在資訊導向的社會裡， 終端機(visual display terminal; VDT)作業廣泛的使用在工作場所及辦公室， 某些勞工如航管人員及工廠製程控制人員通常須以坐姿長時間專注進行心智活動，因此在工作場所中，常見終端機作業導致之心智疲勞。在先前研究，我們使用腦波功率指標及事件關聯電位(event-related potential; ERP) P300 成分波進行工作負荷之觀察研究。功能性近紅外線光譜 (functional near-infrared spectroscopy; fNIRS)最近已發展為可用在現場試驗之非侵入性量測設備，此種技術以往只有在其他神經造影模組，如功能性磁振造影(fMRI)方可行。在本計畫共同主持人最近設置之近紅外線光譜儀的協助下，本研究團隊擬進一步探究大腦攜氧/脫氧血紅素變化，並結合覺醒水準、認知功能，來評估長時間終端機作業造成之心智疲勞。本研究擬分二年執行，第一年：以功能性近紅外線光譜評估與工作記憶(working memory)相關之各種心智負荷(mental workload)水準之偵測與區辨能力，徵募之受測者以坐姿佩戴測試專用帽，其上裝置有測試光纖在頭部之前額及枕部(視覺區)，受測者須對出現在電腦螢幕上之正六面體之五個面計算每種顏色出現的次數，作為負荷測試作業來進行認知功能活化的型態，出現在電腦螢幕上之正六面體之轉動及顏色分布係以電腦軟體控制。第二年：結合近紅外線光譜及腦波分析評估終端機作業心智疲勞之歷程。分析心智作業造成心智疲勞歷程之fNIRS 光學強度變化及腦波能量頻譜、腦波事件關聯電位間的關係，來評估受測者之心智疲勞狀況，並使用NASA 作業負荷指標量表(NASA-Task Load Index (TLX) rating scale)，受測者自行記錄評估作業負荷，以主觀評估心智疲勞狀況，與客觀之生理量測數據交叉比對。在增加認知負荷有關之大腦部位之血液氧化作用變化，可用以區辨不同心智負荷水準，藉由fNIRS 在時間及空間有好的解析度之特點，量測大腦活躍區之氧消耗及代謝情況，結合腦波事件關聯電位及頻譜分析以評估人之心智活動狀態及覺醒水準，結合此兩種分析技術可獲得更多之疲勞所伴隨之生理變化資訊，本研究所提供之技術從職業風險管理、生產效能及職業衛生的觀點，對勞工疲勞狀態的評估有極高之應用潛力，可提供職業安全衛生有關心智疲勞管理之參考。 As the progression towards highly technological and information-oriented society, the uses of computers or visual display terminals (VDT) in modern society are omnipresent. Some workers, e.g. aviation control and factory process personnel, require prolonged vigilance and mental activity with sedentary work, fatigue caused from VDT task frequently occurs in the workplace. In our previous study, we have utilized electroencephalography (EEG) power indices and P300 component of event-related potential (ERP) to observe the work load. Recent development of functional near-infrared spectroscopy (fNIRS) has enabled the noninvasive measurement of brain hemodynamic changes in a field test environment which was only possible in other neuroimaging modalities, such fMRI. With the assist of newly setup NIRS by co-PI, it becomes feasible to explore the changes in oxy/deoxyhemoglobin incorporated with arousal level cognitive functions to evaluate mental fatigue induced during a prolonged VDT task. The first year of this two-year project, we aim to detect and discriminate varied levels of mental workload involving working memory from the recording of hemodynamic data during different workload conditions. The recruited subject will be seated with specific design of helmet holding the optical fibers mounted on the subject’s head located at the forehead or at the visual cortex area. The cognitive activation paradigm is workload testing task, which requires individuals to count the total number of color titles in five cube sides from a three-dimensional cube generated by computer software. The second year, we will evaluate the process of mental fatigue in VDT task by incorporating fNIRS and EEG. The hemodynamic changes from fNIRS and the power spectrum and event relate potential (ERP) from EEG can be analyzed. In addition to, the subjects will report the NASA-Task Load Index (TLX) rating scale at different mental workload condition to estimate subjectively the degree of mental fatigue. The NASA-Task Load Index is used to correlate with the observations from fNIRS and EEG. It is expected that changes in blood oxygenation in relevant areas of the brain should be associated with increasing cognitive workload which can be used to distinguish different levels of mental workload. By taking advantage of the high temporal and spatial resolution of fNIRS data, we can acquire more physiological information owing to mental fatigue by measuring the oxygenation and metabolism of active area of cortex incorporated the spectrum power and ERP from EEG for mental activity and arousal level. The method proposed in this study is potentially applicable to the evaluation of the fatigued state of workers and to the management of mental fatigue from the viewpoints of occupational risk management, productivity, and occupational health.
