Biomechanics Commons^™

Temporal Structure Of Variability Decreases In Upper Extremity Movements Post Stroke, Amit Sethi, Tara Patterson, Theresa Mcguirk, Carolynn Patten, Lorie G. Richards, Nikolaos Stergiou

Journal Articles

Methods: Sixteen participants with chronic stroke and nine age-matched controls performed three trials of functional reach-to-grasp. The amount of variability was quantified by computing the standard deviation of shoulder, elbow, wrist and index finger flexion/extension joint angles. The temporal structure of variability was determined by calculating approximate entropy in shoulder, elbow, wrist and index finger flexion/extension joint angles.

Findings: Individuals with stroke demonstrated greater standard deviations and significantly reduced approximate entropy values as compared to controls. Furthermore, motor impairments and kinematics demonstrated moderate to strong correlations with temporal structure of variability.

Interpretation: Changes in the temporal structure of variability in …

Stroke Survivors Control The Temporal Structure Of Variability During Reaching In Dynamic Environments, Mukul Mukherjee, Panagiotis Koutakis, K.-C. Siu, Pierre B. Fayad, Nikolaos Stergiou

Journal Articles

Learning to control forces is known to reduce the amount of movement variability (e.g., standard deviation; SD) while also altering the temporal structure of movement variability (e.g., approximate entropy; ApEn). Such variability control has not been explored in stroke survivors during reaching movements in dynamic environments. Whether augmented feedback affects such variability control, is also unknown. Chronic stroke survivors, assigned randomly to a control/experimental group, learned reaching movements in a dynamically changing environment while receiving either true feedback of their movement (control) or augmented visual feedback (experimental). Hand movement variability was analyzed using SD and ApEn. A significant change in …