Article

Stroke survivors with motor deficits often have pyramidal tract
atrophy caused by degeneration of corticospinal fibers. The authors hypothesized
that the degree of atrophy correlates with severity of motor impairment in
patients with chronic stroke and predicts the response to rehabilitation
training. They performed a post hoc analysis of 42 hemiparetic patients
(>6 months) who had been randomized to either 6 weeks of bilateral arm training
with rhythmic auditory cueing (BATRAC) or dose-matched therapeutic exercise
(DMTE). Arm function was measured using the Fugl-Meyer (FM) and modified Wolf
Motor Function Test (WMFT). Structural MRI and diffusion tensor imaging (DTI) on
the pontine level measured corticospinal tract (CST) atrophy by planimetric
measurement of the mesencephalon (mesencephalic atrophy ratio) and fractional
anisotropy (FA), respectively. Voxel-based lesion symptom mapping (VLSM) was used
to determine the lesions associated with highest degrees of atrophy. The
predictive value of CST atrophy for impairment and training response was
analyzed. RESULTS: CST atrophy predicted baseline motor arm function measured by
the FM and WMFT. The authors found only a trend for the correlation with FA. No
measure of atrophy predicted response to either BATRAC or DMTE. CST atrophy was
higher with larger lesions and those that affected the CST. VLSM identified
internal capsule lesions as being associated with highest CST atrophy.
CONCLUSION: Larger lesions, internal capsule lesions, and those overlapping the
pyramidal tract are associated with greater CST atrophy. CST atrophy explains in
part the variability of baseline deficits but does not seem to predict the
response to BATRAC or unilateral arm training on upper-extremity function.

Langue : ANGLAIS