Auditory eye opening response at onset of sleep (AEOR: Suzuki & Notoya, 1980) is an acousticpalpebral reflex in which subject's eyelids open when weak sound stimuli are presented immediately after his or her eyelids are closing before fall to sleep. The effectiveness of a hearing-screening program using AEOR for the first step was investigated. Subjects were 42, 000 about 14, 000 each year, infants younger than 12 months of age during 1981-1983 period in Ishikawa Prefecture. In the first step, AEOR was checked by their mothers at home using the test stimulus of repeated sounds produced by tongue clicking of 50-55dB (A), but 257 (0.6%) of 42, 000 infants failed to respond. In the second step, BOA were performed at health care centers for the infants who failed at first step, and 50 (0.12%) were considered possibly hearing-impaired. In the last step, a battery of standard audiometric tests were performed at the University Hospitals to those referred from the health care centers, and 14 (0.03%, Mean 4.6 months) infants were identified as definitely hearing-imparied (mild to profound). The screening ratio was rather effective compared with those reported in other studies.
A review and discussion of criteria for construction of the Japanese monosyllable list presently used, rank order of frequency of the CV syllable in the printed matters were presented. Item-analysis studies, including difficulty, selectivity, and correlation-to-total of items (syllables) of the list were performed on 300 clinical cases whose discrimination scores by the list itself distributed rectangularly from 32 to 90%. The results indicated that difficulty of syllables did not distribute uniformly, and selectivity of syllables were not distinctive, and some syllables had dead weight. It was concluded that the better criteria for Japanese monosyllable list should be set up on phonemic auditory discrimination rather than linguistic statistics on the syllables.
Eight infants with profound sensorineural hearing loss were studied for the development of gross motor function, and classified into two types by recordings of the damped rotation test on ENG. One group included four patients with normal vestibular reflex and the other four with poor vestibular reflex. Each patient was assessed by four major items of gross motor function, comprising 30 minor items, and 10 minor items of fine motor function. All patients with poor vestibular function revealed a delay of the development from two to eight months in each item of gross motor function and a slight delay in each item of fine motor function. However, all delays of gross motor function were developed by two years of age. On the other hand, all patients with normal vestibular function showed normal development of gross and fine motor functions. Our study demonstrated that gross motor function in young infants with labyrinth-hypoacctivity would be delayed, and that such delays would be acquired at least until two years of age. The mechanism of acquisition of motor function in these patients may depend on other spinal tracts that are controlled by the central nervous system.
In the previous study we reported electrophysiological phenomenon of hypothermia on the cochlea of guinea pigs. The most interesting finding was a transient increase of AP amplitude evoked by a click up to 28°C, followed by gradual decrease with the further temperature decline. The purpose of the present study is to clarify the mechanism of this transient increase of AP amplitude. Narrow band analysis, AP tuning curve, thresholds of AP and CM were determined using 30 normal guinea pigs. The AP and CM thresholds and the tip of AP tuning curves were elevated as the temperature was lowered and this tendency was the most remarkable in the responses at 12kHz. Narrow band-APs above 8kHz obviously demonstrated the transient increase in amplitude, although those below 8kHz showed the linear decrease with the temperature decline. These findings suggest that there are differences in sensitivity and response to hypothermia between the basal turn and second turn, and the transient increase in AP amplitude is due to the increased response originating from the basal turn.
The purpose of this study was to investigate the correlation between the Tsunoda Method and AEP-method as a cerebral dominance test. The cerebral dominance of normal Japanese and normal non-Japanese were compared far verbal, non-verbal sounds and some environmental sounds. The subjects were 25 normal Japanese (16 males, 9 females) and 9 normal non-Japanese (6 males, 3 females). The follawing results were obtained; 1) In the normal Japanese, the amplitudes of the evoked responses over the left temporal area T3 were significantly greater than the right T4 for the natural vowel /a/, the CV-syllable /ga/, chirping of crickets, sounds of rushing streams, moo of cow, Shinobue, Shakuhachi (bamboo flute) and Biwa (Japanese string instrument), and the right ones were significantly greater than the left for flute A note, violin A note, a pure tone 1010Hz and white noise. 2) In the normal non-Japanese, the amplitudes of the evoked responses over the left temporal area T3 were significantly greater than the right T4 for the CV-syllable /ga/, and the right ones were significantly greater than the left for the natural vowel /a/ and a pure tone of 1010Hz. 3) All the contra-normal subjects showed the exactly reversed pattern to the normal. 4) The above results of Japanese and non-Japanese showed a perfect agreement with those of the Tsunoda Method in each case.
