緒論：根據姿勢不穩定理論，動暈的發生是因為個體動態環境中，長時間無法控制姿勢穩定所致。本研究探討交通器上閱讀發生動暈之議題，檢驗移動環境中進行視覺搜尋之動暈與姿勢控制。方法：參與者為高與低動暈易感者各30名，隨機分派至外增視覺移動、支撐面移動、座艙模擬等不同動態環境組別，以坐姿注視前方或執行視覺搜尋。實驗過程中收集頭部及移動室之動作，用以分析頭部擺動之前後軸向與左右軸向變異性。結果：顯示，執行視覺搜尋時，頭部擺動之左右軸向變異性增加。在座艙模擬環境中，頭部擺動變異性顯著高於外增視覺移動及支撐面移動環境。實驗中有10%－40%的高動暈易感者在動態環境中產生動暈。視覺搜尋工作後動暈症狀嚴重程度顯著高於單純注視工作，而視覺搜尋與注視工作的動暈發生率相同。在動態環境中閱讀發生動暈者，其身體擺動變異性高於未發生動暈的低易感者。結論：與閱讀相似的視覺搜尋工作，並不會引發較高動暈發生率，而是引發較強烈的動暈症狀。動暈易感性、不同動態環境、及視覺工作會影響姿勢擺動變異性。在動態環境中執行視覺搜尋，動暈者在動暈前姿勢較不穩定。

Introduction: According to postural instability theory, motion sickness is result from long-term instability when controlling posture in moving environment. This study aimed at the issue of motion sickness while reading in transportations. Postural control and motion sickness while visual searching in moving environments were investigated. Methods: Thirty adults with higher and thirty with lower motion sickness susceptibility (MSS) were recruited as participants. They were randomly assigned to imposed visual motion, moving support surface, and cabin simulation groups of moving environments. Participants sat and performed visual search or looked straight in static and moving environments. Movement of head and moving room were collected to analyze variables of body sway variability in anterior-posterior (AP) axis and mediolateral (ML) axis. Results: ML variability of head motion is significantly higher in visual search task than that in looking task. Body sway variability is significantly higher in cabin simulation than in imposed visual motion and moving support surface. There were 10% - 40% of higher MSS subjects reported motion sickness when exposure to moving environment. Compared to looking task, motion sickness symptoms severity is higher after visual search. However, motion sickness incidence has no difference between visual search and looking task. When visual searching in moving environments, body sway variability was higher for participants who reported motion sickness compared to those who did not. Conclusion: Visual search task that is similar to reading did not induce higher motion sickness incidence, but induced higher symptoms. Body sway variability can be affected by motion sickness susceptibility, moving environments, and visual tasks. Participants who reported motion sickness when visual searching in moving environments showed higher body sway variability before the onset of motion sickness.