注意偏誤(attentional bias)是維持失眠(insomnia)的重要認知因子之一,失眠者在睡前可能會對於內在(例如:身體感覺)和外在(例如:環境噪音)的睡眠相關刺激產生選擇性的注意偏誤,使其產生入睡困難或入睡時間延宕的不良後果。而且睡前的認知活動(例如:憂慮),將會使此注意偏誤更為明顯(Harvey, 2002)。然而,過去有關失眠者的注意偏誤研究較少,研究結果亦不一致。根據回顧,以點偵測作業探討失眠者注意偏誤的研究,不曾使用過睡眠相關威脅圖片為刺激,亦未考量到失眠者在入睡前的認知活動(例如:憂慮)對注意偏誤及失眠之影響。本研究的目的在於以點偵測作業,探討失眠者的注意偏誤歷程,並以睡眠相關威脅圖片與睡眠相關中性圖片作為刺激材料,再以憂慮引發作業(worry induction task),使受試者在實驗期間處於與睡前相似的認知激發(cognitive arousal)程度。研究中使用兩組受試者,分別是29位臨床失眠者與30位良好睡眠者,所有受試者皆必須完成兩次的點偵測作業(憂慮引發作業前與憂慮引發作業後)。本研究以年齡為共變項進行共變數分析,比較兩組受試者在憂慮引發作業前後,對於睡眠相關中性刺激與睡眠相關負向刺激的注意偏誤情形。結果顯示憂慮引發作業能夠引發部分受試者的憂慮感受。良好睡眠組受試者在認知激發狀態下,對於睡眠相關負向刺激出現投注注意的傾向,而臨床失眠組的受試者則是在認知激發狀態下對於睡眠相關負向刺激出現逃避的傾向;兩組受試者在兩次的點偵測作業中,對睡眠相關刺激皆無顯著的注意偏誤情形。此研究結果與過去對於失眠者的注意偏誤研究結果不完全一致,但與Mogg、Mathews與Weinman (1987)提出臨床焦慮者在認知歷程上的警覺-逃避(vigilance-avoidance)模式相似,顯示失眠者可能試圖以逃避策略調節負向刺激所帶來的不愉快情緒,造成睡眠歷程由自動化轉為意識控制歷程,進而促使失眠的持續。而良好睡眠者在認知激發狀態下的注意偏誤,則是一般個體面對威脅情境中的威脅刺激所出現的適應行為。本研究有助於了解失眠維持的病理機制,然而未來仍需對失眠者在不同時程下的注意偏誤情形與憂慮引發作業的修正更進一步的研究,並且嘗試將修正認知偏誤納入失眠者的治療當中。 關鍵詞:失眠、注意偏誤、點偵測作業、認知激發、憂慮、逃避。
Attentional bias may be one of the prominent factors for maintaining insomnia. People with insomnia may show selective attention to either internal cues (e.g. body sensation) or external sleep-relevant stimuli (e.g. environmental noise), result in multiple sleep complaints. In addition, cognitive activities (e.g. worry) before sleep may amplify the effect of attentional bias(Harvey, 2002). Few studies have investigated attentional bias in insomnia via dot-probe task. However, the results of these studies are inconsistent. According to the review, the using of sleep-related negative pictures and the effect about presleep cognitive activities (e.g. worry) are not be considered in these studies. The present study aimed to investigate in whether individuals with insomnia show an attentional bias toward neutral and negative sleep-related picture stimuli in the dot-probe task. Furthermore, in order to increase the level of participant's cognitive arousal, we use the worry-induction manipulation .Twenty-nine people with insomnia and thirty good sleepers were asked to complete twice random dot-probe task before and after the worry-induction task respectively. An attentional bias index were subjected to a analysis-of covariance(ANCOVA), with age as an covariate. Results indicate that worry-induction task could make some of the participants worried. And good sleepers demonstrated a tendency towards negative sleep-related attentional bias , while insomnia individuals showed a tendency to attentional avoidance to negative sleep-related stimuli. There was no significant attentional bias toward neutral sleep-related stimuli in both groups. Our findings are not entirely consistent with previous studies in insomnia, but line with the vigilance-avoidance model in clinical anxiety (Mogg, Mathews, & Weinman, 1987). Which suggests that insomnia individuals may attempting to strategically regulated negative affect via attentional avoidance. Thus, this attempt turns automatic sleep process into conscious control, and insomnia becomes sustained. On the other hand, the good sleepers prioritizing of threat cues in a threat situation is adaptive behavior. The results of this study improve our understanding of the mechanism that maintains insomnia. Further work, time- course of attentional bias in insomnia individuals, and modify the worry-induction task, is still necessary. Moreover, try to use the Attention Bias Modification Treatment (ABMT) into the therapy of insomnia. Key words: insomnia, attentional bias, dot-probe task, cognitive arousal, worry, avoidance.