title: Characterization of global synkineses during hand grip in hemiparetic patients.
abstract: OBJECTIVE
  Global synkineses are defined as nonpurposive associated movements on the involved side of hemiparetic subjects that are triggered during a voluntary movement. The purpose of this study was to characterize the intensity and pattern of upper limb global synkineses in hemiparetic subjects with a static biarticular dynamometer and electromyography during maximal progressive hand grip on the unaffected side.
  
  
  METHODS
  Survey, convenience sample.
  
  
  METHODS
  University secondary care rehabilitation center.
  
  
  METHODS
  Global synkineses (ie, torques and electromyographic activities) in patients with severe (n = 8) and moderate (n = 7) deficits in motor performance, as evaluated by the Fugl-Meyer assessment, were compared with those obtained in a group of healthy subjects (n = 11). Clinically the subjects from the severe deficit group were more spastic and showed less strength at the elbow than the subjects from the moderate deficit group.
  
  
  RESULTS
  Results of analyses of variance showed significant increases of shoulder torque in flexion and internal rotation, and elbow torque in flexion, with increasing force exertion during contralateral hand grip in subjects with severe deficits (p < .05). Furthermore, in these subjects increases of electromyographic activity were also observed in biceps brachii, brachioradialis, and triceps brachii muscles with increasing hand grip force levels. In contrast, no significant torques or electromyographic increases were observed in subjects with moderate deficits and in control subjects during contralateral hand grip exertions.
  
  
  CONCLUSIONS
  These results provide a quantitative assessment of the kinematic and electromyographic patterns of global synkineses and their correlates with clinical observations. Within the limits of the experimental results presented in this study, it is suggested that global synkineses result from contralateral overflow of the voluntary command to hyperexcitable motoneuron pools.
authors.affiliation: Research Center, Montreal Rehabilitation Institute, Quebec, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Boissy
authors.forename: D
authors.initials: D
authors.lastname: Bourbonnais
authors.forename: C
authors.initials: C
authors.lastname: Kaegi
authors.forename: D
authors.initials: D
authors.lastname: Gravel
authors.forename: B A
authors.initials: BA
authors.lastname: Arsenault
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004576:Electromyography; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000503:physiopathology*; D010291:Paresis / Q000503:physiopathology*; D012785:Shoulder Joint / Q000503:physiopathology; D019415:Torque