Vestibular function analysis of sudden sensorineural hearing loss with dizziness.

BACKGROUND: A considerable number of patients with sudden sensorineural hearing loss (SSNHL) have been reported to have dizziness. OBJECTIVE: To analyze vestibular functions and identify the clinical characteristics of SSNHL with dizzinessMETHODS:71 patients with SSNHL who complained of dizziness were investigated retrospectively. The patients underwent vestibular function tests consisting of video-nystagmography, video head impulse test and vestibular evoked myogenic potentials. RESULTS: Among 35 patients with spontaneous nystagmus (SN), 21 showed ipsilesional posterior canal gain deficit, 11 showed a gain deficit in the posterior canal only and 9 showed both horizontal and posterior canal gain deficit in video head impulse test. In only one subject with bilateral horizontal canal gain deficit with contralesional SN, AICA infarction was observed.Among 36 patients without SN, 10 were diagnosed as benign paroxysmal positional vertigo and 5 had ipsilesional canal paresis in caloric test. Other 21 patients showed no abnormal signs in vestibular function tests. CONCLUSIONS: In VFT analysis of SSNHL with dizziness, diverse patterns were identified. In the absence of SN, no definite vestibular organ involvement was the most frequent. But in the case with SN, posterior canal deficit was most common and cerebellar ischemic stroke was rare.

Comparing the Suppression Head Impulse Paradigm and the Head Impulse Paradigm in Vestibular Neuritis.

OBJECTIVE: To compare the results of suppression head impulse paradigm (SHIMP) and head impulse paradigm (HIMP) in acute vestibular neuritis (AVN). STUDY DESIGN: Retrospective study. SETTING: Tertiary otology clinic. PATIENTS AND INTERVENTIONS: We tested 21 patients with AVN with the HIMP, SHIMP, and caloric tests, and we analyzed the relationships between the tests' results. MAIN OUTCOME MEASURES: For this study, we adopted vestibulo-ocular reflex (VOR) gains in the SHIMP and HIMP, peak saccade velocity (PSV) of SHIMP which is another indicator of residual vestibular function, and canal paresis of caloric test. RESULTS: VOR gains showed significant correlation (R = 0.926, p < 0.001) between the SHIMP and HIMP, but VOR gains were slightly lower in the SHIMP than in the HIMP (mean difference 0.07 ±â€Š0.09, p < 0.001). The difference between the HIMP and SHIMP gains was slightly larger on the affected side (0.10 ±â€Š0.09) than on the healthy side (0.03 ±â€Š0.09). The PSV of SHIMP had significant correlation with HIMP gain and canal paresis. Sixteen of 21 patients showed 100% ipsilesional caloric canal paresis, and eight (50%) of them showed no anti-compensatory saccade (direction toward head rotation) in the SHIMP. However, they showed not extremely low VOR gain but variable VOR gain. CONCLUSION: The new parameters of SHIMP might be used as complement for evaluating vestibular function in AVN. However, the clinical impact of the saccades of SHIMP in AVN has not been revealed clearly yet. This question should be investigated in further studies.

Does the Width of the Bony Cochlear Nerve Canal Predict the Outcomes of Cochlear Implantation?

A narrow bony cochlear nerve canal (BCNC) is associated with sensorineural hearing loss necessitating cochlear implantation (CI). This study evaluated the implications of BCNC width for post-CI outcomes. A total of 56 children who had received CIs were included. The patients were divided into three groups according to the width of the BCNC (Group 1: diameter < 1.4 mm, n = 17; Group 2: diameter 1.4-2.0 mm, n = 14; Group 3: diameter > 2.0 mm, n = 25). The post-CI speech performances were compared among the three groups according to BCNC width. The correlation between BCNC width and post-CI speech performance was evaluated. Logistic regression analysis was also performed to investigate factors that can impact post-CI speech performance. Cochlear nerve deficiency (CND) occurred more frequently in Group 1. Groups 1 and 2 had significantly worse post-CI outcomes. Patients with intact cochlear nerves had significantly better post-CI outcomes than those with CND. When the cochlear nerve was intact, patients with a narrower BCNC showed less favorable results. Therefore, patients with either a narrow BCNC or CND seemed to have poorer outcomes. A narrow BCNC is associated with higher CND rates and poor outcomes. Measurement of BCNC diameter may help predict CI outcomes.

