Endolymphatic hydrops (EH) is considered as the pathological correlate of Menière’s disease (MD) and cause of hearing loss. The mechanism of EH, remaining unrevealed, poses challenges for formalized clinical trials.This study aims to investigate the development of hearing loss, as well as the effect of dehydration treatment on EH animal models.In this study, different severity EH animal models were created. The laser Doppler vibrometer (LDV) and auditory brainstem responses (ABR) were used to study the effects of EH and the dehydration effects of mannitol. The LDV was used to measure the vibration of the round window membrane (RWM) reflecting the changes in inner ear impedance. ABR was used to evaluate the hearing changes. Furthermore, tissue section and scanning electron microscopy (SEM) observations were used to analyze the anatomical change to the cochlea and outer hair cells.The RWM vibrations decreased with the severity of EH, indicating an increase in the cochlear impedance. The dehydration therapy lowered the impedance to restore acoustic transduction in EH 10- and 20-day animal models. Simultaneously, the ABR thresholds increased in EH models and were restored after dehydration. Moreover, a difference in the hearing was found between ABR and LDV results in severe EH animal models, and the dehydration therapy was less effective, indicating a sensorineural hearing loss (SNHL).Endolymphatic hydrops causes hearing loss by increasing the cochlear impedance in all tested groups, and mannitol dehydration is an effective therapy to restore hearing. However, SNHL occurs for the EH 30-day animal models, limiting the effectiveness of dehydration. Our results suggest the use of dehydrating agents in the early stage of EH. By combining analogical observations and objective measurement of hearing loss (ABR and LDV measurement of RWM vibration). The highlights of this study are:1.EH induced hearing loss progressed with the development of EH, it starts at low frequencies, and later involves medium to high frequencies.2.EH increases the cochlear impedance, causing conductive dysfunction. This dysfunction can be cured by dehydration treatment in early stage. But irreversible sensorineural component becomes significant for long-time EH.3.Early dehydration treatment is suggested for reserving hearing.- This study gives an overview of the development of hearing loss in EH, and partly revealed the mechanical basis and biological influences of EH. Moreover, the investigation of dehydration treatment may provide a reference for clinical practice.in vivo and further confirmed EH is a common pathological feature of inner ear diseases characterized by low-frequency hearing loss, including MD (Menière’s disease (MD) is an inner ear disorder named after Prosper Menière , who in uding MD .The physiological mechanisms of Méniere are still poorly understood, yet causative relationships between EH and disordered auditory physiology in MD have been supported by much clinical and experimental evidence. It is widely believed that the dysregulation of endolymph volume may lead to EH and cause a chain reaction. Since morphological changes such as the collapse of stereocilia of outer hair cells  or losinAs the hearing ability can be predicted by the mechanical transfer of acoustic vibration and the round window is considered as an accurate proxy for cochlear fluid displacement , we propHealthy albino guinea pigs , with a positive Preyer reflex and free of tympanic membrane perforation or otitis media, were used in this study. Pre-recruiting ABR measurements (click stimuli) were conducted to exclude animals with abnormal hearing function.Guinea pigs were classified into 10-day EH, 20-day EH, 30-day EH, and blank control groups equally . For the EH group, ABR (tone burst stimuli) was conducted to evaluate the auditory responses of one-third  of the animals, and LDV measurement was used for the other two-thirds . For all EH groups , the ABR measurements were conducted both before and after dehydration with mannitol. Bilateral ears were used in all measurements.For the LDV measurements, the twelve animals in each EH group were divided into two subgroups, one for direct LDV measurement and the other for vibrometry after mannitol treatment. An operation is necessary for LDV measurement, making it hard to keep the animals healthy if further mannitol treatments are followed, which may influence the effect of dehydration. The ABR and LDV results were also obtained as baselines by the blank control groups. After the measurements, the animals were sacrificed using an overdose of anesthetic. The cochleas were sectioned and stored in 10% polymerized formaldehyde or 2.5% glutaraldehyde for further histography.The research program follows the principles of the guidelines for care and use of laboratory animals and was approved by the Ethics Committee of the Eye and ENT Hospital of Fudan University.As several studies report the importance of the endolymphatic sac and further confirm its function of regulating endolymph , we usedThe EH guinea pig model was conducted by intraperitoneal injection of desmopressin acetate , once a day, at a dose of 8 μg/kg weight. The dose of desmopressin reported to induce EH models was variable, but there was evidence supporting increasing dosage and injection days can provide a more severe EH status in animal models at a low dose level . The dosDifferent kinds of hyperosmolar dehydration agents, such as glycerol, urea, isosorbide, sodium bicarbonate, and mannitol, were used to discuss their influence on the inner ears . Given tBefore the ABR measurement, the animals were anesthetized with an intramuscular injection of ketamine hydrochloride (40 mg/kg) and xylazine hydrochloride (10 mg/kg).The ABR measurements were conducted in a soundproof, electromagnetically shielded room. The measurements were conducted using the RZ6/BioSigRZ system . Electrodes were inserted into the skin, one electrode at the vertex for signal recording and two electrodes at the bilateral mastoids as reference and ground. Repeated tone bursts  were presented by a closed-field speaker at a rate of 21 stimuli/s. The test frequency points are 2, 4, 8, 16, 24, and 32 kHz. The sound-intensity level ranges from 20 to 90 dB sound pressure level (SPL) at an interval of 5 dB. ABR responses were recorded and averaged after 1,024 stimuli. The threshold for each frequency point was determined typically by the ABR I, III, and V waves.The vibration of the RWM was measured to evaluate the hearing function of normal, EH-modeled, and mannitol-treated guinea pigs. The feasibility of using RWM vibration as a measure of auditory function has been previously proven .2, < 0.01 mg Polytec, Germany) was carefully placed on the center of the RWM. The tympanic membrane and the ossicular chain were kept intact.The guinea pig was anesthetized using an intramuscular injection of ketamine hydrochloride (40 mg/kg) and xylazine hydrochloride (10 mg/kg). For the duration of the surgery, the animal was placed on a heating blanket to maintain its body temperature. Bilateral auricles were partially removed, and the dorsal auditory bulla was opened to sufficiently expose the RWM . A refleAn LDV  was adopted to measure the vibration of the RWM. The measuring laser beam generated by the device was controlled so that the measuring angle was greater than 70°. The RWM velocity (sensitivity: 2 mm/s/V) and input sound pressure (sensitivity: 20 Pa/V) were simultaneously recorded using a four-channel data acquisition card . Two channels were used. An in-house MATLAB code was developed for measurement control, data acquisition, and analysis. The FFT algorithm was used to obtain the velocity amplitude and sound pressure.For histology, specimens  were decalcified in 10% ethylenediaminetetraacetic acid (EDTA), dehydrated with 15 and 30% sucrose solution, and coated with Optimum Cutting Temperature (OCT) compound. Then the cochlea was frozen and sectioned in the plane parallel to the modiolus (section thickness: 8 μm), followed by hematoxylin and eosin (H&E) stain.For scanning electron microscopy (SEM), during specimen collection, the apical of the cochlea and RWM were opened, poured, and fixed with 2.5% glutaraldehyde at 4°C for 48 h. Then the membranous labyrinth was fully exposed. All other tissues were removed, leaving only the basement membrane, fixed in osmium tetroxide solution, and treated with tannic acid. Finally, the specimens were dehydrated with alcohol, dried, sprinkled with gold, and observed by a scanning electron microscope .Upeak-to-peak = V/(π⋅f) . Then the displacement is normalized by the sound pressure near the tympanic membrane. To statistically analyze the displacement and ABR threshold, the mean and standard deviation (SD) were calculated for each group. Two-tailed Student t-tests were used for data comparison, and p-values of < 0.05 were considered as a significant difference.For sections, since the EH model is induced by desmopressin, the SAM ratio is not suitable for our case. We provided changes in the angle formed by Reissner’s membrane and basilar membrane (BM) to reflect the severity of EH and response to mannitol. For LDV measured data, the RWM velocity amplitude was converted to peak-to-peak displacement according to the mathematical relation: p < 0.05), but low-frequency thresholds were still more prominent . In the EH 30-day group, the ABR thresholds increased over a broad frequency range .Auditory brainstem response thresholds of all groups are presented in p < 0.05) and almost went back to normal. In the EH 20-day group, significant improvements of approximately 10 dB (p < 0.05) were observed in all frequencies. The improved thresholds were still notably higher than that of the normal baseline (refer to The mannitol dehydration treatment effect on ABR thresholds is shown in refer to . In the refer to .p < 0.05). In the EH 20-day group, the peak-to-peak displacements also showed a great improvement. However, at the range of 0.5–1 kHz, the recovery exhibited a mild reduction, compared with the normal curve  and progressed to higher frequencies  are commonly used in the diagnosis and treatment of MD , as theiHearing restoration after dehydration treatment was also evaluated in this study. As shown in both ABR  and RWM Typically, patients with MD experience fluctuating low-frequency hearing loss followed by medium- to high-frequency involvement. Our results support this assumption. In the EH 10-day group, the injury stereocilia of OHC at turn 2 is minimal, and turn 3 is almost normal. The RWM vibration decreased by 7.6, 15.0, and 7.0 dB at 2,4, and 8 kHz, respectively  and objective measurements of hearing loss (ABR and LDV measurement of RWM vibration), we are able to obtain an overview of the development of hearing loss in EH, both mechanically and biologically. The main conclusions of this study are as follows:1.EH-induced hearing loss progressed with the development of EH; it starts at low frequencies and later involves medium to high frequencies.2.EH increases the cochlear impedance, causing conductive dysfunction. This dysfunction can be cured by dehydration treatment at an early stage. But the irreversible sensorineural component becomes significant for long-time EH.3.Early dehydration treatment is suggested for preserving hearing.The original contributions presented in the study are included in the article/The animal study was reviewed and approved by institutional animal care and use committee at Eye and ENT Hospital of Fudan University.S-QW: methodology, formal analysis, visualization, and writing—original draft. C-LL: methodology, formal analysis, visualization, and writing—review and editing. J-QX and L-LC: methodology. Y-ZX and P-DD: writing—review and editing. L-JR: conceptualization, software, writing—review and editing, supervision, and funding acquisition. W-JY: supervision and funding acquisition. T-YZ: conceptualization, supervision, and funding acquisition. All authors contributed to the article 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.


