Pattern Of Hearing Loss Research Articles

Mechanisms of Hearing Loss in a Guinea Pig Model of Superior Semicircular Canal Dehiscence.

Defective acoustic transmission in the cochlea is closely related with various auditory and vestibular symptoms. Among them, semicircular canal dehiscence (SCD) with a defective semicircular bone is typical. Currently, the pathogenesis of SCD is usually explained by the third window hypothesis; however, this hypothesis fails to explain the variability in the symptoms and signs experienced by superior SCD (SSCD) patients. We evaluated the mechanism of hearing loss in a guinea pig model of bony dehiscence with various sizes and locations along the superior semicircular canal. Auditory brainstem responses (ABRs) and laser Doppler velocimetry were used to measure hearing loss and vibration changes before and after fenestration, as well as after restorative patching. ABR thresholds at low frequencies (e.g., 1000 Hz) increased after fenestration and decreased back to the normal range after we repaired the defect. Energy leakage from the surgically introduced third window was detected in the range of 300–1500 Hz, accompanied by increased vibration at the umbo, stapes head, and the dehiscence site, while decreased vibration was observed at the round window membrane in the same frequency range. After the patching procedure, the deviant vibrations were recovered. The degree of postfenestration energy leakage was proportional to the size of fenestration and the proximity of the fenestration site to the oval window. These results suggest that the bony fenestration of the superior semicircular canal mimics the hearing loss pattern of patients with SSCD. The decrease in perilymph wave impedance likely accounts for the auditory changes.

Biomarkers of Presbycusis and Tinnitus in a Portuguese Older Population.

Introduction: Presbycusis or age-related hearing loss (ARHL) is a ubiquitous health problem. It is estimated that it will affect up to 1.5 billion people by 2025. In addition, tinnitus occurs in a large majority of cases with presbycusis. Glutamate metabotropic receptor 7 (GRM7) and N-acetyltransferase 2 (NAT2) are some of the genetic markers for presbycusis.Objectives: To explore patterns of hearing loss and the role of GRM7 and NAT2 as possible markers of presbycusis and tinnitus in a Portuguese population sample.Materials and Methods: Tonal and speech audiometry, tinnitus assessment, clinical interview, and DNA samples were obtained from patients aged from 55 to 75 with or without tinnitus. GRM7 analysis was performed by qPCR. Genotyping of single nucleotide polymorphisms (SNPs) in NAT2 was performed by PCR amplification followed by Sanger sequencing or by qPCR.Results: We screened samples from 78 individuals (33 men and 45 women). T allele at GRM7 gene was the most observed (60.3% T/T and 33.3% A/T). Individuals with a T/T genotype have a higher risk for ARHL and 33% lower risk for tinnitus, compared to individuals with A/A and A/T genotype, respectively. Being a slow acetylator (53%) was the most common NAT2 phenotype, more common in men (55.8%). Intermediate acetylator was the second most common phenotype (35.9%) also more frequent in men (82.6%). Noise exposed individuals and individuals with ‘high frequency’ hearing loss seem to have a higher risk for tinnitus. Our data suggests that allele AT of GRM7 can have a statistically significant influence toward the severity of tinnitus.Conclusion: For each increasing year of age the chance of HL increases by 9%. The risk for ARHL was not significantly associated with GRM7 neither NAT2. However, we cannot conclude from our data whether the presence of T allele at GRM7 increases the odds for ARHL or whether the A allele has a protective effect. Genotype A/T at GRM7 could potentially be considered a biomarker of tinnitus severity. This is the first study evaluating the effect of GRM7 and NAT2 gene in tinnitus.

Evaluation of Maximal Speech Intelligibility With Vibrant Soundbridge in Patients With Sensorineural Hearing Loss.

