岡野 高之

BACKGROUND/OBJECTIVES: The OTOG gene is responsible for autosomal recessive non-syndromic sensorineural hearing loss and is assigned as DFNB18B. To date, 44 causative OTOG variants have been reported to cause non-syndromic hearing loss. However, the detailed clinical features for OTOG-associated hearing loss remain unclear. METHODS: In this study, we analyzed 7065 patients with non-syndromic hearing loss (mean age 26.4 ± 22.9 years, 2988 male, 3855 female, and 222 without gender information) using massively parallel DNA sequencing for 158 target deafness genes. We identified the patients with biallelic OTOG variants and summarized the clinical characteristics. RESULTS: Among the 7065 patients, we identified 14 possibly disease-causing OTOG variants in 26 probands, with 13 of the 14 variants regarded as novel. Patients with OTOG-associated hearing loss mostly showed congenital or childhood-onset hearing loss. They were considered to show non-progressive, mild-to-moderate hearing loss. There were no symptoms that accompanied the hearing loss in OTOG-associated hearing loss patients. CONCLUSIONS: We confirmed non-progressive, mild-to-moderate hearing loss as the clinical characteristics of OTOG-associated hearing loss. These findings will contribute to a better understanding of the clinical features of OTOG-associated HL and will be useful in clinical practice.

OBJECTIVE: To determine whether the combination of the pharyngeal tonsil grade and palatine tonsil grade results in differences in the apnea-hypopnea index (AHI) and to determine whether each parameter separately (pharyngeal tonsil grade and palatine tonsil grade) results in differences in severe obstructive sleep apnea (OSA). METHODS: This cross-sectional study involved 107 children (mean age, 7.2 years; range, 4-12 years) suspected of having OSA because of snoring or sleep-related complaints. The patients underwent polysomnography, and their palatine and pharyngeal tonsils were graded. RESULTS: In examining whether the palatine tonsils and pharyngeal tonsils could be risk factors for severe OSA, the adjusted odds ratios were 4.42 for palatine tonsil grade 4 versus 1-3 and 10.40 for pharyngeal tonsil grade 4 versus 1-3; both were highly statistically significant. We also found that the AHI when both the pharyngeal and palatine tonsils were grade 4 was higher than the AHI expected for the pharyngeal and palatine tonsils alone. CONCLUSIONS: The combination of grade 4 pharyngeal tonsils and grade 4 palatine tonsils resulted in an AHI much higher than the AHI of other combinations (pharyngeal tonsils grades 1-3 and 4, palatine tonsils grades 1-3 and 4). We believe that grade 4 pharyngeal tonsils and grade 4 palatine tonsils have a great influence on severe OSA and that grade 4 pharyngeal tonsils increase the AHI.

OBJECTIVES: The aim of this study was to evaluate the safety and efficacy of microdebrider adenoidectomy on sleep-disordered breathing among pediatric patients with OSA. METHODS: In the microdebrider group (Group I), there were 30 Japanese OSA patients consisting of 26 boys and 4 girls. For comparison, we had 15 children (13 boys and 2 girls) who underwent classical adenoidectomy (Group II). Patients in Group I were selected from a pool of 95 pediatric Japanese OSA patients and were matched by age, preoperative AHI, and Kaup index with those in Group II.Parameters such as the amount of residual adenoid tissue, bleeding, duration of the procedure, and sleep-related metrics were compared between the two groups. RESULTS: A significant improvement in postoperative AHI was observed in Group I (p<0.05). The prevalence of AHI <1 was significantly higher in Group I compared with Group II (p<0.05). Additionally, the amount of postoperative residual adenoid was significantly less in Group I (3/30 of Grade 3 and 4 adenoid size) than in Group II (7/15, p<0.05). Furthermore, a reduction in postoperative AHI was proportionally associated with a decrease in residual adenoid. CONCLUSIONS: The newly developed microdebrider adenoidectomy technique for pediatric OSA patients with adenotonsillar hypertrophy demonstrated greater accuracy and efficacy in ameliorating sleep apnea symptoms compared with the standard adenoidectomy approach.

OBJECTIVES: In the present study, we performed a detailed analysis of deglutitive dynamics during sleep in patients with obstructive sleep apnea (OSA) using a methodology developed by Sato et al. We hypothesized that the frequency of deglutition would decrease with increasing severity of OSA. The aim of this study is to clarify the involvement of deglutitive dynamics during sleep in OSA by investigating the correlations between deglutition and sleep parameters. METHODS: This study included 30 adult patients with OSA. To analyze deglutition dynamics during sleep, surface electromyography recordings of the suprahyoid and thyrohyoid neck muscles, which are involved in deglutition, were performed simultaneous with conventional polysomnography. The "index of deglutition" was defined as the frequency of deglutition per hour of sleep. We examined correlations between this index and sleep parameters (apnea-hypopnea index [AHI], apnea index, hypopnea index, and lowest blood oxygen saturation). RESULTS: By analyzing the obtained polysomnography and electromyography waveforms, we identified two deglutition patterns with and without respiratory arousal during sleep. We found a significant negative correlation between the index of deglutition in sleep stage 1 and the AHI, with a correlation coefficient of -0.48. (p=0.02). CONCLUSIONS: In the current study, we distinguished deglutition during sleep with and without arousal. In addition we discovered a significant negative correlation between the index of deglutition in sleep stage 1 and the AHI. This new finding will provide a platform for future research on OSA in aspiration pneumonia.

BACKGROUND: There has been a significant increase in scientific investigations of the hearing-dementia association among the research on potentially modifiable risk factors for cognitive impairment. We tested two clinical questions. Analysis 1: does persistent hearing aid (HA) use decrease the decline in cognitive function caused by ageing? Analysis 2: does cognitive function at the time of HA fitting predict future persistent HA use? METHODS: This case-control study performed at two referral centres reported data obtained over a 4.5-year period. We recruited a group of patients with cognitive decline, aged 65 or older with or without hearing loss. The intervention consisted of the use of HAs. The primary outcome measures were adherence to continuous HA use and cognitive function measured using the Japanese version of the Mini-Mental State Examination Test and the Reading Cognitive Test Kyoto. RESULTS: Eighteen HA users and 18 controls were included in the first analysis. HA use was associated with a deceleration of cognitive decline 12 months later. In the second analysis, 11 participants with good adherence to HA use were compared with 12 participants who showed poor adherence to HA use. Among the variables employed in this study, cognitive function measured using the Reading Cognitive Test Kyoto was significantly lower in participants with poor adherence to HA. CONCLUSIONS: HA use in cognitively impaired individuals with hearing loss can slow age-related cognitive decline. Cognitively impaired people with hearing loss who fail to commit to HA use tend to have lower cognitive measurement scores before HA fitting. HA use is generally more challenging as people age and their cognitive abilities decline. Therefore, it is desirable that HAs be used when hearing loss and dementia are in their early stages.