http://stroke.ahajournals.org/content/49/2/433?platform=hootsuite
Abstract
Background and Purpose—Patient
heterogeneity reduces statistical power in clinical trials of
restorative therapies. Valid predictors of treatment responsiveness are
needed, and several have been studied with a focus on corticospinal
tract (CST) injury. We studied performance of 4 such measures for
predicting behavioral gains in response to motor training therapy.
Methods—Patients
with subacute-chronic hemiparetic stroke (n=47) received standardized
arm motor therapy, and change in arm Fugl-Meyer score was calculated
from baseline to 1 month post-therapy. Injury measures calculated from
baseline magnetic resonance imaging included (1) percent CST overlap
with stroke, (2) CST-related atrophy (cerebral peduncle area), (3) CST
integrity (fractional anisotropy) in the cerebral peduncle, and (4) CST
integrity in the posterior limb of internal capsule.
Results—Percent
CST overlap with stroke, CST-related atrophy, and CST integrity did not
correlate with one another, indicating that these 3 measures captured
independent features of CST injury. Percent injury to CST significantly
predicted treatment-related behavioral gains (r=−0.41; P=0.004).
The other CST injury measures did not, neither did total infarct volume
nor baseline behavioral deficits. When directly comparing patients with
mild versus severe injury using the percent CST injury measure, the
odds ratio was 15.0 (95% confidence interval, 1.54–147; P<0.005) for deriving clinically important treatment-related gains.
Conclusions—Percent
CST injury is useful for predicting motor gains in response to therapy
in the setting of subacute-chronic stroke. This measure can be used as
an entry criterion or a stratifying variable in restorative stroke
trials to increase statistical power, reduce sample size, and reduce the
cost of such trials.
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