| 摘要: | 本研究試圖以腦波功率指標及腦波事件關聯電位P300成份波，評估噪音對人覺醒狀態、注意力及動作反應的影響。徵求20位男性受測者，年齡介於23～32歲之間進行受測，受測環境分為無噪音刺激與有噪音刺激下進行比較，本研究中在有噪音刺激下的環境所選用的噪音源正弦波(sine wave)純音，分別以音量80、85及90dBA；頻率250Hz、1000Hz及4000Hz計9種組合之純音為噪音源，在這些噪音環境下進行腦波及修改之旁側夾擊作業誘發之事件關聯電位測定，最後經由電腦紀錄行為反應及腦波相關數據。
研究結果顯示出在腦波測定方面，基本指數(basic indices) θ頻帶、α頻帶、β頻帶方面，θ頻帶在90dBA、250Hz，90dBA、1000Hz，90dBA、4000Hz均有顯著增加，而α頻帶則在三個頻率之噪音均顯著減少，β頻帶在各個噪音無顯著上差異變化；另外頻譜比例(ratio indices)指數θ/α、β/α、(α+θ)/β方面，θ/α在90dBA、1000Hz呈現顯著的上升，β/α在各個噪音環境下較無顯著性的變化，在(α+θ)/β也無顯著變化；事件關聯電位P300成份波結果的潛時與振幅大致呈現增加趨勢，尤其在90dBA、1000Hz均有顯著的增加，如F3、F4、FZ、FCz、T3、T4；修正後旁側夾擊結果失誤次數在85dBA、250Hz，85dBA、1000Hz，85dBA、4000Hz，90dBA、250Hz，90dBA、1000Hz、90dBA、4000Hz噪音下有顯著的增加，則反應時間在各個噪音源下的呈現減少現象；血壓方面則只在90dBA、1000Hz有顯著升高，但在各個噪音源下，心跳方面則無顯著的變化。
綜合以上實驗結果，發現在90dBA下的三種頻率(250, 1000, 4000Hz)噪音源下的腦波、失誤率、反應時間、血壓都有明顯增加情形，這表示覺醒水準與注意力減弱，其中又發現在90dBA、1000Hz噪音源下最為顯著，此項結果可提供噪音對生理指標影響參數及噪音控制管理之參考。
In this study, an attempt was made to evaluate human response to noise using electroencephalography (EEG) power indices and P300 component of event-related potential (ERP). Three different volume (80, 85, and 90 dBA) of noise sources including three frequencies of pure tone (250, 1000, 4000 Hz), were generated via function generator, amplified and output form speaker. Twenty subjects conducted EEG measures and acquired the ERP induced from a modified Flanker task under various sound environment including silence, and 9 noises conditions, 80dBA in 250, 1000, 4000Hz; 85dBA in 250, 1000, 4000Hz; 90dBA in 250, 1000, 4000Hz. Behavior response and EEG measurement were recorded on a personal computer. For EEG power, three basic indices and three ratio indices were calculated from preprocessed EEG signals. The heart beat and blood pressure of participant was measured after EEG measurement.
The basic indices of θ and α bands showed significant increase and decrease respectively between silence and noise conditions at 90dBA in 250Hz, 1000Hz, 4000Hz.
The basic index of β revealed no significant difference between silence and noise conditions at 90dBA in various frequencies. On the other hand, ratio indices of β/α and(α+θ)/β showed indistinct variation in different frequencies; The latency and the amplitude of ERP P300, exhibit an increased tendency, especially under noise condition at 90dBA in 1000Hz. For Eriksen flanker task, the number of mistake has significant increase at 85dBA in 250Hz, 1000Hz and 4000Hz; 90dBA in 250Hz, 1000Hz and 4000Hz, respectively. Moreover, reaction times were decreased in different noise conditions. For the blood pressure, only at 90dBA in 1000Hz has significant increase. However, the heartbeat revealed indistinct variation in different noise condition.
The study finds that EEG power, error ratio, reaction time and blood pressure has significant increase at 90dBA of three stimulate noise source compared with background noise, the results indicate the subjects’ arousal and attention levels were decreased, especially at 90dBA in 1000Hz the level decreased more than the other two frequencies. The study would offer the references for physiological indices of noise effect and management for no |