The study investigated improvements in maximal speech intelligibility after Vibrant Soundbridge (VSB) implantation and analyzed the effect of the hearing loss pattern on maximal speech intelligibility represented by a phonetically balanced word score (PBmax). The effect of middle ear implants on PBmax has not been evaluated yet. Study. Tertiary academic medical center. Sixty patients who underwent VSB from December 2011 to January 2016 were retrospectively reviewed. All the patients had hearing aids preoperatively. Pure-tone and speech audiometry were checked with and without hearing aids and then with the VSB. The patients were divided into two groups: flat and down-sloping type of hearing loss. PBmax score was evaluated at the most comfortable listening level before and after VSB implantation and compared with scores with/without HA. PBmax for both conventional HA and VSB were significantly higher compared with the unaided condition. The improvement in speech recognition was significantly better using VSB than using HA (p = 0.003). However, there was no significant difference in the improvement provided by VSB and HA in patients with a flat hearing loss. Patients with a down-sloping audiogram showed significantly better improvement with VSB than with HA (p = 0.003). Moreover, patients with greater preoperative high-frequency hearing loss had greater improvement in PBmax after VSB implantation. Speech intelligibility can be significantly improved by VSB implantation, especially in patients with a down-sloping hearing loss. This finding can help select patients who will benefit most from VSB implantation.

Tone perception in Mandarin-speaking school age children with otitis media with effusion.

ObjectivesThe present study explored tone perception ability in school age Mandarin-speaking children with otitis media with effusion (OME) in noisy listening environments. The study investigated the interaction effects of noise, tone type, age, and hearing status on monaural tone perception, and assessed the application of a hierarchical clustering algorithm for profiling hearing impairment in children with OME.MethodsForty-one children with normal hearing and normal middle ear status and 84 children with OME with or without hearing loss participated in this study. The children with OME were further divided into two subgroups based on their severity and pattern of hearing loss using a hierarchical clustering algorithm. Monaural tone recognition was measured using a picture-identification test format incorporating six sets of monosyllabic words conveying four lexical tones under speech spectrum noise, with the signal-to-noise ratio (SNR) conditions ranging from -9 to -21 dB.ResultsLinear correlation indicated tone recognition thresholds of children with OME were significantly correlated with age and pure tone hearing thresholds at every frequency tested. Children with hearing thresholds less affected by OME performed similarly to their peers with normal hearing. Tone recognition thresholds of children with auditory status more affected by OME were significantly inferior to those of children with normal hearing or with minor hearing loss. Younger children demonstrated poorer tone recognition performance than older children with OME. A mixed design repeated-measure ANCOVA showed significant main effects of listening condition, hearing status, and tone type on tone recognition. Contrast comparisons revealed that tone recognition scores were significantly better under -12 dB SNR than under -15 dB SNR conditions and tone recognition scores were significantly worse under -18 dB SNR than those obtained under -15 dB SNR conditions. Tone 1 was the easiest tone to identify and Tone 3 was the most difficult tone to identify for all participants, when considering -12, -15, and -18 dB SNR as within-subject variables. The interaction effect between hearing status and tone type indicated that children with greater levels of OME-related hearing loss had more impaired tone perception of Tone 1 and Tone 2 compared to their peers with lesser levels of OME-related hearing loss. However, tone perception of Tone 3 and Tone 4 remained similar among all three groups. Tone 2 and Tone 3 were the most perceptually difficult tones for children with or without OME-related hearing loss in all listening conditions.ConclusionsThe hierarchical clustering algorithm demonstrated usefulness in risk stratification for tone perception deficiency in children with OME-related hearing loss. There was marked impairment in tone perception in noise for children with greater levels of OME-related hearing loss. Monaural lexical tone perception in younger children was more vulnerable to noise and OME-related hearing loss than that in older children.

Applications of direct-to-consumer hearing devices for adults with hearing loss: a review.

