Cochlear implantation in patients with Charcot-Marie-Tooth disease: two cases with a review of the literature.

PURPOSE: To report two cases of bilateral cochlear implantation (CI) in Charcot-Marie-Tooth disease (CMT) patients with novel mutations. Furthermore, we conducted a detailed literature review on the profile and outcomes of CI in this uncommon clinical circumstance. CASE PRESENTATION: Case 1 involved a 25-year-old woman who was referred for sudden hearing loss (HL) in her left ear and had a 7-year history of HL in her right ear. She was diagnosed with CMT type 1 with a thymidine phosphorylase gene mutation. CI was performed on her left side because her hearing gradually worsened to deafness in both ears. At 3 months post-operation, her speech discrimination score without lip-reading improved from 0 to 100%. She underwent a second CI on her right ear 6 months after her first CI. Two years from her first operation, the speech discrimination score was 100%. Case 2 received her first CI on her right ear at the age of nine for her bilateral HL. She was diagnosed with CMT type 2 with a Twinkle mitochondrial DNA helicase gene mutation. Preoperatively, the speech discrimination score in both ear-aided conditions was 70%. At the 7-year post-operation follow-up, the speech discrimination score was 76%. A second CI was performed due to decreasing hearing ability in her left ear. The speech discrimination score showed 100% at 7 months after the second CI. CONCLUSIONS: CI is an effective hearing rehabilitation option for CMT patients with severe-to-profound SNHL. Neuro-otologists should consider CI as a treatment option, even though hearing loss in CMT is associated with auditory neuropathy spectrum disease (ANSD).

The Multifaceted Clinical Characteristics of Congenital Cytomegalovirus Infection: From Pregnancy to Long-Term Outcomes.

BACKGROUND: The aim of this study was to capture multifaceted clinical characteristics of congenital cytomegalovirus (CMV) infection from diagnosis to treatment using a multidisciplinary approach including obstetrics, pediatrics, pathology, and otorhinolaryngology-head and neck surgery. METHODS: This is a retrospective study including 30 consecutive cases of congenital CMV infection that were diagnosed at a single tertiary hospital located in Seoul, Korea from January 2009 to December 2020. Congenital CMV infection was defined as a positive result by polymerase chain reaction from urine, saliva or cerebrospinal fluid or positive CMV IgM from neonatal blood sampled within 3 weeks after birth. All cases were analyzed with respect to whole clinical characteristics from diagnosis to treatment of congenital CMV by a multidisciplinary approach including prenatal sonographic findings, maternal immune status regarding CMV infection, detailed placental pathology, neonatal clinical manifestation, auditory brainstem response test, and antiviral treatment (ganciclovir or valganciclovir). Long-term outcomes including developmental delay and hearing loss were also investigated. RESULTS: The total number of births during the study period in our institution was 19,385, with the prevalence of congenital infection estimated to be 0.15%. Among 30 cases of congenital CMV, the median gestational age at delivery was 32.2 weeks [range, 22.6-40.0] and 66.7% of these infants were delivered preterm at less than 37 weeks. Suspected fetal growth restriction was the most common prenatal ultrasound finding (50%) followed by ventriculomegaly (17.9%) and abnormal placenta (17.9%), defined as thick placenta with calcification. No abnormal findings on ultrasound examination were observed in one-third of births. Maternal CMV serology tests were conducted in only 8 cases, and one case each of positive and equivocal IgM were found. The most common placental pathologic findings were chronic villitis (66.7%) and calcification (63.0%), whereas viral inclusions were identified in only 22.2%. The most common neonatal manifestations were jaundice (58.6%) followed by elevation of aspartate aminotransferase (55.2%) and thrombocytopenia (51.7%). After excluding cases for which long-term outcomes were unavailable due to death (n = 4) or subsequent follow up loss (n = 3), developmental delay was confirmed in 43.5% of infants (10/23), and hearing loss was confirmed in 42.9% (9/21) during the follow-up period. In our cohort, 56.7% (17/30) of neonates were treated for congenital CMV with ganciclovir or valganciclovir. CONCLUSION: Our data show that prenatal findings including maternal serologic tests and ultrasound have limited ability to detect congenital CMV in Korea. Given that CMV is associated with high rates of developmental delay and hearing loss in infants, there is an urgent need to develop specific strategies for the definite diagnosis of congenital CMV infection during the perinatal period by a multidisciplinary approach to decrease the risks of neurologic impairment and hearing loss through early antiviral treatment.

