Article

Bimanual coordinated movements may be impaired after stroke, so an
assessment of causes is necessary to optimize rehabilitation strategies.
We assessed the role of afference-based sources of coordination,
including phase entrainment and error correction based on visual and
somatosensory feedback. METHODS: In all, 10 persons with unilateral chronic
stroke and 8 age-matched controls participated in a kinesthetic tracking
protocol, in which the hemiparetic upper limb was passively driven by the
machine. The task consisted of matching the trajectory of the driven limb as
accurately as possible with the freely moving limb in 2 conditions: eyes closed
and eyes open. We analyzed the continuous relative phase (CRP), the mean absolute
difference between positions (ADP) between the positions of the 2 limbs, and the
jerk of the matching limb. RESULTS: Coordination instability (CRP standard
deviation) and mean ADP were significantly higher for patients with eyes closed,
compared with patients with eyes open, controls with eyes closed, and controls
with eyes open. Moreover, the jerk was higher for the nonparetic limb of patients
than for the control group. Thus, the nonparetic limb did not produce optimally
smooth movements even as the motor-driven paretic limb did. CONCLUSION: Besides
deficits caused by interhemispheric competition and motor execution of the
paretic limb, somatosensory feedback is a limiting factor in bimanual
coordination after stroke. The findings have clinical implications pertaining to
the design and individualization of efficient bimanual movement therapy.

Langue : ANGLAIS