Forty-one patients with Vogt-Koyanagi-Harada disease were examined by pure tone audiometry from 1974 to 1984. And the incidence of hearing impairment, subjective complaints, grade and change of hearing level were studied. The following results were obtained: 1) Hearing impairment was observed in 64 ears (78.0%) 2) 21 cases (51.2%) had no subjective complaints of vestibular and auditory function. 15 patients presented tinnitus, 8 hearing loss and only 3 vertigo or dizziness. 3) In many cases hearing level was slightly or moderately impaired. 4) With improvement of ophthalmic symptoms hearing impairment was also improved, but many of the patients showed a little change of their hearing in high frequency range.
Intra-uterine sound (IUS) to newborns reportedly soothes the fussy babies. This study investigated the auditory responses of 15 neonates to IUS during the first three months of their life. All of them were soothed within a week by IUS at a level of 90dB SPL, and in the first month at 65dB to 80dB SPL. Within the first month, the minimum responsive level decreased in 10 to 25dB SPL, and the latencies were reduced in 14 babies, because of the development of their auditory function. Six crying babies (40%), in the second month, became alert and inactive in response to IUS. In the third month, there were no positive responses for 15 babies. After the second month, the soothing effect decreased, as their memory to IUS seemed to be disappearing. The finding indicated that IUS can be used for screening infants within the first month of their life for severe hearing impairment.
The cases with low tone sensorineural deafness were studied using the transtympanic-electrode technique of electrocochleography. The results obtained were as follows: 1) Low tone sensorineural deafness of sudden onset without vertigo: All the cases showed high AP and -SP amplitude and satisfactory CM response. These findings resembled the electrocochleographic findings of type I of Ménière's disease suggesting of the relationship with endolymphatic hydrops. The hearing returned to normal range in a half of the cases but remained hardly changed in the other half. The difference between these two groups could not be clarified electrocochleographically. 2) Familial progressive deafness showed low tone sensorineural deafness: This case showed a high threshold and a low amplitude of CM at low frequency, and showed cochlear hair cell damage at low frequency range. 3) Low tone sensorineural deafness due to retrolabyrinthine lesion: This case showed a normal CM but a low AP amplitude, and lacked a rapid increase of AP amplitude with increasing click intensity in the intensity region of AP input-output functions.
Five cases of so-called retrocochlear deafness with impaired speech intelligibility in spite of nearly normal pure-tone sensitivity were presented and discussed on the origins of this deafness. These patients presented with the following common audiological findings, as almost normal audiogram, extremely poor speech discrimination scores, fluctuation in hearing acuity, increased threshold of interaural time discrimination, essentially broad action potential in cochleogram and no auditory brainstem responses. Based on the above findings, we supposed that the impaired speech perception might be due to interference with the precise neural timing relations required by such tasks, and these patients might have main lesions in the peripheral auditory nerve. However, we could not confirm the presence of lesions on the other levels of the central auditory nervous system. We brought forward the tentative diagnostic name of “essential retrocochlear lesion” to such deafness, and we were accumulating the electrophysiological data of these patients.
Following the auditory brain stem response measurement, tympanogram was recorded and analyzed in infants and childen during narcoticinduced sleep. In 71.4% of the patients the middle ear cavity pressure was increased in course of sleeping, and we called this type as type+A tympanogram. It reverted from type +A to normal type A after yawning or arousal from sleep. When the patients was kept on upright position, type A pattern was persisted; However, the postural change to the recumbent position produced type +A tympanogram. The mechanism of the positive pressure cannot fully be explained by the present knowledges about the functional physiology of the eustachian tube.
The purpose of this report is to clarify whether noise induced sudden deafness (N. I. S. D) should be classified into acute noise injury (A. N. I) or sudden deafness (S. D.). Four cases of N. I. S. D. (A group) and 6 cases of A. N. I (B group), presenting with unilateral hearing loss and tinnitus, were investigated. Mean hearing level (0.25-8kHz) was 73dB in A group and 69dB in B group. Audiogram patterns of both groups could be classified into three types as flat contour, down slope and saucer. No one was improved more than 15dB by treatment. with respect to their clinical features, there were no differences between both groups. Békésy tracing, SISI, electrocochleogram and vestibular function test were also performed, but no significant difference was found between two groups. N. I. S. D. different from S. D at the points that although S. D with flat contour or down slope audiogram had good prognosis, N. I. S. D with the same ones had poor prognosis, and although prognosis of S. D showing recruiting AP and nomal N1-latency in electrocochleogram was good, that of N. I. S. D with the same finding was poor. Then we concluded that N. I. S. D is one of A. N. I.
Power spectral analysis of normal and abnormal ABRs were experimentally investigated in cats. In the normal ABR, three major peaks were recognized at around 100-200Hz (A peak), 700-800Hz (B peak) and 1000-1200Hz (C peak) (A peak>B peak≅C peak). In the abnormal ABRs, their power spectra revealed different distribution in accordance with the ABR modality: shift of the each peak to lower or higher frequency range, and changes in power balance of each peak. The morphological abnormalities of ABR are possibly classified by power spectral analysis clearly enough to apply this data for clinical use in neurological field.