Glomus tumors, also called paragangliomas, originate from nonchromaffin cells. The tumor is typically vascular and grows from capillary and pre-capillary vessels in-between epithelial cells. It is worth mentioning that the most common symptoms are pulsating tinnitus and hearing loss. Imaging studies (CT and MRI) are necessary for diagnosis. This paper shows five patients seen at the Hospital between 1995 and 2001 presenting glomus tympanicum. Women were most commonly affected, and the age ranged from 48 to 60 years (mean age of 50 years). The most common complaints were pulsating tinnitus and hearing loss. All patients were treated surgically. Glomus tumor affecting the temporal bone is an uncommon neoplasia of the middle ear. These tumors grow from paraganglion or glomus bodies, normal structures of the temporal bone. Glomus bodies originate from nonchromaffin cells; these cells, originating from the primitive neural crestAccording to Rosenwaser, histologically, the material from the middle ear contained in tumor cells has granular eosinophilic cytoplasm and small oval nucleus, separated by fibrous tissue containing dilated veins. Tumor cells are close to capillaries, and sometimes they seem to project into the lumen. It is worth mentioning that intravagal tumors have less vascularization, in comparison with jugulotympanic paragangliomas. Polymorphism and hyperchromatism are frequent; however, these features are not associated with malignancyThe most frequent symptoms are hearing loss and pulsating tinnitus, usually unilateral; adjacent structures are usually eroded due to massive vascularization. Tumor growth into the middle ear can destroy the ossicle chain, resulting in conductive hearing loss, facial palsy when fallopian tube is affected, and projection into the outer ear. Otoscopy shows a purple-red mass in the middle ear. Larger masses may be noted as polyps in the external ear and they may present massive bleeding when handledAudiometry shows either conductive hearing loss during early development, or sensorineural hearing loss, whenever the cochlea in affected. Impedanciometry may help the diagnosis: during the examination, tumor pulsation will shift the balance-meter needle synchronically to patient's pulseThe only treatment that can lead to cure is surgical removal. In patients where surgery is contraindicated, radiotherapy can be indicated. In tympanic tumors, surgery is carried out in the middle ear; an amplified transcanal approach may be enough to entirely remove the tumor. In cases where the tumor affects aditus and mastoid, a transmastoid approach and removal of the posterior part of the ear canal is indicatedWe will report 5 cases examined at the Hospital from 1995 to 2001.L. D., 49 years old, female, complaining of pulsating tinnitus on her right ear and ipsilateral hearing loss for 5 years. Otoscopy showed retrotympanic purple tumor; audiometry diagnosed mixed-type hearing loss, without discrimination, SRT of 80 dB. Tympanic mastoidectomy and resection of the glomus tumor was carried out, resulting in massive cavity. Histopathologic examination confirmed the diagnosis of glomus tumor. Postoperative audiometry showed mixed hearing loss and SRT of 90 dB. There was no recurrence after 3 years.S. B. A., 50 years old, female, complaining of pulsating tinnitus and hearing loss on her right ear for four years. Otoscopy showed retrotympanic red tumor; audiometry diagnosed conductive hearing loss and gap of 25 dB. CT scan showed retrotympanic tumor. Tympanic mastoidectomy and tumor resection were carried out.M. C. S., 53 years old, female, complaining of pulsating tinnitus for two years and hearing loss for one year on her left ear. Otoscopy showed retrotympanic tumor; audiometry diagnosed mild conductive hearing loss on her left ear. CT scan showed retrotympanic tumor. She underwent surgery through retroauricular approach, for complete removal of the tumor. Postoperative audiometry was normal.I. M., 46 years old, female, complaining of pulsating tinnitus and hearing loss on her right ear for two years. Audiometry diagnosed mild sensorineural hearing loss of 15 dB. CT scan showed retrotympanic tumor and thickening of the right side of the mastoid. Tympanic mastoidectomy and tumor resection were carried out. Postoperative audiometry showed the same mild hearing loss of 15 dB.T. C., 60 years old, female, complaining of frequent tinnitus and hearing loss on her right ear for one year. Otoscopy showed retrotympanic red tumor. Audiometry diagnosed mild conductive hearing loss. CT scan showed tumor on meso- and hypotympanic areas. She underwent surgery through retroauricular transcanal approach and total tumor resection. Postoperative audiometry showed sensorineural hearing loss in high frequencies. Control CT scan was normal.Glomus tumors are uncommon slow-growing and hypervascularized benign tumors. Gaffey called them chemodectomas, he believed that jugulotympanic paraganglions had chemoreceptor properties, and associated them with aortic and carotid bodies, which could modulate cardiopulmonary reflexes from changes in pO2 and blood pressure. They originate from glomus bodies, non-functioning chemoreceptors also located on the temporal bone, originating from the primitive neural crest. Clinically, the first symptoms of glomus tympanic are pulsating tinnitus and sensorial hearing loss; these symptoms were reported in all patients. The most frequent symptom reported in the literature is pulsating tinnitus, evidenced in all of our patients. However, due to the slow growing feature of this tumor, the symptoms will often occur when the tumor has already grown. The second most common symptom is hearing loss, conductive at first; when the inner ear is affected, in cases of central tumor growth, sensorineural hearing loss may occur. This occurred in our patients, possibly due to late diagnosisThe literature also mentions that females are more prone to developing this tumor, on a 4-6:1 rate: we corroborate this, however, we found a rate of 100%. The physical examination showed that the finding of purple retrotympanic mass during otoscopy is important; we could observe that in all cases. We chose to surgically remove the tumor in all cases through retroauricular approach, performing mastoidectomy whenever the tumor was too large. Tympanic mastoidectomy plus resection seemed to be associated with late diagnosis in our patientsTympanic paragangliomas are slow-growing benign tumors in weak areas within the temporal bone. In the literature, there are rare reports of malignancy. The most common symptom is pulsating tinnitus, followed by conductive hearing lossAs a result of these symptoms, audiometry and radiographs are mandatory . Incision biopsies and paracentesis are contraindicated because there is high risk for complications resulting from bleeding. Surgical resection and histopathologic examinations are necessary to differentiate it from other tumors. When there is no contraindication, all patients must undergo surgery


There is a high demand for audiologists throughout the United States. Previous research has supported an additional demand for these providers within Appalachia.The purpose of the study was to determine if Appalachia has a disproportionally high demand for audiologists compared to the rest of the United States.A cross-sectional retrospective study was performed with population data from the Appalachian Regional Commission, the American Academy of Audiology, and the United States Census Bureau. County-level population-weighted averages of individuals with perceived hearing loss and number of audiologists per capita were compared between Appalachian and non-Appalachian counties.A mean weighted 5.76 % of individuals reported hearing loss within Appalachia, which was 1.1% higher than the rest of the United States. The 1.14 audiologists per 100,000 individuals in Appalachian counties was not significantly lower than the 1.32 audiologists per 100,000 individuals found in non-Appalachian counties. Audiologists per capita decreased with increases in Beale code and percent reporting hearing loss.The high number of individuals reporting hearing loss supports an increased demand for audiologists in rural Appalachia. More research is needed to determine how to meet this demand or improve the efficacy of the limited number of providers. Approximately 21.7% of U.S. adults are affected by hearing loss, which negatively impacts oral communication.1Hearing loss treatment has been shown to increase activity participation and overall quality of life.Audiologists are the only healthcare provider specially trained to diagnose the site of lesion of a hearing loss within the ear or along the neural auditory pathway, identify the need for referrals through advanced diagnostic testing, select and program hearing aids and implantable devices, and provide aural rehabilitation.The availability of audiologists is a problem throughout the United States.11Those who live in rural areas have a high demand for hearing health care, which is caused by both a decrease in access to healthcare providers and an increase in hearing loss.20Appalachia is a primarily rural region in the U.S. that may have a high demand for adult audiological services. As found in many rural regions, adults living in Appalachia have reported that both the cost of audiological services and the distance to the nearest provider made seeking treatment prohibitive.24Previous studies