Comparison of speech recognition performance with and without a face mask between a basic and a premium hearing aid in hearing-impaired listeners.

BACKGROUND: The mask mandate during the COVID-19 pandemic leads to communication challenges as sound energy gets reduced and the visual cues are lost due to the face mask. This study examines the impact of a face mask on sound energy and compares speech recognition performance between a basic and a premium hearing aid. METHODS: Participants watched four video clips (a female and a male speaker with and without a face mask) and repeated the target sentences in various test conditions. Real-ear measurement was performed to investigate the changes in sound energy in no mask, surgical, and N95 mask conditions. RESULTS: With the face mask on, sound energy significantly decreased for all types of masks. For speech recognition, the premium hearing aid showed significant improvement in the mask condition. CONCLUSION: The findings emphasize and encourage health care professionals to actively use communication strategies, such as speaking slowly and reducing background noise, when interacting with individuals with hearing loss.

Percutaneous Bone-Anchored Hearing Implant: Is It Clinically Useful in Korean?

BACKGROUND: The aim of this study is to investigate the clinical effectiveness of Ponto in Korea, a recently released percutaneous bone-anchored hearing implant. METHODS: 16 patients with single-sided deafness (SSD) and mixed or conductive hearing loss who underwent Ponto implantation from December 2018 to September 2020 were enrolled in the study. Puretone audiometry, the Korean version of the Hearing in Noise Test (K-HINT), sound localization test (SLT), and Pupillometry were performed pre- and three months post-operation. Standardized questionnaires, the Hearing Handicap Inventory for the Elderly (HHIE) and Speech, Spatial and Qualities of Hearing Scale (SSQ), were administered. RESULTS: The mean age of subjects was 55.5 (range, 48-67) years. Four males and 12 females participated in the study. The mean puretone average was 73.17 dB hearing level (HL) before surgery and significantly improved to 36.72 dB HL three months after surgery. The mean word recognition score improved from 26.0% to 90.75% after implantation. In the case of K-HINT, there was a significant difference in summation (Z = -2.250, P = 0.024) and head shadow effects (Z = -3.103, P = 0.002). There was no significant difference in root mean square error degree (RMSE) and hemifield identification scores for SLT testing. Pupillometry was performed to measure listening effort and the results revealed that the degree of pupillary dilatation decreased under the condition of quiet, 0 dB signal to noise ratio (SNR) and 3 dB SNR. The total score for HHIE decreased significantly (Z = -3.130, P = 0.002) while the SSQ score increased significantly (Z = -2.216, P = 0.027). CONCLUSIONS: The Ponto bone-anchored hearing system showed significant clinical benefit in Korean patients with conductive and mixed hearing loss and SSD.

Factors Influencing Hearing Aid Adoption in Patients With Hearing Loss in Korea.

BACKGROUND: The purpose of this study was two-fold: 1) to identify differences in the characteristics of adopters and non-adopters of hearing aids (HAs); and 2) to investigate factors influencing the purchase of HA. METHODS: This study was conducted among 1,464 subjects (818 male and 646 female) with hearing loss. A national face-to-face survey was performed from August 2019 to October 2020 by otologists or HA experts. The questionnaire consisted of three domains: demographic, audiological, and HA-related domains. Multivariate logistic regression analysis was performed after adjusting for degree of hearing loss. RESULTS: The mean age of the participants was 70.4 ± 12.2 years. Of the 1,464 respondents, 1,190 (81.3%) had already purchased HA. We identified educational level, household income, hearing loss period, place of HA purchase, and government HA assistance program status as factors influencing HA adoption. Among these factors, third party reimbursement was the most important factor affecting HA purchase intent. The main reasons for not adopting HA were feeling that their hearing was adequate, inability to afford HA, and perceptions that HA are uncomfortable. CONCLUSION: Various factors are involved in the purchase of HA, but disabled registration status and third party reimbursement were identified as the most critical factors. In the future, the government should take a more active role in increasing the distribution of HA to patients with hearing loss.

