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 (ACT(3D)) 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.
Sukal
Theresa M
TM
Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N. Michigan Ave, Suite 1100, Chicago, IL 60611, USA.
Ellis
Michael D
MD
Dewald
Julius P A
JP
D000010:Abducens Nerve / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D004550:Elbow / Q000294:innervation; D005246:Feedback / Q000502:physiology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012782:Shoulder / Q000294:innervation*; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology*