles were assessed using the Newcastle-Ottawa Scale (NOS). This scStata 16.1 software was used for the meta-analyses  using the ‘metan’ command. We used the measure of risk and respective 95 % confidence interval of each individual study to calculate the overall summary estimate of risk for all studies. Results that were adjusted for confounders were used when available. In this review, we use the generic term ‘risk ratio’ to describe the odds ratio, relative risk or hazard ratio reported by the individual studies. Separate analyses were undertaken for different study designs . A random effects model was chosen because of study heterogeneity. Most studies reported hearing and frailty status in a dichotomous manner. Some studies reported these in several categories according to their severity, such as normal, mild, moderate or severe for hearing loss, and normal, pre-frail or frail for frailty. For these studies, data of the most severely impaired category was used for the purposes of the meta-analyses.2 tests were conducted to examine heterogeneity. Significant Q test results (P < 0.10) provides evidence of heterogeneity. I2 test was used to quantify heterogeneity. Heterogeneity with I2 values lower than 40 % is generally considered low, 41-60 % is considered medium, and I2 values over 60 % is considered high. Heterogeneity was then explored by conducting subgroup analyses and sensitivity analyses. Sensitivity analysis was conducted by repeating the meta-analysis while sequentially removing individual studies.Q and IFigure Table The studies used various methods to define frailty. Most n = 13) used the Fried criteria  to defin used theFollow-up periods for the five longitudinal studies varied, with 10 years of follow up reported by Kamil et al. (2016) , five yeThree studies were conducted in the USA , 31, 32,Fourteen studies were included in the meta-analysis. Among them, seven , 37, 39 Study quality is summarised in eTable The overall association between hearing loss and frailty for cross-sectional studies included in this meta-analysis was associated with a RR of 1.87 (95 %CI 1.63–2.13). For longitudinal studies the RR was 1.56 (95 %CI 1.29–1.88) – see Fig. 2 = 75.2 %) and low (I2 = 15.9 %) heterogeneity present in the meta-analysis of cross-sectional and longitudinal studies, respectively. The funnel plots indicated that publication bias may have been present and that positive studies may have been more likely to appear in print (figure not shown).There was high .Among cross-sectional studies, Castellana et al. , Closs eThe association between hearing loss and frailty remained significant regardless of study size although heterogeneity did vary across the three sample size categories eFigure . The gro2 = 78.9 % vs. I2 = 0 %). The summary effect was also higher in the ‘fair’ quality studies, but it was associated with a less precise effect estimate .Estimates of study quality did not seem to affect the results of the meta-analysis eFigure , althougThe aim of this systematic review and meta-analysis was to determine if there is an association between hearing loss and frailty by reviewing currently available studies. We found that the risk of frailty is greater among older people with than without hearing loss, regardless of study design , method of assessment of hearing and frailty, sample size or study quality.Apart from the positive association between hearing loss and increased risk of frailty, other findings merit mention. Kamil et al. (2014)  showed tThere are a number of strengths and limitations worth considering in this review. The possible publication bias suggests that the effect of the association between hearing loss and frailty may have been overestimated. Limiting our literature search to English language may also raise questions regarding the generalisability of the findings. We were only able to include 14 publications with 15 separate datasets  in the meta-analyses, thereby limiting the power and generalizability of the study. Nonetheless, most studies included in this review had good methodological quality and our sensitivity and subgroup analyses suggest that the observed associations are most likely robust.Heterogeneity, especially clinical heterogeneity, needs to be considered. Hearing ability in most studies were self-reported or measured by simple screening test such as whisper test or finger friction test. The self-reported degree of hearing impairment tends to be underestimated by middle-aged to older adults , so thatn = 15)[Likewise, the heterogeneity associated with the assessment of frailty raises doubts about how best to interpret these results. Most of the studies (n = 15), 35 thatn = 15) used then = 15) noted a Eleven out of 16 articles reviewed used available data from existing population studies. These large studies collect data from multi-disciplines and were not specifically designed for hearing and frailty analysis. This could account for the limitations in study design in most of the articles we reviewed. Moreover, most studies had a cross-sectional design, so that the direction of the observed associations was not clear. Five articles reported longitudinal results, but follow-up periods varied from 1 year to 10 years.Currently there is insufficient evidence to conclude that a causal relationship between hearing loss and frailty exists. More research is needed to investigate the plausibility of such hypotheses. It is important to further confirm and investigate this relationship. If hearing loss is found to be a marker of frailty, then health care providers should consider medical review for frail or pre-frail status when hearing loss is present. If hearing loss contributes significantly to frailty, then appropriate management may delay frailty and death in later life. Either way, considering the high prevalence of hearing loss among aged adults and the relatively straightforward management of this, regular assessments of older adults at risk of hearing loss and the proper management of hearing impairment could improve the quality of life of older adults and, potentially, lower costs of healthcare and social support systems by delaying the onset of frailty.Our review and meta-analysis of observational studies suggest that hearing loss is associated with higher prevalence and risk of frailty in later life. Whether this relationship is causal remains to be determined.Additional file 1.