Hearing and Speech Perception for People With Hearing Loss Using Personal Sound Amplification Products.

BACKGROUND: Hearing loss (HL) is the most common chronic disease and has been linked to negative health outcomes. Hearing aids (HAs) are regarded as the gold standard for HL management, however, the adoption rate of HAs is relatively low for various reasons. With this background, hearing devices, such as personal sound amplification products (PSAPs) received significant attention as an alternative to conventional HAs. This study aimed to evaluate the clinical efficacy of PSAPs in patients with mild to moderately severe HL. METHODS: Nineteen patients with mild hearing loss (MHL), 23 with moderate hearing loss (MDHL), and 15 with moderately severe hearing loss (MSHL) participated in the study. Electroacoustic analysis, simulated real-ear measurements (REMs), and three clinical evaluations were implemented. RESULTS: All devices satisfied the electroacoustic tolerances. All devices provided sufficient gain for MHL and MDHL audiograms. However, in MSHL audiogram, the gains of PSAPs were insufficient, especially for high frequencies. In terms of clinical evaluations, sound-field audiometry showed significant improvements between aided and unaided thresholds in all groups for all devices (P < 0.001). Significant improvements of word recognition scores were only shown for HAs between aided and unaided conditions. The Korean version of the Hearing In Noise Test did not show any consistent findings for all devices and groups. CONCLUSION: Certain PSAPs are beneficial for improving hearing and speech perception in patients with HL. Well-chosen PSAPs could be an alternative hearing rehabilitation option for these patients.

Predicting the Cochlear Dead Regions Using a Machine Learning-Based Approach with Oversampling Techniques.

Background and Objectives: Determining the presence or absence of cochlear dead regions (DRs) is essential in clinical practice. This study proposes a machine learning (ML)-based model that applies oversampling techniques for predicting DRs in patients. Materials and Methods: We used recursive partitioning and regression for classification tree (CT) and logistic regression (LR) as prediction models. To overcome the imbalanced nature of the dataset, oversampling techniques to duplicate examples in the minority class or to synthesize new examples from existing examples in the minority class were adopted, namely the synthetic minority oversampling technique (SMOTE). Results: The accuracy results of the 10-fold cross-validation of the LR and CT with the original data were 0.82 (±0.02) and 0.93 (±0.01), respectively. The accuracy results of the 10-fold cross-validation of the LR and CT with the oversampled data were 0.66 (±0.02) and 0.86 (±0.01), respectively. Conclusions: This study is the first to adopt the SMOTE method to assess the role of oversampling methods on audiological datasets and to develop an ML-based model. Considering that the SMOTE method did not improve the model's performance, a more flexible model or more clinical features may be needed.

Cochlear Dead Regions in Sporadic Unilateral Vestibular Schwannomas Using the Threshold-Equalizing Noise Test.

BACKGROUND: Vestibular schwannoma (VS) is a benign intracranial neoplasm originating in the Schwann cells of the vestibular nerve. Despite its origin, the most common symptom is sensorineural hearing loss which is presented in more than 90% of patients. The underlying pathophysiology of this hearing loss has not been fully understood. OBJECTIVE: To assess the in vivo function of cochlear inner hair cells and spiral ganglion neurons in VS, cochlear dead regions (DRs) were evaluated via the threshold-equalizing noise (TEN) test in untreated VS patients. METHOD: Untreated patients diagnosed with sporadic unilateral VS and normal contralesional hearing were enrolled from July 2011 to June 2016. Audiometric evaluation including TEN tests were performed. Based on the magnetic resonance findings, characteristics of individual tumors were assessed. RESULTS: The average pure-tone threshold (word recognition score [WRS]) of 23 enrolled patients was 42.7 dB (76.1%). Nineteen DRs (11.8% of 161 tested frequencies) were found in 8 patients (34.8% of enrolled cases). Among the intracanalicular (IAC) tumors, 6 out of 10 ears (60%) carried DRs, while 2 of 13 (15.4%) showed DRs among the cerebellopontine angle (CPA) lesions (p = 0.039). Pure-tone thresholds and WRS were not different between the two groups. Logistic regression analysis showed that the tumor location, IAC versus CPA, was significantly associated with DRs (p = 0.041, Nagelkerke R2 = 0.471), whereas age, sex, tumor size, distance from the tumor to the cochlea, T2-weighted hypointensity on the MRI and pure-tone thresholds showed no significance. CONCLUSIONS: Cochlear DRs are detected in hearing losses associated with unilateral sporadic VS using the TEN test. Individual DRs were detected variously in high, mid, or low frequencies. In our preliminary data, IAC tumors showed a higher number of DRs than CPA tumors despite similar average hearing thresholds. Further studies including longitudinal follow-up of hearing as well as change in DRs may provide useful information about VS patients.

