The results of screening hearing test was statistically analyzed.
The screening hearing test was conducted at the spring and autumn regular physical examinations in 1990 in a company of the so-called third industries. This screening hearing test was conducted according to the recommendation of “The Method of Screening Hearing Test at General Physical Examination” proposed by the Oto-Rhino-Laryngological Society of Japan. No response against the test pure tone of either 30dB at 1kHz or 40dB at 4kHz produced by screening audiometer was defined as the positive finding (non-responder) at screening hearing test. These non-responders were called to receive the further examinations such as otoscopic examination, standardized pure tone audiometry, temporal bone X-ray and so on by otorhinolaryngology specialist.
The results obtained were as follows;
1) About 90% of employees in this company participated in the screening hearing test.
2) No response at screening hearing test was found in 172 subjects out of 1697 participants (10.1%).
3) There was no clear difference of the incidence of non-responders at screening hearing test between males and females.
4) Out of 172 non-responders, 147 subjects (85.5%) received further precise otorhinolaryngological examinations including standardized pure tone audiometry.
5) The incidence of non-responders at screening hearing test became higher along the age increased.
6) When the number of no response for test frequencies of both ears was analyzed, no response at only one test frequency was most frequently observed.
7) When the combination of test frequencies of both ears was analyzed, no response at 4kHz in one ear was most frequently observed.
8) When the accuracy of screening hearing test was analyzed by the comparison between the results of screening hearing test and those of standardized pure tone audiometry, it was 89.1% at 1kHz and 82.0% at 4kHz.
9) As far as the type of hearing loss in no-responded ears at screening hearing test was concerned, sensorineural hearing loss was most frequently observed (66.7%), followed by normal hearing, mixed hearing loss and conductive hearing loss.
10) When the audiometric configuration in no-responded ears at screening hearing test was analyzed, high tone gradual loss type was most frequently found (48.0%), followed by normal type, c⁵ dip type, flat type, convex type, high tone abrupt loss type and low tone hearing loss type.
11) The final diagnosis by otorhinolaryngology specialist was analyzed in no-responded ears at screening hearing test. Only 18.4% was diagnosed as the normal ear and the other ears (81.6%) were diagnosed as having some kinds of ear disease. The etiology of hearing loss was able to be clarified in 30.4%. The most frequently observed etiology of hearing loss in these ears was the sequel of otitis media, followed by chronic supprative otitis media and ototoxic drug induced sensorineural hearing loss.
12) The ears in which surgical treatment was indicated were found in 6.1% of no-responded ears at screening hearing test. These included not only chronic supprative otitis media, cholesteatoma and adhesive otitis media, but also acoustic neuroma.
13) It was speculated that 17-25% of non-responders at screening hearing test were of age-related hearing loss (so-called presbyacusis) in males of forties and fifties.
14) Based upon these results, it was concluded that screening hearing test conducted at annual (or regular) physical examination in companies bears great meanings when the following conditions are satisfied; (1) the majority of employees in each company participates in screening hearing test, (2) the accuracy of screening hearing test is excellent and (3) all non-responders at screening hearing test can receive the further precise examination by otorhinolaryngology specialist and optimal treatment can be done if necessary.

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Audiometric profile, self-and care workers' judgement of hard-of-hearing, and reported handicaps were investigated in 219 adults ranging from 65 to 100 years old who resided in the facilities for the elderly. Dementia primarily appeared to prevent an administration of screening test of hearing for approximately a half of the subjects. Most subjects demonstrated a mild or moderate hearing loss slightly sloping in the high-frequencies, consequently being determined to have a hard-of hearing due to aging. The subjects were not fully aware of their hard-of-hearing while the care workers indeed ignored the problem. Although the subjects felt their loss of auditory sensitivity and/or speech intelligibility, only two of them were fitted to hearing aids.

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The Disabled Persons Welfare Act can give a certificate for the physically handicapped to the qualified person through the prefectural governor under Article 15 of the act. The hearing-impaired persons with the certificate will be afforded with a lot of benefit, including welfare annuity. The otolaryngologist designated by the act has qualification to screen the handicapped. The physicians must decide the grade of disability accurately. However, it is not easy to classify the grade at the first examination. We followed up the handicapped with hearing problem after the judgement, and have obtained data concerning reliability of the judgement. There were approximately 53% misjudgements (appropriate to 31% in ±10dB limitation) which were caused from several reasons. The most important problem is for the elderly handicapped not to be able to respond the standard pure-tone audiometry or the speech audiometry accurately.
Finally the authors realized that it was necessary to determine the hearing threshold of the elderly person carefully before applying the Welfare Act.

