Stein J, Hughes R, D'Andrea S, Therrien B, Niemi J, Krebs K, Langone L, Harry J: Stochastic resonance stimulation for upper limb rehabilitation poststroke.
Previous studies have shown that subthreshold electrical or mechanical noise can reduce the sensory threshold and impart short-term improvements in sensorimotor function. We undertook this study to examine the effects of combined subsensory electrical and vibratory stimulation in conjunction with exercise training on long-term motor performance.
Thirty subjects were recruited from adult community-dwelling stroke survivors with residual hemiparesis. Subjects were screened for residual motor ability using a functional task, and those who functioned below this level were excluded. All subjects had a history of a single unilateral ischemic or hemorrhagic stroke at least 6 mos before study entry and were not actively receiving occupational or physical therapy. Subjects were stratified by baseline upper extremity Fugl-Meyer (UEFM) (more impaired [28–35] and less impaired [36–55]) and were randomized to one of two groups: treatment (stochastic resonance stimulation [plus over minus sign] exercise: 15 subjects) and control (sham stimulation [plus over minus sign] exercise: 15 subjects).
No significant difference was found between the stochastic resonance treatment and control group in the UEFM or in any of the secondary measures. The combined group showed modest improvements in UEFM from baseline to completion of therapy (mean improvement, 2.6 points) (P = 0.004); however, these improvements declined by 1-mo follow-up to 1.5 points (P = 0.055). No change in sensory function was detectable.
Stochastic resonance therapy combined with occupational therapy was no more effective than occupational therapy alone in restoring sensorimotor performance. Other stochastic resonance stimulation montages or protocols might prove more effective.
From the Department of Physical Medicine and Rehabilitation (JS, RH, KK, LL), Spaulding Rehabilitation Hospital; Department of Physical Medicine and Rehabilitation (JS), Harvard Medical School, Boston, Massachusetts; Department of Rehabilitation and Regenerative Medicine (JS), Columbia University College of Physicians and Surgeons; Division of Rehabilitation Medicine (JS), Weill Cornell Medical College, New York, New York; Afferent Corporation (Defunct) (SDA, BT, JN); The Gait and Motion Analysis Lab (SDA), The Center for Restorative and Regenerative Medicine; Bioengineering Laboratory (BT), Department of Orthopaedics, The Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island; and Wyss Institute at Harvard University (JN), Boston, Massachusetts.
All correspondence and requests for reprints should be addressed to Joel Stein, MD, Department of Rehabilitation and Regenerative Medicine, Columbia University College of Physicians and Surgeons, Harkness Pavilion Room 1-165, 180 Fort Washington Avenue, New York, NY 10032.
This study was funded by Afferent Corporation, Providence, RI, which has since ceased operations. Joel Stein, Richard Hughes, Kathryn Krebs, and Lisa Langone have no equity or other financial interest in Afferent Corporation. Susan D'Andrea, James Niemi, Bethany Therrien, and Jason Harry were employees of Afferent at the time the study was conducted and had equity interests in the company in the form of stock and/or stock options.