Diverse clinical and laboratory manifestations of bilateral vestibulopathy.

OBJECTIVES/HYPOTHESIS: To identify the clinical and laboratory characteristics of bilateral vestibulopathy (BVP) on the video head impulse test (vHIT). STUDY DESIGN: Retrospective chart analysis. METHODS: During 23 months, 1,789 patients with dizziness underwent vHIT in our tertiary referral hospital. Of these patients, 65 (3.6%) patients had bilaterally positive catch-up saccades. Based on the caloric test, 15 (group 1) had bilateral caloric weakness, 13 (group 2) had unilateral caloric weakness, and 37 (group 3) had normal caloric responses on both ears. We collected data on these patients regarding demographics, symptoms, gain, and type of saccade on horizontal canal plane vHIT, as well as gain and time constant on velocity step of the rotatory chair test. RESULTS: The average age of group 2 (70.38 ± 11.96 years) and group 3 (69.03 ± 11.01 years) were significantly older than that of group 1 (54.80 ± 11.96 years) (P = 0.029, P = 0.003, respectively). Although all patients had bilaterally positive vHIT, 10 of 15 in group 1 were finally diagnosed as classical BVP by clinical features. On comparison of average gain on bilateral horizontal vHIT, groups 2 (0.71 ± 0.17) and 3 (0.80 ± 0.14) had higher gain compared to group 1 (0.45 ± 0.22) (P = 0.001, P = 0.000, respectively). On velocity step test, time constant and gain of group 3 (11.60 ± 3.07, 0.49 ± 0.13) was significantly higher than those of group 1 (4.92 ± 1.36, 0.22 ± 0.17) (P = 0.000, P = 0.004, respectively). On the receiver operating characteristic curve analysis, vHIT alone seemed to be a discordant method for diagnosis of BVP compared to the caloric and step velocity tests. CONCLUSION: About 3.6% patients with dizziness showed bilateral vestibular ocular reflex deficit during high-frequency acceleration, which was prevalent especially in elderly patients. Also, positive bilateral vHIT does not always correlate with caloric or rotatory chair test results. This may imply that a diverse spectrum of vestibulopathies exist according to the stimulation frequency of deficit. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:E42-E49, 2017.

Optimal use of CT imaging in pediatric congenital cholesteatoma.

OBJECTIVE: This study aimed to determine the radiation dose of temporal bone computed tomography (TBCT) to detect pediatric congenital cholesteatoma (CC), and suggests strategy for lowering perioperative radiation dose. METHODS: Fifty-three CC patients followed up for more than 12 months after surgery. Perioperative clinical findings and the effective radiation dose (ERD) of TBCT were investigated. Patients' mean age at initial TBCT was 60 months; the mean follow-up period was 43 months. RESULTS: In 33 (62.3%) of 53 patients, only one TBCT was performed postoperatively. Postoperative CT imaging was performed to evaluate before second-stage ossiculoplasty, due to suspicion of CC recurrence on examinations, or as part of follow-up. When TBCT was performed on more than two occasions after surgery as a part of follow-up, there was no difference in the distribution of stage or type of CC compared to patients subjected to TBCT on less than three occasions (p=0.093 and p=0.744, respectively). During the most-recent follow-up of these 53 cases, there was no CC recurrence. The mean ERD of a single TBCT was 1.2mSv, and the mean cumulative ERD of TBCT was 2mSv per patient. CONCLUSION: Mean and cumulative ERD of TBCT performed in CC cases was not too high to consider radiation hazard. However, efforts to minimize the number of CT scans should be taken basically.

