Effect of spectral degradation on speech intelligibility and cortical representation.

Noise-vocoded speech has long been used to investigate how acoustic cues affect speech understanding. Studies indicate that reducing the number of spectral channel bands diminishes speech intelligibility. Despite previous studies examining the channel band effect using earlier event-related potential (ERP) components, such as P1, N1, and P2, a clear consensus or understanding remains elusive. Given our hypothesis that spectral degradation affects higher-order processing of speech understanding beyond mere perception, we aimed to objectively measure differences in higher-order abilities to discriminate or interpret meaning. Using an oddball paradigm with speech stimuli, we examined how neural signals correlate with the evaluation of speech stimuli based on the number of channel bands measuring N2 and P3b components. In 20 young participants with normal hearing, we measured speech intelligibility and N2 and P3b responses using a one-syllable task paradigm with animal and non-animal stimuli across four vocoder conditions with 4, 8, 16, or 32 channel bands. Behavioral data from word repetition clearly affected the number of channel bands, and all pairs were significantly different (p < 0.001). We also observed significant effects of the number of channels on the peak amplitude [F(2.006, 38.117) = 9.077, p < 0.001] and peak latency [F(3, 57) = 26.642, p < 0.001] of the N2 component. Similarly, the P3b component showed significant main effects of the number of channel bands on the peak amplitude [F(2.231, 42.391) = 13.045, p < 0.001] and peak latency [F(3, 57) = 2.968, p = 0.039]. In summary, our findings provide compelling evidence that spectral channel bands profoundly influence cortical speech processing, as reflected in the N2 and P3b components, a higher-order cognitive process. We conclude that spectrally degraded one-syllable speech primarily affects cortical responses during semantic integration.

Consensus Statements on the Definition, Classification, and Diagnostic Tests for Tinnitus: A Delphi Study Conducted by the Korean Tinnitus Study Group.

BACKGROUND: Tinnitus is a bothersome condition associated with various symptoms. However, the mechanisms of tinnitus are still uncertain, and a standardized assessment of the diagnostic criteria for tinnitus is required. We aimed to reach a consensus on diagnosing tinnitus with professional experts by conducting a Delphi study with systematic review of the literature. METHODS: Twenty-six experts in managing tinnitus in Korea were recruited, and a two-round modified Delphi study was performed online. The experts evaluated the level of agreement of potential criteria for tinnitus using a scale of 1-9. After the survey, a consensus meeting was held to establish agreement on the results obtained from the Delphi process. Consensus was defined when over 70% of the participants scored 7-9 (agreement) and fewer than 15% scored 1-3 (disagreement). To analyze the responses of the Delphi survey, the content validity ratio and Kendall's coefficient of concordance were evaluated. RESULTS: Consensus was reached for 22 of the 38 statements. For the definition of tinnitus, 10 out of 17 statements reached consensus, with three statements achieving complete agreement including; 1) Tinnitus is a conscious perception of an auditory sensation in the absence of a corresponding external stimulus, 2) Tinnitus can affect one's quality of life, and 3) Tinnitus can be associated with hearing disorders including sensorineural hearing loss, vestibular schwannoma, Meniere's disease, otosclerosis, and others. For the classification of tinnitus, 11 out of 18 statements reached consensus. The participants highly agreed with statements such as; 1) Vascular origin is expected in pulse-synchronous tinnitus, and 2) Tinnitus can be divided into acute or chronic tinnitus. Among three statements on the diagnostic tests for tinnitus only Statement 3, "There are no reliable biomarkers for sensory or emotional factors of tinnitus." reached consensus. All participants agreed to perform pure-tone audiometry and tinnitus questionnaires, including the Tinnitus Handicap Inventory and Tinnitus Questionnaire. CONCLUSION: We used a modified Delphi method to establish a consensus-based definition, a classification, and diagnostic tests for tinnitus. The expert panel reached agreement for several statements, with a high level of consensus. This may provide practical information for clinicians in managing tinnitus.

Personalized Neuromodulation: A Novel Strategy for Improving Tinnitus Treatment.

