Improvements in hand function in adults with chronic tetraplegia following a multiday 10-Hz repetitive transcranial magnetic stimulation intervention combined with repetitive task practice

Abstract

Background and Purpose: Evidence suggests that the use of stimulation to increase corticomotor excitability improves hand function in persons with cervical spinal cord injury. We assessed effects of a multiday application of 10-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the corticomotor hand area combined with repetitive task practice (RTP) in participants with tetraplegia and neurologically healthy participants. Methods: Using a double-blind, randomized, crossover design, 11 participants with chronic tetraplegia and 10 neurologically healthy participants received 3 sessions of 10-Hz rTMS+RTP and 3 sessions of sham-rTMS+RTP to the corticomotor hand region controlling the weaker hand. Repetitive transcranial magnetic stimulation was interleaved with RTP of a skilled motor task between pulse trains. Hand function (Jebsen-Taylor Hand Function Test, pinch, and grasp strength) and corticomotor excitability (amplitude of motor-evoked potential) were assessed before and after the rTMS+RTP and shamrTMS+ RTP phases.We assessed significance, using paired t tests on pre-post differences, and effect sizes, using the standardized response mean. Results: RTMS+RTP was associated with larger effect sizes compared with sham-rTMS+RTP for improvement in Jebsen-Taylor Hand Function Test for both the trained hand (standardized response mean = 0.85 and 0.42, respectively) and non-trained hand (0.55 and 0.31, respectively), and for grasp strength of the trained hand in the group with cervical spinal cord injury (0.67 and 0.39, respectively) alone. Effect sizes for all othermeasures were small and there were no statistical between-condition differences in the outcomes assessed. Discussion and Conclusions: Repetitive transcranial magnetic stimulationmay be a valuable adjunct to RTP for improving hand function in persons with tetraplegia. Higher stimulation dose (frequency, intensity, and the number of sessions) may be associated with larger effects. Video Abstract available (see Supplemental Digital Content 1, http: //links.lww.com/JNPT/A82) for more insights from the authors.