Amikacin Inhalation as Salvage Therapy for Refractory Nontuberculous Mycobacterial Lung Disease.

Although guidelines recommend amikacin (AMK) inhalation therapy for difficult-to-treat nontuberculous mycobacterial lung disease (NTM-LD), data are limited regarding the safety and clinical efficacy of this salvage therapy. We retrospectively evaluated the treatment outcomes of 77 patients with refractory NTM-LD caused by Mycobacterium abscessus complex (MABC) or M. avium complex (MAC) who initiated AMK inhalation therapy between February 2015 and June 2016. MABC was the most common etiology (n = 48, 62%), followed by MAC (n = 20, 26%) and mixed infections (n = 9, 12%). Isolates with macrolide resistance and baseline AMK resistance were identified in 63 (82%) patients and 5 (6%) patients, respectively. At 12 months after AMK inhalation therapy, 49% of patients had symptomatic improvement, whereas 42% had radiological improvement. Conversion to a negative sputum culture occurred in 14 (18%) patients, and the culture conversion rate was higher in patients infected with macrolide-susceptible isolates (7/14, 50%) than in those infected with macrolide-resistant isolates (7/63, 11%) (P = 0.003). Significant decreases in sputum semiquantitative culture positivity occurred after AMK inhalation therapy (P < 0.001). On multivariate analysis, conversion to a negative sputum culture was associated with mixed infections (P = 0.009), a forced expiratory volume in 1 s of greater than 60% (P = 0.008), and the absence of macrolide resistance (P = 0.003). Thirty-eight percent of patients experienced adverse effects, with ototoxicity (n = 15) being the most common. AMK inhalation salvage therapy may improve the treatment responses in some patients with refractory NTM-LD. However, considering the common adverse effects, further evaluation of the optimal dosage and intervals for AMK inhalation therapy is needed.

Application of endoscopy in otology: Changes over the last 8years in Korean Otological Society.

OBJECTIVES: Despite the worldwide availability of endoscope in otology, it still has not replaced the microscopic surgery as it has for nose surgery. In 2008, we administered a questionnaire on the preference of using otoscopes in Korea. In light of the worldwide availability of endoscopic ear surgery, we have now conducted a more detailed survey to determine if this preference has changed over 8years. SUBJECTS AND METHODS: A questionnaire consisting of 10 questions was used to survey members of the Korean Otological Society who were actively performing middle ear surgery. The responses to this questionnaire were compared to those from 2008. The study also determined the preference for endoscope use based on the surgeon's experience. RESULTS: The mean surgical experience of the otologists was 12.7years. Endoscopy for tympanoplasty and tympanomastoidectomy increased over a period of 8years. In the outpatient clinic, the use of endoscopy also increased; over 8-year period, it surpassed the microscope as the most preferred diagnostic tool in the outpatient clinic. Greater than half of the operating rooms were equipped with endoscopic sets; however, only 4.5% of otologists acknowledged having endoscopic instruments. CONCLUSION: Endoscopy for surgery and in outpatient clinic assessment increased in otology in Korea; however, endoscopes have consistently been used as an adjuvant to the microscope to improve visualization of the tympanic cavity rather than as a tool for totally endoscopic ear surgery.

Sound Localization and Speech Perception in Noise of Pediatric Cochlear Implant Recipients: Bimodal Fitting Versus Bilateral Cochlear Implants.