This study evaluated the efficacy of personalized neuromodulation, where treatment modalities are chosen based on the patient's responses in a pilot trial. A total of 71 patients with tinnitus were divided into two groups: a personalized group and a randomized neuromodulation group. In the personalized group (n = 35), repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS) were assessed in a pilot trial, and responsive modalities were administered to 16 patients, while the non-responders (n = 19) were randomly assigned to rTMS, tDCS, or combined modalities. Patients in the randomized group (n = 36) were randomly allocated to rTMS, tDCS, or combined modalities. The Tinnitus Handicap Inventory (THI) score improvement after 10 sessions of each neuromodulation was significantly greater in the personalized group than in the randomized group (p = 0.043), with no significant differences in tinnitus loudness, distress, or awareness. The treatment success rate was highest in the personalized responder subgroup (92.3%), and significantly greater than that in the non-responder subgroup (53.0%; p = 0.042) and the randomized group (56.7%; p = 0.033). Personalized neuromodulation, where the treatment modality is chosen based on the patient's responses in a pilot trial, is an advantageous strategy for treating tinnitus.

Effect of face masks on speech perception in noise of individuals with hearing aids.

Although several previous studies have confirmed that listeners find it difficult to perceive the speech of face-mask-wearing speakers, there has been little research into how masks affect hearing-impaired individuals using hearing aids. Therefore, the aim of this study was to compare the effects of masks on the speech perception in noise of hearing-impaired individuals and normal-hearing individuals. We also investigated the effect of masks on the gain conferred by hearing aids. The hearing-impaired group included 24 listeners (age: M = 69.5, SD = 8.6; M:F = 13:11) who had used hearing aids in everyday life for >1 month (M = 20.7, SD = 24.0) and the normal-hearing group included 26 listeners (age: M = 57.9, SD = 11.1; M:F = 13:13). Speech perception in noise was measured under no mask-auditory-only (no-mask-AO), no mask-auditory-visual (no-mask-AV), and mask-AV conditions at five signal-to-noise ratios (SNRs; -16, -12, -8, -4, 0 dB) using five lists of 25 monosyllabic Korean words. Video clips that included a female speaker's face and sound or the sound only were presented through a monitor and a loudspeaker located 1 m in front of the listener in a sound-attenuating booth. The degree of deterioration in speech perception caused by the mask (no-mask-AV minus mask-AV) was significantly greater for hearing-impaired vs. normal-hearing participants only at 0 dB SNR (Bonferroni's corrected p < 0.01). When the effects of a mask on speech perception, with and without hearing aids, were compared in the hearing-impaired group, the degree of deterioration in speech perception caused by the mask was significantly reduced by the hearing aids compared with that without hearing aids at 0 and -4 dB SNR (Bonferroni's corrected p < 0.01). The improvement conferred by hearing aids (unaided speech perception score minus aided speech perception score) was significantly greater at 0 and -4 dB SNR than at -16 dB SNR in the mask-AV group (Bonferroni's corrected p < 0.01). These results demonstrate that hearing aids still improve speech perception when the speaker is masked, and that hearing aids partly offset the effect of a mask at relatively low noise levels.

Enhanced Dichotic Listening and Temporal Sequencing Ability in Early-Blind Individuals.

