Contralesional Hemisphere Control of the Proximal Paretic Upper Limb following Stroke.

Lynley Bradnam, Cathy Stinear, P Barber, Winston Byblow

    Research output: Contribution to journalArticlepeer-review

    145 Citations (Scopus)

    Abstract

    Cathodal transcranial direct current stimulation (c-tDCS) can reduce excitability of neurons in primary motor cortex (M1) and may facilitate motor recovery after stroke. However, little is known about the neurophysiological effects of tDCS on proximal upper limb function. We hypothesized that suppression of contralesional M1 (cM1) excitability would produce neurophysiological effects that depended on the severity of upper limb impairment. Twelve patients with varying upper limb impairment after subcortical stroke were assessed on clinical scales of upper limb spasticity, impairment, and function. Magnetic resonance imaging was used to determine lesion size and fractional anisotropy (FA) within the posterior limbs of the internal capsules indicative of corticospinal tract integrity. Excitability within paretic M1 biceps brachii representation was determined from motor-evoked potentials during selective isometric tasks, after cM1 sham stimulation and after c-tDCS. These neurophysiological data indicate that c-tDCS improved selective proximal upper limb control for mildly impaired patients and worsened it for moderate to severely impaired patients. The direction of the neurophysiological after effects of c-tDCS was strongly related to upper limb spasticity, impairment, function, and FA asymmetry between the posterior limbs of the internal capsules. These results indicate systematic variation of cM1 for proximal upper limb control after stroke and that suppression of cM1 excitability is not a one size fits all approach.

    Original languageEnglish
    Pages (from-to)2662-2671
    Number of pages10
    JournalCerebral Cortex
    Volume22
    Issue number11
    DOIs
    Publication statusPublished - Nov 2012

    Keywords

    • corticospinal tract
    • ipsilateral pathways
    • magnetic resonance imaging
    • stroke prediction
    • transcranial direct current stimulation

    Fingerprint Dive into the research topics of 'Contralesional Hemisphere Control of the Proximal Paretic Upper Limb following Stroke.'. Together they form a unique fingerprint.

    Cite this