It is unclear whether visual and hearing acuity are independently or synergistically associated with muscle strength. We aimed to examine the associations of visual and self-reported hearing acuity with low handgrip strength and the additive interaction between visual and hearing acuity on low handgrip strength in people over 60 years.Data of 3,075 individuals aged over 60 years from the 2017 and 2018 Korea National Health and Nutrition Examination Survey were used for this cross-sectional study. Low handgrip strength was defined based on the 20th percentile of the study population . Visual and self-reported hearing acuity were each divided into three categories: good, moderate, and impaired. Multiple logistic regression and relative excess risk due to interaction (RERI) were performed.Of the 3,075 participants, 993 (32.3 %) demonstrated low handgrip strength. Low handgrip strength was more prevalent in participants with moderate  and impaired visual acuity . Both moderate and impaired self-reported hearing acuity were significantly associated with low handgrip strength . The more severe the sensory function decline, the higher the association with muscle weakness. Moreover, combined sensory impairments were associated with deteriorating low handgrip strength (AOR = 8.38), with significantly strong additive interactions .Awareness is needed regarding the risk of reduced muscle strength in individuals with moderate and impaired sensory function. Older people with sensory function decline in clinical settings may benefit from programs such as exercise prescription to prevent muscle weakness.The online version contains supplementary material available at 10.1186/s12877-021-02470-w. Age-related decline of physical function and increasing functional disability are associated with adverse health outcomes in older people, including reduced quality of life and increased all-cause mortality , 2. AmonVisual and hearing impairment increase with age. In the older Korean population (aged ≥ 60 years), the prevalence of hearing loss is 16.8 % , and visFurthermore, the problem becomes aggravated if visual and hearing impairment occur concomitantly. Combined visual and hearing impairment have a greater effect on the functional status of ADL and instrumental activities of daily living than solitary sensory impairment . AdditioDespite the functional connection between sensory and motor areas , little Moreover, studies evaluating the association between sensory function and handgrip strength divided sensory function dichotomously (mainly into good or impaired); thus, the dose-response effect of sensory function decline on handgrip strength could not be evaluated , 24. OwiTherefore, we aimed to evaluate the association of visual and self-reported hearing acuity with LHGS in older Koreans. The current study used a measure that has more than two levels, which allows more sensitivity in comparing various degrees of impairment with those with normal acuity. Furthermore, we investigated the interaction of visual and hearing acuity with LHGS and performed subgroup analyses stratified by sex, age, physical activity level, and BMI.This cross-sectional study used data obtained from the 2017 and 2018 Korea National Health and Nutrition Examination Survey (KNHANES), which is a nationwide population-based survey designed to acquire information regarding the health and nutrition of people in South Korea . The surA total of 16,119 participants were involved in the 2017–2018 KNHANES. In this study, persons aged < 60 years were excluded  because we aimed to evaluate the association of visual and hearing acuity with LHGS in older Koreans; those who did not undergo visual acuity evaluation or assessment via an auto-refractor/keratometer were also excluded (n = 952). Furthermore, those who answered “do not know,” refused to respond to the questions, or had missing data for the question, “Which statement best describes your hearing (without a hearing aid)?” were excluded (n = 12). Additionally, persons whose handgrip strength data were unavailable and those who did not answer the query regarding the dominant hand were excluded (n = 108). Finally, after excluding participants with missing variables in covariates in this study (n = 409), 3,075 participants  were selected  and the following method was employed: after determining the dominant hand for each participant through verbal queries, both hands of the participants were measured thrice alternately, starting with the dominant hand, which was followed by a resting period of 60 s. For measuring handgrip strength, participants were instructed to face forward while standing upright, straighten the shoulders, let both arms hang straight down naturally, and grasp the dynamometer with no flexion or extension of the wrist and elbow during the measurement. The maximum handgrip strength of the dominant hand was measured and used for the analysis. The criteria for LHGS were based on the 20th percentile of the study population . ConsequThe independent variables were visual and self-reported hearing acuity. Visual acuity was measured at a distance of 4 m using an international standard vision chart based on the Snellen scale, called the Jins vision chart . ParticiSociodemographic, health-related factors, and year of survey  were all used as covariates in our study . In socip-value < 0.05 was considered to indicate statistical significance.Chi-squared tests were performed to evaluate differences in the frequency and proportion of categorical variables. Multiple logistic regression analysis was conducted to examine the associations of visual and hearing acuity with LHGS, with adjustment for covariates. The results are presented as adjusted odds ratios (AORs) and 95 % confidence intervals (CIs). We examined multiplicative interaction using a series of logistic regression models with a product term and employed relative excess risk due to interaction (RERI) to investigate the presence of interactions on an additive scale of whether the combination of decreased visual and hearing acuity poses greater risk than the