Several studies have reported the better auditory performance of early-blind subjects over sighted subjects. However, few studies have compared the auditory functions of both hemispheres or evaluated interhemispheric transfer and binaural integration in blind individuals. Therefore, we evaluated whether there are differences in dichotic listening, auditory temporal sequencing ability, or speech perception in noise (all of which have been used to diagnose central auditory processing disorder) between early-blind subjects and sighted subjects. The study included 23 early-blind subjects and 22 age-matched sighted subjects. In the dichotic listening test (three-digit pair), the early-blind subjects achieved higher scores than the sighted subjects in the left ear (p = 0.003, Bonferroni's corrected α = 0.05/6 = 0.008), but not in the right ear, indicating a right ear advantage in sighted subjects (p < 0.001) but not in early-blind subjects. In the frequency patterning test (five tones), the early-blind subjects performed better (both ears in the humming response, but the left ear only in the labeling response) than the sighted subjects (p < 0.008, Bonferroni's corrected α = 0.05/6 = 0.008). Monosyllable perception in noise tended to be better in early-blind subjects than in sighted subjects at a signal-to-noise ratio of -8 (p = 0.054), the results at signal-to-noise ratios of -4, 0, +4, and +8 did not differ. Acoustic change complex responses to/ba/in babble noise, recorded with electroencephalography, showed a greater N1 peak amplitude at only FC5 electrode under a signal-to-noise ratio of -8 and -4 dB in the early-blind subjects than in the sighted subjects (p = 0.004 and p = 0.003, respectively, Bonferroni's corrected α = 0.05/5 = 0.01). The results of this study revealed early-blind subjects exhibited some advantages in dichotic listening, and temporal sequencing ability compared to those shown in sighted subjects. These advantages may be attributable to the enhanced activity of the central auditory nervous system, especially the right hemisphere function, and the transfer of auditory information between the two hemispheres.

Coprevalence of Presbycusis and Its Effect on Outcome of Voice Therapy in Patients With Presbyphonia.

OBJECTIVE: To identify the coprevalence of presbycusis and presbycusis and analyze the effect of presbycusis on compliance and result of voice therapy in presbycusis patients. METHODS: This cross-sectional, prospective cohort study initially screened patients aged ≥65 years who visited our hospital from February 2019 to January 2020. Unaided pure tone audiometry was performed in these subjects to determine the presence of presbycusis. Perceptual voice assessment by an examiner was conducted for screening of presbycusis, and its diagnosis was confirmed through the voice handicap index-10 (VHI-10) questionnaire and a laryngoscopic exam. Patients with presbycusis underwent voice therapy and were assessed for their compliance and outcomes of the treatment according to the coexistence of presbycusis. RESULTS: Among the 221 patients, presbycusis and presbycusis were diagnosed in 125 (56.6%) and 110 (49.8%) patients, respectively. The copresence of these two disorders were identified in 87 (39.4%) patients, and there was a significant correlation between presbycusis and presbycusis. The effects of voice therapy were examined in the consecutive 40 patients who were diagnosed with presbycusis. There were 21 patients without presbycusis and 19 patients with presbycusis. The average pretreatment voice handicap index-10 score was significantly higher in presbycusis patients; there was no significant difference in the incidence of dropout from voice therapy between the groups. The patients without presbycusis showed a significant improvement in the functional communication measurement (FCM) level and maximum phonation time (MPT) compared with those of patients with presbycusis after voice therapy. CONCLUSIONS: Presbyphonia and presbycusis coexisted in many elderly people. The improvement in the FCM level and MPT after voice therapy was relatively low if patients with presbycusis accompanied by presbycusis. The copresence of presbycusis did not significantly affect compliance with voice therapy in the patients.

Postoperative results of ventilation tube insertion: a retrospective multicenter study for suggestion of grading system of otitis media with effusion.

BACKGROUND: In otitis media with effusion (OME), it is important to know when to surgically intervene and when careful monitoring is more appropriate. This study aimed to visualize and classify the clinical manifestations of OME and the correlation between the new grading system and postoperative results after ventilation tube insertion (VTI). METHODS: We classified the collective 1,012 ears from 506 patients into six groups: grade 0 (no effusion), grade I (scant effusion, but abnormal), grade II (effusion less than half of the tympanic cavity), grade III (effusion over half of the tympanic cavity, with air bubbles), grade IV (complete effusion), and grade V (retracted tympanic membrane or hemotympanum without air bubbles). RESULTS: The mean age at VTI was 5.2 (±2.9) years and mean duration between diagnosis and operation was 4.1 (±1.8) months. Between the grades, the nature of the middle ear effusion was also significantly different (p < 0.001). The duration of ventilation tube retention after VTI was significantly different when compared between two groups: grade I-IV and grade V (p = 0.019). Our results showed that the recurrence rate, as well as rate of revision VTI, increased as the grade increased (p < 0.001). CONCLUSIONS: The new grading system of OME using endoscopic otoscope evaluation had a significant correlation with the age at VTI, the nature of middle ear effusion, the recurrence rate of OME, and the rate of revision VTI.