have supported a lack of access to hearing healthcare in Appalachia. The primary purpose of this study is to compare the demand for adult audiological services in Appalachia to the demand of audiological services throughout the rest of the country. Demand will be evaluated by measuring the percent of individuals reporting hearing loss and the count of audiologists per capita. Additionally, this study is designed to determine how rurality may play a role in this demand. Identifying an Appalachian-specific disparity in access to audiologists may support expansion of access to hearing services provided to this area.Percentage of reported hearing loss, number of audiologists registered with the American Academy of Audiology (AAA), Beale codes, and county level classifications throughout the contiguous U.S. were downloaded from publicly available databases within five organizations: (1) U.S. Census Bureau, (2) American Academy of Audiology, (3) U.S. Department of Agriculture, (4) Appalachian Regional Commission, and (5) National Oceanic and Atmospheric Administration. The data collected from these organizations were used to evaluate the demand for audiological services in Appalachia compared to the rest of the contiguous U.S.All counties in the contiguous U.S. were placed into one of ten regional groups to measure the demand for audiological services in Appalachia compared with other geographical regions . To accoThe total population for each county was downloaded from the U.S. Census Bureau, which sends out a survey, either by mail or by visit, to every home in America every ten years. The results of this survey were accessed using the U.S. Census Bureau data exploration tool.The demand for audiological services was evaluated by first measuring the estimated percentage of individuals reporting hearing loss in each county. These measurements were obtained from the American Community Survey. This survey is sent out through the internet, mail, or phone interview to approximately 10% of homes in the United States.The demand for audiological services was further evaluated by tallying AAA registered audiologists per 100,000 individuals in each county. The number of AAA registered audiologists was obtained through email correspondence with the AAA, the largest organization of audiologists in the United States.Beale Codes  have been assigned to each county by the U.S. Department of Agriculture.All analyses were conducted with population-weighted county-level data compared between Appalachian and non-Appalachian regions across the ten geographical regions previously described. All data were averaged within regions or across non-Appalachian regions to reduce the effects of sampling variability caused by the American Community Survey, which only sampled 10% of the population. Also, comparing means across regions reduced the effects of sampling bias because biases likely equally affect both Appalachian and non-Appalachian counties. These comparisons cancel out their effects. For all tests, alpha values were set to 0.001 to account for multiple tests based on a Bonferroni correction. All analyses were conducted using SPSS (Armonk NY: IBM Corp).To evaluate the demand for audiological services in Appalachia, percent of individuals reporting hearing loss, the number of AAA registered audiologists per 100,000 individuals, and Beale codes were compared between Appalachian and non-Appalachian regions. First, the percent of individuals reporting hearing loss, number of AAA registered audiologists per 100,000 individuals and Beale codes were compared between Appalachian and non-Appalachian counties using a three separate t-tests. Then, the percent of individuals reporting hearing loss, number of AAA registered audiologists per 100,000 individuals, and Beale codes for each county were compared between Appalachia and the other nine regions using three separate post hoc analyses of variance.Linear regression analyses were used to evaluate the relationship of county-specific variables, without considering region. The association between the pairwise combinations of the percent of individuals reporting hearing loss, the number of AAA registered audiologists per 100,000 individuals, and the Beale code was assessed across all counties in the contiguous United States.Two multiple linear regression analyses were used to assess the combined relationship of the region , the percent of individuals reporting hearing loss, the number of AAA registered audiologists per 100,000 individuals, and Beale codes. The first multiple linear regression analysis was used to assess the effect of Beale code and region on the percentage of individuals reporting hearing loss. This analysis was performed to determine if Beale codes were associated with individuals reporting hearing loss, after adjusting for region, and to determine if regions were associated with percent of individuals reporting hearing loss, after adjusting for Beale codes. To complete the regression analyses, counties were set to 0 for non-Appalachian counties and 1 for Appalachian counties. Then, a second multiple linear regression analysis was used to measure the effect of Beale codes and percent of individuals reporting hearing loss on the number of AAA registered audiologists per 100,000 individuals. This second analysis was performed to determine if Beale codes were associated with the number of audiologists per 100,000 individuals, after adjusting for the percent of individuals reporting hearing loss and determine if the percent of individuals reporting hearing loss and the number of audiologists per 100,000 individuals were associated, after adjusting for Beale codes.The mean population-weighted percent of individuals reporting hearing loss was compared between Appalachian and non-Appalachian counties. The mean was found to be 5.76 percent in Appalachia, which was significantly (p<0.001) higher than the 4.66 percent found throughout the rest of the country . When thThe mean population-weighted count of audiologists per 100,000 individuals was compared between Appalachian and non-Appalachian counties. This mean was 1.14 for Appalachian counties, which was not significantly less than the 1.32 found in non-Appalachian counties . The meaMean population-weighted Beale codes were also compared between Appalachian and non-Appalachian counties. This mean was 4.54 for Appalachian counties, which was not significantly different from the 4.07 found in non-Appalachian counties . HoweverLinear regression analyses were used to measure associations between the three pairwise comparisons among (1) the percent with reported hearing loss, (2) the number audiologists per 100,000 individuals, and (3) Beale codes . Again, Two multiple linear regression analyses were used to assess the combined relationship of region , the percent of individuals reporting hearing loss, the number of AAA registered audiologists per 100,000 individuals, and the Beale code. First, the effect of Beale code and Appalachian classification on the percent reported hearing loss was measured. Both Beale code and Appalachian classification were significantly and independently associated with percent reported hearing loss . AdjustiIn the second analysis, the effect of Beale codes and percent reported hearing loss on the count of audiologists per 100,000 individuals was evaluated. BothBeale codes and the percent reported hearing loss were significantly and independently associated with the count of audiologists per 100,000 individuals. Adjusting for the Beale code did not affect the association between the count of audiologists per 100,000 individuals and percent reported hearing loss and adjusting for percent reported hearing loss did not affect the association between Beale codes and the count of audiologists per 100,000 individuals.An estimated 5.76% of Appalachians reported hearing loss, which is about 1.1% higher than non-Appalachian regions. The estimated number of audiologists per 100,000 individuals in Appalachia was 1.14, which was not significantly lower than the 1.32 found in non-Appalachian counties. These findings collectively indicate that rural Appalachians have an increased demand for audiological services compared to the rest of the country. Previous studies demonstrating a lack of access to hearing care providers in Appalachia likely found the greatest access restriction in the more rural counties.7A multilinear regression model showed that those from Appalachia had more hearing loss than those from non-Appalachian counties, even after accounting for differences in Beale code. These findings were further supported with region-specific analyses which showed that overall, there was a higher percent of reported hearing loss in Appalachia compared to many regions, regardless of each region’s Beale code relative to Appalachia. The Appalachian-specific hearing loss may have been caused by the Appalachian coal miner’s reluctance to wear hearing protection in the 1990s.20Audiologists are struggling to fill the need for hearing health care. Also, the future of audiology is projected to worsen as the age of the population increases and the overall number of audiologists is expected to decrease.Appalachia may benefit from motivating audiologists to work in this region, as well as an increased partnership with other healthcare providers. Incentives, such as student loan forgives, have motivated other healthcare professions to relocate to other rural