[A study on the quantitative evaluation method of human alertness and its application].

This article presents an alertness evaluation method being analyzed by the authors, and discusses its application. With the aim of quantifying the physiological activity of the living body, the alpha-attenuation test (AAT) for evaluation of alertness was assessed. AAT is a method of quantitatively determining alertness level from alpha-wave power spectra during eye closure and opening. 1. The potential for quantification of diurnal change of alertness by the use of the AAT is suggested. Also rated, are a performance evaluation method based on reaction time and target tracking error and a subjective feeling evaluation method using an analog scale on a computer display. Using these methods of evaluation, measurements were made in 9 healthy men and women at 2-hour intervals over the period from 09: 30 to 19: 30. The findings are summarized as follows: 1) Alertness lowered from 13: 30 to 15: 30, as rated by diurnal change determined by the AAT 2) The performance test and subjective feeling scoring revealed decreased target tracing ability and extended reaction time from 13: 30 to 15: 30, accompanied by reduced performance, increased sleepiness, and failure to achieve accurate, quick action. 2. The relation between the quality of rest and the alpha-attenuation coefficient (AAC), the quantitative index of the AAT, was rated. There were some statistical significances between the quality of rest and the AAC. These results suggest that the AAC is found applicable to the quantitative assessment of diurnal changes of physiological activity, and that the AAC is reflected in the quality of rest.