OBJECTIVES: The aim of this study was to compare binaural performance of auditory localization task and speech perception in babble measure between children who use a cochlear implant (CI) in one ear and a hearing aid (HA) in the other (bimodal fitting) and those who use bilateral CIs. DESIGN: Thirteen children (mean age ± SD = 10 ± 2.9 years) with bilateral CIs and 19 children with bimodal fitting were recruited to participate. Sound localization was assessed using a 13-loudspeaker array in a quiet sound-treated booth. Speakers were placed in an arc from -90° azimuth to +90° azimuth (15° interval) in horizontal plane. To assess the accuracy of sound location identification, we calculated the absolute error in degrees between the target speaker and the response speaker during each trial. The mean absolute error was computed by dividing the sum of absolute errors by the total number of trials. We also calculated the hemifield identification score to reflect the accuracy of right/left discrimination. Speech-in-babble perception was also measured in the sound field using target speech presented from the front speaker. Eight-talker babble was presented in the following four different listening conditions: from the front speaker (0°), from one of the two side speakers (+90° or -90°), from both side speakers (±90°). Speech, spatial, and quality questionnaire was administered. RESULTS: When the two groups of children were directly compared with each other, there was no significant difference in localization accuracy ability or hemifield identification score under binaural condition. Performance in speech perception test was also similar to each other under most babble conditions. However, when the babble was from the first device side (CI side for children with bimodal stimulation or first CI side for children with bilateral CIs), speech understanding in babble by bilateral CI users was significantly better than that by bimodal listeners. Speech, spatial, and quality scores were comparable with each other between the two groups. CONCLUSIONS: Overall, the binaural performance was similar to each other between children who are fit with two CIs (CI + CI) and those who use bimodal stimulation (HA + CI) in most conditions. However, the bilateral CI group showed better speech perception than the bimodal CI group when babble was from the first device side (first CI side for bilateral CI users or CI side for bimodal listeners). Therefore, if bimodal performance is significantly below the mean bilateral CI performance on speech perception in babble, these results suggest that a child should be considered to transit from bimodal stimulation to bilateral CIs.

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.

Assessment of Spectral and Temporal Resolution in Cochlear Implant Users Using Psychoacoustic Discrimination and Speech Cue Categorization.

OBJECTIVES: This study was conducted to measure auditory perception by cochlear implant users in the spectral and temporal domains, using tests of either categorization (using speech-based cues) or discrimination (using conventional psychoacoustic tests). The authors hypothesized that traditional nonlinguistic tests assessing spectral and temporal auditory resolution would correspond to speech-based measures assessing specific aspects of phonetic categorization assumed to depend on spectral and temporal auditory resolution. The authors further hypothesized that speech-based categorization performance would ultimately be a superior predictor of speech recognition performance, because of the fundamental nature of speech recognition as categorization. DESIGN: Nineteen cochlear implant listeners and 10 listeners with normal hearing participated in a suite of tasks that included spectral ripple discrimination, temporal modulation detection, and syllable categorization, which was split into a spectral cue-based task (targeting the /ba/-/da/ contrast) and a timing cue-based task (targeting the /b/-/p/ and /d/-/t/ contrasts). Speech sounds were manipulated to contain specific spectral or temporal modulations (formant transitions or voice onset time, respectively) that could be categorized. Categorization responses were quantified using logistic regression to assess perceptual sensitivity to acoustic phonetic cues. Word recognition testing was also conducted for cochlear implant listeners. RESULTS: Cochlear implant users were generally less successful at utilizing both spectral and temporal cues for categorization compared with listeners with normal hearing. For the cochlear implant listener group, spectral ripple discrimination was significantly correlated with the categorization of formant transitions; both were correlated with better word recognition. Temporal modulation detection using 100- and 10-Hz-modulated noise was not correlated either with the cochlear implant subjects' categorization of voice onset time or with word recognition. Word recognition was correlated more closely with categorization of the controlled speech cues than with performance on the psychophysical discrimination tasks. CONCLUSIONS: When evaluating people with cochlear implants, controlled speech-based stimuli are feasible to use in tests of auditory cue categorization, to complement traditional measures of auditory discrimination. Stimuli based on specific speech cues correspond to counterpart nonlinguistic measures of discrimination, but potentially show better correspondence with speech perception more generally. The ubiquity of the spectral (formant transition) and temporal (voice onset time) stimulus dimensions across languages highlights the potential to use this testing approach even in cases where English is not the native language.

