title: Effect of predictive sign of acceleration on heart rate variability in passive translation situation: preliminary evidence using visual and vestibular stimuli in VR environment.
abstract: OBJECTIVE
  We studied the effects of the presentation of a visual sign that warned subjects of acceleration around the yaw and pitch axes in virtual reality (VR) on their heart rate variability.
  
  
  METHODS
  Synchronization of the immersive virtual reality equipment (CAVE) and motion base system generated a driving scene and provided subjects with dynamic and wide-ranging depth information and vestibular input. The heart rate variability of 21 subjects was measured while the subjects observed a simulated driving scene for 16 minutes under three different conditions.
  
  
  RESULTS
  When the predictive sign of the acceleration appeared 3500 ms before the acceleration, the index of the activity of the autonomic nervous system (low/high frequency ratio; LF/HF ratio) of subjects did not change much, whereas when no sign appeared the LF/HF ratio increased over the observation time. When the predictive sign of the acceleration appeared 750 ms before the acceleration, no systematic change occurred.
  
  
  CONCLUSIONS
  The visual sign which informed subjects of the acceleration affected the activity of the autonomic nervous system when it appeared long enough before the acceleration. Also, our results showed the importance of the interval between the sign and the event and the relationship between the gradual representation of events and their quantity.
authors: Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, Japan. h.watanabe@aist.go.jp
authors: Hiroshi
authors: H
authors: Watanabe
authors: Wataru
authors: W
authors: Teramoto
authors: Hiroyuki
authors: H
authors: Umemura
mesh_terms: D000054:Acceleration; D000328:Adult; D019317:Evidence-Based Medicine; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010865:Pilot Projects; D011930:Reaction Time / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D014584:User-Computer Interface