Non-invasive Electrical Spinal Cord Stimulation To Restore Upper Extremity Function in Multiple Sclerosis

A two-channel transcutaneous spinal cord stimulator (SCONE, SpineX, Inc.) will deliver non-invasive electrical stimulation during hand therapy sessions. For each session, two self-adhesive hydrogel electrodes will be positioned along the midline of the C3-C4 and C6-C7 spinous processes over the skin as cathodes to stimulate the cervical spinal cord at two vertebral levels. An additional pair of electrodes will be symmetrically positioned over either the iliac crests or shoulders, functioning as anodes. The electrical current employed for the transcutaneous spinal cord stimulation is biphasic, featuring a 1-millisecond pulse width, a base frequency of 30 Hz, and an overlapping frequency of 10 kHz. Stimulation intensity will range from 0 to 120 milliamperes (mA), with incremental increases of 5 mA until reaching the level that facilitates voluntary movement. The stimulation amplitude will be fine-tuned for each specific activity based on the therapist's observation.

The hand therapy program is comprised of intensive, progressive, functional task practice following a standardized protocol. The protocol consists of repetitive activities of gross upper limb movement, isolated finger movements, bimanual task performance, simple and complex pinch, and grip performance. Several activities with various difficulty levels are designated for each category, and the participant will perform 1-2 activities within each category in each training session. Activities are chosen according to the participant's ability, interests, and needs and are modified as function progresses over time.