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(Stroke. 2009;40:537.)
© 2009 American Heart Association, Inc.

Original Contributions

Association Between Gait Asymmetry and Brain Lesion Location in Stroke Patients

Lisa D. Alexander, MPT; Sandra E. Black, MD; Kara K. Patterson, BScPT, MSc; Fuqiang Gao, MD; Cynthia J. Danells, BScPT, MSc William E. McIlroy, PhD

From the Heart and Stroke Foundation Centre for Stroke Recovery (L.D.A., S.E.B., K.K.P., F.G., C.J.D., W.E.M.); Sunnybrook Health Sciences Centre Research Institute (L.D.A., S.E.B., K.K.P., F.G., C.J.D., W.E.M.), Toronto; University of Toronto (L.D.A., K.K.P., F.G., C.J.D.); L.C. Campbell Cognitive Neurology Research Unit (S.E.B., F.G.), Toronto; Department of Medicine (Neurology) at Sunnybrook Health Sciences Centre & University of Toronto (S.E.B., W.E.M.); Graduate Department of Rehabilitation Science (S.E.B., K.K.P.), University of Toronto; Rotman Research Institute (S.E.B.), Baycrest, University of Toronto; Toronto Rehabilitation (K.K.P.); and the Department of Kinesiology (W.E.M.), University of Waterloo, Ontario, Canada.

Correspondence to William E. McIlroy, Heart and Stroke Foundation Centre for Stroke Recovery, Room A421-2075 Bayview Avenue, Toronto, ON, M4N 3M5. E-mail wmcilroy{at}healthy.uwaterloo.ca

Background and Purpose— Associations between the site of brain injury and poststroke gait impairment are poorly understood. Temporal gait asymmetry after stroke is a salient index of gait dysfunction that has important functional consequences. The current study investigated whether subtraction lesion analysis could distinguish brain regions associated with persisting temporal gait asymmetry in chronic stroke patients.

Methods— Analysis was conducted on 37 chronic ambulatory stroke patients (17 symmetrical gait, 20 asymmetrical gait). Spatiotemporal gait parameters were recorded using an instrumented walking surface. Lesions were traced from 3D T1-MRI, and region of interest images were generated. The lesion overlay of patients with symmetrical gait was subtracted from patients with asymmetrical gait to highlight voxels more frequently lesioned in asymmetrical patients and relatively spared in symmetrical patients.

Results— Demographic data were comparable between the 2 groups. Asymmetrical patients exhibited significantly higher National Institute of Health Stroke Scale neglect scores and more severe motor impairment. Gait asymmetry was significantly correlated to Chedoke-McMaster Stroke Scale leg (r=–0.767, P<0.001) and foot (r=–0.759, P<0.001) scores, whereas gait speed correlated less strongly. After subtraction analysis, injury to the posterolateral putamen was evident 60% to 80% more frequently in the asymmetrical group compared to the symmetrical group.

Conclusions— In this sample of ambulatory chronic stroke patients, damage to the posterolateral putamen was associated with temporal gait asymmetry. Further advances in our understanding of the neural correlates of gait asymmetry may provide prognostic markers for future persistent gait dysfunction and lead to early targeted rehabilitation when key regions are damaged.

Key Words: stroke • gait • MRI • rehabilitation • putamen