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In the field of medical science of audiology that deals with sacial problems, discussion has mainly focused on occupational hearing loss among factory workers, professional drivers and so on.
In recent years, discos, scuba diving as a hobby, and music headsets are the newer issues facing hearing loss. The purpose of this report is to discuss hearing loss among athletes.
Ninety students of the Physical Education Department of Juntendo University were surveyed for this study. Twenty-one among them are field and track athletes, 22 baseball players, 22 swimmers, and 25 Kendo competitors. All complete at the national level and strive daily to improve their competitive ability. Their training is based on the method of sports medicine.
From the results of the survey, we found that there was a hearing loss on high frequencies among athletes and baseball players, and on low frequencies among swimmers. Among Kendo competitors, there exists more hearing deterioration.
Since the sound enviroment seems to influence the atheletes hearing level, especially in highly competitive sports, we think that we need to further investigate these hearing loss.

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This study is to find whether Kendou causes sensori-neural hearing loss or not. Subjects were 98 male and 6 female aged 16.4 years in avarage, and they had played Kendou for 1-50 years.
All subjects were examined by pure tone audiometry with or without electrochachleography.
The results obtained were that out of the 104 examinees, 26 showed a C⁵-dip or high tone impairment audiograms. Hearing loss might have depended on the period of experience of Kendou. The noise occured during Kendou practice consists of mainly a low tone with high pressure sound (90-110dBnHL).
From this study, the possibility of Kendou caused sensori-neural hearing loss is suggested.

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The purpose of this study is to analyze hearing impairment in primary school children in Sendai City from 1968 through 1987.
The following results were obtained:
1) The prevalence of hearing impaired children had rapidly decreased yearly from a peak of 1.94% in 1972 and was 0.6-0.7% since 1983. The cause of this reduction was mainly due to the decrease of a conductive hearing loss.
2) Hearing loss was more predominant in boys (60%). Sensorineural and conductive hearing losses were also more frequently among boys.
3) Unilateral hearing loss was found more common than bilateral hearing loss.
4) The prevalence of a hearing loss due to secretory otitis media had decreased, although it still accounts for approximately 60% of a conductive hearing loss and 30% of all cases with hearing impairment.
5) The prevalence of impaired hearing caused by chronic otitis media had been constantly decreased to 0.02% in 1985.

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There are two types acute sensorineural hearing loss: the type in which the etiology of hearing loss is presumed as hearing loss after exposure to loud sound, and the type where the etiology is unclear as in sudden deafness.
The hearing impairment after a music concert was clinically investigated in this study, and the results of treatment for music concert hearing loss were compared with those of cases with hearing loss from other sound exposure and cases of sudden deafness.
As a result, a hearing loss due to music concert hearing loss showed more improvement after treatment than those cases having hearing loss due to exposure to other loud sounds, as compared with sudden deafness.
Therefore, in the acute sensorineural hearing loss due to sound exposure, it is necessarry to receive an immediate treatment as possible.

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Auditory Brainstem Responses (ABR) were recorded in 177 ears of infants, who were considered to have normal auditory function, ranged in age from a month to 5 years old and a 3-day-old boy. The off-time analysis was performed, and ABR was divided into two components, slow components in the range of 10-200Hz and fast-slow complex components in the range of 10-2000Hz. In the slow components of infants under 1 year of age, two positive waves, “P” and “p” ware observed in more than 90%. In their fast-slow complex components the a large negative deflection “NII” was observed following wave II. The power spectral analysis of the 3-day-old boy revealed the frequency range of “NII” at around 400-700Hz. The possibility of the decreased amplitudes of “NII” as a function of age was examined. The results revealed that decremeats of “NII” amplitude correlated with age. These studies might lead us to a presumption that the modality of the “NII” indicates the maturation of auditory pathway in infantile term, between the cochlear nucleus and the superior olivary complex of nuclei such as dorsal nuclei and ventral nuclei.