BackgroundThis systematic literature review is aimed at investigating applications of direct-to-consumer hearing devices for adults with hearing loss. This review discusses three categories of direct-to-consumer hearing devices: 1) personal sound amplification products (PSAPs), 2) direct-mail hearing aids, and 3) over-the-counter (OTC) hearing aids.MethodA literature review was conducted using EBSCOhost and included the databases CINAHL, MEDLINE, and PsycINFO. After applying prior agreed inclusion and exclusion criteria, 13 reports were included in the review.ResultsIncluded studies fell into three domains: 1) electroacoustic characteristics, 2) consumer surveys, and 3) outcome evaluations. Electroacoustic characteristics of these devices vary significantly with some meeting the stringent acoustic criteria used for hearing aids, while others producing dangerous output levels (ie, over 120-dB sound pressure level). Low-end (or low-cost) devices were typically poor in acoustic quality and did not meet gain levels necessary for most adult and elderly hearing loss patterns (eg, presbycusis), especially in high frequencies. Despite direct-mail hearing aids and PSAPs being associated with lower satisfaction when compared to hearing aids purchased through hearing health care professionals, consumer surveys suggest that 5%–19% of people with hearing loss purchase hearing aids through direct-mail or online. Studies on outcome evaluation suggest positive outcomes of OTC devices in the elderly population. Of note, OTC outcomes appear better when a hearing health care professional supports these users.ConclusionWhile some direct-to-consumer hearing devices have the capability to produce adverse effects due to production of dangerously high sound levels and internal noise, the existing literature suggests that there are potential benefits of these devices. Research of direct-to-consumer hearing devices is limited, and current published studies are of weak quality. Much effort is needed to understand the benefits and limitations of such devices on people with hearing loss.

Pattern of hearing loss among patients visiting ENT OPD at Janaki Medical College: A cross sectional study

Background and Objectives: To study the pattern of hearing loss among patients visiting ENT OPD in Janaki medical college teaching hospital.Material and Methods: The study was conducted in department of ENT- head and neck surgery in Janaki medical college teaching hospital from June to December 2016. All the clinically diagnosed cases Demographic data and PTA assessment were taken. with hearing impairment were enrolled in the study and hearing assessment done.Results: Total of 119 patients were enrolled. Among them, male were 58(48.7%) and female 61(51.3%). In age distribution, commonly affected age group was 21-30 years followed by 31-40 years group.On comparing hearing level between both the ears, right ear was having mean hearing threshold of 45.4454 dB and left ear having 47.3277 dB with standard deviation 16.54665, 15.98363 respectively. The difference between both the values is statistically not significant (p value- 0.165). On evaluating type of hearing loss between both the ears, there were almost similar frequencies of hearing loss pattern (p value- 0.190).Out of 119 patients, 20(8.4%) were having unilateral hearing loss. So total of 218(91.6%) ears were affected out of 238 ears. Among them 116(48.8%) ears had conductive hearing loss, 30(12.6%) ears had sensori-neural hearing loss and 48(20.2%) ears had mixed hearing loss.On evaluating degree of hearing loss, patients were mostly having mild hearing loss (41.2%) followed by severe hearing loss (25.2%), moderate hearing loss (24.4%). There was almost similar degree of hearing loss in both the ears with statistically insignificant (p value- 0.379).Conclusion: Hearing impairment commonly involved female with younger population involvement. Hearing impairment was mostly conductive type. Hearing loss was mostly mild degree and bilateralism is common.

Different Patterns of Hearing Loss among Tinnitus Patients: A Latent Class Analysis of a Large Sample.

The heterogeneity of tinnitus is a major challenge for tinnitus research. Even if a complex interaction of many factors is involved in the etiology of tinnitus, hearing loss (HL) has been identified as the most relevant etiologic factor. Here, we used a data-driven approach to identify patterns of hearing function in a large sample of tinnitus patients presenting in a tinnitus clinic. Data from 2,838 patients presenting at the Tinnitus Center of the University Regensburg between 2007 and 2014 have been analyzed. Standard audiometric data were frequency-wise categorized in four categories [a: normal hearing (0-20 dB HL); b: moderate HL (25-50 dB HL; representing outer hair cell loss); c: severe HL (>50 dB HL; representing outer and inner hair cell loss); d: no data available] and entered in a latent class analysis, a statistical method to find subtypes of cases in multivariate categorical data. To validate the clinical relevance of the identified latent classes, they were compared with respect to clinical and demographic characteristics of their members. The classification algorithm identified eight distinct latent classes with an excellent separation. Patient classes differed with respect to demographic (e.g., age, gender) and clinical characteristics (e.g., tinnitus location, tinnitus severity, gradual, or abrupt onset, etc.). Our results demonstrate that data-driven categorization of hearing function seems to be a promising approach for profiling tinnitus patients, as it revealed distinct subtypes that reflect prototypic forms of HL and that differ in several relevant clinical characteristics.

