The relation between language (articulation) ability and hearing levels at each frequency (500⋅1000⋅2000⋅4000Hz) was studied in 92 cases (5-12 years) with mild and moderate sensorineural hearing impairment, who had neither any auditory training nor hearing aid. The results obtained were as follows. (1) The children with hearing levels below 25dB at 500⋅1000⋅2000Hz and over 50dB at 4000Hz, exhibited normal language development. But almost all of them exhibited articulation disorders. (2) Many children with hearing levels below 25dB at 500⋅1000Hz and over 50dB at 2000⋅4000Hz, exhibited normal language development. But almost all of them exhibited articulation disorders. (3) The children with hearing levels below 25dB at 500Hz and over 50dB at 1000⋅2000⋅4000Hz, exhibited language retardation and articulation disorders. (4) Many children with hearing levels of 40-60dB at 1000⋅2000Hz and below 25dB at 4000Hz, exhibited language retardation. But a few children exhibited articulation disorders. (5) Many children with hearing loss at 1000⋅2000⋅4000Hz more than 40dB, exhibited language retardation and articulation disorders.
FM hearing aid is useful in school education, however, as it is a box type, many users have trouble to move around with the hearing aid which picks up noise of clothes rustling. Through clinical testing, I found the FM-BTE system very effective not only for school children but also for adults. Patient I was a 16-year-old boy who has severe sensorineural hearing loss in both ears. Speech reception threshold with the former hearing aid was 61% in 5 meters from the speaker, and 25% in 10 meters. With the FM-BTE hearing aid system, the results were 86%, and 85%, respectively.
The effects of wearing an air-conduction receiver on the results of tinnitus test were investigated in 25 patients suffering from unilateral tinnitus. Pitch match and loudness balance tests were performed by presenting comparative sounds to the uninvolved ear, with or without wearing an air-conduction receiver on the involved ear. The results indicated that pitch of the tinnitus was differently perceived by presence of the receiver in 9 of 25 patients (36%), while that of loudness in 15 patients (60%). According to a proposal in “Tinnitus Test 1984”, pitch match and loudness balance tests should be performed by presenting the comparative sounds to the involved ear. This is advantageous in testing tinnitus irrespective to the hearing level of the contralateral ear. However, as proved in the present study, wearing an air-conduction receiver modifies nature of the tinnitus due to acoustical effects of ear canal obstruction.
The authors applied wavelet transform to analysis of the transiently evoked otoacoustic emissions (TEOAEs). Changes in the TEOAE wave forms after contralateral noise stimulation were evaluated in certain frequency bands and in certain time segments in terms of amplitude and phase. TEOAEs of 12 normal hearing ears were evoked and recorded by ILO88. White noise was delivered to the contralateral ear by 10dB steps below the stapedial reflex threshold in random sequences. TEOAEs were transformed with six gaussianshaped complex wavelets centered at 500, 750, 1000, 1500, 2000, and 3000Hz. This gave two profiles, amplitude and phase, for each center frequency as continuous functions of time. Wave forms before and after the contralateral noise stimulation were compared based on these amplitude and phase profiles. Dose dependent amplitude reduction and phase lead were observed in each frequency band, but the transfer function differed among individual ears and even between different time segments (early: 6-10ms, late: 14-18ms) in some ears. In one ear with a spontaneous OAE (SOAE) at 2000Hz, TEOAE amplitude in the 2000Hz band was slightly increased. Our results imply that the active process might contribute to TEOAEs to different degrees in different time segments and that SOAE might modify the effect of contralateral noise stimulation.
Otological screening tests consisting of tympanometry and questionnaires have been performed since 1991 as part of health examination for three-year-old children in Miyagi Prefecture, Japan. The records of 41 children (78 ears) who later underwent tympanoplasty or tube insertion were analyzed. Among 32 (62 ears) out of the 41 children, 19 children (36 ears) were detected for the first time as being abnormal at the screening, while 13 (26 ears) had been treated before. The 19 children (36 ears) newly detected at the screening consisted of 33 ears with intractable secretory otitis media (SOM), 2 ears with adhesive otitis media, and one ear with chronic otitis media. Although they all showed sympanometric abnormalities, only 7 of them were selected through questionnaires. These results suggest the importance of tympanometry in this screening system to detect SOM effectively and other intractable middle ear diseases in addition to sensorineural hearing loss.
For the purpose of evaluation of data obtained from transtympanic electrocochleography (ECochG), intertest reliability was studied in 5 ears with normal hearing or sensorineural hearing loss. Two examinations were performed for one test ear with an interval of three hours to two weeks. Short tone bursts were employed as acoustic stimulation to evoke ECochG-CMs and clicks were used to measure ECochG-AP. The results were as follows. 1. Detection thresholds (dBnHL) of AP and CM, and the range of intensities in which delayed CMs were recorded, were stable between the two tests. It is considered that these indeces are useful criteria for the diseases which might have variable cochlear functions such as sudden deafness and Meniere's disease. 2. Input-output curves of AP and CM were similar. It is supposed that this index is also valuable to estimate cochlear function. On the other hand, amplitudes (μV) differed markedly in some cases suggesting that function cannot be evaluated only from the amplitude.
Nature of tinnitus was investigated in 97 unilateral sudden deafness patients who received treatments within 2 weeks after the onset. Tinnitus was evaluated every 2 days using the subjective tinnitus score, pitch match test and loudness balance test in order to investigate the relationship between the tinnitus change and hearing recovery. The results obtained were as follows; 1) There was no statistical difference in the incidence of tinnitus at the first tinnitus test between each group which was classified regarding to the hearing recovery using the criteria proposed by the Ministry of Japan Health and Welfare. On the other hand, the higher the incidence of patients whose tinnitus disappeared within 2 weeks after treatment was, the higher was the hearing recovery rate. 2) Subjective score of tinnitus gradually decreased with hearing recovery, especially in the patients with good prognosis of hearing. From this result, the subjective score of tinnitus might be a good indicator for the recovery of cochlear function. 3) Although the subjective score of tinnitus decreased in patients with good prognosis in hearing, the tinnitus loudness measured with sensation level increased in some patients. This discrepancy might be caused by the recruitment phenomenon in the early stage of sudden deafness. 4) From the analysis of onomatopoetic expressions and simulated tones in audiomentry, the noisy onomatopoeia or tinnitus simulated by noise in audiometry tended to change to the pure-tonal onomatopoeia or tinnitus simulated by pure-tone in patients with good prognosis. Thus, the change in nature of tinnitus also seemed to be correlated with the recovery of cochlear dysfunction. 5) Further study will be needed to clarify the relationship between the changes in nature of tinnitus and the cochlear function in sudden deafness patients.