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The intensity levels of monosyllables were measured against a 1kHz calibration tone using a 57-word list in CD record (TY-89) and a 57S-word list in tape record. The averaged intensity level of monosyllables, corresponding to the VU meter level, was lower by 10.2dB than the calibration tone in the 57-word list and higher by 2.1dB in the 57S-word list.
Speech discrimination scores under noises were compared between the 57-word list and the 57S-word list. The discrimination scores of the 57-word list were better than those of the 57S-word list when S/N was small. In comparing the discrimination scores of consonant groups, the 57-word list was found to have better scores with voiceless (h, k, s, t), voiced (b, d, g, r, z) and semivowel consonants (j, w). In contrast, the 57-word list had worse scores with nasal consonants (m, n).
The different characteristics of the two word lists must be taken into consideration when they are used as test materials.

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Evoked otoacoustic emission (e-OAE) and promontory stimulation test (PST) were investigated in 15 cases of surgically proven unilateral acoustic neuroma (AN) which showed the profound deafness with more than 80dB in pure tone audiometry.
The e-OAE was elicited by tone-bursts with frequencies at 1kHz and 2kHz and more than 10dB of interaural difference of pseudothreshold was defined as the significant impairment of cochlear function. The PST was conducted with the stimulation of bursts mode at 6 stimulus frequencies by the Nucleus promontory stimulator. When the auditory sensation was obtained at either 6 stimulus frequencies, it was defined as the PST positive. Also, when the auditory sensation was obtained at all 6 stimulus frequencies, it was defined as the PST score 6, and when the auditory sensation could not be acquired at any 6 stimulus frequencies, it was defined as the PST score 0.
The results obtained were as follows;
1) The mean interaural difference of e-OAE pseudothreshold was 16.0dB at 1kHz and 8.0dB at 2kHz.
2) The positive PST was found in only 40.0% of the subjects and the mean PST score was 0.93.
3) When the pathophysiology of hearing impairment was speculated from the results of e-OAE and PST, it was found that pure cochlear impairment was in 33.3%, pure retrocochlear impairment in 13.3% and cochlear-retrocochlear impairment in 46.7%.
4) It was concluded that the analysis of both e-OAE and PST could clarify the pathophysiology of hearing impairments in AN with profound deafness.

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Eight hearing impaired children with inner ear anomalies which were revealed by temporal bone CT scanning were studied for the devolopment of hearing and language with auditory training. All of eight children had other anomalies such as cleft palate. facial paresis, choroidal defect of the eyes and so on. These children were classified into two groups including were a group with oral language consisting three children and a group without oral language consisting five children. The group with oral language, was characterized by mild inner ear anomalies, moderately impaired hearing (threshold: 60dB-80dB), slightly delayed or normal development of intelligence and good outcome of auditory training. On the other hand, the group without oral language was characterized by severely impaired hearing or severely delayed development of intelligence and poor outcome of auditory training. Our study shows that auditory training for children with severe inner ear anomalies and hearing loss should be utilized not only oral language teaching method through hearing aid but also visual input communication like body language and written language because most of these children associate with various kinds of anomalies and handicaps.

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The most effective method to induce transient local anoxia in the inner ear of guinea pigs is to obstruct the blood flow by pressure at the orifice of the internal auditory canal. By the ventral approach, the orifice is located behind the brainstem and the direct observation is impossible. In the present study, the three dimensional measurement on the location of the orifice was performed with various parameters. According to these measured values, a metal stick was inserted into the cerebellopontine angle toward the orifice until the inner ear became anoxic. Anoxia was confirmed by measuring the EP and the cochlear blood flow using the Laser Doppler method. With this method, a transient local anoxia was induced with high success rate.

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A protocol body worn hearing aid was designed with an application of an expansion amplification circuit in search of a “quiet hearing aid”. An expansion circuit is activated in higher frequencies with an expansion ratio of 1:2, contrary to the linear amplification in the lower frequencies. Thus the higher frequency speech element is boosted while the backgroud noise is reduced to a marked degree.
A comparison was made on the sound quality and intelligibility of speech between the protocol aid and the users' own hearing aid, and discussion was made on the significance of expansion amplification in hearing aid design.

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