Cochlear Implantation in Patients With CHARGE Syndrome.

OBJECTIVE: To determine the optimal surgical approach for cochlear implantation (CI) preoperatively based on the spatial relation of a displaced facial nerve (FN) and middle ear structures and to analyze clinical outcomes of CHARGE syndrome. METHODS: Facial nerve displacement and associated deviation of inner ear structures were analyzed in 13 patients (17 ears) with CHARGE syndrome who underwent CI. Surgical accessibility through the facial recess was assessed based on anatomical landmarks. Postoperative speech performance and associated clinical characteristics were analyzed. RESULTS: The most consistently identified ear anomalies were semicircular canal aplasia (100%), ossicular anomaly (100%), and vestibular hypoplasia (88%). Facial nerve displacement was found in 77% of cases (anteroinferior: 47%, anterior: 24%, inferior: 6%). The width of available surgical space around facial recess was significantly greater in cases of facial recess approach (2.85 ± 0.9 mm) than those of alternative approach (0.12 ± 0.29 mm, P = .02). Postoperatively, 53% achieved better than category 4 on the categories of auditory perception (CAP) scale. The CAP category was significantly correlated with internal auditory canal diameter (P = .025) and did not differ according to the applied surgical approach. CONCLUSION: Preoperative determination of surgical accessibility through facial recess would be useful for safe surgical approach, and successful hearing rehabilitation was achievable by applying appropriate surgical approaches.

Long-term functional and behavioral-emotional outcomes in children with early cochlear implants: Parental testimonies.

OBJECTIVES: (1) To assess the long-term effects of cochlear implantation (CI) on speech perception and school life, and (2) to evaluate behavioral and emotional development, including social skills, post-implantation. METHODS: We telephoned caregivers and asked them a standardized questionnaire. We used the data to explore the daily lives (including school life) of children who had undergone CI before the age of 4 years and who had used the device for >10 years. We also evaluated behavioral/emotional development. RESULTS: Most children used CI devices for virtually all their waking moments and attended mainstream schools. Moreover, more than 75% of them could comprehend common phrases or conversations without lip-reading and carry out a telephone conversation with a person known to them. The mean T-scores for all scales of behavioral/emotional assessment, including those concerning social skills, were within the normal ranges, although scores on the competence scale were lower than those on other scales. CONCLUSIONS: This long-term study of early-CI children shows that CI improves not only speech perception, but also behavioral/emotional development, including social skills.

Incus footplate assembly: Indication and surgical outcome.

OBJECTIVES/HYPOTHESIS: To review surgical findings and hearing outcomes of incus footplate assembly (IFA) for the patients with conductive hearing loss due to missing stapes superstructure with a mobile stapes footplate. STUDY DESIGN: Retrospective case review and survey. METHODS: Pre- and postoperative audiometric data and intraoperative findings were reviewed. Postoperative air-bone gap (ABG) and ABG closure (postoperative air-conduction threshold-preoperative bone-conduction threshold) were analyzed. RESULTS: The causes of missing stapes superstructure and conductive hearing loss were congenital ossicular anomaly (n = 5), chronic otitis media (n = 2), and congenital cholesteatoma (n = 1). The prosthesis was designed to fit between the medial side of the incus and stapes footplate and had a mean length of 3.6 ± 0.5 mm. The mean pre- and postoperative ABG were 38.3 ± 4.8 and 13.3 ± 10.0 dB, respectively. The postoperative ABG at frequencies of 0.25, 0.5, 1.0, 2.0, 3.0, and 4.0 kHz were 20.0 ± 15.4, 16.9 ± 11.9, 16.3 ± 10.3, 10.6 ± 7.3, 12.9 ± 14.0, and 23.1 ± 16.2 dB, respectively. The mean ABG closure was 9.5 dB (range, -1.3∼35.8 dB). Seven cases obtained the best results (mean ABG closure ≤10 dB). In the remaining patient, the mean ABG closure was 9.5 dB until 6 months after surgery, but was 35.8 dB 1 year after surgery. CONCLUSIONS: IFA seems to be a reasonable surgical option in patients with missing the stapes superstructure, but with a mobile footplate in which the long process of incus is preserved. LEVEL OF EVIDENCE: 4 Laryngoscope, 126:2569-2573, 2016.

