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Abstract
Objective: A prospective longitudinal cohort study in stroke patients was performed to better understand the role of γ-aminobutyric acid–dependent intracortical inhibition (ICI) for recovery after stroke.
Methods: Patients with acute first-ever subcortical stroke and hand paresis were recruited, and motor function as well as ICI were measured up to 1 year after stroke. Motor recovery was defined as the change in hand motor function from the acute to the chronic stage (Δ = recovery over 1 year). Primary outcome measures for hand motor function were the recovery of grip strength (ΔGS) and finger-tapping speed (ΔFT). Using double-pulse transcranial magnetic stimulation, we studied ICI in the ipsilesional primary motor cortex during the preparation of a movement with the paretic hand at different time points during recovery (first week, 7 weeks, 3 months, and 1 year after stroke).
Results: Eleven patients were enrolled (mean age 62.9 ± 3.8 years). The results of a multiple regression analysis showed a significant association of movement-related ICI in the acute stage only (first week) with motor recovery over 1 year (ΔGS: R2 = 0.75, F = 17.6, p = 0.006; ΔFT: R2 = 0.55, F = 7.3, p = 0.035). More disinhibition of ICI in the acute phase of stroke predicted more improvement in ΔGS (β = −0.86, p = 0.006) and ΔFT (β = −0.74, p = 0.035), independent of the initial motor deficit.
Conclusions: Movement-related ICI one week after a subcortical stroke is associated with better outcome of hand motor function. Disinhibition in the ipsilesional primary motor cortex could be a mechanism of how the brain attempts to promote motor recovery after stroke.
GLOSSARY
- ARAT=
- action research arm test;
- FMS=
- Fugl-Meyer score;
- FT=
- finger tapping;
- GABA=
- γ-aminobutyric acid;
- GS=
- grip strength;
- ICI=
- intracortical inhibition;
- MEP=
- motor evoked potential;
- MRC=
- Medical Research Council;
- rmANOVA=
- repeated-measures analysis of variance;
- TMS=
- transcranial magnetic stimulation
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Editorial, page 192
Supplemental data at www.neurology.org
- Received November 28, 2012.
- Accepted in final form August 28, 2013.
- © 2014 American Academy of Neurology
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