Four cases of bilateral hearing loss detected by screening tests at school were reported. All cases had moderate or severe hearing impairment in pure tone audiometry but had no trouble in conver sation. It was observed that they had the type V pattern in Békésy audiometry, the discrepancy between their pure tone thresholds and speech reception thresholds and the normal estimated thresholds in ABR. We tried to obtain so called true thresholds using band noise audiometry, frequent examinations in pure tone audiometry, long time presentation at one hearing level in pure tone audiometry and an original SRT measurement. We confirmed the usefulness of these methods in the diagnosis of functional hearing loss. Finally we discussed the difference between psychogenic deafness and hearing problems shown in this paper.
Tympanogrames were obtained from 650 (3 to 6-year-old) preschool children with a new tympanometer and a data processing system. Tympanometry is composed of middle ear pressure, physical volume, compliance and gradient. The 3.5 inch floppy disk (2DD TYPE) can save data of 1000 children. The floppy disk is available for the personal computer which plays the data processing system. The normal range of the middle ear pressure, physical volume, compliance and gradient can be freely changed on TV monitor. In our investigation the normal range of the middle ear pressure was determined at +50--200daPa; the physical volume at 0.3-15 ml; the peak compliance at 0.2-1.6 ml; the gradiant at 30%~70%. Therefore this instrument system can almost automatically analyze tympanograms and show “normal” or “abnormal” If any data indicates a boundary between normal and abnormal range, the otolaryngologist studies these conditions on the TV monitor.139 children had the abnormal tympanograms as a result. Forty four (31.0%) of 142 tree-year-old children had the abnormal tympanograms; that shows the highest rate among the children groups investigated. The rate of the abnormal tympanograms went down with the age of the children examined going up.
Serum IgA levels in 306 patients between the ages of 3 and 14 years with secretory otitis media were measured. In only thirteen patients, the amount of serum IgA was a low level of between 28mg/dl and 77 mg/dl. We tried the insertion of ventilating tubes into such patients and the insertion of ventilating tube into 52 patients with secretory otitis media with a normal range of serum IgA level as the control group. In the group with a low level of IgA, the tube was extruded spontaneously from the tympanic membrane from 4 to 13 months and their hearing was not improved. In the control group, the tube was extruded spontaneously from the tympanic membrane from 9 to 20 months and this group showed remarkable improvement in their hearing. This result suggested that serum IgA was significant for prolong factor.
Twenty-six children from six to 13 years of age with sensorineural hearing loss levels between 30and 70 dB were investigated. Parents initially noticed hearing loss and speech difficulties between one and 8 years of age, average five years. More severe hearing loss tended to be noticed at an earlier age. All 26 cases were advised to use a hearing aid but the parents of six of the children declined. The average of these six children was 43.1 dB, slightly below the 45 dB loudness level of ordinary conversation. The average of the 20 cases using hearing aids was 55.3 dB. It was therefore assumed that the six children not using hearing aids had some difficulties in school.
Twenty-eight multiply-handicapped children with hearing impairment were fitted with hearing aids and investigated at educational institutes in the preschool and elementary school periods. a)Seventeen of 28 children who were observed for more than six months demonstrated fair or good effects of hearing aid use. In the preschool period,65% of those in special schools for disabled children and 11% in kindergarten and 24% in the deaf school were educated. In the elementary school period,53% of those were educated in the school for disabled children and 12% in the elementary school and 35% in the deaf school were educated. b) Five children showed no improvement in auditory behavior. c) Six children had diffculty with the fitting of hearing aids because they did not like ear molds being put in their ears. Children in groups b and c were educated in schools for disabled children in the preschool and the elementary school periods.
Evoked otoacoustic emissions (e-OAE) were examined in 62 ears of 6 to 7 year-old children with normal hearing or with sensori-neural hearing loss; in which 26 ears were normal hearing,8 were mumps deafness,8 were functional deafness and 18 were deaf ears of unknown origin. Mean detection threshold of e-OAE was 5.2 dBnHL in the normal hearing ears and 8.8 dBnHL in the ears of functional deafness, whereas mean threshold was 42.5 dBnHL in the ears of inner ear impairment and 40.9 dBnHL in the deaf ears of unknown origin. The results indicate that the ears with sensorineural hearing loss of unknown origin are mostly inner ear impairment and that the e-OAE may be useful as a screening hearing test for preschool age.