Article

Skilled hand movements require a precise coordination between the grip force and
the load force. To coordinate those forces, we rely on both a predictive and a
reactive control. On the basis of specific impairments observed previously in
children with hemiplegic cerebral palsy, we aimed to assess the predictive or
reactive nature of hand deficits in stroke patients. This case-control study was
carried out with eight stroke patients and eight control participants. The load
of a handheld object was rapidly increased by dropping a mass attached to the
object. We tested predictive and reactive aspects of the movement in the same
task as the drop was triggered either unexpectedly by the examiner (reactive
condition) or by the patient himself (predictive condition). Deficits observed in
the paretic hand were similar to those highlighted previously in children with
hemiplegic cerebral palsy. Under predictive conditions, temporal deficits were
observed after impact. Under reactive conditions, the reflex latency was slightly
increased in the paretic hand. The nonparetic hand showed similar results to
controls. The predictive mechanism is present but altered in the paretic hand.
These alterations suggest an inability to anticipate the consequences of dynamic
perturbations in the paretic hand only.

Langue : ANGLAIS