Sensory Stimulation to Enhance Hand Function Post Stroke

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 hand therapy as well as the central nervous system responsiveness in chronic stroke survivors.

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.

The control group will wear the vibration device with no vibration. Both groups cannot feel the vibration since the vibration intensity is set below the perceptible level. The vibration device is a generic, commercially-available, vibrator, not particularly used for this peripheral skin stimulation purpose.

Change in hand motor function as measured by the Box and Block Test. This test measures the number of blocks that a participant moved in a minute. The scale ranges from 0 to a positive number. Higher numbers represent better outcomes.

post intervention (about a week after the 2-week therapy, or week 3) compared to baseline (before 2-week therapy)

Change in hand motor function as measured by the Box and Block Test. This test measures the number of blocks that a participant moved in a minute. The scale ranges from 0 to a positive number. Higher numbers represent better outcomes.

follow up (at least 2 weeks after the 2-week therapy, or week 5) compared to baseline (before 2-week therapy)

change in hand motor function as measured by the Wolf Motor Function Test hand items time. This test measures time to complete movements in seconds. More negative values represent greater reduction in time and thus better outcomes.

post intervention (about a week after the 2-week therapy, or week 3) compared to baseline (before 2-week therapy)

change in hand motor function as measured by the Wolf Motor Function Test hand items time. This test measures time to complete movements in seconds. More negative values represent greater reduction in time and thus better outcomes.

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

Seo NJ, Woodbury ML, Bonilha L, Ramakrishnan V, Kautz SA, Downey RJ, Dellenbach BHS, Lauer AW, Roark CM, Landers LE, Phillips SK, Vatinno AA. TheraBracelet Stimulation During Task-Practice Therapy to Improve Upper Extremity Function After Stroke: A Pilot Randomized Controlled Study. Phys Ther. 2019 Mar 1;99(3):319-328. doi: 10.1093/ptj/pzy143.