Within-Subject Comparisons of the Auditory Brainstem Response and Uncomfortable Loudness Levels in Ears With and Without Tinnitus in Unilateral Tinnitus Subjects With Normal Audiograms.

OBJECTIVE: To evaluate whether cochlear synaptopathy is a common pathophysiologic cause of tinnitus in individuals with normal audiograms. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. METHODS: We enrolled 27 subjects with unilateral tinnitus and normal symmetric hearing thresholds, and 27 age- and sex-matched control subjects with normal symmetric hearing thresholds. We measured 1) the amplitudes of waves I and V with 90 dB nHL click stimuli in quiet conditions; 2) the latency shift of wave V with 80 dB nHL click stimuli in background noise, varying from 40 dB HL to 70 dB HL; and 3) uncomfortable loudness levels (UCLs) at 500 Hz and 3000 Hz pure tones. RESULTS: There were no significant differences in the wave V/I amplitude ratio or the latency shift in wave V with increasing noise levels among the tinnitus ears (TEs), nontinnitus ears (NTEs), and control ears. There were no significant differences in UCLs at 500 Hz or 3000 Hz between TEs and NTEs, but the UCLs were lower in TEs (mean 111.3 dB or 104.1 dB) and NTEs (mean 109.4 dB or 100.6 dB) than in control ears (mean 117.9 dB or 114.1 dB, p < 0.017). No subject met our criteria for cochlear synaptopathy or increased central gain in terms of all three parameters. CONCLUSION: Based on these results for UCL, increased central gain is a major mechanism of tinnitus in humans with normal audiograms. However, this compensatory mechanism for reduced auditory input may originate from other pathophysiologic factors rather than from cochlear synaptopathy.

Predictive Factors for the Success of Intratympanic Dexamethasone Treatment of Acute Subjective Tinnitus.

OBJECTIVES: The purpose of this study was to determine the factors predicting the success or failure of intratympanic dexamethasone (ITD) injection in the treatment of acute subjective tinnitus (AST). MATERIALS AND METHODS: We enrolled patients who were treated with ITD within 3 months of the onset of tinnitus, between 2013 and 2017. We compared the clinical characteristics and audiological data of the patients in the cured group (n=38, 45.6±13.3 years old) and the nonresponder group (n=40, 48.9±18.6 years old). RESULTS: The cured group was predominantly female (p=0.002). The mean duration of tinnitus before ITD was shorter in the cured group than the nonresponder group (p=0.002). The pure-tone averages in both sides were lower in the cured group than in the nonresponder group (p=0.018). The time of tinnitus awareness was shorter in the cured group than in the nonresponder group (p=0.014). Multivariable analysis showed that the duration of tinnitus (odds ratio [OR]=1.045), a history of exposure to noise just before tinnitus development (OR=7.766), and distortion product otoacoustic emissions results (OR=4.580) predicted the outcome of ITD treatment in AST. CONCLUSION: A short duration of tinnitus, no history of immediate noise exposure, and normal distortion product otoacoustic emissions could be favorable prognostic factors for AST treated with ITD injection.

Intratympanic steroid injection for sudden sensorineural hearing loss: Impact of injection interval on therapeutic efficacy.

OBJECTIVE: To compare the effect of injection time intervals of intratympanic (IT) dexamethasone (DEX) in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). METHODS: Seventy-five adults with ISSNHL were grouped into four groups according to the IT DEX interval. In addition to concurrent oral steroid medication for two weeks, patients received IT DEX injections every 1, 2, 3, and four days, respectively. (Group 1, Group 2, Group 3, and Group 4). We evaluated the treatment outcomes according to modified criteria from "Clinical Practice Guideline: Sudden Hearing Loss" of the American Academy of Otolaryngology-Head and Neck Surgery (AAOHNS) to justify treatment success. RESULTS: There were no significant differences in demographic and baseline audiometric data. The mean of pure tone audiometry (PTA) and speech discrimination score (SDSs) were significantly improved after oral steroid and IT DEX treatment in all four groups. Group 1 showed significantly higher improvement than Group 4 in PTA after treatment. There was a significantly higher complete recovery (CR) rate in Group 1 than Group 4. CONCLUSION: We found a statistically significant difference in the complete hearing recovery rate and audiometric results (PTA) between the group with a daily interval of injections and the group with a four-day time interval. Therefore, daily time intervals in intratympanic steroid injection may be considered as an option for better improvement of hearing in patients with ISSNHL.

