Pre-Validation of a Virtual Reality Tool to Quantify the Severity of Friedreich's Ataxia

Existing clinical scales to evaluate the severity of Friedreich's ataxia (FA) impairment rapidly reach a plateau when patients lose the ability to walk, and they rely on the examiner to quantify ataxia. Therefore, more objective tools are necessary to complement the neurological examination and distinguish subtle changes in ataxia over time. Using virtual reality (VR), we aim to develop precise tools to measure the progression of FA. The purpose of this study was to evaluate a series of 5 different upper limb tasks in VR with FA patients in order to determine how well they were tolerated, if they allow to distinguish FA patients from a control group, and if they correlate to clinical measures. Twelve FA patients and 9 healthy partici-pants underwent traditional assessment of upper limb function and of FA severity (patients only), performed the series of five VR task, and completed a subjective evaluation. Only 6 out of 12 FA patients were able to successfully complete all tasks, primarily due to the challenges associated with manipulating the controllers for patients with advanced stages of FA. Different performance metrics of the tasks were significantly different between groups and had strong correlations to a clinical assessment scale. All participants reported very low simulator sickness and a high level of virtual presence. The results of this study demonstrate the feasibility of using VR with FA patients, although adaptation of the technology may be necessary for those with more severe impairments.