A 20-year-old female was found bilateral hearing impairment at the age of 3 years. She had no family history of hearing loss or deafness. Her hearing loss was fluctuating and gradually progressive. In April, 2001, her left hearing loss became profound. Audiometric examination showed a mixed hearing loss of 83.75dB in the right ear, and 92.5dB in the left. Ear CT showed the remarkable enlargement of the bilateral vestibular aqueducts. At the age of 13 years she was found a goiter but thyroid function was within normal limits except for positive perchlorate discharge test. From those findings the present case was strongly suspected of Pendred's syndrome. The further examination of PDS gene is needed for final diagnosis.
Factors affecting disappearance time of tinnitus in residual inhibition test were analyzed with the use of quantitative method I. One hundred thirty-five patients with unilateral tinnitus of a single kind were studied. Major factors influencing the time in residual inhibition test were found to be subjective pitch, purity and impurity of tinnitus tonality, age, and period of tinnitus. The disappearance time of tinnitus tended to prolonged in subjective low frequency, purity of tinnitus tonality and aged patients. These results may associated with physiological background of the tinnitus mechanism which produces such a tonality and/or aged patients.
Fifty-two normal hearing listeners (normal listeners) and 21 listeners with sensorinueral hearing loss (hearing-impaired listeners) with and without hearing aids participated in monaural speech recognition threshold (SRT) tests using single digits of the 67-S speech audiometric test list in a sound field with equalized frequency responses. SRTs were measured in conditions of both quiet and noise. Speech signals and competing noise were generated from two loudspeakers located at angles of incidence of 0° and 45°, respectively. In SRT tests in noise, the level of competing noise was increased with that of speech signals fixed. Ambient sound pressure levels in the 1/3 octave band at the test position were within maximally permissible levels for when 0dBHL is to be tested for bone conduction audiometry (ISO 8253-1). Speech noise was used as a calibration signal because of its high spacial homogeneity. Mean SRT in quiet in normal listeners was 10.7dBSPL (SD 3.3dB), which was 6.7dB higher than the reference monaural threshold sound pressure level for sound field listening at 1000Hz (ANSI S3.6). As the level of speech signal increased in the range of low sensation level, signal-to-noise ratio (SNR) for SRT decreased. This result suggests that a fixed sensation level of the speech signals should be used to cancel the effect of different aided hearing thresholds when the performances of hearing aids are to be compared by SRT in noise. For hearing-impaired listeners without hearing aids, SNR for SRT in noise was higher than that of normal hearing listeners, and was higher still when hearing aids were used.
Since 1998, neonatal hearing screening using automated auditory brainstem response (AABR) has become increasingly widespread in Japan. We evaluated its implementation through questionnaires on neonatal hearing screenins distributed to screeners in 65 hospitals and 202 clinics. Screeners were asked how and when they conducted neonatal hearing screening and were asked to provide comments on follow-up, and neonatal hearing screening networks. We found that although various hearing screening programs being implemented, a lack of audiology involvement, hospital support, effective follow-up and tracking methods prevents the achievement of truly effective neonatal hearing screening in Japan.
As a part of the research about psychological mechanisms underlying P300, in this paper, we studied latencies and amplitudes for the P300s elicited by more than one target stimuli and/or more than one standard rtimuli. We administered to 10 healthy adults four blocks of oddball paradigm using verbal sounds i.e., 1) single-single condition constituted of single target stimulus and single standard stimulus (condition 1), 2) single-multi condition constituted of single target stimulus and five standard stimuli (condition 2), 3) multi-single condition constituted of five target stimuli and single standard stimulus (condition 3), 4) multi-multi condition constituted of five target stimuli and five standard stimuli (condition 4). The results were as follows; 1) P300 latency was shortest in condition 1, and delayed in condition 3, then in condition 2, and the last was condition 4. 2) P300 amplitude was largest in condition 1, and decreased in condition 3, and then in condition 2, and the last was condition 4. These results showed that weakness of the contrast between figure (target) and ground (standard) in working memory caused by multi target stimuli and/or multi standard stimuli influence the P300 latency and amplitude, i.e., latency is delayed and amplitude is decreased. And besides, in order to elicit P300, the ground made by single standard stimulus is thought to be more important rather than the figure made by single target stimulus to make up contrast between the figure and the ground in working memory.
The threshold of hearing was measured on 1521 random samples of Japanese and the results were analyzed according to the age and sex. The hearing sensitivity decreased with increasing age accerelatively, specifically in high tone area and in advanced age group. Sex difference exists. Men are more affected than the women, but it was only slight degree, in high tone area and in older age group. The results of the present study was, as a rule, almost the same as previous one appeared in the literature. Accordingly, the results obtained is considered to be the standard of “the age effect on hearing of Japanese”.
The howling effect in use of hearing aids among infants and children used to be a frequent and common problem in the past. The narrowness of their ear canal, their physically active nature and, use of high-powered hearing aid derived from severe hearing loss were accounted for the occurrence of howling effect. Furthermore, their little and tender auricles created a disadvantage in fitting a hearing aid. ‘The Ear Mold for Children’ is the meliorated version of its predecessor ‘Improved Ear Mold’ which was developed mainly for senior users. The main improved features for this new type of mold are; 1) resilient entering part of the ear canal can enhance close fitting and easy handling, 2) flexible body of the mold creates further fitness, 3) tightly attached tube between the hearing aid and the ear mold generates high stability. After putting ‘The Ear Mold for Infants and Children’ to trial, we found that it not only eliminated the howling effect but also steadied the hearing aid into the ear. We created the hearing aid that is comfortable to hear and easy rest behind the ear.
Four female patients with Pendred's syndrome were studied from the viewpoint of hearing loss for the periods of 5, 18, 18, and 21 years. Three of the 4 patients revealed a PDS gene mutation, and one refused gene study. Dilatation of the vestibular aqueduct was demonstrated bilaterally by CT in all patients. They developed bilateral, moderate to severe hearing loss in childhood. The audiograms showed high-tone hearing loss type. The hearing loss was slowly progressive. However, all patients experienced abrupt hearing loss of 10-50dB at intervals ranging from 0.1 to 10 years. The exacerbation occurred bilaterally or unilaterally. In 60% of the exacerbations, the hearing loss completely recovered to the previous level with steroid treatment.