areas.32Appalachia may also benefit from new service delivery models that use eHealth technology and either community healthcare workers or audiology assistants to increase affordability.36Increasing cooperation between audiologists and physicians may also improve hearing care in rural Appalachia. Physician advocacy was a major factor predicting patient’s history of receiving a hearing test.14Limitations of this study include estimates based on sample size. Reported hearing loss was estimated from surveys that were only distributed to 10% of the population, and audiologists per capita were estimated from the count of audiologists registered with the American Academy of Audiology and population data.Appalachians have more reported hearing loss than the rest of the contiguous united states, even after adjusting for rurality. There is an overall shortage of audiologists, which increases with rurality. Combined, these findings indicate that there is a demand for improvements in audiological services in rural Appalachia. These improvements may include incentivizing audiologists to work in Appalachia, utilizing electronic health care, or improved cooperation between audiologists and physicians in this region. More work is needed to evaluate the efficacy of these interventions.What is already known about this topic? Appalachians have reduced access to health care compared to the rest of the country and a history of noise exposure.What is added by this report? This study found that Appalachians have an increased number of individuals reporting hearing loss compared to the rest of the country and may have fewer audiologists.What are the implications for future research? More work is needed to determine where in Appalachia the demand for audiological care is highest so that changes can be made to support the needs of the communities.


Globally, hearing loss is the second leading cause of disability, affecting approximately 18.7% of the world’s population. However, the burden of hearing loss is unequally distributed, with the majority of affected individuals located in Asia or Sub-Saharan Africa. Following the 2014 West African Ebola Outbreak, disease survivors began to describe hearing loss as part of the constellation of symptoms known as Post-Ebola Syndrome. The goal of this study was to more fully characterize hearing loss among Ebola Virus Disease (EVD) survivors.EVD survivors and their household contacts were recruited  from Eastern Sierra Leone. Each individual completed a symptom questionnaire, physical exam, and a two-step audiometry process measuring both air and bone conduction thresholds. In comparison to contacts, EVD survivors were more likely to have complaints or abnormal findings affecting every organ system. A significantly greater percentage of EVD survivors were found to have hearing loss in comparison to contacts . Additionally, survivors were more likely to have bilateral hearing loss of a mixed etiology. Logistic regression revealed that the presence of any symptoms of middle or inner ear (p < 0.001), eye (p = 0.005), psychiatric (p = 0.019), and nervous system (p = 0.037) increased the odds of developing hearing loss.This study is the first to use an objective and standardized measurement to report hearing loss among EVD survivors in a clinically meaningful manner. In this study it was found that greater than 1/5th of EVD survivors develop hearing loss. The association between hearing impairment and symptoms affecting the eye and nervous system may indicate a similar mechanism of pathogenesis, which should be investigated further. Due to the quality of life and socioeconomic detriments associated with untreated hearing loss, a greater emphasis must be placed on understanding and mitigating hearing loss following survival to aid in economic recovery following infectious disease epidemics.The online version contains supplementary material available at 10.1186/s12879-022-07604-y. Data from the global burden of disease study indicates that hearing loss is currently the second leading cause of disability-adjusted life years (DALYs) . ApproxiIt is well known that individuals living in these environments suffer from higher rates of bacterial and viral meningitis and the neurologic sequelae associated with these infections , 15. HeaEbola virus has caused several large epidemics throughout Sub-Saharan Africa costing thousands of lives , 20. TheThe case control study described here sought to characterize Post-Ebola Syndrome hearing loss. Characterization of this and other sequelae may help elucidate the pathogenesis of Post-Ebola Syndrome, identify treatment and intervention options, and increase understanding of the full disease course of EVD. An increased understanding of this disease course will allow for improved ability to design interventions and treatments to mitigate and prevent the acute and chronic symptoms of EVD affecting these tropical and LMIC.This study was conducted in eastern Sierra Leone from July 2018 to June 2019. Most participants were already enrolled in an ongoing longitudinal study of EVD survivors and household contacts in Sierra Leone . EVD surAll individuals completed an extensive questionnaire concerning constitutional, psychiatric, neurologic, ocular, audiovestibular, respiratory, cardiac, gastrointestinal, urorenal, and reproductive or sexual symptoms experienced at the time of the audiometry testing. Additionally, all individuals were given a full physical exam completed by a government hospital physician and a two-step audiometry process.The first step of the audiometry exam employed the use of a portable Ambco 650AB audiometer . Pure tone air conduction thresholds were measured from 0.25 to 8 kHz and pure tone averages (PTA) were calculated using 0.5, 1, 2, and 4 kHz thresholds for each ear. If individuals were found to have a threshold ≥ 25 dB in at least one ear at one or more frequencies, they were referred to the second confirmatory step of the audiometry process. The second step of audiometry testing measured pure tone air and bone conduction thresholds using the SHOEBOX® Audiometry Pro Edition . PTAs were then calculated to determine the presence of any hearing loss . At the Data was collected on standardized forms, entered into Microsoft Access  databases, imported into R statistical software, and manipulated within the RStudio environment , 37. SigBy the end of the study period in May 2019, a total of 1,012 individuals were enrolled into the study cohort and completed at least one study visit including audiometry testing. All subjects enrolled in this study were recruited from the Kailahun, Kenema, and Kono Districts in Eastern Sierra Leone  EVD survivors and 199  household contacts failed the first step of the audiometric exam and completed additional audiometry testing. One hundred thirty-seven individuals were confirmed to have pure tone averages ≥ 25 dB in at least one ear and met criteria for hearing loss . The most common type of hearing loss found among this survivor cohort was bilateral of either a mixed or sensorineural etiology. The majority of individuals with hearing loss were found to have mild hearing loss. Several previous studies have indicated that hearing loss is associated with an impaired ability to complete activities of daily living, increased rates of isolation, increased risk of depression, early cognitive decline in the elderly; increased risk of under- or unemployment, and lower socioeconomic status in adults; and increased risk of non-completion of secondary education, lower scores on IQ and verbal intelligence tests, and impaired language development in children , 58–64.The relationship between hearing loss and decreases in economic output further emphasize the importance of providing treatment in these areas. Several previous studies have noted poverty as an important risk factor for infection and disease epidemics –69. SpecThe results of this study are not without limitations. Significant differences were found between the age and gender distributions of the survivor and contact groups. This difference can be explained due to the higher incidence among women during the West African Ebola epidemic , 77. ThiIn conclusion, the results of this study demonstrate that 23% EVD survivors were found to have hearing loss following the resolution of the acute phase of illness. This hearing impairment was found to be significantly associated with the simultaneous development of symptoms affecting the eye and nervous systems. The association between ophthalmologic and neurologic symptoms and hearing loss may indicate a similar mechanism of pathogenesis. Future studies of EVD and Post-Ebola Syndrome would benefit from a more robust examination of the disease processes affecting the inner and middle ear in order to gain a fuller understanding of the spectrum of Post-Ebola Syndrome and to inform future interventions. The capacity to diagnose and provide treatment to affected individuals is severely limited in many tropical and low-income areas. Strategies designed to mitigate hearing loss in EVD survivors may also indirectly benefit other individuals affected by hearing loss.Additional file 1:Table S1. Ebola symptom questionnaire. Table S2. Ebola physical exam data. Figure S1. Decision tree modeling predicting sensorineural or mixed hearing loss among EVD survivors. Table S3. Odds ratios of logistic regression analysis of sensorineural or mixed hearing loss among EVD survivors.


