The objective of this study is to determine if the acute effect of vibration from a smartwatch on hand function is comparable to the effect of an existing laboratory prototype.

More than 4 million stroke survivors in the U.S. suffer from post-stroke hand disability. As hands are our primary means of interacting with the world, post-stroke hand impairment diminishes stroke survivors' abilities for activities of daily living including self-care, hygiene, employment, and leisure, and lowers independence. Hand impairment is difficult to treat. Limited resources in rehabilitation services and financial burdens make it impractical to simply increase rehabilitation service visits within the current healthcare system.

One way to augment hand function recovery is peripheral sensory stimulation. Afferent input is a powerful driver of change in the motor cortex. Sensory stimulation has been shown to improve motor recovery in previous studies. In particular, promising preliminary results have been obtained by using imperceptible random-frequency vibration applied via a watch. However, the laboratory prototype device for delivering this vibration must be improved in the form factor for patient adoption.

Therefore, we developed an App that can be installed in smartwatches and control the vibrator within the smartwatch to deliver vibratory stimulation to the user. The objective of this study is to determine if the acute effect of vibration from a smartwatch on hand function is comparable to the effect of an existing laboratory prototype.

Inclusion Criteria:

• Age = 18 or older
• At least 6 months post stroke
• The ability to perform The Box and Block Test with a score greater than zero and less than 40.

Exclusion Criteria:

• Rigidity (Modified Ashworth Scale=5)
• Complete upper limb deafferentation
• Comorbidity (peripheral neuropathy, orthopaedic conditions in the hand that limit ranges of motion, premorbid neurologic conditions, compromised skin integrity of the hand/wrist due to long-term use of blood thinners)
• Language barrier or cognitive impairment that precludes following instructions and/or providing consent.