Clinical observations and molecular variables of patients with hearing loss and incomplete partition type III.

OBJECTIVES/HYPOTHESIS: To analyze the clinical manifestations and genetic features of patients with hearing loss (HL) and incomplete partition (IP) type III malformation, and to evaluate speech performance after cochlear implantation (CI) in these patients. STUDY DESIGN: Individual retrospective cohort study. METHODS: Of 206 probands with inner ear malformations (IEMs), we constructed a homogeneous cohort of 11 genetically documented IP type III (DFNX2). Mutations affecting POU3F4 were classified as extension (n = 2), truncation (n = 3), large genomic deletion (n = 2), or missense substitution (n = 4). Postoperative outcomes were rigorously assessed with focus on POU3F4 genotypes and compared with 80 age-matched implantees without IEMs. RESULTS: HL in our cohort was prelingual in onset irrespective of degree. Serviceable hearing was obtained by wearing conventional hearing aids in three, and eight subjects required CI. No correlation was found between mutation types and initial auditory phenotype. As for the eight cochlear implantees, average Categories of Auditory Perception score was <1 preoperatively and 3.9 at 2 years post-CI. Speech performances improved over the first 3 months postoperatively in a manner comparable to implantees without IEMs. However, it then tended to slow down until 1 year postoperatively, leading to worse scores at 2 years than implantees without IEMs. Furthermore, this was more evident in those with a truncation or deletion mutation. CONCLUSIONS: CI surgeons should be aware that postoperative auditory performance may be not as good in IP type III patients as in patients without IEMs. In particular, our study implies that certain types of POU3F4 mutations may have poorer prognoses than other types after CI. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:E123-E128, 2016.

Facial nerve stimulation in the narrow bony cochlear nerve canal after cochlear implantation.

OBJECTIVES/HYPOTHESIS: To evaluate the correlation between a narrow bony cochlear nerve canal (BCNC) and facial nerve stimulation (FNS) after cochlear implantation (CI) and their underlying mechanisms and to predict the risk of FNS preoperatively. STUDY DESIGN: Retrospective cohort study. METHODS: A total of 64 pediatric cases that underwent CI were included. Among them, 32 cases experienced FNS after CI, and another 32 cases were selected from 817 pediatric implantees by stratified random sampling. The width of the BCNC, the status of the cochlear nerve (CN) and the internal auditory canal (IAC), T level, and C level were compared and analyzed. Strategies for eliminating FNS were also analyzed. RESULTS: The FNS group showed a narrower BCNC (1.09 ± 0.52 mm) than the control group (1.99 ± 0.61 mm; P < .01), a lower CN/facial nerve ratio (0.32 ± 0.36) than the control group (1.34 ± 0.76; P < .01), and narrower IAC diameter (4.06 ± 1.71 mm) than the control group (5.66 ± 1.36 mm; P < .01). The FNS group also showed higher T level (165.7 ± 28.3 µA) than the control group (142.2 ± 21.2 µA; P < .01). Adjustment of the C levels and/or pulse width and switching off offending electrodes were attempted to eliminate FNS, with a 75.0% success rate. The FNS group still showed low Categories of Auditory Performance scores (3.00 ± 1.90) compared with the control group (5.94 ± 1.41, P < .01) after adjustment. CONCLUSIONS: A narrow BCNC could be a cause of FNS after CI. Therefore, careful selection of the side for CI and programming strategies are required to reduce FNS. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:1433-1439, 2016.

Corrigendum: Determinants of Conductive Hearing Loss in Tympanic Membrane Perforation: Correction of the Sixth Author Name.

