Contralesional motor pathway enhancement after stroke: multimodal insights into lower limb function

<p dir="ltr"><b>Introduction:</b> We used complementary measures of motor pathway organization to determine whether relative contralesional pathway enhancement is associated with lower-limb function and whether this relationship depends on damage to the ipsilesional corticospinal tract (CST). <b>Methods:</b> In individuals with chronic stroke, we measured: 1) transcranial magnetic stimulation (TMS) corticomotor excitability; 2) functional magnetic resonance imaging (fMRI) brain activation; and 3) diffusion tensor imaging (DTI) fractional anisotropy in the corticospinal tracts.

Relative excitability, functional activation, and structural integrity between hemispheres was calculated, and a single composite index of hemisphere predominance was developed. We tested associations with motor impairment, walking speed and endurance, and interlimb coordination, and whether these associations varied with ipsilesional CST lesion load. <b>Results:</b> 33 individuals with chronic stroke [60.7 (8.3) years old; 24 male; 8.6 (6.6) years post-stroke] were enrolled.