Time configuration of combined neuromodulation and motor training after stroke: A proof-of-concept study

Elizabeth S. Powell, Cheryl Carrico, Philip M. Westgate, Kenneth C. Chelette, Laurie Nichols, Lakshmi Reddy, Emily Salyers, Andrea Ward, Lumy Sawaki

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

BACKGROUND: Intensive motor training is a therapeutic intervention that supports recovery of movement function after stroke by capitalizing on the brain's capacity for neuroplastic change. Peripheral nerve stimulation and transcranial direct current stimulation are neuromodulation techniques that can upregulate neuroplasticity and, in turn, enhance outcomes of motor training after stroke. Few studies have investigated possible adjuvant effects between peripheral nerve stimulation, transcranial direct current stimulation, and intensive motor training. OBJECTIVE: This proof-of-concept study investigated whether timing variations in neuromodulation paired with robot-assisted motor training effect differential outcomes for subjects with chronic, moderate-to-severe upper extremity impairment after stroke. METHODS: Ten subjects in the chronic phase (>12 months after stroke) of recovery completed the study. Subjects received 10 daily sessions of transcranial direct current stimulation either at the start (n = 4) or at the end (n = 6) of peripheral nerve stimulation preceding intensive motor training. Pre-post changes in motor function (Fugl-Meyer Assessment; Stroke Impact Scale) and neuroplasticity (transcranial magnetic stimulation) were assessed by condition. RESULTS: Significant improvement in Stroke Impact Scale (p = 0.02) and no change in Fugl-Meyer Assessment were associated with the start condition. No changes in Stroke Impact Scale and Fugl-Meyer Assessment were associated with the end condition. Only 1 subject in the start group had measurable neuroplastic responses and demonstrated an increase in ipsilesional cortical map volume. Only 1 subject in the end group had measurable neuroplastic responses and demonstrated a decrease in ipsilesional cortical map volume. Opposite shifts in ipsilesional cortical centers of gravity occurred relative to condition. CONCLUSION: In cases of moderate-to-severe impairment after stroke, transcranial direct current stimulation at the start, rather than the end, of peripheral nerve stimulation prior to motor training may effect better functional outcomes. Future research with a larger sample size is needed to validate the findings of this proof-of-concept study.

Original languageEnglish
Pages (from-to)439-449
Number of pages11
JournalNeuroRehabilitation
Volume39
Issue number3
DOIs
StatePublished - 2016

Bibliographical note

Funding Information:
Acknowledgments We extend our heartfelt appreciation to our study participants, to Dr. David Jackson for referrals, and to our research assistants, Daniel Aken and Candy Pettry. The contents of this article were developed under a grant from the Department of Education, NIDRR grant number H133G120086, and the Cardinal Hill Endowment for Stroke and Spinal Cord Injury Research (1215375670).

Publisher Copyright:
© 2016 - IOS Press and the authors. All rights reserved.

Keywords

  • Peripheral nerve stimulation
  • neuroplasticity
  • robot-assisted upper extremity motor training
  • transcranial direct current stimulation
  • transcranial magnetic stimulation

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation
  • Clinical Neurology

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