Pattern of Hearing Loss among Patients Attending Otorhinolaryngology Outpatient Department at Kathmandu University Hospital

Pattern of Hearing Loss among Patients Attending Otorhinolaryngology Outpatient Department at Kathmandu University Hospital

Endocrine Glands and Hearing: Auditory Manifestations of Various Endocrine and Metabolic Conditions.

The aetiology of hearing loss in humans is multifactorial. Besides genetic, environmental and infectious causes, several endocrine and metabolic abnormalities are associated with varying degrees of hearing impairment. The pattern of hearing loss may be conductive, sensori-neural or mixed. The neurophysiology of hearing as well as the anatomical structure of the auditory system may be influenced by changes in the hormonal and metabolic milieu. Optimal management of these conditions requires the integrated efforts of the otolaryngologist and the endocrinologist. The presence of hearing loss especially in the young age group should prompt the clinician to explore the possibility of an associated endocrine or metabolic disorder for timely referral and early initiation of treatment.

Auditory Processing Abilities of Parkinson's Disease Patients.

Since Parkinson's Disease (PD) primarily affects older people, a majority of PD patients have age-related hearing loss (HL) that will worsen over time. The goal of this study was to assess peripheral and central auditory functions in a population of PD patients and compare the results with a group of age-matched control subjects. Study participants included 35 adults with PD (mean age = 66.9 ± 11.2 years) and a group of 35 healthy control subjects (mean age = 65.4 ± 12.3 years). Assessments included questionnaires, neuropsychological tests, audiometric testing, and a battery of central auditory processing tests. Both study groups exhibited patterns of sensorineural hearing loss (slightly worse in the PD group) which were typical for their age and would contribute to difficulties in communication for many participants. Compared to the control group, PD patients reported greater difficulty in hearing words people are speaking. Although 27 PD patients (77%) were good candidates for amplification, only 7 (26%) of these hearing aid candidates used the devices. Because it is important for PD patients to optimize communication with their family members, caregivers, friends, and clinicians, it is vital to identify and remediate auditory dysfunction in this population as early as possible.

Characteristics of Patients with Hearing Aids according to the Degree and Pattern of Hearing Loss.

Background and ObjectivesThis study was designed to assess the characteristics of patients according to the degree and audiogram shape of hearing loss and the association of these characteristics with hearing aids (HA) choice, return rate, and cause of return.Subjects and MethodsThis study included 460 individuals who received HAs from 2011 to 2015. The relationships between type of HA and age, primary and accompanying symptoms, HA choice and return and cause of return were evaluated according to the degree and pattern of hearing loss.ResultsHA type did not differ significantly according to the degree and pattern of hearing loss. Intensity of hearing loss was greater in male than in female (p<0.05). Open and completely-in-canal types of HA decreased with age (p<0.05). As degree of hearing loss intensified, behind-the-ear and in-the-ear types increased and Open type decreased (p<0.05). The HA return rate was 9.7%, but was not associated with degree or pattern of hearing loss. The main causes of HA return were costs, psychological fears and adaptive failure.ConclusionsChoice of HA is affected by age, sex, and degree and pattern of hearing loss. HA for hearing rehabilitation in patients with hearing loss can be personalized according to each patient's characteristics and tendencies.

Audiologic Patterns of Otic Capsule Preserving Temporal Bone Fracture: Effects of the Affected Subsites.

Objectives.This study was aimed to assess the relationship between the type of temporal bone area involved and conductive hearing loss.Methods.We enrolled 97 patients who visited the otolaryngology clinics of Seoul National University Hospital or Boramae Medical Center, Seoul Metropolitan Government-Seoul National University with temporal bone fracture between January 2004 and January 2014. Audiometric parameters, including initial and improved air-bone (AB) conduction gap values, were reviewed in accordance with the temporal bone computed tomography (external auditory canal [EAC], middle ear [ME], mastoid [M], and ossicle [O]).Results.Patients with ossicular chain involvement exhibited a larger AB gap compared to those with no ossicular chain involvement at 250, 1,000, 2,000, and 4,000 Hz. Among the groups without ossicular chain involvement, the initial AB gap was largest in patients with EAC+ME+M involvement, followed by the ME+M and M-only involvement groups. The greatest improvement in the AB gap was observed in the EAC+ME+M group followed by the ME+M and M-only groups, irrespective of ossicular chain involvement. Improvements in AB gap values were smallest at 2,000 Hz.Conclusion.Conductive hearing loss pattern differed according to the temporal bone area involved. Therefore, areas such as the hematoma and hemotympanum, as well as the fracture line of the temporal bone area, must be evaluated to predict audiologic patterns with otic capsule preserving temporal bone fracture.

