変調周波数追随反応の眠気依存性に関する研究

摘要

眠気を催したドライバーに眠気を自覚させるためにはどのような高さの音が適しているのかを探索するために，眠気の強さと変調周波数追随反応(AMFR)との関係を調べた.本研究では，AMFRの惹起に変調周波数f_cが500, 1000, 4000および8000Hzである振幅変調音を用いたところ，16名の被験者で応答が確認された.被験者のパフォーマンスをボタン押しタスクの反応潜時(RT)により3状態に分けた結果，どのf_cの音に対するAMFRでも眠気が強くなるほど応答が小さくなる傾向が見られた.さらに，高パフォーマンスの状態はα波のパワーが強い状態と弱い状態とに分けた.その結果，f_c = 500Hzの音に対する応答ではα波が高い状態の方が低い状態よりも小さくなる傾向が見られたが，その他の音に対する応答では見られなかった.以上の結果は，ドライバーに眠気を気付かせるには高い音の方が適しているということを示唆している.%We investigated the relationship between sleepiness and amplitude of amplitude-modulation following response (AMFR) to find the best tone to raise awareness of sleepy drivers. In this study, auditory responses which were evoked by amplitude modulated tones whose carrier frequencies were 500, 1000， 4000, and 8000 Hz were recorded in 16 subjects. Performance level was divided into three stages by using reaction time of psychomotor vigilance test, and the amplitude of AMFR was found to be decreased as the decrement of the performance in all frequency range. The high performance stages were further divided into two stages, those with alpha wave and without alpha wave. We found that auditory responses evoked by 500 Hz AM tone in alpha wave state were smaller those in no-alpha state, but those evoked by the other AM tone were consistent. These results suggest that the high frequency tone could make drivers aware of their sleepiness.