Intra-limb coordination and control in individuals with stroke. Conceptual and methodological considerations

Abstract

Stroke results in substantial difficulties in reaching and grasping actions, which may emerge at different levels of coordination and control, in both the spatial and temporal domains. In the context of motor control, these issues relate broadly to the Degrees of Freedom Problem (Bernstein, 1967), as well as to many other theoretical models (e.g., Models of Constraints) that fall under this conceptual umbrella. Over the last few decades, a substantial amount of studies have been published to examine these issues, including various systematic reviews. However, the majority of this work failed to explicitly address the level at which these issues occur, the impact of different constraints on the emerging patterns, and the conceptual relevance of the emerging inferences. As such, the purpose of this study was threefold. The first purpose was to examine whether the selected studies examined the issue in coordination and/or control, and to determine the conceptual framework underpinning these investigations. The second purpose was to delineate which individual, task, and environmental constraints have been examined in previous work, and infer the degree to which these factors affected the nature of the emerging movement trajectories. Lastly, the third purpose was to address the methodological aspects of the existing studies, by identifying the prevalence of different measures of coordination (angle-angle plots; correlations) and control. [...]