The current gold standard of clinical hearing assessment includes a pure-tone audiogram combined with a word recognition task. This retrospective study tests the hypothesis that deficits in word recognition that cannot be explained by loss in audibility or cognition may reflect underlying cochlear nerve degeneration (CND). We collected the audiological data of nearly 96,000 ears from patients with normal hearing, conductive hearing loss (CHL) and a variety of sensorineural etiologies including (1) age-related hearing loss (ARHL); (2) neuropathy related to vestibular schwannoma or neurofibromatosis of type 2; (3) Ménière’s disease; (4) sudden sensorineural hearing loss (SSNHL), (5) exposure to ototoxic drugs  or (6) noise damage including those with a 4-kHz “noise notch” or reporting occupational or recreational noise exposure. Word recognition was scored using CID W-22 monosyllabic word lists. The Articulation Index was used to predict the speech intelligibility curve using a transfer function for CID W-22. The level at which maximal intelligibility was predicted was used as presentation level (70 dB HL minimum). Word scores decreased dramatically with age and thresholds in all groups with SNHL etiologies, but relatively little in the conductive hearing loss group. Discrepancies between measured and predicted word scores were largest in patients with neuropathy, Ménière’s disease and SSNHL, intermediate in the noise-damage and ototoxic drug groups, and smallest in the ARHL group. In the CHL group, the measured and predicted word scores were very similar. Since word-score predictions assume that audiometric losses can be compensated by increasing stimulus level, their accuracy in predicting word score for CHL patients is unsurprising. The lack of a strong age effect on word scores in CHL shows that cognitive decline is not a major factor in this test. Amongst the possible contributions to word score discrepancies, CND is a prime candidate: it should worsen intelligibility without affecting thresholds and has been documented in human temporal bones with SNHL. Comparing the audiological trends observed here with the existing histopathological literature supports the notion that word score discrepancies may be a useful CND metric. This type of neural loss does not elevate behavioral or electrophysiological thresholds until it becomes extreme6, partly because the most vulnerable cochlear neurons to both noise and aging do not contribute to threshold detection in quiet8. However, the silencing of cochlear neurons degrades auditory processing and may translate into a variety of perceptual abnormalities including speech discrimination difficulties, particularly in noisy environments12. CND may also be key to the genesis of other perceptual anomalies associated with sensorineural hearing loss (SNHL) including hyperacusis and tinnitus, via an induction of central gain adjustment secondary to loss of afferent input to the auditory central nervous system18.Recent studies on aging and noise exposure from animal models and human temporal bones show that outer hair cell loss accompanies, or is preceded by, cochlear nerve degeneration (CND), a loss of synaptic connections between the inner hair cells and a subset of auditory-nerve fibers19, may not fully assess the hearing impairment associated with CND. While a number of clinical centers have enhanced evaluation protocols , particularly in patients reporting difficulty in noisy environments despite normal or near-normal audiometric thresholds, retrospective studies of CND must rely on traditional audiometric data.Thus, audiology best practices for hearing evaluation in adults, i.e. a standard audiogram and a word-recognition task in quiet20. This sigmoidal performance-intensity function is computed from the patient’s audiogram combined with a transfer function appropriate to the speech material. In absence of multiple word presentation levels, the SIC can be a useful predictor of the maximal word recognition score (WRS). However, the assumptions behind the SIC treat a hearing loss as if it were simply a frequency-specific attenuation of the incoming speech sounds. This is largely true for a conductive hearing loss (CHL), i.e. one due to dysfunction in the sound transmission apparatus of the external and middle ears. However, for sensorineural hearing loss (SNHL), i.e. impairments arising from pathologies in the transduction of sound-induced vibration by the inner ear’s sensory cells into action potentials in cochlear nerve fibers, the pathophysiology is much more complex and cannot, in general, be corrected by simply increasing stimulus level.One tool of particular interest is the speech intelligibility curve (SIC), which describes the cumulative distribution of useful speech information as word presentation level is increased21. In addition to threshold elevation, outer hair cell loss broadens the frequency tuning of cochlear neurons and changes their response phase, which can desynchronize the ensemble neural signal23. These changes in the way sounds are coded in the cochlear nerve cannot be corrected by amplification, and any loss of cochlear neurons will further degrade the information being transmitted to the central nervous system.In SNHL, the elevation of pure-tone thresholds is typically due to loss of, or damage to, the outer hair cells, which normally function as biological motors, amplifying the sound-evoked vibrations of the sensory epitheliumThese basic concepts suggest that the discrepancies between predicted and measured word scores should be smaller in those with CHL than those with SNHL of similar magnitude. Furthermore, among those with SNHL of similar magnitude, and thus a similar degree of sensory cell damage, word-score discrepancies should be greatest in those with the most CND. To test these ideas, we analyzed data from nearly 96,000 ears from patients seen at the Massachusetts Eye and Ear, with normal hearing, CHL or SNHL of several etiologies, including age-related hearing loss (ARHL), noise damage, ototoxic drugs, sudden SNHL, Ménière’s disease and vestibular schwannomas. We observed that the WRS discrepancies were largest in those SNHL etiologies associated with the greatest degree of CND, consistent with the idea that loss of cochlear neurons is a major contributor to the loss of speech intelligibility in SNHL.We collected audiological data from a large sample of adult patients who underwent a comprehensive hearing evaluation at the Massachusetts Eye & Ear between 1993 and 2017  of Mass Eye & Ear and all methods were performed in accordance with the relevant guidelines and regulations of our institution. A waiver of informed consent was obtained by the same IRB.24. Only pure-tone air-conduction (AC) thresholds measured at standard audiometric frequencies from 0.25 kHz to 8 kHz (in octave steps) using TDH39 headphones or ER-3A insert earphones were considered. Bone-conduction (BC) thresholds were acquired from 250 Hz to 4000 Hz with a Radioear B-71 vibrator over the mastoid. Word recognition was assessed using a recorded CID  W-22 test, consisting of 50 monosyllabic word lists presented with a contralateral masker (speech-shaped noise). The Articulation Index (AI) was used to predict the speech intelligibility curve  was chosen as the presentation level. If this value, however, fell below 70 dB HL, presentation level remained at 70 dB HL. To assess word recognition deficits that cannot be accounted by a loss of audibility, we measured either (1) the WRS obtained at predicted PBmax and (2) the difference between the measured vs. predicted WRS (∆WRS) as defined by the SIC in each patient , Interacoustics AC-30, Virtual 320 and Interacoustics Equinox, running under the same Harvard Audiometer Operating System (AOS)0, GS-16,Using Matlab R2018a , Pearson correlation coefficients were used to assess relationships between pure-tone thresholds and age. Ordinary least square regression was used to estimate the effect of age on pure-tone thresholds and word recognition scores. Visual inspection, medians and non-parametric Wilcoxon rank-sum tests were used to compare the WRS of groups according to pure-tone thresholds.250Hz + AC500Hz + AC1kHz + AC2kHz + AC4kHz + AC8kHz, whereby AC refers to Air-Conduction threshold. We fitted the regression using the linear model “lm” function in R software environment with the default parameters and the above model. We then computed the respective commonality coefficients and determined the unique and common effects for each predictor variable using R29 with the statistical package described by Nimon and col30.To assess the relative contribution of each test frequency to WRS, we designed the following model: WRS or ∆WRS ~ ACTo assess the impact of hearing sensitivity at each test frequency on word recognition, we used SAS  to conduct a principle component analysis (PCA) of the thresholds at each test frequency. These analyses provided a set of 6 linearly independent components as well as the proportion of the total variance in the data that is explained by each component. We use these components as predictors in linear regression models with WRS as outcomes.Using Excel , linear regression analyses were used to investigate the relationship between etiologies and age or hearing loss on outcomes (WRS or ∆WRS). The parameter estimates and associated p-values are detailed in Supplementary Table The threshold for statistical significance was p = 0.05.In total, 81,822 ears  from patients aged 18 to 103 years old, presenting with