Virtual reality as a tool to modulate attention and motor activity in functional tremor patients: a pilot study

This is the authors' abstract. We don't add key points for this paper.

Functional tremor is characterized by abnormal attention allocation to the affected body part. The present study aimed to investigate the potential of virtual reality (VR) to guide attentional shifts in patients with functional tremor. Nine patients with functional tremor and nine healthy, matched controls performed various hand movement tasks in VR using their less affected hand or, in the case of the controls, their non-dominant hand. Their virtual hands were depicted either as realistic hand models or abstract hand models (i.e., skeletal hands) to modulate attentional and emotional states. Outcome measures included neuronal responses assessed via electroencephalography (EEG), reaction times, and movement activity of the more affected hand measured using electromyography (EMG). Using the more attention-capturing skeletal hand model resulted in faster reaction times in functional tremor patients during a simple button-pressing task and elicited more pronounced event-related potentials (P300) in the EEG, indicating stronger attentional processing. During a more complex grip task, the skeletal hand model led to greater activation of hand motor areas in the brain when the more affected hand was depicted as an inactive resting hand with no movement, compared to a condition where the inactive hand was not visible in the VR scenario. Additionally, in the condition where the inactive skeletal hand model was visible, the patient group exhibited stronger active inhibition of motor brain areas following the movement task compared to healthy controls. Participants also demonstrated fewer involuntary movements of the inactive resting hand (the tremor hand in the patient group) when the inactive skeletal resting hand was visible. Importantly, the VR interaction did not result in negative side effects, such as cybersickness. These findings suggest that the design of VR scenarios can effectively shift attention in functional tremor patients and may serve as a basis for future VR-based interventional strategies.