２音融合値による疲労の測定と分析 特にフリッカー値と比較して

Abstract

According to the acoustical method introduce here, a pair of pure tones, of 2 kHz with a duration of 20 msec, was given repeatedly as acoustical stimuli. The interval of the two tones was changed stepwisely to determine the threshold, Tm, of acoustical fusion of the two tones. Simultaneously, the traditional optical flicker fusion technique was used to determine the corresopnding threshold, Fm. Then, Tm was examined whether it could be utilized to measure fatigue. The following three kind of experiments were carried out: 1) Tm showed a reasonable diurnal change, which was just in the counter phase of that of Fm. 2) A questionnaire survey about various factors ascribable to subjective fatigue in daily activities was conducted, and made measurement and analysis of these various factors of fatigue including Tm and Fm. (a) The weights of the factors contributing to Tm and Fm was assessed by Hayashi's Quantification Theory (I). The result showed that Fm was determined chiefly by the major activity of the day, the type of drinks taken just before the measurement, and the degree of waking level, while Tm tended to be determined by the day of the week, weather conditions, etc. also, it was found that both of Fm and Tm were determined similarly by the activity prior to measurement, the subjective fatigue level, and the time of measurement. (b) The weights of factors contributing to subjective fatigue was determined by Hayashi's Quantification Theory (II). The result showed that the subjective fatigue was mainly determined by the degree of waking level, Tm, the activity prior to the measurement, and Fm. 3) Fm and Tm were changed by VDT workload. Fm was changed in the negative direction, while Tm was changed in the positive. Thus, it may be concluded that Tm is acceptable as a indicator of work-indused fatigue.