[This corrects the article on p. 92 in vol. 8, PMID: 26045905.].

Factors Contributing to Speech Performance in Elderly Cochlear Implanted Patients: An FDG-PET Study: A Preliminary Study.

OBJECTIVE: The purpose was to evaluate brain plasticity that contributes to speech performance after cochlear implantation (CI) in postlingual elderly (>60 years) patients. MATERIALS AND METHODS: Fifteen elderly postlingual deaf patients who underwent preoperative brain fluorodeoxyglucose positron emission tomography (FDG-PET) and were followed-up for more than 1 year after CI were included. The mean age of these patients was 64.6 years (range, 60-80 years). Based on their sentence score at 1 year after CI surgery, the patients were classified into two groups: poor performers (CID score of <80) and good performers (CID score of ≥80). The duration of deafness, age at operation, preoperative residual hearing, and preoperative brain metabolism were analyzed. SPM5 software was used for FDG-PET image preprocessing and statistical analysis. RESULTS: Neither deafness duration nor preoperative residual hearing was associated with speech performance. The age at operation had little association with speech performance. Deaf patients whose brain metabolism was higher in frontotemporal regions became good CI users but those with higher metabolism in visual association areas became poor CI users. No significant cortical area of higher metabolism was associated with the duration of deafness. CONCLUSION: Overactivation in the visual processing pathway correlated with a poor CI outcome at 1 year. Deaf patients who are going to be poorer performers with CI devices maintain visual information processing during preoperative silent resting periods.

Determinants of conductive hearing loss in tympanic membrane perforation.

OBJECTIVES: Tympanic membrane perforations are common, but there have been few studies of the factors determining the extent of the resulting conductive hearing loss. The aims of this study were to determine whether the size of tympanic membrane perforation, pneumatization of middle ear & mastoid cavity, and location of perforation were correlated with air-bone gap (ABG) of patients. METHODS: Forty-two patients who underwent tympanoplasty type I or myringoplasty were included and preoperative audiometry were analyzed. Digital image processing was applied in computed tomography for the estimation of middle ear & mastoid pneumatization volume and tympanic membrane photograph for the evaluation of perforation size and location. RESULTS: Preoperative mean ABG increased with perforation size (P=0.018), and correlated inversely with the middle ear & mastoid volume (P=0.005). However, perforations in anterior versus posterior locations showed no significant differences in mean ABG (P=0.924). CONCLUSION: The degree of conductive hearing loss resulting from a tympanic membrane perforation would be expected with the size of perforation and pneumatization of middle ear and mastoid.

Auditory brainstem responses to CE-Chirp® stimuli for normal ears and those with sensorineural hearing loss.

OBJECTIVE: Evaluation of the characteristic differences between click-and CE-Chirp-evoked auditory brainstem responses (ABRs) in normal hearing and sensorineural hearing loss. DESIGN: A prospective study. Ears with normal hearing and with sensorineural hearing loss were evaluated. Pure-tone audiometry and click-and CE-Chirp evoked ABRs exams were conducted for all ears. Visual detection levels, wave-V amplitudes, and latencies of the ABRs were assessed. STUDY SAMPLE: Twenty-two ears with normal hearing and 22 ears with sloping type sensorineural hearing loss were examined. RESULTS: In normal-hearing ears, mean amplitudes were larger for CE-chirps than for clicks at all intensities until 80 dB nHL, at which the amplitudes dropped off, presumably due to upward spread of excitation. In ears with sensorineural hearing loss, however the drop-off was less significant at 80 dB nHL. Comparisons with pure-tone audiometry findings revealed ABRs to CE-Chirps to correlate at 0.5, 1, 2, and 3 kHz, and to clicks at 1, 2, 3, and 4 kHz. CONCLUSIONS: The CE-Chirp has advantages over clicks for examining normal ears. However, under high-level stimulation, these advantages are no longer present. In ears with sensorineural hearing loss, the upward spread of excitation is less prominent. The CE-Chirps results correlate significantly to low frequency audiometric findings at 0.5 kHz, while clicks do not.

