Presentation description

The long-term goal of this research is to improve the quality of life for stroke patients by developing a wrist-wearable sensory stimulation device to help reduce post-stroke hand spasticity. Each year, about 800,000 people in the U.S. experience a stroke, and approximately 43% develop spasticity-a condition where muscles become stiff and difficult to control. Previous studies have shown that non-invasive sensory stimulation, such as vibrotactile stimulation (VTS), can reduce hand spasticity. However, VTS requires actuators to be placed at the fingertips, limiting hand dexterity during daily activities. This study explores an alternative method: transcutaneous electrical stimulation (TENS), which delivers sensory feedback to the fingers via currents applied at the wrist. We developed and tested a multi-condition stimulation protocol to evaluate the effects of wrist and fingertip stimulation on spasticity reduction in post-stroke patients. Four stimulation conditions were applied: vibrotactile stimulation on all fingertips (VTSA), on a subset of fingertips (VTSS), transcutaneous stimulation at the wrist (TENS), and a sham condition (CTRL). Spasticity was measured using the Modified Ashworth Scale (MAS) at three time points: before stimulation (T0), immediately after (T1), and after a rest period (T2). Preliminary data from seven participants showed the following average changed in MAS scores (mean ± standard deviation): for TENS, -0.83 ± 1.17 between T1 and T0, and -1.17 ± 0.75 between T2 and T1; for VTSA, -0.17 ± 0.75 from T0 to T1, and -0.33 ± 1.03 from T1 to T2; for CTRL, -0.83 ± 0.75 between T1 and T0, and -0.5 ± 0.55 between T2 and T0. Future work will include formal statistical analysis of the full sample (n = 15) to assess the significance of these changes. These findings suggest that non-invasive wrist-based sensory feedback may reduce spasticity and support the development of wearable technologies for managing motor dysfunction in conditions like spinal cord injury or cerebral palsy.