Influence of Cochlear Dead Regions on Hearing Outcome in Sudden Sensorineural Hearing Loss.

OBJECTIVE: The aims of this multicenter study were to prospectively evaluate the prevalence of dead regions (DRs) in sudden sensorineural hearing loss (SSNHL) and compare the clinical characteristics and hearing outcomes of SSNHL according to the presence of DRs. STUDY DESIGN: Prospective study. SETTING: Multicenter study. PATIENTS AND METHODS: The threshold-equalizing noise (TEN) test was prospectively performed on a total of 130 patients diagnosed with SSNHL. All patients received systemic steroid therapy and/or intratympanic steroid injection within 1 month after onset. Pure-tone audiograms and the TEN test were conducted before and after steroid treatment. Age, sex, side of affected ear, recurrence, onset of symptoms, presence of dizziness, and comorbid diseases were also collected. The prevalence of DRs in SSNHL and clinical factors related to the DRs were assessed. Hearing outcomes for SSNHL according to DRs were evaluated in 68 patients who followed a pure-tone audiogram. RESULTS: The overall prevalence of one or more DRs in SSNHL evaluated using the TEN test was 20.8% (27/130 subjects) and the overall frequency-specific prevalence of DR was 6.7% (61/910 DRs). Although the DRs (+)and DR (-) groups had similar initial pure-tone thresholds, the DRs (+) group had significantly worse initial WRS compared to the DRs (-) group (p = 0.015). The presence of DRs was not associated with hearing recovery in a multivariate logistic regression model, but it was significantly associated with the degree of hearing gain in a multivariate linear regression model (p = 0.018). CONCLUSIONS: The presence of DRs can be considered one of the poor prognostic factors for SSNHL and the TEN test may contribute to assess the prognosis of SSNHL in clinical settings.

Effect of Digital Noise Reduction of Hearing Aids on Music and Speech Perception.

BACKGROUND AND OBJECTIVES: Although many studies have evaluated the effect of the digital noise reduction (DNR) algorithm of hearing aids (HAs) on speech recognition, there are few studies on the effect of DNR on music perception. Therefore, we aimed to evaluate the effect of DNR on music, in addition to speech perception, using objective and subjective measurements. SUBJECTS AND METHODS: Sixteen HA users participated in this study (58.00±10.44 years; 3 males and 13 females). The objective assessment of speech and music perception was based on the Korean version of the Clinical Assessment of Music Perception test and word and sentence recognition scores. Meanwhile, for the subjective assessment, the quality rating of speech and music as well as self-reported HA benefits were evaluated. RESULTS: There was no improvement conferred with DNR of HAs on the objective assessment tests of speech and music perception. The pitch discrimination at 262 Hz in the DNR-off condition was better than that in the unaided condition (p=0.024); however, the unaided condition and the DNR-on conditions did not differ. In the Korean music background questionnaire, responses regarding ease of communication were better in the DNR-on condition than in the DNR-off condition (p=0.029). CONCLUSIONS: Speech and music perception or sound quality did not improve with the activation of DNR. However, DNR positively influenced the listener's subjective listening comfort. The DNR-off condition in HAs may be beneficial for pitch discrimination at some frequencies.

Influence of Visual Deprivation on Auditory Spectral Resolution, Temporal Resolution, and Speech Perception.

