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Can we help the injured nervous system relearn skilled hand control, without surgery?
 

This project asks a simple question: if we gently stimulate the brain and the spinal cord at the same time, can we boost short-term recovery of hand and arm function more than stimulating either one alone, or using a sham condition?

To test this, we compare four sessions: brain stimulation only, spinal stimulation only, both together, and sham.

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Why this matters

After a stroke or a spinal cord injury, the intention to move may still be there, but the signals can have trouble traveling through damaged pathways.

Rehabilitation helps, but many people reach a plateau, especially for fine hand function.

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The idea in one sentence

We pair two non-invasive stimulation methods, tDCS (a weak current on the scalp) and tSCS (stimulation through the skin over the spine), while the person performs a motor task combined with a cognitive task, and we compare the effects against control conditions.

You can think of it like tuning the same movement circuit at two points, one in the brain and one in the spinal cord, to make useful signals easier to pass through.

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Overview of the brain spine stimulation project. Muscle activity reading sensors (shown as black blocks on right hand), green is the area where we place the stimulating electrodes (shown as red rectangles).  The blue area shown in spine is involved in sending signals between the brain and the arm (including the hand). In healthy people the stimulation just changes the muscle signals a little bit (cyan spheres). These normal signals that reach the arms are reduced after spinal damage (SCI) and stroke. Using the electrodes on brain to stimulate (red patches on scalp) and/or magnetic stimulation can help restore the normal signals to the arm and hand. 

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What happens in the study

The study is designed so the same participant can go through multiple stimulation conditions, with a rest period between sessions.
Participants are in three groups, healthy controls, people with spinal cord injury, and people after stroke, and the stimulation sessions are done in the two neurological groups.

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It is all about personalized stimulation

Because anatomy differs across people, and injuries differ even more, we first map the brain and spinal cord so stimulation can be targeted for each participant.
Across the study, the participant completes these visits:

  • MRI scan visit: brain and upper spinal cord scans are used to plan stimulation targets and estimate lesion volume (for stroke or spinal cord injury).

  • Spinal mapping, passive: brief spinal stimulation pulses are delivered at different levels while muscle activity is recorded from the arm.

  • Spinal mapping, active: spinal stimulation is tested across different frequencies during grasping tasks while muscle activity and grasp performance are recorded.

  • Brain mapping: magnetic stimulation is used to find the best motor cortex target by recording muscle responses, then a short brain stimulation block is applied and the measurements are repeated to see immediate changes.

  • Four stimulation sessions (spinal cord injury and stroke groups only): each session tests one condition (brain only, spinal only, combined, sham), includes at least 2 days between visits, and uses a 20-minute cognitive plus motor task with an upper-limb rehab robot in virtual reality; sham uses brief ramp up and ramp down to mimic skin sensation, and participants report whether they think stimulation was real or sham.

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What we measure (in plain language)

The main question is: does hand and arm function improve more after one approach than another?
We measure function, track brain and nerve signals, and test whether imaging helps predict who benefits most.

  • Functional measure: a clinical hand and arm test that captures sensation and grasp quality, measured before and after each session, then compared across conditions.

  • Possible mechanisms: measures based on magnetic stimulation that estimate how strongly the brain can activate arm and hand pathways.

  • Cognitive changes: attention and working-memory tests before and after each session to see whether cognitive-motor performance shifts alongside movement.

  • Imaging predictors: lesion volume from MRI (brain for stroke, spinal cord for spinal cord injury) used in models that test who responds best to which stimulation.

  • Feasibility and tolerability: a short questionnaire after sessions to track comfort and practicality across visits.

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Safety and what success looks like

Sessions include monitoring, including cardiovascular measures and muscle recordings, and stimulation is stopped if concerning symptoms or abnormal values appear.
Success would look like a reliable improvement in hand and arm measures after the combined stimulation, plus better signals in the physiology measures, and clear clues from MRI or brain measurements about who benefits most.

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Takeaway

This study tests whether combining brain and spinal stimulation during a cognitio-motor training task can unlock extra gains beyond standard single-site stimulation.
If it works, it could point to a practical, personalized way to boost upper-limb rehabilitation without invasive procedures.​

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