Article

Recovery of arm function after stroke is often incomplete. An
improved understanding of brain structure-motor behavior relationships is needed
for the development of novel and targeted rehabilitation interventions.
OBJECTIVE: To examine the relationship between skilled reach performance and the
integrity of two putative white matter motor pathways, corticospinal tract and
corpus callosum, after stroke. METHODS: Eleven individuals with chronic stroke
(poststroke duration, mean 62.5 +/- 42.4 months) and mild motor impairment (upper
extremity Fugl-Meyer score, mean 54.2 +/- 7.6) reached to six targets presented
at three distances and two directions. Fractional anisotropy (FA) obtained from
diffusion tensor imaging was used to determine the structural integrity of the
corticospinal tract and the corpus callosum. RESULTS: Overall reach performance
was decreased in the paretic arm compared with the nonparetic arm. While FA was
decreased in the ipsilesional corticospinal tract, FA in the corticospinal tract
did not correlate with variability in reach performance between individuals.
Instead, FA in the premotor section of the corpus callosum correlated with reach
performance; individuals with higher FA in premotor corpus callosum tended to
reach faster with both the paretic and nonparetic arms. CONCLUSIONS: The
structural connections between the two premotor and supplemental cortices that
traverse the premotor corpus callosum may play an important role in supporting
motor control and could become a target for interventions aimed at improved arm
function in this population.

Langue : ANGLAIS