Targeted Exome Sequencing of Deafness Genes After Failure of Auditory Phenotype-Driven Candidate Gene Screening.

OBJECTIVE: To demonstrate the efficacy and advantages of targeted exome sequencing (TES) of known deafness genes in cases with failed or misleading auditory phenotype-driven candidate gene screening. STUDY DESIGN: Prospective cohort survey. SETTING: Otolaryngology department of a tertiary referral hospital. PATIENTS: Six hearing-impaired probands with seemingly non-syndromic features from six deaf families were enrolled in this study after failure of genetic diagnosis using auditory phenotype-driven candidate gene screening. INTERVENTION: TES of known deafness genes was performed in the six probands, and a final causative variant was pursued using subsequent filtering steps. MAIN OUTCOME MEASURE: Potential causative variants determined using TES were confirmed by previously introduced filtering steps. RESULTS: We detected causative variants in three (50%) of six families, and these variants were in the COCH, PAX3, and GJB2 genes. Additionally, we also recapitulated the recent finding from other report arguing for the non-pathogenic potential of MYO1A variant. CONCLUSIONS: TES of a deafness panel provides a comprehensive genetic screening tool that can be implemented without being misled by the audiogram configuration information and can complement incomplete clinical physical examinations. In addition, the secondary incidental finding obtained by TES contributes useful information regarding the deafness field.

Assessing the effects of tinnitus retraining therapy in patients lost to follow-up: a telephone survey.

OBJECTIVE: To evaluate the efficacy of tinnitus retraining therapy (TRT), especially in patients who did not revisit the clinic after starting the program, and to determine the current status of patients who were lost to follow-up. STUDY DESIGN: Telephone survey. SETTING: Tertiary referral center. PATIENTS: Forty-seven patients enrolled in a TRT program at Seoul National University Hospital. Twenty-four patients who regularly visited the clinic were deemed the good follow-up (GF) group, and 23 patients who did not return after the initial counseling were deemed the follow-up loss (FL) group. INTERVENTIONS: Post-TRT questionnaires with the Tinnitus Handicap Inventory (THI) and a tinnitus visual analog scale (VAS), performed with a telephone survey. MAIN OUTCOME MEASURES: TRT efficacy, evaluated via the THI, and tinnitus VAS scores. A questionnaire on reasons for non-attendance after TRT was used. RESULTS: Pre-TRT VAS and THI scores showed no significant difference between groups. After TRT, both groups showed significant decreases in tinnitus VAS and THI scores. Post-TRT VAS scores for awareness, effects on daily life, and post-TRT THI scores were significantly lower in the FL group. CONCLUSIONS: Treatment outcomes were better in the FL group than in the GF group in several parameters. The FL group was greatly influenced by the first TRT counseling and obtained sufficient relief that they no longer felt the need for additional treatment. Treatment outcomes in patients lost to follow-up may not be as bad as presumed.

Long-term outcome of cochlear implant in patients with chronic otitis media: one-stage surgery is equivalent to two-stage surgery.

This study compared long-term speech performance after cochlear implantation (CI) between surgical strategies in patients with chronic otitis media (COM). Thirty patients with available open-set sentence scores measured more than 2 yr postoperatively were included: 17 who received one-stage surgeries (One-stage group), and the other 13 underwent two-stage surgeries (Two-stage group). Preoperative inflammatory status, intraoperative procedures, postoperative outcomes were compared. Among 17 patients in One-stage group, 12 underwent CI accompanied with the eradication of inflammation; CI without eradicating inflammation was performed on 3 patients; 2 underwent CIs via the transcanal approach. Thirteen patients in Two-stage group received the complete eradication of inflammation as first-stage surgery, and CI was performed as second-stage surgery after a mean interval of 8.2 months. Additional control of inflammation was performed in 2 patients at second-stage surgery for cavity problem and cholesteatoma, respectively. There were 2 cases of electrode exposure as postoperative complication in the two-stage group; new electrode arrays were inserted and covered by local flaps. The open-set sentence scores of Two-stage group were not significantly higher than those of One-stage group at 1, 2, 3, and 5 yr postoperatively. Postoperative long-term speech performance is equivalent when either of two surgical strategies is used to treat appropriately selected candidates.

