抄録
By means of Motokawa's method of electric flicker (EF), we measured variations of electric flicker values (EFV) of 5 subjects caused by exposure to pure tones or noise. The pure tones used were 500, 1000, 2000, 4000 and 6000 cps.
1. 4 subjects were exposed to a tone of 500 cps and 70 db for 30 minutes. EFVs increased and reached a highest level in about 5-10 minutes and continued so long as the stimulus lasted.
2. Measurements of EFVs in exposure to each of 5 pure tones of 70 db were made in 4 subjects. EFVs in response to tones of 500 and 6000 cps were remarkably great in comparison with those to tones of 1000 and 2000 cps.
3. In 3 subjects similar measurements were made at various intensity levels of tones, and it was found that the higher the intensity, the greater the change of EFV caused.
4. Hearing loss caused by two kinds of ear plugs A and B were investigated by an audiometer. With A hearing loss occurred above 2000 cps and with B over the whole range of frequencies. EFVs measured with the ear plug A were found to be remarkably low in comparison with control over the frequency range higher than 2000 cps. This finding corresponds with the audiometric one mentioned above.
5. In 3 subjects, the relation between intensity of noise and EFVs was investigated, and it was found that the larger the intensity of noise, the greater the change of EFV caused by exposure to noise.
