Influence of the injured brain hemisphere and of sensory deficits on body balance post-stroke

Author(s)

Corina Aparecida Fernandes

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola de Educação Física e Esportes (EEFE/BT)
• Defense date: 2014-12-12

Examining board members

Luis Augusto Teixeira

• Advisor: Luis Augusto Teixeira

Abstract

The influence of the injured brain hemisphere post-stroke and of the visual information were evaluated in this study in the control of quiet stance, in sensory and mechanical perturbation. The effect of tactile information during sensory perturbation and postural responses following unpredictable external postural pertubation were also assessed. Participated in this study 11 post-stroke individuals in the right brain hemisphere, 11 post-stroke individuals in the left brain hemisphere and 24 without neurological disease individuals. Body balance performance was evaluated in quiet stance, in standing posture with a malleable surface (foam pad), and after mechanical perturbation caused by unexpected load release. The assessment was made under conditions of full vision and visual occlusion. The results revealed an increase in quiet stance and greater variability of postural sway in the mediolateral plane of post-stroke individuals compared to without neurological disease. Post-stroke individuals in the right brain hemisphere showed increased postural sway in the anteroposterior plane compared to post-stroke individuals in the left brain hemisphere and without neurological diseases. The visual occlusion condition to increased postural sway in pos-stroke individuals compared to without neurological disease individuals, indicating that vision contributes postural stability in poststroke. The results of sensory pertubation showed an increase and greater variability of postural sway in anteroposterior and mediolateral both planes as post-stroke individuals compared to without neurological disease individuals. Increased postural instability was evident in anteroposterior as mediolateral both planes post-stroke in the right brain hemisphere individuals compared to with post-stroke in the left brain hemisphere and without neurological diseases. Post-stroke in the left brain hemisphere individuals were more unstable in the anteroposterior plane as compared to without neurological disease individuals. Visual information favoured postural stability while the condition of visual occlusion increased postural sway in post-stroke individuals. Results from mechanical pertubation revealed post-stroke in the right brain hemisphere individuals showed increased postural sway as compared to post-stroke in the left brain hemisphere and without neurological disease individuals, which did not differ. The visual information had no effect on postural sway after pertubation. Individuals post-stroke showed increased latency of the medial gastrocnemius muscle and biceps femoris, and smaller magnitude of muscle activation of the medial gastrocnemius muscle as compared to without neurological disease individuals. Comparisons between the paretic and non-paretic leg showed lower contribution of the paretic leg in reactive postural control. The vision favoured the onset of reactive postural responses, and verified the participation of both the right and left brain hemisphere in the body balance recovery after unpredictable external postural perturbation. The results showed reduced balance and increased body instability in post-stroke individuals, and suggest an advantage of the right brain hemisphere in the control of quiet stance and sensory perturbation. The visual information influenced in the control of quiet stance, sensory perturbation and reactive postural responses. Both the right and the left brain hemisphere participated in reactive postural control after mechanical perturbation (AU)

• FAPESP's process: 11/16667-9 - Interhemispheric asymmetries in postural control in post-stroke: quiet stance and recovering from perturbation
• Grantee: Corina Aparecida Fernandes
• Support Opportunities: Scholarships in Brazil - Master