Cognitive Impairments After Stroke Do Not Attenuate Explicit Visuomotor Adaptation in Reaching and Savings With the Unaffected Arm

Background: Accumulating evidence suggests that motor performance is affected by the cognitive control abilities of the subject. Performance in motor tasks in populations with cognitive deficits such as older adults and subjects with stroke is therefore expected to deteriorate. The goal of this study is to investigate the relationship between cognitive impairments and motor control and learning impairments in a visuomotor adaptation task in subjects with stroke.

Methods: Twenty-seven post-stroke, 31 age matched controls, and 30 young control subjects completed a sensorimotor adaptation task composed of 2 adaptation blocks separated by a washout block. Explicit learning was assessed by cueing subjects to suppress their strategy. Cognitive assessment was conducted using the Montreal Cognitive Assessment (MoCA) and a verbal learning test. Subjects with stroke performed the task with their unaffected arm.

Results: Despite the cognitive deterioration, the adaptation and savings of the stroke group and age matched controls were comparable. Adaptation and savings were smaller with respect to the young subjects. Savings was associated with a significant improvement in the explicit component across blocks. Finally, the explicit enhancement between blocks was significantly correlated with the MoCA scores in the stroke group and with the results of the verbal learning test in the young controls.

Conclusion: The lack of stroke-induced attenuation on adaptation, despite a correlation between cognitive abilities and explicit learning in adaptation, suggests that subjects with stroke have enough cognitive resources to support sensorimotor adaptation. The availability of cognitive resources for motor learning following brain damage could be utilized in the rehabilitation process.