We evaluated whether blind subjects have advantages in auditory spectral resolution, temporal resolution, and speech perception in noise compared with sighted subjects. We also compared psychoacoustic performance between early blind (EB) subjects and late blind (LB) subjects. Nineteen EB subjects, 16 LB subjects, and 20 sighted individuals were enrolled. All subjects were right-handed with normal and symmetric hearing thresholds and without cognitive impairments. Three psychoacoustic measurements of the subjects' right ears were performed via an inserted earphone to determine spectral-ripple discrimination (SRD), temporal modulation detection (TMD), and speech recognition threshold (SRT) in noisy conditions. Acoustic change complex (ACC) responses were recorded during passive listening to standard ripple-inverted ripple stimuli. EB subjects exhibited better SRD than did LB (p = 0.020) and sighted (p = 0.003) subjects. TMD was better in EB (p < 0.001) and LB (p = 0.007) subjects compared with sighted subjects. SRD was positively correlated with the duration of blindness (r = 0.386, p = 0.024). Acoustic change complex data for ripple noise change at the Cz and Fz electrodes showed trends toward significant correlations with the behavioral results. In conclusion, compared with sighted subjects, EB subjects showed advantages in terms of auditory spectral and temporal resolution, while LB subjects showed an advantage in temporal resolution exclusively. These findings suggest that it might take longer for auditory spectral resolution to functionally enhance following visual deprivation compared to temporal resolution. Alternatively, a critical period of very young age may be required for auditory spectral resolution to improve following visual deprivation.

Canal Wall-Down Mastoidectomy plus Meatoplasty for Extensive Verruca Vulgaris in the Ear Canal and Mastoid Bone.

Verruca vulgaris is commonly seen on the hands, feet, and face, but rarely in the external auditory canal. We report the case of a 57-year-old woman with a huge papillary mass filling the entire external auditory canal, with destruction of the posterior canal wall and excavation into the mastoid bone. We performed en bloc resection of the whole region affected by verruca vulgaris, including the external auditory canal, mastoid skin, and tympanic membrane using canal wall-down mastoidectomy plus meatoplasty. There was no evidence of recurrence 12 months postoperatively. Complete surgical removal by mastoidectomy is a promising option for wide-spread verruca vulgaris in the external auditory canal.

Further Beneficial Effect of Hearing Aids on Speech Recognition Performance Besides Amplification: Importance of the Restoration of Symmetric Hearing.

OBJECTIVE: To identify the improvement in auditory spectral resolution, temporal resolution, and speech recognition conferred with various hearing-aid (HA) technologies when the amplification effect of the HA is excluded, and to compare the beneficial effects depending on the restoration of symmetric hearing with different amplification settings in various hearing impairment conditions. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. SUBJECTS: Sixty-two subjects who had used HAs for more than 3 months were divided into four groups: group 1, bilateral HAs (n = 28); group 2, unilateral HA in the better ear (n = 12); group 3, unilateral HA in the worse ear (n = 12); group 4, unilateral HA with symmetric hearing thresholds (n = 10). METHODS: Aided performance and unaided performance were compared in each group. Four different psychoacoustic measurements were made: 1) spectral ripple discrimination; 2) temporal modulation detection; 3) speech recognition threshold in white noise; and 4) speech discrimination score (SDS) under quiet conditions. All test signals were presented by a loudspeaker located 1 m in front of the subject in a sound-attenuating booth, at their most comfortable levels, with or without HAs. RESULTS: In group 1, the use of HAs significantly improved both SDS under quiet conditions and speech recognition in noise compared with the unaided condition. Group 2 showed better SDS under quiet conditions with HAs, and group 3 showed improved speech recognition in noise with HAs. In contrast, in group 4, no measurements differed with or without HAs. CONCLUSIONS: These results demonstrate the benefits of HAs on speech perception in noise, in addition to their amplification effect, but only when HA restores symmetric hearing.

Epidemiology of Clinically Significant Tinnitus: A 10-Year Trend From Nationwide Health Claims Data in South Korea.

