Electrocochleography (ECochG) refers to examination of auditory evoked potentials, in which the electrical responses of the cochlea and the cochlear nerve evoked by sound stimuli are measured. Either a transtympanic or extratympanic electrode is used as the primary electrode for ECochG. The electrocochleogram consists of the cochlear microphonic (CM), summating potential (SP), and cochlear nerve compound action potential (AP). These responses are recorded within 3 msec of application of the acoustic stimuli. Although ECochG is technically and methodologically complex, it is very valuable for pathophysiological evaluation of cochlear function. In this report, the procedure and the clinical significance and application of ECochG are described in detail, with a review of the literature.
This study was conducted to investigate the factors associated with post-implant language ability in twenty-eight children with congenital deafness without any associated developmental disorder, who had received cochlear implants. The subjects were implanted with the Nuchleus-24 or 22 system between the two and four years of age. The subjects were administered teh Wechsler Intelligence Scale for Children (Third Edition) and the speech perception test just before they enrolled into elementary school. Sets of selected factors that were supposed to be correlated with language ability were analyzed statistically. The results revealed that the language ability after cochlear implantation was significantly correlated with the age at diagnosis and the time of start of habilitation for the hearing disorder. The better the language development before the implantation, the younger the age at the implantation and the longer the duration of the device use, the better the speech recognition and perception abilities. The language ability was related most strongly to the speech perception ability, and in turn, the speech perception ability was related most strongly to the age at the time of the cochlear implantation and the duratron of the device use. Half of the subjects enrolled into mainstream elementary schools, and were superior in language ability, and speech perception and recognition perception abilities than the subjects who enrolled into special schools.
One hundred nineteen patients (63 men, 56 women) complaining of severe tinnitus were seen at the Department of Otolaryngology in Nippon Koukan Hospital and Koukan Clinic during the two-year period from April 2004 to March 2006. Of these, 61 (33 men, 28 women) underwent TRT (Tinnitus Retraining Therapy) with the TCI (Tinnitus Control Instrument) and were followed up. We conducted a questionnaire survey of the patients, using the THI (Tinnitus Handicap Inventory). Then, we divided the cases into 2 groups, namely, the Hearing Gap (+) group (19 cases; 10 men and 9 women) and the Hearing Gap (-) group (42 cases; 24 men and 18 women), based on the presence or absence, respectively, of a greater than 10dB difference in the ear of hearing loss between in the right ear and the left ear between the affected ear and the contralateral ear? in the patients. We compared the two groups in terms of the age, score in the? THI (Tinnitus Handicap Inventory), VAS (Visual Analoque Scale) score, and the average hearing level. tinnitus loudness pitch match type of hearing loss type, origin of tinnitus, THI (Tinnitus Handicap Inventory) score, and average of mean hearing level, and the loudness of the tinnitus loudness at the first examination between the two groups The loudness pitch of the tinnitus was related to the type of hearing loss, the origin of the tinnitus, the THI score, the average hearing level and the loudnss pitch of the tnnnitus at the first examination in both the groups??. The results revealed that the THI score, average hearing level and tinnitus loudness were higher in the Hearing Gap (+) group than in the Hearing Gap (-) group. The results revealed that many patients chose speech noise or white noise. We observed that many patients in the Hearing Loss (-) group chose the speech noises of the TCI, which are low-frequency sounds, but whereas many patients in the Hearing Gap (+) group tended to choose the white noise of the TCI, representing which sounds of all frequencies level which is composed of sounds of diverse frequency levels. These results may be of help in guiding physicians to determine the noise type of a the TCI for TRT.
When sound field speech audiometry is evaluated with competing noise, monosyllable and word intelligibility significantly vary according to the speech sound materials or the competing noise presentation method, even in the same subjects. Various competing noise methods in addition to the conditions described in ISO 8253-3 have been evaluated. In this study, monosyllable and word intelligibility were evaluated under three different types of competing noise conditions in a sound field, in 20 normal hearing subjects. As a result, in tests using speech material with less variable sound pressure levels of the word list, neither monosyllable not word intelligibility differed significantly between noise presentation from a loudspeaker placed in front of the subject and the competing noise conditions described in ISO 8353-3.
The participants were 9 children who were referred to the Kitasato University Hospital after Newborn Hearing Screening and were diagnosed to have moderate hearing loss (screened children). Twenty-four children with moderate hearing loss who had not undergone Newborn Hearing Screening (non-screened children) were enrolled as the control group? We compared the age in lunar months of the screened and non-screened children at the first audiometry, at the time of fitting of the first hearing aid, at first language acquisition, and so on. The mean age of the infants at the first audiometry was 5.4 months, and that at the time of fitting of the first hearing aid was 11.1 months in the screened children. On the other hand, the mean age at the first infant audiometry was 61.0 months, and that at the time of fitting of the first hearing aid was 63.5 months in the non-screened children. Both the age at the first audiometry and at the time of the hearing aid fitting were significantly lower in the screened children. The interval from the first audiometry to the first hearing aid fitting was 5.7 months in the screened children, while it was 2.5 months in the non-screened children. All the screened children started their first language by the age of 21 months. We need to keep these children under observation to detect signs of possible language retardation.
In recent years, the ambient noise levels at the workplace have been reduced in large-sized corporations. However, little is known about the noise exposure levels and the prevalence of occupational hearing loss in small-sized companies in Japan. The purpose of this study was to determine whether noise-induced hearing loss still remains a prevalent occupational health problem, especially in small-sized companies with less than 50 employees. The investigation revealed the following: 1. Although noise levels were well controlled in large-sized corporations, high levels of noise at the workplace were still confirmed in small-sized companies. 2. Two companies provided consent for measurement of the ambient noise levels and of the hearing levels in its employees. Although the noise levels were not extremely high at either company, hearing loss, supposedly noise-induced, was identified in 5 of the 7 employees in one company and 4 of the 14 employees at the other company. 3. In conclusion, specialists of noise-induced hearing loss authorized by the Oto-Rhino-Laryngological Society of Japan should play a role in shedding light on possible methods to prevent occupational hearing loss, especially in small-sized companies.