Associations Between Perceived Discomfort, Postural Control Alterations and Disability in People with Multiple Sclerosis Exposed to Immersive Virtual Reality

The current availability of low-cost immersive Virtual Reality (VR) systems, opens interesting perspectives for neurorehabilitation of people with Multiple Sclerosis (pwMS). However, it is known that immersive VR can trigger the onset of unpleasant effects such as dizziness, headache, nausea, disorientation and balance alterations. Since MS is associated with similar symptoms, it appears important to clarify the role of disability in exacerbating such possible negative effects. To this aim, we combined instrumental data on postural sway (using Center of Pressure COP data) and perceived discomfort in 56 pwMS and 33 unaffected individuals before and after a 10-minute session of immersive VR consisting in a simulated rollercoaster. The results indicate the presence of temporary impairments of postural control in terms of significantly increased sway area in presence of visual input. Interestingly, when the visual input was removed, a reduction of sway area and COP path length in pwMS with mild-moderate disability and unaffected individuals was observed, thus suggesting the existence of a sort of "balance training" effect. All participants complain about blurred vision and nausea after the VR session. In pwMS, changes in most postural sway parameters originated by the VR session were found moderately correlated with changes in SSQ symptoms scores, particularly those of the disorientation domain. Such findings seem to indicate that a short immersive VR session originates contrasting effects on postural control of pwMS, according to their disability level and to the presence of the visual sensory input. At the same time, participants relevant negative symptoms especially in the disorientation domain. Although immersive VR can be generally considered safe and tolerable, the use in pwMS requires the definition of specific guidelines on aspects like exposure time, posture to assume during use and assessment of possible adverse effects to guarantee efficacy of the treatment, safety and comfort.