either normal  or elevated thresholds  met our inclusion criteria for the normal hearing or ARHL groups, respectively  is well above threshold, a very large degree of hearing loss is needed to reduce the predicted WRS. Accordingly, > 99% of our cases have a predicted word score > 95% correct. In practice at the Massachusetts Eye and Ear, word tests are presented at a level at which the SIC has asymptoted (PBmax), or at 70 dB HL, whichever is lower.We examined the differences between predicted and measured scores on the standard clinical test of word recognition in quiet. When the measured WRS is lower than the predicted WRS, it means the deficit is not simply one of audibility, and one contributing factor can be loss of auditory nerve fibers, i.e. CND. WRS predictions are derived from the Speech Intelligibility Curve (SIC), which treats a threshold shift like an acoustic filter applied to the words, and quantifies the fraction of the speech spectrum remaining in the filtered output as a function of presentation levelThe mean WRSs in our normal hearing and ARHL groups declined monotonically Fig. A, in a rFor one set of analyses, we considered only patients from the normal hearing and ARHL groups with predicted WRSs ≥ 99%, then averaged data according to the measured WRS Fig. . The meaTo further clarify the relative contribution of different cochlear regions to the WRS and ∆WRS, we took two approaches. First, we used a linear regression model to compute commonality coefficients to determine the unique and common contribution of each test frequency to the explained variance (R-squared) in the regression model; i.e., to WRS and ∆WRS see “”. As sho35. Converting both to z-score measures as a function of age  or to the opposite healthy ear  and/or neurofibromatosis of type 2 , both of which are known to cause damage to the cochlear nerveoup Fig. A, and thoup Fig. B, consis p < 0.00 for both39. In our study, we separated patients who did not receive gentamicin to control vertigo (n = 628 ears) from those who did (n = 128 ears). The Ménière’s groups both had similar age distributions to the ARHL group  with similar age distribution to the ARHL group  platinum-based cancer therapeutics  or an ototoxic antibiotic, either (2) vancomycin (n = 32 ears), a glycopeptide, or (3) gentamicin (n = 42 ears), an aminoglycoside. All these drugs are known to cause hearing loss, as measured in a standard audiogram platinumols Fig. E. ScoresFinally, we identified patients with putative noise-induced hearing loss, either presenting with an audiometric notch ≥ 20-dB at 4 kHz n = 1448 ears) or with an explicit history of occupational or recreational noise exposure (n = 2091 ears). In these younger and male-dominated groups Fig. A,B, ∆WRS448 ears 48 if we restrict our age range to match theirs (i.e. 48 to 92 years) and use similar definitions of hearing loss. The overall hearing loss prevalence in the Framingham study was even higher (83%)51. Clearly, hearing loss is rampant and may be underestimated here, since these studies included more females than males (58% vs. 42% in the present study), and females tend to have better hearing at most ages than males  is similar to that in the Beaver Dam study (80%) of a more random sampleIt is worth noting that 45% of patients in our cohort had “normal” hearing. While some of this arises because some of the audiometric referrals were unrelated to an ear or hearing complaint , this rate emphasizes that many patients report a hearing issue that is not captured by a standard hearing test.52). At the highest frequencies, threshold decline was significant even from the youngest ages examined (18 yrs), and mean thresholds fell outside the “normal” range (20 dB HL) by age 45, consistent with previous studies54.Hearing sensitivity decreased with age and increasing test frequency Fig. , followi3. However, the most comprehensive histological analyses show prominent apical and basal loss of outer hair cells, with a relative sparing of mid cochlear regions56. Apical OHC degeneration is not well reflected in the audiogram, because (1) the lowest frequency tested (250 Hz) is far (~ 14%) from the apical extreme of the human cochlea57, (2) the contribution of OHC electromotility to cochlear amplification decreases with increasing frequency21 and (3) low-frequency auditory-nerve fibers are so broadly tuned that apical losses are hidden by neighboring cochlear regions with minimal increase in sound pressure level58. Despite the minimal effect on the audiogram, the loss of information due to the silencing of apical neurons must decrease the fidelity of stimulus representation especially in difficult listening environments.The sloping audiometric pattern of ARHL is consistent with the basal-turn loss of outer hair cell loss in aging humans59. Increased hearing loss in males has been linked to occupation, noise exposure history and income level61. However, even after adjusting for these risk factors, sex differences remained significant, and smoking, atherosclerosis and other factors have been suggested as possible contributors48. Past age 65, hearing loss accelerated at the lower frequencies (≤ 1 kHz), with larger losses in females  deficits in WRS with age are minimal in patients with conductive hearing loss when compared to age-matched patients with sensorineural hearing loss  in a sample of 26 cases suggested a mean neural loss of 46% by age 60 years , and an extrapolated loss of 69% by age 902. Referring to the mean WRSs for normal-aging 60 y.o. found here  revealed a 34% mean loss of the peripheral axons of cochlear nerve fibers in the affected vs. contralateral ears78. Assuming the latter are normal for their age, as the present WRS data suggest  and/or neurofibromatosis of type 2 (NF2) showed poorer WRSs than the normal-aging group Fig. . VSs areoup Fig. .80, with relatively little loss of either inner or outer hair cells41. In an ultrastructural study of a case of unilateral Ménière’s in an 83 year. old, there was a 75% loss of cochlear nerve synapses re the opposite ear, i.e. ~ 3 per inner hair cell on the affected side vs. ~ 12 contralaterally39. Given that the normal ear of this 83 year. old had likely lost ~ 65% of cochlear neurons81, the affected ear had only about 8% of its original innervation remaining. According to the audiometric record, the WRS in the affected ear of this patient was 34%, compared to a predicted score of 99.3%, based on the speech intelligibility curve and the audiogram. These values also fit well on the summary curve in Fig. Of all the etiologies we studied, patients with Ménière’s disease showed the worst WRSs Fig. . This de83. A survey of cochlear histopathology in SSNHL cases with unrecovered thresholds concluded that roughly half (7/15) showed marked CND41; however, the neural loss has not been well quantified enough to make any meaningful comparison to the other etiologies.Patients with SSNHL also showed discrepancies between measured and predicted WRSs that were larger than in normal-aging controls Fig. C, but th3 found a small increase in CND (~ 15%) across all audiometric frequencies in the latter, but only among patients aged 50–74 years and not among individuals from 75 to 100 years. This age effect is opposite to that seen here, where differences from normal-aging were maximal in the older group. However, both studies agree that the added effects of noise on CND in the aging ear are small. Furthermore, both studies acknowledge the difficulties in identifying normal-aging humans who have not suffered ear abuse, and in relying on self-report as a reliable metric of cumulative noise exposure. That problem is evidenced here by the presence of a 4 kHz notch in the mean audiograms of the normal-aging group  or SNHL attributable to diagnosable disease or cochlear insult of several etiologies. Intelligibility worsened monotonically with age and degree of hearing loss. Results from patients with conductive hearing loss suggested that cognitive decline was not a major confound. In SNHL, larger intelligibility deficits were observed in etiologies known, or suspected, to cause greater cochlear nerve loss. After accounting for age and degree of hearing loss, word performance deficits were greatest (in descending order) in Ménière’s disease, in those with acoustic tumors and after sudden sensorineural hearing loss. Intelligibility deficits were considerably smaller in those with a history of exposure to noise or ototoxic drugs (either aminoglycosides or platinum-containing chemotherapeutics). This ranking is consistent with the fragmentary data on CND in human temporal bones. A compilation of those data suggests that auditory nerve loss must exceed 60% before word scores in quiet fall below 90%. The relation between CND and performance on more difficult listening tasks could be much steeper.87, middle-ear muscle reflex77, envelope following responses88, in vivo imaging of auditory nerve diameter89 and computational models13. While the evidence implicates CND in the intelligibility challenges of hearing impairment, CND also likely serves as a peripheral trigger for excess central gain and other maladaptive plasticity in central auditory pathways that further degrade perceptual accuracy for complex sounds beyond that predicted by viewing the audiogram as a simple acoustic filter90.These findings agree with a number of studies linking speech perception or signal-in-noise detection with neural deficits measures by ABRs/electrocochleographySupplementary Figure 1.Supplementary Table 1.


