Abstract
Objective: Muscle weakness develops rapidly after stroke, adversely affecting motor performance, and contributing to reduced functional ability. While the contributions of structural and functional alterations in skeletal muscle to post-stroke weakness have been well described, the relationship between motor pathway integrity, measured using both radiological and electrophysiological techniques, and post-stroke muscle weakness is not clear. This study sought to determine the role of corticospinal tract (CST) integrity on knee extensor weakness in chronic stroke survivors. Methods: Knee extensor strength and activation testing were performed at 90° of knee flexion using an interpolated triplet technique. CST integrity was evaluated using data obtained from Diffusion Tensor Imaging and transcranial magnetic stimulation. Results: Recordings in nine stroke subjects indicated substantial knee extensor weakness and activation deficits in the paretic legs of the stroke survivors. Regression analysis revealed that asymmetry in CST integrity was strongly related to between-leg differences in knee strength. Conclusions: The results of this study suggest a strong link between CST integrity and lower extremity strength, and add to the growing evidence of substantial knee extensor weakness and activation impairments in stroke survivors. Significance: The findings from this study further our understanding of the anatomical and neurophysiological contributions to motor impairments after stroke, which may benefit clinicians and researchers in the field of stroke rehabilitation.
Original language | English (US) |
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Pages (from-to) | 1588-1594 |
Number of pages | 7 |
Journal | Clinical Neurophysiology |
Volume | 122 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2011 |
Funding
This work was supported in part by K01HD056216, R21HD059287, NIDRR H133F090009, and NIDRR H133E070013. The authors would like to thank T.George Hornby, PT, PhD for providing access to his lab facility for data collection.
Keywords
- Diffusion Tensor Imaging
- Muscle weakness
- Quadriceps
- Stroke
- Transcranial magnetic stimulation
- Voluntary activation
ASJC Scopus subject areas
- Clinical Neurology
- Neurology
- Sensory Systems
- Physiology (medical)