動態環境中閱讀之動暈與行動因應

Abstract

姿勢控制是個體－環境系統中，知覺－行動配連的作為，藉身體擺動產生的視覺與機械本體覺訊息，控制姿勢穩定。基於生態觀點，Riccio and Stoffregen (1991) 提出姿勢不穩定理論，認為姿勢不穩定是動暈發生的原因。本研究針對搭乘交通器閱讀容易動暈之議題，探討個體於動態環境中閱讀時的姿勢控制與動暈。本研究招募高與低動暈易感者各30名為參與者，並以移動室與移動表面操弄視覺與機械本體覺訊息，分為3種動態環境組別：外增視覺移動組、支撐面移動組、與座艙模擬組。參與者在實驗中處於靜態與動態環境，進行自然坐姿或坐姿閱讀工作。實驗中擷取並記錄個體的頭部與軀幹移動、移動室移動等資料，進一步分析身體擺動、頸部控制、以及人－環境配連等變項。研究結果顯示，閱讀時頭部擺動之左右變異會增加，有11% 至 40% 高動暈易感者曝露於動態環境後發生動暈，但低動暈易感者皆未產生動暈。座艙模擬環境下，身體擺動最大，其次為支撐面移動，而視覺移動情境則有較小的身體擺動。各環境與閱讀情境之動暈發生率皆相同，在閱讀試作中產生動暈者，身體擺動在試作後期高於未動暈之低動暈易感者，支持姿勢不穩定理論。Postural control is an act resulting from perception-action coupling in the individual- environment system. People control their posture by picking up visual and mechanical proprioception information that is generated from body sway. Based on Ecological Psychology perspective, Riccio and Stoffregen(1991) proposed postural instability theory and regarded postural instability as the major factor of motion sickness. This study aimed at the issue of motion sickness while reading in transportations. Postural control and motion sickness were investigated while reading in dynamical environments. Thirty adults with higher motion sickness susceptibility (MSS) and thirty with lower MSS were recruited as participants. Moving room and moving surface were used to manipulate the visual and mechanical proprioception information. Three dynamic environment groups were: 1) imposed visual motion group; 2) moving support surface group; and 3) cabin simulation group. Participants sat only or read simultaneously in static and dynamic environments. Motions of participants’ head and trunk, as well as that of moving room were collected. Motion data was analyzed to verify the variables of body sway, neck control, and individual-environment coupling. The findings showed that head motion variability in ML-axis would increase as individual read. After exposure to dynamic environments, motion sickness was found by 11% - 40% of higher MSS individuals, but was not found by any lower MSS indiviual. The largest body sway was observed in cabin simulation, then in moving support surface, and the smallest one was in imposed visual motion environment. The motion sickness incidence did not differ among environments and reading conditions. Higher body sway was found in participants who reported motion sickness after reading compared to those who did not. The findings in this study confirmed postural instability theory.