OBJECTIVES: Prevalence of tinnitus has been reported to vary according to the target population and definition of tinnitus. To improve the understanding of tinnitus, authors used the nation-wide health claim data to study the tinnitus in the entire population of South Korea. STUDY DESIGN: Retrospective big data review. SETTING: Analysis of big data from the National Health Information Database. PATIENTS: Patients diagnosed with tinnitus according to International Classification of Diseases code 10th edition (ICD-10) and requested to receive National Health Insurance claim at least once from January 2006 to December 2015. INTERVENTION: None. MAIN OUTCOME MEASURE: Epidemiologic data, association of tinnitus with the otologic and systemic diseases. RESULTS: The number of patients who received medical care because of tinnitus was 1.44% (0.78 million per 51 million) in 2015. There was a higher prevalence of tinnitus in women, and the overall prevalence increased with increasing age of patients and peaked at patients in their 70s (4.43%). The prevalence of tinnitus among patients aged 10 to 30 years, showed a tendency to increase during study period. In the regional analysis, highest prevalence was observed in Gwangju (2.02%). In comparison with the control group, the patients with tinnitus showed a higher frequency in otologic and systemic disease. Especially, noise induced hearing loss (adjusted odds ratio [AOR] = 82.1, 95% confidence interval [95% CI] = 74.8-90.2) and sudden sensorineueal hearing loss (AOR = 49.7, 95% CI = 48.4-51.0) showed high frequency in tinnitus patient group. CONCLUSIONS: The prevalence and incidence of tinnitus in this study for entire nation were lower than previously reported studies. These results have limitation because the study only covered patient using the medical service for tinnitus and missed tinnitus sufferers not seeking medical service. However, this study is meaningful in that it was targeting entire nation, reflected the characteristics of clinically significant tinnitus patient enough to visit medical service.

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms.

OBJECTIVE: Recently, "hidden hearing loss" with cochlear synaptopathy has been suggested as a potential pathophysiology of tinnitus in individuals with a normal hearing threshold. Several studies have demonstrated that subjects with tinnitus and normal audiograms show significantly reduced auditory brainstem response (ABR) wave I amplitudes compared with control subjects, but normal wave V amplitudes, suggesting increased central auditory gain. We aimed to reconfirm the "hidden hearing loss" theory through a within-subject comparison of wave I and wave V amplitudes and uncomfortable loudness level (UCL), which might be decreased with increased central gain, in tinnitus ears (TEs) and non-tinnitus ears (NTEs). SUBJECTS AND METHODS: Human subjects included 43 unilateral tinnitus patients (19 males, 24 females) with normal and symmetric hearing thresholds and 18 control subjects with normal audiograms. The amplitudes of wave I and V from the peak to the following trough were measured twice at 90 dB nHL and we separately assessed UCLs at 500 Hz and 3000 Hz pure tones in each TE and NTE. RESULTS: The within-subject comparison between TEs and NTEs showed no significant differences in wave I and wave V amplitude, or wave V/I ratio in both the male and female groups. Individual data revealed increased V/I amplitude ratios > mean + 2 SD in 3 TEs, but not in any control ears. We found no significant differences in UCL at 500 Hz or 3000 Hz between the TEs and NTEs, but the UCLs of both TEs and NTEs were lower than those of the control ears. CONCLUSIONS: Our ABR data do not represent meaningful evidence supporting the hypothesis of cochlear synaptopathy with increased central gain in tinnitus subjects with normal audiograms. However, reduced sound level tolerance in both TEs and NTEs might reflect increased central gain consequent on hidden synaptopathy that was subsequently balanced between the ears by lateral olivocochlear efferents.

Comparison of Long-Term Outcome of Intratympanic Dexamethasone Therapy between Acute Noise-Induced Tinnitus and Acute Idiopathic Tinnitus.

