Extended Reality Biofeedback for Functional Upper Limb Weakness: Mixed Methods Usability Evaluation

Area of Science:

• Neuroscience
• Rehabilitation Technology
• Human-Computer Interaction

Background:

• Functional neurological disorder (FND) disrupts the perception-action cycle, impacting motor control and agency.
• Extended reality (XR) neurotechnologies offer novel rehabilitation for FND, particularly functional limb weakness.
• Current rehabilitation methods need enhancement through integrated sensory feedback for motor retraining.

Purpose of the Study:

• To co-design and evaluate an XR-based biofeedback platform for upper-limb rehabilitation in FND.
• To incorporate multisensory (visual and haptic) feedback to improve motor retraining efficacy.
• To assess user requirements and usability of XR training tasks for FND patients.

Main Methods:

• Mixed methods design involving a Delphi survey (N=20) for user requirements and a co-design workshop (N=6).
• Evaluation of three XR tasks: VR relaxation, XR position feedback ('Hoop Hustle'), and XR force feedback (haptic robot-assisted).
• Usability assessed via System Usability Scale (SUS) questionnaires and qualitative thematic analysis.

Main Results:

• The XR position feedback task achieved excellent usability (4/6 participants >85 SUS).
• VR relaxation task showed polarized usability scores, with some participants experiencing motion discomfort.
• XR force feedback task had mixed usability, with significant individual variability and challenges for some participants.

Conclusions:

• The XR biofeedback platform is feasible and usable for FND rehabilitation, with XR position feedback being highly accepted.
• Personalization features and hardware refinement are crucial for optimizing XR rehabilitation tools.
• Future research should focus on enhancing usability, accessibility, and conducting larger clinical trials to evaluate effectiveness.