Kinematic Motion Analysis and Muscle Activation Patterns of Continuous Reaching in Survivors of Stroke

Abstract

Coordinated reaching requires continuous interaction between the efferent motor output and afferent feedback; this interaction may be significantly compromised following a stroke. The authors sought to characterize how survivors of stroke generate continuous, goal-directed reaching. Sixteen survivors of stroke completed functional testing of the stroke-affected side and a continuous reaching task between 2 targets with both sides. Motion analysis and electromyography data were collected to determine segmental contributions to reach (e.g., amount of compensatory trunk), spatiotemporal parameters (e.g., peak velocities), and muscle activation patterns (MAP). Repeated measures analyses of variance compared how survivors of stroke reach with the stroke-affected versus less affected sides. Correlations were determined between kinematic outcomes and functional ability. Participants used significantly more trunk movement and less shoulder flexion and elbow extension when reaching with the stroke-affected side. This corresponded with less muscle activity in the proximal musculature including the anterior, middle, and posterior deltoid on the stroke-affected side. There were significant correlations between the segmental contributions to reach, functional ability, and MAPs. Survivors of stroke generate reduced MAPs in the stroke-affected side corresponding to altered segmental kinematics and function ability. These findings suggest that impairments in the ability to generate sufficient MAPs may contribute to the difficulty in generating continuous reaching motions.

Trunk Restraint to Promote Upper Extremity Recovery in Stroke Patients

“…Numerous studies have demonstrated that stroke patients exhibit excessive trunk movements during pointing and reaching, [6][7][8][9][10][11][12][13] a compensatory motor strategy to extend arm reach when shoulder and elbow movement and control is impaired. 14,15 Excessive use of compensatory movements can result in secondary complications such as muscle contractures, joint misalignment, pain, limb disuse, and increased energy expenditure.…”

Portable Myoelectric Brace Use Increases Upper Extremity Recovery and Participation But Does Not Impact Kinematics in Chronic, Poststroke Hemiparesis

“…13 Subjects were seated in a 45cm chair with no arm rests, and their hands flat (about shoulder width apart) on a 70cm table in front of them. Their chest was restrained by a Velcro strap to limit compensatory trunk movements, 16,17 and their humerus was hanging down their body. Each subject performed 5 repetitions of two reaching tasks with the paretic and non-paretic UE.…”

Augmented muscle activation in reaching movements after stroke

“…In this context, loss of some functional abilities can be observed; among them is reaching [11]. The ability to achieve adequate reach is a fundamental component of daily activities [12] and, considering that this task requires precise planning [13,14], damage to the central nervous system can result in reduced capacity to activate and modulate the muscles involved in its execution [8]. Therefore, the individual will often compensate [15] in the execution of motor tasks, e.g.…”