Spatial and temporal asymmetries in gait predict split-belt adaptation behavior in stroke.
BACKGROUND
Step asymmetries during gait in persons after stroke can occur in temporal or spatial domains. Prior studies have shown that split-belt locomotor adaptation can temporarily mitigate these asymmetries.


OBJECTIVE
. We investigated whether baseline gait asymmetries affected how patients adapt and store new walking patterns.


METHODS
Subjects with stroke and age-matched controls were studied walking at a 2:1 speed ratio on the split-belt during adaptation and assessed for retention of the learned pattern (the after-effect) with both belts at the same speed.


RESULTS
Those with stroke adapted more slowly (P < .0001), though just as much as healthy older adults. During split-belt walking, the participants with stroke adapted toward their baseline asymmetry (eg, F = 14.02, P < .01 for step symmetry), regardless of whether the subsequent after-effects improved or worsened their baseline step asymmetries. No correlation was found between baseline spatial and temporal measures of asymmetry (P = .38). Last, the initial spatial and temporal asymmetries predicted after-effects independently of one another. The after-effects in the spatial domain (ie, center of oscillation difference) are only predicted by center of oscillation difference baseline (F = 15.3, P = .001), while all other parameters were nonsignificant (all Ps > .17). Temporal coordination (ie, phasing) after-effects showed a significant effect only from phasing baseline (F = 26.92, P < .001, all others P > .33).


CONCLUSIONS
This work demonstrates that stroke patients adapt toward their baseline temporal and spatial asymmetries of walking independently of one another. We define how a given split-belt training session would affect asymmetries in these domains, which must be considered when developing rehabilitation interventions for stroke patients.
1The Johns Hopkins School of Medicine, Baltimore, MD, USA.
Laura A
LA
Malone
Amy J
AJ
Bastian
D000222:Adaptation, Physiological; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D013647:Task Performance and Analysis; D013997:Time Factors; D016138:Walking / Q000502:physiology; D055815:Young Adult
kinematics; locomotor rehabilitation; motor adaptation; poststroke; split-belt treadmill; walking