Compensatory Versus Noncompensatory Shoulder Movements Used for Reaching in Stroke

Mindy F. Levin, Dario G. Liebermann, Yisrael Parmet, Sigal Berman

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


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.

Original languageEnglish
Pages (from-to)635-646
Number of pages12
JournalNeurorehabilitation and Neural Repair
Issue number7
StatePublished - 1 Aug 2016


  • adaptation
  • arm movement
  • compensation
  • kinematics
  • recovery
  • rehabilitation

ASJC Scopus subject areas

  • Rehabilitation
  • Neurology
  • Clinical Neurology


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