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Neurology. 2011 Sep 13;77(11):1076-83. doi: 10.1212/WNL.0b013e31822e1482. Epub 2011 Aug 31.

Anatomy and physiology predict response to motor cortex stimulation after stroke.

Author information

1
Department of Neurology, University of California, Irvine, CA, USA.

Abstract

OBJECTIVES:

Preclinical studies found that epidural motor cortex stimulation improved motor deficits after stroke, but a phase III trial in humans did not corroborate these results. The current retrospective analysis examined subjects randomized to stimulation in order to identify features distinguishing responders from nonresponders.

METHODS:

Anatomic (MRI measures of gray matter thickness and of white matter tract injury) and physiologic methods (motor evoked responses) were examined as predictors of treatment response.

RESULTS:

Among 60 subjects randomized to cortical stimulation, both anatomic and physiologic measures at baseline predicted behavioral response to therapy. Anatomically, those achieving the primary efficacy endpoint had a smaller fraction of the corticospinal tract injured by stroke compared to those who did not (44% vs 72%, p < 0.04), and rarely had severe tract injury. Physiologically, the primary efficacy endpoint was reached more often (67%) by those with preserved motor evoked responses (MER) upon cortical stimulation compared to those lacking MER (27%, p < 0.05). Those with an elicitable MER also had a lower rate of precentral gyrus injury (0% vs 33%, p < 0.05) by stroke, as compared to those lacking MER, and had higher gray matter volume compared to those lacking MER in regions including ipsilesional precentral gyrus.

CONCLUSIONS:

In this clinical stroke trial, the more that the physiologic integrity of the motor system was preserved, the more likely that a patient was to derive gains from subsequent therapy, consistent with preclinical models. Functional and structural preservation of key brain substrates are important to deriving gain from a restorative therapy.

PMID:
21880996
PMCID:
PMC3265049
DOI:
10.1212/WNL.0b013e31822e1482
[Indexed for MEDLINE]
Free PMC Article

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