Shoulder abduction-induced reductions in reaching work area following hemiparetic stroke: neuroscientific implications
A stroke-related loss of corticospinal and corticobulbar pathways is postulated to result in an increased use of remaining neural substrates such as bulbospinal pathways as individuals with stroke are required to generate greater volitional shoulder abduction torques. The effect of shoulder abduction on upper extremity reaching range of motion (work area) was measured in 18 individuals with stroke using the Arm Coordination Training 3-D (ACT3D) device. This robotic system is capable of quantifying movement kinematics when a subject attempts to reach while simultaneously generating various levels of active shoulder abduction torque. We have provided data demonstrating an incremental increase of abnormal coupling of elbow flexion for greater levels of shoulder abduction in the paretic limb that results in a reduction in available work area as a function of active limb support. The progressive increase in the expression of abnormal shoulder/elbow coupling can be explained by a progressive reliance on the indirect cortico-bulbospinal connections that remain in individuals following a stroke-induced brain injury.
KeywordsStroke Arm Coordination Kinematic Synergies Strength
- Beer RF, Ellis MD, Holubar BG, Dewald JP (2007) Impact of gravity loading on post-stroke reaching and its relationship to weakness. Muscle Nerve [E-pub ahead of print]Google Scholar
- Brunnstrom S (1970) Movement therapy in hemiplegia: a neurophysiological approach. Harper and Row, New YorkGoogle Scholar
- Sukal T, Ellis M, Dewald JP (2005) Use of a Novel Robotic System for Quantification of Upper Limb Work Area Following Stroke. In: 27th IEEE EMBS annual international conference, Shanghai, ChinaGoogle Scholar
- Van der Linde R, Lammertse P, Fredericksen E, Ruiter B (2002) The HapticMaster, a new high-performance haptic interface. In: Eurohaptics, Edinburgh, pp 1–5Google Scholar
- Zatsiorsky V, Seluyanov V (1985) Estimation of the mass and inertia characteristics of the human body by means of the predictive regression equations. In: Winter DA, Norman RW, Wells RP, Hayes KC, Patla AE (eds) Biomechanics IX-B, vol 5B. Human Kinetics, Chicago, pp 233–239Google Scholar