Effects of congruent and incongruent visual cues on speech perception and brain activity in cochlear implant users.

While deafness-induced plasticity has been investigated in the visual and auditory domains, not much is known about language processing in audiovisual multimodal environments for patients with restored hearing via cochlear implant (CI) devices. Here, we examined the effect of agreeing or conflicting visual inputs on auditory processing in deaf patients equipped with degraded artificial hearing. Ten post-lingually deafened CI users with good performance, along with matched control subjects, underwent H 2 (15) O-positron emission tomography scans while carrying out a behavioral task requiring the extraction of speech information from unimodal auditory stimuli, bimodal audiovisual congruent stimuli, and incongruent stimuli. Regardless of congruency, the control subjects demonstrated activation of the auditory and visual sensory cortices, as well as the superior temporal sulcus, the classical multisensory integration area, indicating a bottom-up multisensory processing strategy. Compared to CI users, the control subjects exhibited activation of the right ventral premotor-supramarginal pathway. In contrast, CI users activated primarily the visual cortices more in the congruent audiovisual condition than in the null condition. In addition, compared to controls, CI users displayed an activation focus in the right amygdala for congruent audiovisual stimuli. The most notable difference between the two groups was an activation focus in the left inferior frontal gyrus in CI users confronted with incongruent audiovisual stimuli, suggesting top-down cognitive modulation for audiovisual conflict. Correlation analysis revealed that good speech performance was positively correlated with right amygdala activity for the congruent condition, but negatively correlated with bilateral visual cortices regardless of congruency. Taken together these results suggest that for multimodal inputs, cochlear implant users are more vision-reliant when processing congruent stimuli and are disturbed more by visual distractors when confronted with incongruent audiovisual stimuli. To cope with this multimodal conflict, CI users activate the left inferior frontal gyrus to adopt a top-down cognitive modulation pathway, whereas normal hearing individuals primarily adopt a bottom-up strategy.

De novo large genomic deletions involving POU3F4 in incomplete partition type III inner ear anomaly in East Asian populations and implications for genetic counseling.

OBJECTIVE: The aim of this study was to understand the prevalence and molecular genetic etiology of incomplete partition type III (IP type III) anomaly in Koreans. We also attempted to verify the prevalence of genomic deletions in the DFNX2 locus and to look for association between inheritance patterns and mutation type in East Asian IP type III subjects. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Subjects with IP type III anomaly and their biological mothers. INTERVENTIONS: Sanger sequencing, array-comparative genomic hybridization (aCGH), and PCR were performed. We also analyzed the type and inheritance of the causative genetic abnormality in East Asian DFNX2 patients. MAIN OUTCOME MEASURE: Mutation type and occurrence. RESULTS: We identified IP type III in 10 (4.8%) of 206 patients with an inner ear abnormality. We confirmed an etiologic homogeneity, DFNX2, of the IP type III in this Korean population. Two (20%) of the 10 DFNX2 carried a large genomic deletion affecting POU3F4, as proved by aCGH. PCR confirmed that the 2 deletions occurred de novo. Genetic alteration occurred de novo in 29.4% (5/17) of all reported Korean IP type III cases. From this study and literature review, we observed a striking difference of de novo occurrence rate (75% versus 12.5%, p = 0.032) between large genomic deletions and point mutations in East Asian population. CONCLUSIONS: Our data suggest that different POU3F4 mutations might show different recurrence rate in siblings of the IP type III families, especially in East Asian population. Genetic counseling should be provided accordingly.