駕駛員之大腦血氧濃度及腦電波與疲勞的相關性

Abstract

疲勞駕駛一般被視為車禍事故的主因，先前研究已發現相關之腦電波動態特徵，但受限於空間解析度不足，與大腦特定區域之關係尚須進一步釐清。因此，本研究透過同時記錄腦波與血氧濃度(使用功能性近紅外線光譜儀)的方式，除瞭解疲勞在模擬駕駛下特定大腦區域之血氧變化，並對腦電波及血液動力學之關係進行初步探討。本研究共有16位受測者參與車道偏移駕車作業，在分析其與作業有關之腦電波及大腦皮質中帶氧與去氧血紅素的變化後，結果發現：在事件相關分析方面，所有腦波頻帶(δ、θ、α與β)在枕葉區域，都會隨著反應時間的增長而顯現非同步之腦波律動；而帶氧血濃度之活化程度也會隨著作業表現變差而有下降的趨勢。在基線方面的嘗試性分析則發現：枕葉的腦波能量在θ、α與β頻帶皆與反應時間的增加有顯著的正相關；帶氧血紅素的相對濃度雖會隨著疲勞程度上升而增加，但當疲勞過高無法繼續維持作業表現時，則明顯地減少。透過相關分析，枕葉腦電波之α及δ能量頻帶與帶氧血紅素間有一明顯之負相關，顯示出駕駛者疲勞程度可能對視覺處理區域上有一定的影響。

Mental fatigue is an important issue because it can be easily induced by prolonged task while not being noticed. Therefore, in this study, we will focus on the influence of fatigue during simulated driving on brain dynamics and hope to explore the relationship between electrical and hemodynamic features for further development in safety oriented supporting system. The event-related lane-departure driving task was implemented for 16 subjects with a combined electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) approach. In tonic analysis, we found that in theta (4-7 Hz), alpha (8-12 Hz) and beta (13-30 Hz) power strongly correlated as reaction time increased; the oxygenated hemoglobin (HbO) concentration increased as fatigue level rose but decreased when failed to perform the task well. Besides, phasic EEG demonstrated the event-related desynchronization (ERD) regarding deviation onset in the four power bands; HbO activation in phasic phase was declined as performance became worse. Furthermore, the negative correlations between tonic EEG delta, alpha power and fNIRS HbO oscillations were the most significant, thus suggesting that HbO might also be considered related to subjects’ mental fatigue level comparative to EEG alpha power.