All subjects underwent a brief, cognitive screening battery and answered the SF-36, APHAB, and HHIA self-assessment questionnaires. For analysis of results, descriptive measures and inferential analysis were used. Results: On the SF-36 questionnaire, scores below 80 points were found in both groups, signifying minimal impact in the domains of pain, general health, vitality, and mental health compared to the other domains. The results of the APHAB questionnaire showed worse scores on the environmental noise subscale, and evaluation with the HHIA revealed a perception of severe restriction in participation in daily life activities. In a comparison between the groups, normal or abnormal BAEPs, no significant differences were found for any of the questionnaires. Conclusions: The results of the self-assessment questionnaires indicate that individuals with hearing loss can experience reduced quality of life, with limitations and restrictions for participation in daily living. The use of BAEPs as a criterion for dividing the groups was not effective in isolating the central component in the results of the self-assessment questionnaires.Objectives: To characterize the results of the Short Form Health Survey-36 (SF-36), Abbreviated Profile of Hearing Aid Benefit (APHAB), and the Hearing Handicap Inventory for Adults (HHIA) questionnaires in individuals with mild to moderate sensorineural hearing loss and compare them with brainstem auditory evoked potentials (BAEPs). Methods: There were 26 individuals with mild to moderate bilateral symmetrical sensorineural hearing loss who participated in the study. They were aged between 13 and 59 years old, right-hand preference, of both sexes, and were assigned to one of two groups according to the result of a BAEP test: normal ( Hearing impairment refers to the inability to perceive everyday sounds in acoustically favorable or unfavorable environments, whereas hearing loss is considered to be the abnormal functioning of the auditory system. These terms include all degrees of objective and subjective hearing impairment, but they do not reflect the difficulty of perceiving speech in daily life and its emotional impact or limitations on social interactions .To quantify the emotional and social consequences resulting from hearing loss, self-assessment questionnaires  are usedHowever, by themselves, the results obtained in an audiological assessment or the performance on a speech recognition test do not explain the variability found in the results of a self-assessment questionnaire . A persoThe interest in separating peripheral from central effects of hearing loss has been a challenge because behavioral tests and clinical manifestations are very similar but undoubtedly must be addressed in different ways. Patients with hearing loss may have other health conditions, comorbidities of organic and/or psychosocial origin that directly impact on the diagnosis, prognosis and process of auditory rehabilitation.In view of the above, the objective of this study was to determine how responses to general and hearing-related quality of life instruments relate to brainstem auditory evoked potentials (BAEPs) in individuals with hearing impairment.The hypothesis examined here is that hearing loss might compromise quality of life, especially in domains that involve social interactions, since difficulties in understanding speech in noise can modify how adults interact with others and therefore that the quality of life will be worse in individuals with altered nerve conduction to the brainstem, which should be treated differently in terms of auditory rehabilitationThe project was approved by the Research Ethics Committee of the Universidade Federal de São Paulo . A cross-sectional observational study was carried out, with a convenience sample selected from the medical records of patients treated at the Integrated Center for Assistance, Research and Teaching in Hearing of the Discipline of Hearing Disorders of the Department of Speech Therapy at Universidade Federal de São Paulo.Over three years, 4516 people with hearing impairment were assisted at the service. All these medical records were analyzed and, according to the eligibility criteria, 105 individuals were considered as possible participants. An initial contact was made by telephone and after explaining the study objectives and the inclusion and exclusion criteria, 72 individuals were invited to undergo the sample selection procedures.The eligibility criteria for participation in both groups were: age between 13 and 59 years, without regard to gender; mother tongue Brazilian Portuguese; having fluent reading, regardless of education level; the presence of mild to moderate sensorineural hearing loss acquired post-lingually  ; type A In addition to the basic audiological assessment, BAEPs were included to differentiate between hearing loss of cochlear and retrocochlear origin. The individuals needed to show waves I, III, and V at 80 dBHL in a BAEP test, and the distinction between a normal or altered BAEP was executed based on the absolute latency of wave V. Individuals were considered normal if their wave V showed an absolute latency of 5.57–5.89 ms at 80 dBHL bilaterally, which follows the normality criterion in the Smart-EP Intelligent Hearing Systems manual [The exclusion criteria were those who had middle ear alterations; had a history of otologic or neurological surgery; confirmed neurological lesion; emotional and/or neurological disorder; previous experience with hearing aids; difficulty with reading; problems with speech and/or language; less than 72% correct answers in the Speech Recognition Index (based on monosyllables presented with a live voice by the same examiner in order to minimize presentation differences); alterations in the Brief Cognitive Screening Battery (BCSB) ; inadequThe evaluations were carried out in two sessions, with each session lasting approximately 45 min.In the first evaluation session, individuals signed a free and informed consent form (or for subjects under 18 years of age a consent form signed by parents or guardians) indicating voluntary participation in the study. Assessments were performed for inclusion in the study .In the second session, electrophysiological measurements were performed and the Short Form Health Survey-36 (SF-36), Abbreviated Profile of Hearing Aid Benefit (APHAB), and the Hearing Handicap Inventory for Adults (HHIA) self-assessment questionnaires were applied. All questionnaires were completed by interview, in which the evaluator read the questions to the evaluated person, who then gave the most appropriate answer.Quality of life can be measured by quantitative and qualitative scales, with the best analyses being derived from multidimensional scales that take into account the socioeconomic and cultural issues of the investigated population. Since hearing is a fundamental factor for a good quality of life, we chose to use the SF-36 because it is a multidimensional instrument translated and validated for the Brazilian population .The Brazilian SF-36  covers tThe APHAB questionnaire ,16 was uIn situations to which the individual was never exposed, the subject was asked to imagine a similar situation and respond appropriately. In cases where the individual could not relate to the situation presented, the item was left blank. The results were recorded in a specific protocol. The analysis was performed by scoring the ease of communication (EC), reverberation (RV), background noise (BN), and aversiveness of sounds (AS) subscales and by the global score . The closer the score was to 100, the greater the limitations on communication in an acoustically unfavorable environment.To assess communication difficulties and the social and emotional consequences of hearing loss, the HHIA Adult Auditory Participation Restriction Questionnaire was applied ,16. It iAll questionnaires were answered in full and all questions were considered in the analyses. The results were collected on a form and transferred to an Excel spreadsheet. The inferential analysis of the results was performed using Minitab , Statistical Package for the Social Sciences , R , and a routine in R for analysis of variance with non-parametric repeated measures. A significance level of 0.05 was set.t-test was used to characterize the sample in terms of wave V latency, 3-tone average of 0.5, 1, and 2 kHz, age, sex, and education level.In the initial exploratory analysis of the data, to assess the possible effect of some variables on the results obtained, a Student’s To compare the sex distributions in the two groups with normal and altered BAEPs, a Fisher’s exact test was applied. The normality of the distributions of continuous variables in the two groups  was evaluated with normal probability plots.U-test.An intra-class correlation coefficient was calculated to measure the agreement between the results obtained in both ears. Comparisons between the groups of normal and altered BAEPs in terms of the distributions of SF-36, HHIA, and APHAB were analyzed using a Mann–Whitney A total of 72 individuals attended for sample selection procedures, but only 26 of them met all of the inclusion criteria and completed all the assessments. The groups were divided according to the qualitative results of BAEPs  and then compared in relation to wave V latency on BAEPs, average sound threshold, age, education, and gender.The mean latency of wave V was 5.65 ms in the right ear and 5.63 ms in the left ear for the group with normal BAEPs and 6.16 ms in the right ear and 6.10 ms in the left ear for the group with altered BAEPs.In evaluating wave V latency, the intra-class correlation