OBJECTIVE: To compare the long-term outcomes of acute noise-induced tinnitus (ANT) and acute idiopathic tinnitus (AIT) to intratympanic dexamethasone (ITD) therapy. MATERIALS AND METHODS: Patients treated for tinnitus occurring immediately after noise exposure comprised the ANT group (n=20) and patients treated for idiopathic tinnitus comprised the AIT group (n=39). All patients were treated with ITD within 3 months of the onset of tinnitus. Quantitative assessment of the improvement in tinnitus using questionnaires and changes in hearing thresholds were compared between the two groups. RESULTS: Mean follow-up durations were 75.90±69.83 weeks in the ANT group and 93.41±101.43 weeks in the AIT group. Patients with ANT were younger in age than those with AIT (38.30±18.28 vs. 53.56±14.08, p=0.00) and were predominately male (Male: Female, M:F 13:7 vs. 13:26, p=0.02, respectively). The subjective tinnitus loudness, time of tinnitus awareness, and Tinnitus Handicap Inventory score improved in both groups, although the changes in these parameters were not significantly different between the groups. The cure and overall improvement rates of the ANT group were and 10.00% and 25.00%, respectively. The cure and overall improvement rates of the AIT groups were 25.64% and 35.90%, respectively and there were no significant differences between the two groups in terms of the cure and overall improvement rates (p=0.19 and 0.40, respectively). CONCLUSION: The long-term outcome in terms of control of tinnitus with ITD in the ANT group was similar to that in the AIT group. Thus, ITD injection may be a useful treatment option for acute tinnitus caused by noise trauma.

Neuroglial Choristoma of the Middle Ear with Massive Tympanosclerosis: A Case Report and Literature Review.

Neuroglialchoristoma is a rare cerebral heterotopia typically involving extracranial midline structures of the head and neck, including the nose, nasopharynx and oral cavity. It rarely involves non-midline structures, such as the middle ear, mastoid and orbit. We report the case of a 63-year-old woman with right-sided hearing loss and aural fullness who was diagnosed with neuroglialchoristoma of the middle ear and mastoid. To our knowledge, this is the first report on neuroglialchoristomawith massive tympanosclerosis. The presence of combination supported the inhalation theory of neuroglialchoristoma, given that tympanosclerosis is typically caused by Eustachian tube dysfunction.

Influence of Tinnitus on Auditory Spectral and Temporal Resolution and Speech Perception in Tinnitus Patients.

Although cochlear damage is believed to trigger the perception of tinnitus in the central auditory system, its pathophysiological mechanism is still unclear. We aimed to investigate the pathophysiology of tinnitus using psychoacoustic assessments of auditory spectral and temporal resolution and speech perception in noise. Human subjects with tinnitus and symmetric hearing thresholds were divided into three groups: nine unilateral tinnitus subjects with normal hearing thresholds (Group 1), 12 unilateral tinnitus subjects with hearing loss (HL; Group 2), and nine bilateral tinnitus subjects with HL. Fifteen normal-hearing subjects without tinnitus were also tested as a control group. Four different tests were administered: (1) the spectral-ripple discrimination (SRD) test, (2) the temporal modulation detection (TMD) test, (3) the Schroeder-phase discrimination (SPD) test, and (4) the speech recognition threshold (SRT) in noise test. There were no significant differences in SRD, TMD, and SPD between the tinnitus-affected ears (TEs) and non-tinnitus ears (NTEs) in Groups 1 and 2 (p > 0.05). In contrast, the TEs showed poorer SRTs than the NTEs in these two subject groups (p = 0.022 and 0.049). No inferiority of spectral/temporal resolution in TEs compared with NTEs suggests that there may be no more outer hair cell (OHC) damage on the tinnitus side given that damaged OHCs are associated with broadening the auditory filters. The decoupling of the SRT results from the spectral/temporal resolution data could imply that the occurrence of tinnitus does not depend upon the degree of damage to the OHCs, but rather upon different plastic changes in the central auditory system after cochlear damage. SIGNIFICANCE STATEMENT: We can easily find unilateral tinnitus patients who have symmetric hearing thresholds. Our research question was what kind of difference would be responsible for the tinnitus in the tinnitus-affected ears but not in the non-tinnitus ears of subjects with symmetric hearing thresholds. The answer to this fundamental question could help us to understand the pathophysiology of tinnitus. We evaluated the potential influence of tinnitus upon the subjects' auditory spectral and temporal resolution and speech perception in noise by comparing these psychoacoustic performances between tinnitus-affected ears and non-tinnitus ears in the same subjects.