A prevalent founder mutation and genotype-phenotype correlations of OTOF in Japanese patients with auditory neuropathy.

Auditory neuropathy is a hearing disorder characterized by normal outer hair cell function and abnormal neural conduction of the auditory pathway. Aetiology and clinical presentation of congenital or early-onset auditory neuropathy are heterogeneous, and their correlations are not well understood. Genetic backgrounds and associated phenotypes of congenital or early-onset auditory neuropathy were investigated by systematically screening a cohort of 23 patients from unrelated Japanese families. Of the 23 patients, 13 (56.5%) had biallelic mutations in OTOF, whereas little or no association was detected with GJB2 or PJVK, respectively. Nine different mutations of OTOF were detected, and seven of them were novel. p.R1939Q, which was previously reported in one family in the United States, was found in 13 of the 23 patients (56.5%), and a founder effect was determined for this mutation. p.R1939Q homozygotes and compound heterozygotes of p.R1939Q and truncating mutations or a putative splice site mutation presented with stable, and severe-to-profound hearing loss with a flat or gently sloping audiogram, whereas patients who had non-truncating mutations except for p.R1939Q presented with moderate hearing loss with a steeply sloping, gently sloping or flat audiogram, or temperature-sensitive auditory neuropathy. These results support the clinical significance of comprehensive mutation screening for auditory neuropathy.

[The development of language and problems in 30 mild, moderate, and moderately severe hearing-impaired children].

Some mild, moderate, and moderately severe-hearing impaired children have poor language and educational problems despite comparatively good hearing. We studied 30 mild, moderate, and moderately severe hearing-impaired children cared for at Showa University and Jiseikai Hospitals. Their ages ranged from 3 to 14 years and average hearing from 35.0 dB HL to 68.8 dB HL. Our findings were as follows: (1) The average age of suspected hearing problem onset was 2 years 10 months. On the average, delayed diagnosis was made at 4 years 2 months and children were fitted with hearing aids at 5 years 3 months. (2) Over 25% them wore hearing aids infrequently. (3) Language delay was observed in 14 of 24 children examined using the WISC-III test. Many wore hearing aids infrequently and exhibited inadequate oral communication in Japanese due, for example, to deaf parents or children educated overseas. (4) According to a questionnaire, many mothers usually talked to the children aware of their hearing condition. But almost mothers of children with delayed development could not teach children if they couldn't hear, and only repeated same words for children's clarification, e.g., "Pardon?". It is important to detect hearing impairment in children as early as possible. Guidance by specialists and communication training are very important, especially for children who are mild, moderate, and moderately severe hearing-impaired.

[Acute otitis media with bone conduction hearing loss associated with acute mastoiditis].

Acute otitis media, generally complicated by conductive hearing loss, sometimes shows raised bone conduction thresholds. Five patients with acute otitis media with mixed hearing loss and much otorrhea were reported. The chief complaints were otalgia in 3 patients, hearing loss in 4, ear fullness in 1 and tinnitus in 1. Four patients had moderate hearing loss. At the first examination, the tympanic membrane showed swelling and injection, while 2 showed bullous myringitis, with swelling of the tympanic mucosa and a yellowish serous discharge following myringotomy. Positive mastoidal CT of all patients without acute inflammatory symptoms in the external ear suggest the complication of acute mastoiditis. After treatment with antibiotics and myingotomy for all patients, steroidal administration for 4, and tympanostomy tube insertion for 3, the hearing levels of 4 patients improved. Sensorineural hearing loss (51.3 dB) remains in 1 patient with sever hearing loss at the first examination. It is important to determine the hearing level for patients with acute otitis media, especially if it is complicated by hearing difficulties.

[Long-term observation of sensorineural hearing-impaired children with hearing aids].

In the long-term observation (9-22 years) of 45 hearing-impaired children, using our own "Hearing Test Progress Table", 36(80.0%) showed fluctuation of the hearing threshold. Twenty-nine of the 36 patients had acute progression of hearing loss. Three peaks of onset of the acute loss were observed: at age 6, 10, 16 years in girls, 7, 11 and 16 years in boys. Twenty-three of the 45 (51.1%) have been able to maintain their good thresholds throughout these periods, with 14 cases of hearing loss restored by our successful treatment of acute sensorineural hearing losses (1-6 times). Twenty-two of the 45 children (48.9%) could not maintain their initial thresholds: gradual hearing deterioration in 7 of the 22, and acute hearing loss (1-10 times) in the remaining 15 cases. Although these 15 patients could not maintain their initial hearing thresholds until the end of the observation period, active treatments for their acute losses were successful in the early period, and almost all patients were able to maintain their initial hearing thresholds until graduation from elementary school. Our "Hearing Test Progress Table" is based on the results of pure tone audiometry for each frequency on every audiometry test. The management (including guidance and treatment) using the table is very effective.

[Effects of speaking tube in patients with dysacousis].

Comparative study was made between the conventional speaking tube and the modern electric hearing aid. The results revealed that the conventional speaking tube was inferior to the electric hearing aid in terms of specificity to various frequencies, advantages and understanding of singular syllables, but almost equal to the latter in terms of understandings of three syllables. Actual comparison by listening with both revealed a face that the speaking tube was more acceptable than the hearing aid in terms of naturalness of voice heard with it. It was assumed that the advantages of the speaking tube like this may be attributable to the less sense closure of eyes as it had an open end and consequently to the better hearing through the speaking tube, which may have made better understandable conversation.