Neural substrates of reduced walking activity after supratentorial stroke: A voxel-based lesion symptom mapping study

Background: Most stroke patients exhibit low levels of walking activity, a key component of secondary stroke prevention. The predictors of walking activity may be multifactorial and are thus far partially understood. We aimed to study the neuroanatomic correlates of low levels of daily walking activity following hemispheric stroke. Methods: In this cross-sectional study, 33 community-dwelling stroke survivors (age: 63.9 +/- 12.9 years; % female: 36.4%; NIHSS at admission: 3.3 +/- 4.0) were prospectively recruited at least 3 months after a first ever, unilateral, supratentorial stroke confirmed by brain magnetic resonance imaging. Walking activity was measured by daily step counts (steps.day(-1)), recorded using an Actigraph GT3x + triaxial accelerometer over 7 consecutive days. Voxel-based lesion-symptom mapping was performed to identify brain areas associated with walking activity following stroke. Results: Participants presented 4491.9 +/- 2473.7 steps.day(-1). Lower levels of walking activity were related to lesions of the posterior part of the putamen, of the posterior limb of the internal capsule and of the anterior part of the corona radiata. No cortical region was associated with walking activity. Conclusions: Our preliminary results identify subcortical neuroanatomical correlates for reduced walking activity following stroke. If confirmed, these results could serve as a rationale for the development of targeted rehabilitative strategy to improve mobility after stroke.