Motion sickness typically occurs when the body is subjected to externally imposed motions, but there are situations in which sickness occurs in the absence of imposed motion. We report a new and unanticipated instance of the latter. Subjects in a study of spontaneous standing postural sway sometimes reported dizziness and motion sickness. Reports of sickness were correlated with changes in postural sway. We consider possible implications of these findings for two current theories of motion sickness etiology: the sensory conflict theory and the postural instability theory.
Bibliographical noteFunding Information:
We thank Lawrence Hettinger, Benoı̂t Bardy and Gary Riccio for helpful discussions about data analysis and Alexis Salaman for assistance with data reduction and analysis. Supported in part by a grant from the National Science Foundation (SBR-9601351) to Thomas A. Stoffregen.
- Motor control