Patterns of Long-term Hearing Loss in Hearing Preservation Cochlear Implant Surgery.

To describe patterns of hearing loss in patients with low-frequency residual hearing after cochlear implantation. Retrospective chart review. Tertiary referral center. Cochlear implant candidates with immediate postoperative residual low-frequency hearing. Hybrid or traditional cochlear implant. Audiograms to measure postoperative hearing. Of the 166 patients reviewed, 17 ears met the inclusion criteria. The age ranged from 3 years 2 months to 86 years. Etiology was unknown (n = 6), presbycusis (n = 5), genetic (n = 4), acoustic trauma (n = 1), and measles virus (n = 1). The Nucleus Hybrid S8 and S12 (n = 7) was the most common electrode array, and then Nucleus 422 (n = 6), Nucleus Contour Advance (n = 2), Med-El Flex 28 (n = 2), and Advanced Bionics Mid Scala (n = 1). Cochleostomy was performed in nine, and round window approach in nine patients. Average follow-up was 28 months (2-68 mo). Postoperative loss was mixed in eight and purely sensorineural in eight. The most common patterns of hearing loss were gradual decline (n = 7), and then fluctuating hearing (n = 6), stable (n = 3), and sudden loss (n = 1). One patient only had one postoperative audiogram. Some long-term hearing preservation was achieved in 94% of patients with immediate postoperative hearing preservation. Patients developed both mixed and sensorineural loss postoperatively. A majority of patients with mixed hearing loss had a supra-preoperative bone curve. Gradual decline and fluctuating hearing loss were the most common patterns of hearing loss; few patients had stable hearing and one had a sudden loss.

Study on Hearing Status of Elderly Patients attending a Specialized ENT Hospital (SAHIC)

Background: Age related hearing loss is a natural process in elderly population all over the world.Objectives: To determine the hearing level of elderly patients in relation to age, sex, socioeconomic condition and to determine the pattern and extent of hearing loss in old age.Method: This cross sectional study was carried out at out patient department of Specialized ENT Hospital of SAHIC, Mohakhali, Dhaka, from October 2012 to March 2013. 200 patients were included with age &gt; 50 years and who have no past history of drug therapy. Data were collected by detailed history, clinical examination and audiometric findings and result were expressed in table form.Result: 57% patients were found with normal hearing and 43% had variable degree of hearing impairment. Highest number of hearing impairment was found in 9th decade. Most of hearing loss were found to be bilateral and sensorineural in type.Conclusion: A good number of elderly people in our country is suffering from some degree of hearing loss, which are mostly sensorineural in type. The prevalence and severity of hearing loss increases with increasing age.Bangladesh J Otorhinolaryngol; October 2015; 21(2): 80-84

Prevalence and Patterns of Hearing Loss among Chronic Kidney Disease of Various Stages in Bangladeshi Patients

Objectives: This study was designed to evaluate the association between chronic kidney disease and sensorineural hearing impairment. Early detection of sensorineural hearing imapirment in CKD patient will allow appropriate treatment which will improve quality of hearing. Hypothesis: Sensorineural hearing impairment is more prevalent in chronic kidney disease patients than control group. Setting: The work was done at a tertiary level hospital in the central part of country. Participants: The subjects were divided into a case group consisting of 55 CKD patients and a control group of 50 people. Subjects with age below 18 years and above 60 years, AKI, audiometric evidence of conductive hearing loss & past medical or surgical treatment of otologic conditions were excluded from the study. Results. Prevalence of sensorineural hearing loss in CKD patients was found to be 54% and the prevalence of hearing loss in control subjects was found to be 16%. Comparison of hearing loss between CKD and the control groups was found to be statistically strongly significant (p value was 0.0004). In CKD patients, 10 % had mild loss of hearing impairment, 30 % had moderate loss, severe loss was present in 40% patients and 20% had profound loss of hearing. By disease stage, the prevalence of hearing loss in CKD patients was as follows: stage III, 6.6%; stage IV, 33.3% and stage V 60 %. Conclusion: The present study showed the relationship between chronic kidney disease and sensorineural hearing impairment to be statitistically significant (P<0.05) which signifies that that hearing loss is relatively prevalent in patients with CKD.

