The role of corticospinal tract damage in chronic motor recovery and neurorehabilitation: a pilot study.
BACKGROUND
With diffusion-tensor imaging (DTi) it is possible to estimate the structural characteristics of fiber bundles in vivo. This study used DTi to infer damage to the corticospinal tract (CST) and relates this parameter to (a) the level of residual motor ability at least 1 year poststroke and (b) the outcome of intensive motor rehabilitation with constraint-induced movement therapy (CIMT).


OBJECTIVE
To explore the role of CST damage in recovery and CIMT efficacy.


METHODS
Ten patients with low-functioning hemiparesis were scanned and tested at baseline, before and after CIMT. Lesion overlap with the CST was indexed as reduced anisotropy compared with a CST variability map derived from 26 controls. Residual motor ability was measured through the Wolf Motor Function Test (WMFT) and the Motor Activity Log (MAL) acquired at baseline. CIMT benefit was assessed through the pre-post treatment comparison of WMFT and MAL performance.


RESULTS
Lesion overlap with the CST correlated with residual motor ability at baseline, with greater deficits observed in patients with more extended CST damage. Infarct volume showed no systematic association with residual motor ability. CIMT led to significant improvements in motor function but outcome was not associated with the extent of CST damage or infarct volume.


CONCLUSIONS
The study gives in vivo support for the proposition that structural CST damage, not infarct volume, is a major predictor for residual functional ability in the chronic state. The results provide initial evidence for positive effects of CIMT in patients with varying, including more severe, CST damage.
Sterr
Annette
A
Department of Psychology, University of Surrey, Guildford, United Kingdom. a.sterr@surrey.ac.uk
Shen
Shan
S
Szameitat
Andre J
AJ
Herron
Katherine A
KA
D000328:Adult; D000368:Aged; D016880:Anisotropy; D020520:Brain Infarction / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010865:Pilot Projects; D011712:Pyramidal Tracts / Q000473:pathology / Q000503:physiopathology*; D020127:Recovery of Function / Q000502:physiology*; D012044:Regression Analysis; D020521:Stroke / Q000473:pathology*; D000071939:Stroke Rehabilitation; D055815:Young Adult