Optimal combination of neural temporal envelope and fine structure cues to explain speech identification in background noise.

The dichotomy between acoustic temporal envelope (ENV) and fine structure (TFS) cues has stimulated numerous studies over the past decade to understand the relative role of acoustic ENV and TFS in human speech perception. Such acoustic temporal speech cues produce distinct neural discharge patterns at the level of the auditory nerve, yet little is known about the central neural mechanisms underlying the dichotomy in speech perception between neural ENV and TFS cues. We explored the question of how the peripheral auditory system encodes neural ENV and TFS cues in steady or fluctuating background noise, and how the central auditory system combines these forms of neural information for speech identification. We sought to address this question by (1) measuring sentence identification in background noise for human subjects as a function of the degree of available acoustic TFS information and (2) examining the optimal combination of neural ENV and TFS cues to explain human speech perception performance using computational models of the peripheral auditory system and central neural observers. Speech-identification performance by human subjects decreased as the acoustic TFS information was degraded in the speech signals. The model predictions best matched human performance when a greater emphasis was placed on neural ENV coding rather than neural TFS. However, neural TFS cues were necessary to account for the full effect of background-noise modulations on human speech-identification performance.

Objective and Subjective Improvement of Hearing in Noise After Surgical Correction of Unilateral Congenital Aural Atresia in Pediatric Patients: A Prospective Study Using the Hearing in Noise Test, the Sound-Spatial-Quality Questionnaire, and the Glasgow Benefit Inventory.

OBJECTIVES: The aim of this study was to assess the objective and subjective long-term binaural benefits of surgical correction in children with unilateral congenital aural atresia, using an open-set sentence test in noise and subjective questionnaires. DESIGN: A prospective study was performed between August 2010 and February 2013. This study included pediatric patients who had unilateral conductive hearing loss (normal bone conduction hearing) on the atretic side but normal air conduction hearing on the normal side and were scheduled to undergo a primary canaloplasty. Pure-tone audiometry, the hearing in noise test (HINT), and questionnaires (Sound-Spatial-Qualities of Hearing Scale; Glasgow Benefit Inventory [GBI]) were administered preoperatively and at 6 and 12 months postoperatively. RESULTS: Among 34 consecutive patients who initially met enrollment criteria, 26 subjects (23 boys and 3 girls) aged 10 to 16 years (mean 12.3 years) completed this study. Canaloplasty and hearing restoration procedures were performed uneventfully in all patients. The mean air conduction thresholds were significantly improved from 63.9 to 35.0 dB (6 months) and 39.4 dB (12 months) after surgery (p < 0.001). In HINT, speech understanding in noise that was presented toward the newly opened atretic ear significantly improved at 1 year postoperatively (p = 0.014). In noise toward the normal ear, speech understanding significantly improved after surgery, from -0.1 dB preoperatively to -2.0 dB at 6 months (p = 0.002) and -1.8 dB at 12 months (p = 0.005) (p for quadratic trend = 0.036). The composite score improved from -2.6 dB preoperatively to -3.4 dB at 6 months and -3.6 dB at 12 months (p = 0.045; p for linear trend = 0.005). The Sound-Spatial-Qualities of Hearing Scale scores in all domains significantly improved 1 year after surgery (p < 0.034). The mean GBI scores in each domain ranged from 14.2 to 49.4. Total GBI score was correlated with better signal to noise ratio in noise toward the atretic ear as measured by HINT at postoperative 1 year (Spearman ρ = 0.482, p = 0.013). CONCLUSIONS: Teenaged patients with unilateral congenital aural atresia showed satisfactory hearing improvement after canaloplasty with hearing restoration surgery. In a serial long-term follow-up, speech understanding in noise measured by HINT improved over time. One year after surgery, teenaged children acquired binaural hearing (binaural squelch), as measured by the HINT with noise presented to the newly opened atretic ear. Subjective questionnaires also showed improvements in binaural hearing function and quality of life.