Otologic and Rhinologic Manifestations of Eosinophilic Granulomatosis with Polyangiitis

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic autoimmune disease that manifests as asthma, recurrent sinusitis and peripheral eosinophilia. In this study, we investigated the clinical features of the ear and nasal manifestations of EGPA in comparison with those of granulomatosis with polyangiitis (GPA). Materials and Methods: Twenty-one patients diagnosed with EGPA were studied. The frequency of otologic manifestations, the degree of hearing loss and the frequency of nasal symptoms were assessed. The onset of ear symptoms, sinusitis and asthma in patients with EGPA were also examined. Results: Eleven patients (52.4%) with EGPA demonstrated otologic symptoms. The EGPA patients commonly presented mild-to-moderate mixed or sensorineural hearing loss. The pattern of hearing loss was mainly flat, and all but 1 patient achieved complete remission from their hearing impairments. Eighteen patients (85.7%) with EGPA demonstrated nasal symptoms. Patients with EGPA showed a significantly higher incidence of nasal polyps than did those with GPA. The median Lund and Mackey scoring system score was 13.7 for patients with EGPA, and ethmoid sinus shadows were more severe than those of the maxillary sinus. Most ear symptoms associated with EGPA were observed after definitive diagnosis, although sinusitis and asthma tended to manifest themselves before diagnosis. There were significant differences between the onset of ear symptoms and those of asthma and sinusitis. Conclusion: As over 80% of patients with EGPA had nasal symptoms and over half had ear symptoms, otolaryngologists should be aware of this disease. Recognition of the characteristic ear and nasal symptoms are thought to be particularly important to obtain an early diagnosis of EGPA.

Prevalence of Otological Disorders in Diabetic Cases with Hearing Loss

Objective: Diabetes mellitus is a systemic metabolic disease, characterized by fluctuating levels of glucose which affects multiple organs. Hearing loss is one of the most common otological disorders in adults with diabetes. This study aims to evaluate the prevalence of otological diseases and hearing loss patterns in adults suffering from diabetes. Methods: A total of 174 diabetic cases with hearing loss visiting MAA ENT Hospitals, Hyderabad, India along with 420 age and sex matched subjects with hearing loss constituted the study subjects. The age group of the cases above 40 years and the diagnosis was confirmed by otological examinations. Hearing loss was evaluated using pure tone audiometry and average for the frequencies at 0.5,1,2,4 and 8 kHz was recorded. Statistical analysis was performed using PASW STATISTICS 18.0 for determining the association of various demographic and otological parameters with hearing loss of diabetes subjects compared with non-diabetics. Results: In the present study, chronic suppurative otitis media (47.1%) and presbycusis (27%) were the common otological disorders prevalent in diabetic patients with hearing loss at elderly age (>60 years). 44.3% of the study subjects showed prevalence of conductive hearing loss followed by sensorineural(38.5%) and mixed hearing loss(17.2%). It was also observed that there was a significant association of sensorineural hearing loss (OR=4.85; 95% CI=2.37-9.96; p 60 years). Conclusion: Therefore, the present study has revealed hearing loss in otological disorders is as an important consequence of diabetes.