sum of their independent effects. RERI was calculated as the difference between the expected value based on the addition of the odds ratios of the two separate risk factors and the observed value in the dual exposed group , where Rn = 87), followed by those with moderate visual acuity  and those with good visual acuity . The distribution of LHGS according to self-reported hearing acuity was also the same as that for visual acuity; LHGS was displayed by 137 (53.9 %) of 254 with impaired hearing acuity, 221 (40.1 %) of 551 with moderate hearing acuity, and 635 (28.0 %) of 2,270 with good hearing acuity.Table p < 0.001]. Participants with impaired hearing acuity demonstrated the highest risk of LHGS than those with good hearing acuity . The more severe the decline in sensory function, the higher the association with LHGS . As age increased, risk of LHGS increased. Low level of physical activity was associated with an increased probability of LHGS , and history of stroke was associated with LHGS. However, participants with obesity were less likely to have LHGS . The sensitivity analysis for self-reported hearing acuity considering the use of hearing aid presented similar results to the main analysis . However, for participants with both risk factors, the AOR of LHGS increased significantly to 8.38 . The RERI was 2.61 . In other words, when impaired visual and hearing acuity were present together, the odds ratio was greater than the sum of the individual effects.Table p = 0.034; impaired, AOR = 2.22, 95 % CI = 1.36–3.62, p = 0.002; low level of physical activity: moderate visual acuity, AOR = 1.71, 95 % CI = 1.13–2.58, p = 0.010; impaired, AOR = 2.26, 95 % CI = 1.40–3.65, p < 0.001).Figure This representative population-based study provided evidence that older Koreans with impaired visual acuity and those with moderate visual acuity had a higher risk of reduced muscle strength, as indicated by LHGS. Moreover, impaired and moderate self-reported hearing acuity were significantly associated with increased risk of LHGS, compared to good hearing acuity. The association between sensory organ function and LHGS demonstrated a progressively increasing pattern as visual and hearing acuity deteriorated. Our results are similar to those of previous research that poor self-rated eyesight was associated with LHGS, and multiple sensory impairments, including hearing impairment, were associated with lower adjusted mean handgrip strength , 24. HowNotably, a combined interaction of impaired visual and hearing acuity that was greater than the sum of their individual impacts was identified. Compared to participants with good visual and hearing acuity, those with concomitant impaired visual and hearing acuity had up to eight times greater odds of having LHGS. Several studies have shown that combined or concurrent impaired visual and hearing acuity are associated with cognitive and functional decline , and funThe mechanism of the association between decreased visual and/or hearing acuity and LHGS remains unclear. There are several hypotheses proposing that decreased visual and/or hearing acuity are related to LHGS or overall muscle strength. Visual acuity plays a leading role in balance control by providing the nervous system with continuously updated information about the position and movement of body segments in relation to each other and the environment . Consequ The subgroup analyses demonstrated prominent associations of LHGS with hearing acuity in male participants and with visual acuity in female participants. It is difficult to explain these sex-specific associations of visual and hearing acuity with LHGS. Sex-differences have been found in the predictors of LHGS , and theSeveral methods can be employed to determine cut-off values for LHGS, which reflect muscle strength as part of the defining criteria for sarcopenia , 54–56, This study has the following limitations. First, the cross-sectional design of this study cannot confirm the causality between sensory function decline and LHGS. However, we mitigated these limitations by employing appropriate methods including adjusting sociodemographic characteristics and well-established risk factors for LHGS and evaluating dose-response relationship. Second, handgrip strength estimation may vary depending on the position or method of handgrip measurement . Third, Nevertheless, the present study has several strengths. First, to the best of our knowledge, this is the first study to identify the synergistic association of visual and hearing acuity with LHGS in the older Korean population. Furthermore, our study is based on a nationally representative survey and random cluster sampling. This makes the data more reliable and representative of the Korean population. Additionally, our findings indicate that awareness is needed regarding risk of reduced muscle strength in individuals with decline of sensory function, even if the level of sensory function decline is minor and not severe. The underlying mechanism and directionality in this relationship needs to be confirmed in future biological or longitudinal studies. Furthermore, if sensory function decline is found in the older participants in a clinical setting, it may be helpful to develop a program such as exercise prescription to prevent muscle weakness in the future.The current study found that older people with decreased visual or hearing acuity had a higher risk of having LHGS than those with good visual or hearing acuity, and the associations differed based on the level of sensory function decline. Additionally, our results provided further evidence that concomitant decreased visual and hearing acuity may be synergistically associated with LHGS, which is considered an estimate of overall muscle strength. This implies that biological or longitudinal prospective studies are needed to understand the effect of decline of sensory organ function on reduced muscle strength. Moreover, in older people clinically diagnosed with sensory function decline, it may be necessary to develop a program to prevent future muscle weakness.Additional file 1.