Invasive cortical stimulation to promote recovery of function after stroke: a critical appraisal

Stroke. 2009 May;40(5):1926-31. doi: 10.1161/STROKEAHA.108.540823. Epub 2009 Apr 9.


Background and purpose: Residual motor deficits frequently linger after stroke. Search for newer effective strategies to promote functional recovery is ongoing. Brain stimulation, as a means of directing adaptive plasticity, is appealing. Animal studies and Phase I and II trials in humans have indicated safety, feasibility, and efficacy of combining rehabilitation and concurrent invasive cortical stimulation. However, a recent Phase III trial showed no advantage of the combination. We critically review results of various trials and discuss the factors that contributed to the distinctive result.

Summary of review: Regarding cortical stimulation, it is important to determine the (1) location of peri-infarct representations by integrating multiple neuroanatomical and physiological techniques; (2) role of other mechanisms of stroke recovery; (3) viability of peri-infarct tissue and descending pathways; (4) lesion geometry to ensure no alteration/displacement of current density; and (5) applicability of lessons generated from noninvasive brain stimulation studies in humans. In terms of combining stimulation with rehabilitation, we should understand (1) the principle of homeostatic plasticity; (2) the effect of ongoing cortical activity and phases of learning; and (3) that subject-specific intervention may be necessary.

Conclusions: Future cortical stimulation trials should consider the factors that may have contributed to the peculiar results of the Phase III trial and address those in future study designs.

Publication types

  • Review

MeSH terms

  • Animals
  • Cerebral Cortex / physiology*
  • Clinical Trials, Phase I as Topic
  • Clinical Trials, Phase II as Topic
  • Clinical Trials, Phase III as Topic
  • Electric Stimulation Therapy
  • Humans
  • Learning / physiology
  • Magnetic Resonance Imaging
  • Movement Disorders / etiology
  • Movement Disorders / prevention & control
  • Movement Disorders / rehabilitation
  • Neural Pathways / pathology
  • Stroke / complications
  • Stroke / therapy*
  • Stroke Rehabilitation
  • Transcranial Magnetic Stimulation*