Hearing threshold of sawmillers in Kaduna, Nigeria

Background: Hearing loss due to occupational noise exposure is a malady with millions of employees having occupational hearing loss (OHL) worldwide though under-appreciated. The neglect of hearing loss, especially OHL has resulted in human and economic consequences worldwide. The WHO estimates a global burden of 1.06 million in Sub-Saharan Africa. Nigeria is experiencing rapid industrial growth, and large number of workers are exposed to industrial noise. Prevention of noise-induced hearing loss is relatively simple and inexpensive. Aims and Objectives: This study was carried out to determine the pattern and prevalence of hearing loss among sawmillers at old Fanteka market, Kaduna. Materials and Methods: This was a cross-sectional descriptive study of the hearing threshold of sawmillers at the old Fanteka market, Kaduna. Ethical clearance was obtained from both the Kaduna state Ministry of Health and the National Ear Care Centre, Kaduna. Questionnaires were duly completed and thereafter the participants had pure tone audiometry in a soundproof booth. Noise meter was used to measure the sound level at the workplace and machines. Pure tone average was calculated for both the left and right ear. Statistical analysis was done using Statistical Package for Social Sciences (SPSS version 16.0, Chicago, Illinois, USA). Results: One hundred and twenty sawmillers with age- and sex-matched controls were assessed. Subjects' age ranged between 20 and 62 years, mean age of 31.36 ± 11.33, whereas controls' age ranged between 20 and 70 years, mean age of 33.29 ± 7.40. All the subjects were males. Prevalence of sensorineural hearing loss (SNHL) was 26.7%. Conclusion: Noise level within the study site environment ranged from 85 to 105 dB. The prevalence of SNHL was 26.70%, moderate type 9–16.70% by pure tone average bilaterally.

Hearing loss patterns after cochlear implantation via the round window in an animal model

PurposeThe mechanism and the type of hearing loss induced by cochlear implants are mostly unknown. Therefore, this study evaluated the impact and type of hearing loss induced by each stage of cochlear implantation surgery in an animal model. Study designOriginal basic research animal study. SettingThe study was conducted in a tertiary, university-affiliated medical center in accordance with the guidelines of the Institutional Animal Care and Use Committee. Subjects and methodsCochlear implant electrode array was inserted via the round window membrane in 17 ears of 9 adult-size fat sand rats. In 7 ears of 5 additional animals round window incision only was performed, followed by patching with a small piece of periosteum (control). Hearing thresholds to air (AC) and bone conduction (BC), clicks, 1kHz and 6kHz tone bursts were measured by auditory brainstem evoked potential, before, during each stage of surgery and one week post-operatively. In addition, inner ear histology was performed. ResultsThe degree of hearing loss increased significantly from baseline throughout the stages of cochlear implantation surgery and up to one week after (p<0.0001). In both operated groups, the greatest deterioration was noted after round window incision. Overall, threshold shift to air-conduction clicks, reached 61dB SPL and the bone conduction threshold deteriorated by 19dB SPL only. Similar losses were found for 1-kHz and 6-kHz frequencies. The hearing loss was not associated with significant changes in inner ear histology. ConclusionsHearing loss following cochlear implantation in normal hearing animals is progressive and of mixed type, but mainly conductive. Changes in the inner-ear mechanism are most likely responsible for the conductive hearing loss.

Audiologic evaluation of vestibular schwannoma and other cerebellopontine angle tumors

Conclusion: Otologic accompanying symptoms, audiogram patterns, and hearing levels according to tumor size differed in patients with CPA tumors classified as VS and non-VS types. Objectives: The diagnosis of CPA tumors is often delayed. Late-diagnosed tumors can grow until they compress and damage vital structures. This study evaluated the otologic symptoms and results of audiologic tests in patients with vestibular schwannomas (VS) and other types of CPA tumors. Methods: This study included 171 patients with otologic symptoms who were diagnosed with CPA tumors, including 116 with VS and 55 with other types of CPA tumors. Factors analyzed retrospectively included tumor type, size, and location and the results of audiometric examinations. Results: The most common chief complaint in patients diagnosed with CPA tumors was asymmetrical hearing loss, with most frequent accompanying symptoms being tinnitus in patients with VS and dizziness in those with other types of CPA tumor. The most frequent patterns of hearing loss were the descending type in patients with VS and the flat type in patients with non-VS tumors (p < 0.05). Pure tone thresholds tended to increase more in patients with VS than non-VS tumors according to tumor size, and pure tone averages were significantly higher in patients with VS than non-VS tumors of 11–25 mm in size (p < 0.05).