Compensatory Versus Noncompensatory Shoulder Movements Used for Reaching in Stroke.
Background The extent to which the upper-limb flexor synergy constrains or compensates for arm motor impairment during reaching is controversial. This synergy can be quantified with a minimal marker set describing movements of the arm-plane. Objectives To determine whether and how (a) upper-limb flexor synergy in patients with chronic stroke contributes to reaching movements to different arm workspace locations and (b) reaching deficits can be characterized by arm-plane motion. Methods Sixteen post-stroke and 8 healthy control subjects made unrestrained reaching movements to targets located in ipsilateral, central, and contralateral arm workspaces. Arm-plane, arm, and trunk motion, and their temporal and spatial linkages were analyzed. Results Individuals with moderate/severe stroke used greater arm-plane movement and compensatory trunk movement compared to those with mild stroke and control subjects. Arm-plane and trunk movements were more temporally coupled in stroke compared with controls. Reaching accuracy was related to different segment and joint combinations for each target and group: arm-plane movement in controls and mild stroke subjects, and trunk and elbow movements in moderate/severe stroke subjects. Arm-plane movement increased with time since stroke and when combined with trunk rotation, discriminated between different subject groups for reaching the central and contralateral targets. Trunk movement and arm-plane angle during target reaches predicted the subject group. Conclusions The upper-limb flexor synergy was used adaptively for reaching accuracy by patients with mild, but not moderate/severe stroke. The flexor synergy, as parameterized by the amount of arm-plane motion, can be used by clinicians to identify levels of motor recovery in patients with stroke.
McGill University, Montreal, Quebec, Canada Center for Interdisciplinary Research in Rehabilitation (CRIR), Montreal, Quebec, Canada mindy.levin@mcgill.ca.
Mindy F
MF
Levin
University of Tel Aviv, Tel Aviv, Israel.
Dario G
DG
Liebermann
Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Yisrael
Y
Parmet
Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Sigal
S
Berman
D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D012782:Shoulder / Q000294:innervation*; D013223:Statistics as Topic; D020521:Stroke / Q000503:physiopathology*; D013997:Time Factors; D060726:Torso
adaptation; arm movement; compensation; kinematics; recovery; rehabilitation