Clinical Evaluation of a Tongue-Controlled Wrist Abduction-Adduction Assistance in a 6-DoF Upper-Limb Exoskeleton for Individuals with ALS and SCI
New study shows tongue-driven wrist assistance cuts spillage by 72% in daily tasks
A team led by Juwairiya S. Khan at Aalborg University, in collaboration with clinical partners, tested the EXOTIC2 exoskeleton—a 6-degree-of-freedom (DoF) upper-limb device controlled via a tongue interface—on one individual with amyotrophic lateral sclerosis (ALS) and five with spinal cord injury (SCI). The study, published on arXiv and submitted to IEEE Transactions on Neural Systems and Rehabilitation Engineering, focused on the impact of adding wrist abduction-adduction (Ab-Ad) assistance during two activities of daily living: drinking from a cup and leveling a scratch stick.
Results showed significant improvements with wrist Ab-Ad enabled. Spillage during drinking dropped from 77.8% to 22.2%, and failed placements in the scratch stick task fell from 66.7% to 16.7%. Participants used task-specific subsets of their wrist range of motion, suggesting that functional control within a comfortable range matters more than maximal joint movement. Usability questionnaires indicated no increase in discomfort with the additional DoF, and users reported perceived gains in task performance. The study provides user-centered evidence that wrist Ab-Ad assistance enhances functional outcomes without compromising comfort, though effectiveness depends on task context and individual strategies.
- Six participants (1 ALS, 5 SCI) tested tongue-controlled EXOTIC2 exoskeleton with and without wrist abduction-adduction assistance
- Wrist Ab-Ad reduced spillage from 77.8% to 22.2% and failed placements from 66.7% to 16.7% during daily tasks
- No discomfort increase reported; users perceived better task performance with the additional degree of freedom
Why It Matters
Tongue-controlled exoskeletons with wrist assistance could restore independence for thousands with severe motor impairments.