Clinical effectiveness of wireless CROS (contralateral routing of offside signals) hearing aids.

This study evaluated the clinical effectiveness of wireless contralateral routing of offside signals hearing aids (CROS) in patients with severe to profound unilateral sensorineural hearing loss (USNHL). Twenty-one patients with USNHL were enrolled in this prospective study. The change of subjective satisfaction was evaluated using three questionnaires (K-HHIE, K-IOI-HA, K-SSQ). Changes in objective measurements were evaluated with sound localization test (SLT) and hearing in noise test (HINT). These tests were performed at pre-CROS fitting, 2 and 4 weeks after use of CROS. Subjects were grouped according to the age: young (<40 years) vs. old (≥40 years) group. The average K-HHIE and K-SSQ scores significantly improved with the use of CROS. SLT result revealed that hit rate and error degree improved in the young group and lateralization ability improved in both groups. In quiet environments, the reception threshold for speech also indicated a significant benefit in the young group. When the noise was presented to the normal ear, HINT revealed benefit of CROS, while loss of performance with CROS use was significant when noise was presented to the impaired ear. Wireless CROS provided increased satisfaction and overall improvement of localization and hearing. Although true binaural hearing cannot be obtained, CROS is a practical option for rehabilitation of USNHL.

Relationship among the physiologic channel interactions, spectral-ripple discrimination, and vowel identification in cochlear implant users.

The hypothesis of this study was that broader patterns of physiological channel interactions in the local region of the cochlea are associated with poorer spectral resolution in the same region. Electrically evoked compound action potentials (ECAPs) were measured for three to six probe electrodes per subject to examine the channel interactions in different regions across the electrode array. To evaluate spectral resolution at a confined location within the cochlea, spectral-ripple discrimination (SRD) was measured using narrowband ripple stimuli with the bandwidth spanning five electrodes: Two electrodes apical and basal to the ECAP probe electrode. The relationship between the physiological channel interactions, spectral resolution in the local cochlear region, and vowel identification was evaluated. Results showed that (1) there was within- and across-subject variability in the widths of ECAP channel interaction functions and in narrowband SRD performance, (2) significant correlations were found between the widths of the ECAP functions and narrowband SRD thresholds, and between mean bandwidths of ECAP functions averaged across multiple probe electrodes and broadband SRD performance across subjects, and (3) the global spectral resolution reflecting the entire electrode array, not the local region, predicts vowel identification.

Association Between Intracochlear Electrode Design and Electrically-Evoked Compound Action Potential Measures in Cochlear Implant Users.

OBJECTIVE: Cochlear implant (CI) electrode design has changed over time. Changes in intracochlear electrode design might influence the spread of neural activation along the auditory nerve and the number of independent channels. This study aimed to investigate the impact of intracochlear electrode design on the electrode-neuron interface using electrophysiological measures. STUDY DESIGN: Prospective cohort study. SETTING: A single tertiary hospital. METHODS: Fifty-two ears who were implanted with CI divided into 3 groups based on the design of intracochlear electrode arrays. Twenty-three ears were implanted with lateral wall straight electrodes. Eighteen ears were implanted with the slim perimodiolar electrode, and 11 ears were implanted with the old perimodiolar electrode. Various electrically-evoked compound action potential (ECAP) metrics were measured to quantify spread of excitation and channel interaction. RESULTS: ECAP threshold and slope were not significantly different among groups. ECAP spread of excitation (SOE) half-width and channel interaction index (CII) were significantly larger in subjects implanted with the lateral wall straight electrodes, indicating a wider spread of excitation compared to those with perimodiolar electrodes. Electrode impedance was significantly lower in subjects implanted with perimodiolar electrodes than those with lateral wall electrodes. CONCLUSION: Perimodiolar electrode groups yielded significantly narrower SOE half-widths and smaller CII than the lateral wall straight electrode group. This may indicate that the electrode array that hugged the modiolus had less overlap in neural excitation between adjacent electrodes, resulting in reduced channel interaction and potentially better spectral resolution than the electrode array positioned more laterally.