Basic study on the measuring of fatigue by the minimum audible pressure

Nowadays, human senses of vision and hearing receive many stimulations. In particular, VDT work is commonly performed by people of all ages. Therefore, in order to regulate working hours we need to measure the fatigue due to VDT work. The current measuring system depends on the flicker value (CFF). This report describes a new measuring system which depends on the measurement of the fluctuation in the minimum audible pressure (MAP) while using the increase of threshold value as an index of fatigue, and the results of the related experiment. In Test 1, the test sound was set at the pure sound of 1,000 Hz. In Test 2, an ordinary hearing acuity inspection room was used, using the method of limit measurement and headphones (Telephonics, TDH39, MX41/AR). As a result, it was verified that the most suitable rate of increasing and decreasing audible pressure was by 2 dB or 1 dB. It was proved from these tests that the minimum audible pressure could be used satisfactorily as a practical index for absolute measurement of hearing sense fatigue.