Anticipatory Postural Control in Individuals with Stroke: Role of Asymmetries and Focused Training

Asymmetry is one the most common consequences of a cerebrovascular accident (CVA) that causes the impaired postural control in individuals with stroke. Although postural control has been studied in people with stroke, information about their ability to generate anticipatory postural adjustments (APAs) for postural control is incomplete. Moreover, there is limited evidence available on whether anticipatory postural adjustments in individuals with unilateral stroke could be improved with training. Therefore, the focus of this dissertation was on the investigation of anticipatory postural adjustments and the role of APA-focused training in enhancement of postural control in people with stroke. First, we demonstrated that individuals with stroke, as compared to healthy counterparts, have impaired ability to generate APAs on the affected side which is compensated by increased early activation of muscles on the contralateral side. Second, we investigated whether APAs could be improved in people with stroke with exercises. We demonstrated that after a single session of targeted exercises involving their unaffected upper extremity individuals with stroke generated early APAs onsets in trunk and leg muscles on the affected side. Finally, we investigated a feasibility of multi-session training involving targeted exercises performed with the unaffected upper extremity in enhancement of postural control of individuals with stroke. The results of the study revealed that after two weeks of perturbation-based training individuals with stroke improved APAs in the muscles on both sides of the body. The outcome of the dissertation provides an evidence that individuals with stroke have impaired ability to generate anticipatory postural adjustments, however, they could enhance APAs with specialized training. This dissertation also provides a background for future investigations focusing on the role of perturbation-based training in enhancement of postural control in individuals with unilateral impairment.