This article is part of a series on Cybersickness, edited by Tohru Kiryu, Richard HY So.

Research

Relationships between sensory stimuli and autonomic nervous regulation during real and virtual exercises

Tohru Kiryu^1,2 , Atsuhiko Iijima³ and Takehiko Bando^2,3

¹  Graduate School of Science and Technology, Niigata University, 8050 Ikarashi-2, Nishi-Ku, Niigata 950-2181, Japan

²  Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi-2, Nishi-Ku, Niigata 950-2181, Japan

³  Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi-dori, Chuo-Ku, Niigata 951-8520, Japan

author email corresponding author email

Journal of NeuroEngineering and Rehabilitation 2007, 4:38doi:10.1186/1743-0003-4-38

Published:	6 October 2007

Abstract

Background

Application of virtual environment (VE) technology to motor rehabilitation increases the number of possible rehabilitation tasks and/or exercises. However, enhancing a specific sensory stimulus sometimes causes unpleasant sensations or fatigue, which would in turn decrease motivation for continuous rehabilitation. To select appropriate tasks and/or exercises for individuals, evaluation of physical activity during recovery is necessary, particularly the changes in the relationship between autonomic nervous activity (ANA) and sensory stimuli.

Methods

We estimated the ANA from the R-R interval time series of electrocardiogram and incoming sensory stimuli that would activate the ANA. For experiments in real exercise, we measured vehicle data and electromyogram signals during cycling exercise. For experiments in virtual exercise, we measured eye movement in relation to image motion vectors while the subject was viewing a mountain-bike video image from a first-person viewpoint.

Results

For the real cycling exercise, the results were categorized into four groups by evaluating muscle fatigue in relation to the ANA. They suggested that fatigue should be evaluated on the basis of not only muscle activity but also autonomic nervous regulation after exercise. For the virtual exercise, the ANA-related conditions revealed a remarkable time distribution of trigger points that would change eye movement and evoke unpleasant sensations.

Conclusion

For expanding the options of motor rehabilitation using VE technology, approaches need to be developed for simultaneously monitoring and separately evaluating the activation of autonomic nervous regulation in relation to neuromuscular and sensory systems with different time scales.