Proof-of-concept for Use of Transcutaneous Spinal Stimulation (TSS) With the ExaStim® Stimulation System in Adults With Chronic Ischemic Stroke (EXA2611)

Week 0 includes one baseline assessment session and two to three parameter optimization sessions. Participants will attend 2 rehabilitation sessions per week for 12 weeks, for a total of 24 sessions. Each session will provide ~60 minutes of rehabilitation, including at least 45 minutes of active stimulation delivered concurrently with therapeutic activity. The therapist will select activities according to participant goals, affected-arm capacity, movement quality, fatigue, pain, and cardiovascular tolerance. Each session will emphasize repeated practice, functional strength or functional practice. Missed sessions will be rescheduled within the 12-week period if appropriate.

Separate assessment visits occur in Weeks 4, 8, 12, and 17 and may last approximately one to two hours with rest breaks.

The final evaluation is scheduled for Week 17. All assessments will use the same participant-specific baseline date as the time reference, and actual visit dates and intervals will be recorded.

The Fugl-Meyer Upper Extremity Assessment is a 66-point stroke-specific scale measuring sensorimotor recovery across reflexes, synergies, isolated movements, wrist stability, hand function, and coordination. Each item is scored from 0 to 2 based on performance completeness and compensation. Changes exceeding the minimal clinically important difference (typically 4 to 10 points) reflect meaningful gains in motor control and functional independence.

The Action Research Arm Test (ARAT) is a 57-point, 19-item observational assessment measuring upper extremity functional capacity and dexterity across grasp, grip, pinch, and gross movement subscales. Each task is scored from 0 to 3 based on completion time, movement quality, and compensation patterns. A score change exceeding the minimal clinically important difference (typically 6 to 10 points) indicates meaningful improvement in real-world arm and hand function.

The Box and Block Test measures unilateral gross manual dexterity by recording the number of one-inch wooden blocks a patient can transport over a partition from one compartment to another in 60 seconds. The scoring system simply counts the total number of successfully transferred blocks per hand, with multiple blocks carried simultaneously counting as a single point. An increase in score exceeding the minimal detectable change (typically around 6 or more blocks for stroke populations) indicates a true, statistically significant improvement in hand transport speed and unilateral functional capacity.

The Nine-Hole Peg Test (9HPT) measures manual dexterity and finger-movement speed by recording the total seconds required for a patient to place and subsequently remove nine pegs into a board. Scoring is based on timing (seconds per trial), where lower times indicate better performance, or converted to "pegs per second" for rate-based analysis. A change in score exceeding the minimal detectable change (typically a reduction of several seconds or roughly 15 to 20% from baseline) indicates a statistically significant improvement in fine motor speed and coordination.

The Visual Analog Scale (VAS) measures subjective symptom intensity, such as pain, using a continuous horizontal line anchored by "no symptom" at one end and "worst imaginable symptom" at the other. Patients mark their perceived level, and the score is quantified from 0 to 10, where higher numbers reflect greater symptom severity. A score change exceeding a 2 point change indicates a clinically meaningful improvement or worsening of the patient's symptom experience.

The Motor Activity Log (MAL) is a structured, semi-structured clinical interview where stroke survivors rate their actual daily arm use in terms of Amount of Use (AOU) and How Well (HW) they perform 30 real-world functional tasks. Each item is scored on a 0-to-5 ordinal scale, ranging from 0 (not used at all) to 5 (used as well as before the stroke), with final scores derived from the average of all items. A change in score exceeding the minimal clinically important difference (typically around 1.0 to 1.1 points for either subscale) indicates a meaningful, real-world translation of laboratory motor gains into spontaneous, daily spontaneous arm use.

The Stroke Impact Scale (SIS) is a patient-reported outcome measure evaluating health-related quality of life across eight domains, including strength, hand function, ADLs, mobility, communication, emotion, memory, and participation. Each item is scored on a 1-to-5 ordinal scale, which is then transformed into a standardized 0-to-100 scale per domain, where higher scores reflect better recovery and fewer stroke-related limitations. A score change exceeding the minimal clinically important difference (typically ranging from about 3 to 17 points depending on the specific domain) indicates a statistically reliable and meaningful improvement in the patient's perceived recovery and daily well-being.

Modified Ashworth Scale (MAS), it grades spasticity and muscle hypertonia on a 6-point ordinal scale from 0 (no increase in tone) to 4 (rigid limb in flexion or extension). A decrease in score indicates a reduction in passive resistance and muscle hypertonia, reflecting successful management of spasticity.