Motion sickness susceptibility and visually induced motion sickness as diagnostic signs in Parkinson's disease

Abstract

Postural instability and loss of vestibular and somatosensory acuity are among the signs encountered in Parkinson's disease (PD). Visual dependency is described in PD. These modifications of sensory input hierarchy are predictors of motion sickness (MS). The aim of this study was to assess MS susceptibility and the effects of real induced MS in posture. Sixty-three PD patients, whose medication levels (levodopa) reflected the severity of the pathology were evaluated, and 27 healthy controls, filled a MS questionnaire; 11 PD patients and 41 healthy controls were assessed by posturography using virtual reality. The levels of levodopa predicted visual MS (p=0.01), but not real induced MS susceptibility. PD patients did not experience postural instability in virtual reality, contrary to healthy controls. Since PD patients do not seem to feel vestibular stimulated MS, they may not rely on vestibular and somatosensory inputs during the stimulation. However, they feel visually induced MS more with higher levels of levodopa. Levodopa amount can increase visual dependency for postural control. The strongest MS predictors must be studied in PD to better understand the effect of visual stimulation and its absence in vestibular stimulation.