In 2000, the Acute Profound Deafness Research Committee of the Ministry of Health, Labour and Welfare of Japan proposed diagnostic criteria for acute low-tone sensorineural hearing loss (ALHL). Based on these criteria, elderly people with high-tone loss resulting from presbycusis are not included in the ALHL category. This situation has produced a bias in the epidemiological features of ALHL. Therefore, the criteria should include these cases as probable ALHL. The short-term outcome of ALHL is generally good, but the long-term prognosis is not necessary good, as recurrences occur in 20-30% of patients and 5-10% of patients develop Méniére disease. In addition, some patients develop hearing deterioration across the frequencies. Among these intractable cases, the possibility of an acoustic tumor exists. An imaging study is required in such intractable cases to rule out such rare diseases. Steroids and isosorbide are the standard medications for the treatment of ALHL; however, reliable evidence of their efficacies has not been obtained to date. A prospective randomized controlled study examining the use of these drugs is needed in the future.
This study investigated language and speech perception abilities, the method of habilitation, and the progress of four children diagnosed as having pervasive developmental disorder (PDD) who received cochlear implants at our center before acquiring any language ability. A control group of thirteen children with cochlear implants but without any associated developmental disorders was used for comparison. All seventeen children were tested using the Wechsler Intelligence Scale for children (Third Edition) and our original speech perception test immediately prior to their enrollment in elementary school. Individual differences in language and speech perception abilities were observed among the PDD subjects. Half of the PDD subjects had acquired language abilities comparable to the children who enrolled in mainstream elementary schools in the control group. One subject had difficulty acquiring language and speech perception abilities. All the PDD subjects were enrolled in special schools and continued to exhibit social skill disorders. The use of both spoken and signed language was effective for the subjects with PDD.
The purpose of this study was to examine the potential benefit of a directional microphone for lessening the influence of reverberation in a lecture room on speech understanding. Sentence lists (HINT Japanese) were played back in a sound proof room and in a university lecture room with a reverberation time of 1.6s and were recorded at a distance of 1m from the speaker (“non-reverberant list”) and at 2m and 8m from the speaker (“reverberant list at 2m, 8m”) using both directional and omni-directional microphones. The speech recognition thresholds (SRTs) of the 6 recordings were then determined by 12 listeners with normal hearing. Among the three lists that were recorded using the omni-directional microphone, the SRTs were significantly higher for the recordings made in the room with the higher reverberation. Under the same reverberant conditions, the SRTs of the lists recorded with the directional microphone were significantly lower than those recorded with the omni-directional microphone. Especially, the SRT of the “reverberant list at 2m” was the same as that of the “non-reverberant list”. This study suggests that difficulties in speech understanding arising from reverberation can be improved if people with hearing impairments sit in the front row of the lecture hall and use a directional hearing aid when listening to lectures in reverberant rooms.
Whether a hearing-impaired patient exhibits a recruitment phenomenon is very important when adjusting the gain of a hearing aid. A frequency-specific examination for detecting recruitment phenomenon in infants has not been established. Therefore, the gain of hearing aids for hearing-impaired infants cannot be adjusted exactly. To solve this problem, we attempted to detect the recruitment phenomenon using ASSR, which is objective and has a high frequency specificity. In this study, we investigated the relationship between the stimulus intensity and some response indexes of ASSR in 10 adults with normal hearing. The correlation between the stimulus intensity and the power was statistically significant. The correlation coefficient was 0.92 to 0.99 (median, 0.96) in waking subjects and 0.8 to 0.99 (median, 0.9) in sleeping subjects. The correlation between the stimulus intensity and the latency was also statistically significant. This correlation coefficient was -0.76 to -0.96 (median, -0.82) in waking subjects and -0.85 to -0.99 (median, -0.97) in sleeping subjects. The correlation between the stimulus intensity and the CSM was not statistically significant.
Tinnitus retraining therapy (TRT), a tinnitus accommodation therapy advocated by Jastreboff, comprises counseling and sound therapy. Since the output noise level of a tinnitus control instrument (TCI) is essentially restricted to a maximum of approximately 70dB to prevent acoustic trauma, patients with profound hearing loss with a mean hearing of 70dB on the affected side tend to fail to hear the TCI noise; for these patients, TRT using sound therapeutic procedures other than TCI, including the use of a hearing aid, are recommended. Of the 183 tinnitus patients (102 men and 81 women) who received TRT at our hospital during the 5-year period from April 2004 to March 2009, 99 patients (54 men and 45 women) purchased a TCI and continued to use it following TRT. In this study, the therapeutic efficacy of TRT was investigated in 6 (1 man and 5 women) of the 99 patients with moderate or profound hearing loss who failed to show a remarkable improvement and received TRT with a hearing aid in addition to TRT with the TCI. Tinnitus patients with moderate or profound hearing loss are considered candidates for the use of a hearing aid for TRT as sound therapy; patients with lateral sensorineural hearing loss tend to resist the use of a hearing aid, since hearing on the healthy side is maintained, and they are more likely to use TCI instead of a hearing aid. When patients with moderate to profound lateral hearing loss received TRT with TCI followed by TRT with a hearing aid, the degree of subjective suffering from tinnitus improved significantly in the patients. These observations indicate that the use of TRT with a hearing aid in addition to TRT with TCI is an effective treatment for tinnitus in patients with moderate to profound lateral hearing loss.