Locomotor adaptation on a split-belt treadmill can improve walking symmetry post-stroke

Abstract

Human locomotion must be flexible in order to meet varied environmental demands. Alterations to the gait pattern occur on different time scales, ranging from fast, reactive adjustments to slower, more persistent adaptations. A recent study in humans demonstrated that the cerebellum plays a key role in slower walking adaptations in interlimb coordination during split-belt treadmill walking, but not fast reactive changes. It is not known whether cerebral structures are also important in these processes, though some studies of cats have suggested that they are not. We used a split-belt treadmill walking task to test whether cerebral damage from stroke impairs either type of flexibility. Thirteen individuals who had sustained a single stroke more than 6 months prior to the study (four females) and 13 age- and gender-matched healthy control subjects were recruited to participate in the study. Results showed that stroke involving cerebral structures did not impair either reactive or adaptive abilities and did not disrupt storage of new interlimb relationships (i.e. after-effects). This suggests that cerebellar interactions with brainstem, rather than cerebral structures, comprise the critical circuit for this type of interlimb control. Furthermore, the after-effects from a 15-min adaptation session could temporarily induce symmetry in subjects who demonstrated baseline asymmetry of spatiotemporal gait parameters. In order to re-establish symmetric walking, the choice of which leg is on the fast belt during split-belt walking must be based on the subject's initial asymmetry. These findings demonstrate that cerebral stroke survivors are indeed able to adapt interlimb coordination. This raises the possibility that asymmetric walking patterns post-stroke could be remediated utilizing the split-belt treadmill as a long-term rehabilitation strategy.

Learning the spatial features of a locomotor task is slowed after stroke

“…However, the results did not support this hypothesis. A previous study of split-belt treadmill adaptation in those with chronic stroke found no relationship between the level of sensorimotor impairment and the magnitude of aftereffects in persons with chronic stroke (Reisman et al 2007). Our results extend these findings and demonstrate that learning of a novel locomotor task over days is also not related to the level of sensorimotor impairment after stroke.…”

“…The split-belt treadmill is a treadmill in which there are two independently controlled belts, one under each foot, that travel at two different speeds. When subjects adapt their walking pattern to these conditions for 10 -15 min, significant asymmetries in step length, double-support times, and limb phase angles are present when normal walking conditions are resumed (Reisman et al 2005(Reisman et al , 2007(Reisman et al , 2009). These responses, of changing interlimb dynamics over a series of steps during one practice period on the rotating or split-belt treadmill, are a form of motor adaptation; participants are adjusting an already well-learned motor skill over a period of trial-and-error practice, as they are exposed to a novel and perturbing environment (Martin et al 1996b).…”

“…These responses, of changing interlimb dynamics over a series of steps during one practice period on the rotating or split-belt treadmill, are a form of motor adaptation; participants are adjusting an already well-learned motor skill over a period of trial-and-error practice, as they are exposed to a novel and perturbing environment (Martin et al 1996b). This adaptation has been extensively studied (Earhart et al 2001;Malone and Bastian 2010;Reisman et al 2005Reisman et al , 2007Reisman et al , 2009Reisman et al , 2010Torres-Oviedo and Bastian 2010;Vasudevan and Bastian 2010) and is thought to be a necessary component of longer-term motor learning (Bastian 2008).…”

Unique characteristics of motor adaptation during walking in young children

“…For example, walking on a split-belt treadmill with the two belts (1 for each leg) running at different speeds disrupts the left-right symmetry (henceforth referred to as "symmetry") of walking. Both temporal symmetry (such as equal durations for comparable periods in the left and right walking cycle) and spatial symmetry (such as equal kinematic excursions of the left and right legs) are disrupted (Reisman et al 2005). Symmetry can be restored with continued stepping on the split-belt treadmill for about 10 min.…”

Learning a Locomotor Task: With or without Errors?

“…they help the subject to do the task better. However, research on motor learning has emphasized that errors are fundamental signals that drive motor adaptation [10][11][12]. Previous studies have shown that healthy subjects can adapt to a force perturbation during stepping [13,14].…”