A GROUP AUDIOMETRY THE TRIAL RECORDING OF A PHONOGRAPH RECORD FOR A GROUP AUDIOMETER TEST

THE TRIAL RECORDING OF A PHONOGRAPH RECORD FOR A GROUP AUDIOMETER TEST

Abstract

At present, there are two principal methods of screening test for loss of hearing in common use. One is the individual and the otherr is the group hearing test. The tape-recorder ani the Rion GA-1012 Group Audiometer were used. They consisted essentially of two parts connecte3 together ellectrically: namely a recorder and 30∼80 telephone receivers. Receivers were matched ellectrically to one another within 5 or 10 decibels over a wide frequency range. (Fig. 2) We made the tape-record and long playing record for the use of the group audiometer test. The tones of stimuli used in our test were the speech sounds of several numerals from 1 to 10 and pure tones at the frequency of 500, 1000 and 4000 cps. A sample of the pattern of presenta- tion of stimuli has been shown in Table 1, 2 and 3. The loudness of the spoken numbers was graduated in such a manner that each succeeding series were 10 or 20 decibels less than the pre- ceeding ser.es.An above threshold pure tone was recorded in spurts of 1, 2, 3, 4 or 5 stimulations. The intensity of the tone for each series of spurts was decreased systematically. The subjects were required to record the frequency of the number of spurts delivered at each intensity level. Tow thousands seven hundreds and thirty-four elementary school children and 487 industrial workers were tested, in the manner described above. It was found that for pupils, 326 cases failed the first group test. Only those cases failing the first test were given the re-test. One hundred and twelve cases failed the re-test. We administered an individual pure tone audiometer test to 112 children who had twice failed the group test. The results showed that only 48 cases (42.9 oea cent) had significant hearing losses for pure tones. For industrial workers, 312 cases failed the first group test. Among them 288 cases (92.3 per cent) had significant hearing losses. It was found that 7 cases among 175 cases passing the group test had impaired hearing. However among them 4 cases had hearing loss only at 8000 cps and the other 3 cases had slight hearing loss for pure tones less than 30 decibels.