coefficient and 95% confidence interval were used. There was strong agreement between the measurements of wave V latency in both ears .p < 0.001 *) using the Student’s t-test. This result confirmed the criterion for dividing the groups.Comparing the groups  in terms of the latency of wave V, it was observed that there was a significant difference between the distributions of latencies in the two groups .As an inclusion criterion, individuals needed to have bilateral sensorineural hearing loss of mild to moderate symmetrical degree, and both groups complied with these criteria. However, descriptive and inferential statistics were performed to verify that there was a difference between the groups. For the group with normal BAEPs, the tritone average of 0.5, 1, and 2 kHz was 42.9 dB in the right ear and 41.7 dB in the left ear. For the group with altered BAEPs, the values were 43.2 dB in the right ear and 42.3 dB in the left ear. No significant differences were found between the groups in terms of the three-tone average of 0.5, 1, and 2 kHz  were found between the means of either age (p = 0.550) or schooling (p = 0.132).Comparing the normal and abnormal BAEPs groups, no significant differences .With regard to sex, the Normal BAEPs group was predominantly formed by males, while the Altered BAEPs group had the same number of men and women . In compIn view of these findings, we concluded that the sample was homogeneous and that the Normal and Altered BAEPs groups could be compared with each other. The results of the descriptive and inferential analyses according to the variables studied are presented below.p-values) obtained by comparing the distributions of each SF-36 domain in the two groups. No statistical differences were observed between the groups.The HHIA analysis was performed following the same steps as the SF-36 analysis. p-values from comparison of the scores between the two groups, for each HHIA subscale and the total values, revealed no significant differences between the scores on the social (p = 0.672) and emotional (p = 0.412) subscales, nor in the total score (p = 0.563).The The same procedures adopted in the analysis of SF-36 were also applied to the APHAB scores. p-values indicated that there were no differences between the groups in terms of subscale scores for ease of communication (p = 0.895), reverberation (p = 0.257), background noise (p = 0.833), aversiveness of sounds (p = 0.304), nor in the global analysis (p = 0.792).Comparing the percentage distributions in the two groups in each APHAB domain, the Since communication is essential for good social and professional interactions, and since hearing loss disrupts that communication and can cause emotional and social difficulties, hearing impairment can negatively impact a person’s quality of life ,18.To test whether an individual has a hearing disorder, several procedures are required, including: a hearing health history, a hearing-focused physical examination, pure tone audiometry (air conduction and bone conduction), speech reception threshold, Speech Recognition Percentage Index, immittance audiometry (tympanometry and acoustic reflex), and may also include otoacoustic emissions and auditory evoked potentials .In this study, we used a qualitative analysis of BAEPs as the criterion for dividing the subjects into two groups  and the groups were compared in relation to wave V latency, average hearing threshold, age, education , and genBAEPs have commonly been used to verify the integrity of the auditory pathway to the brainstem. In the literature, no differences have previously been observed in the results of absolute latency of wave V in BAEPs from individuals with mild to moderate hearing loss, even when the hearing losses have a descending audiometric configuration ,20. In tHearing tests provide information about degree of loss, type of loss, and audiometric configuration, giving clues as to which portion of the auditory system might be affected, but they do not gauge the psychosocial impact of hearing loss on an individual’s life. Here is where self-assessment questionnaires come to the fore, as they can assess limitations in function and restrictions on participation, as well as the level of benefit provided by a hearing aid. In the clinic, these tools can provide quantitative information to assist in auditory rehabilitation.Depending on the way in which a questionnaire is administered, the quality of the data may be limited by the respondent’s cognitive resources. A self-completed questionnaire tends to give less reliable answers than an interview, since for the latter the interviewee necessarily understand each questionnaire item . To try In this study, we chose to assess quality of life with the Brazilian version of the SF-36 questionnaire, as it is a generic multidimensional instrument  that incThe results of the Brazilian version of the SF-36 questionnaire showed a high score (above 70 points) in seven of the eight domains evaluated ; the onlComparing the scores in each SF-36 domain, according to the normal and altered groups, in all domains, there was no significant difference (at the level of 0.05) between the scores in the two groups . IndividThe findings here cannot be compared to those of other studies, since most of the studies carried out on hearing-impaired people with the SF-36 questionnaire involved elderly individuals, most of whom had other general health impairments (in addition to hearing loss) which can negatively impact on their quality of life. In other words, the impact of hearing loss on quality of life cannot be measured without considering age ,23,24.The individuals showed a good perception of health, but energy and aptitude for life, which corresponded to the vitality domain, were impaired in relation to the other aspects evaluated. A possible explanation for loss of vitality might be the listening effort that individuals with peripheral hearing loss require in order to hear and/or understand in acoustically unfavorable environments ,25. If iAnother hypothesis might be an elevated exposure to environmental noise in the modern world. Continuous exposure to noise can lead to, in addition to hearing disorders, other non-auditory symptoms such as lack of attention, tiredness, difficulty concentrating, and stress.In the long term, more hearing effort in a hearing-impaired person can lead to chronic stress and social isolation, with negative consequences for cognition, general health, well-being, and quality of life . These fTo assess the impact of hearing loss on daily activities, we used the HHIA and APHAB questionnaires. The HHIA is an excellent self-assessment tool because it has great sensitivity in detecting communication difficulties, and can also be used to assess the benefits of different hearing aids . For theThe self-perception of a degree of hearing difficulty cannot be correlated with the degree of hearing loss ,28,29, aWe used APHAB to quantify the deterioration that hearing loss causes in an individual’s performance in a day-to-day situation . The resThese factors are a possible justification for the severe perception of restriction of participation in activities of daily living, since all the individuals included in the study were young adults with a great demand on hearing for work, education, and social activities.The main limitation of this study was the difficulty in creating the sample, since many individuals who fitted the audiological criteria failed in the tests that preceded the assessment of self-perception of hearing difficulties, especially in the electrophysiological assessment and cognitive screening.In clinical practice, electroacoustic and electrophysiological assessments should be carried out in conjunction with self-assessment questionnaires, since the results obtained with a questionnaire need not correspond with the results of an auditory assessment obtained with behavioral and electrophysiological audiological tests , which mDespite the small sample size, based on the data presented, we have found that it is important to evaluate not only peripheral hearing but also the self-perception of hearing difficulties in patients with mild to moderate SNHL. This paper also underlines the usefulness of complementary audiological tests, such as electrophysiological assessment, assessment of central auditory processing, and some type of cognitive screening; however, our initial hypothesis, that the group with abnormal results in BAEPs would show a poorer quality of life, was not confirmed. These tests potentially allow hearing difficulties to be linked to factors such as elevations in thresholds as well as issues related to auditory or cognitive processing , but a lIn future, the questionnaires could be administered on a larger group of patients, and after adaptation to the hearing device, if quality of life did not improve, behavioral and central auditory processing tests should be carried out, such as long latency auditory evoked potential (p300).Finally, the use of validated questionnaires in clinical practice can alert patients and clinicians to difficulties in daily activities and provide better therapeutic planning. For successful rehabilitation, it is necessary to be aware of issues that may not be statistically significant but are still clinically relevant .The results of the self-assessment questionnaires indicate that individuals with hearing loss may have reduced quality of life, and limitations or restrictions for participating in daily activities. The use of BAEPs as a criterion for dividing the groups was not effective in isolating the central component in the results of the self-assessment questionnaires.