The objective is to determine if continuous use of TheraBracelet in the home has a clinically meaningful effect in chronic stroke survivors. The study design is a double-blinded randomized controlled trial. We will enroll 40 chronic stroke survivors with moderate hand impairment. Subjects will be randomly assigned to the treatment or control group (n=20 per group). All subjects will wear the TheraBracelet device on the paretic wrist for 8 hours/day every day during their normal daily activity for 1 month. The device will deliver vibration (treatment) or no vibration (control). Double-blinding is possible because the treatment vibration is imperceptible (i.e., subthreshold). Measures of neural plasticity, the amount of the paretic arm use in daily living, clinical hand function, biomechanical grip control, and self-reported abilities for activities of daily living will be assessed at baseline, once a week during the month of wearing the device, and for 3-month follow-up, allowing determination of the efficacy and persistence.