Sensory Stimulation to Enhance Hand Function Post Stroke

Stroke survivors suffer from persistent hand impairment that diminishes their functional
abilities and independence, despite multiple courses of rehabilitation. Sensory stimulation
can prime central excitability to increase therapy outcome. The investigators developed a new
sensory stimulation technique for the hand, using imperceptible vibration applied to the
wrist skin. Wearable devices with a vibrating function are low cost and can be easily adopted
for rehabilitation purposes to impact a wide range of patients with sensorimotor impairment.
Despite the potential for clinical benefits and easy adoption for high impact, knowledge
about the long-term efficacy of this new sensory stimulation technique and its underlying
mechanism is limited.

The objective of this pilot project is to assess the impact of the novel sensory stimulation
technique the investigators have developed in enhancing outcomes of 2-week hand therapy as
well as the central nervous system responsiveness in chronic stroke survivors. This impact
will be assessed in a double-blind stratified randomized controlled trial. The hypothesis is
that (a) improvement in hand function will be greater for the experimental group receiving
the wrist subthreshold vibrotactile stimulation during therapy compared with the control
group who will wear the device with no vibration (placebo). (b) Improvement in hand function
is associated with neurophysiologic measures of central nervous system responsiveness.
Clinical and neurophysiologic evaluations will be performed before, immediately after, and 2
weeks after a 2 week standardized hand therapy program with the subthreshold vibrotactile
stimulation to the wrist vs. sham. The investigators preliminary studies demonstrated an
acute effect of the remote subthreshold vibrotactile stimulation on immediately improved
clinical sensory and motor function of the hand as well as cortical excitability in healthy
young adults and chronic stroke survivors in single-session studies.

The expected outcome is the demonstration that the subthreshold vibrotactile stimulation at
the wrist enhances hand function, not only immediately (preliminary studies) but also as a
complement to therapy in chronic stroke survivors. This project will also provide preliminary
insights regarding plasticity occurring with hand therapy augmented by the subthreshold
vibrotactile stimulation. This research will have a positive impact by leading to a portable
sensorimotor orthosis worn at the wrist to improve hand function for patients with
sensorimotor deficits.

Inclusion Criteria:

- mild to moderate impairment in upper extremity function

Exclusion Criteria:

- cognitive dysfunction

- stroke<3 months

- treatment with botulinum toxin in the affected arm within 3 months of start of study