EARLY POST-STROKE PERIOD: A PRIVILEGED TIME FOR SENSORY RE-WEIGHTING?

Background: Shortly after stroke, patients exhibit excessive sensitivity to visual, proprioceptive and vestibular perturbations regarding balance control. Objective: To evaluate the stability of this perceptual behaviour after stroke and test the relationships between sensory sensitivity and balance. Methods: Thirty subjects following a hemispheric stroke (mean age 54.7 (standard deviation (SD) 10.6 years), 21 men, right hemisphere lesion = 13) and 30 control subjects (mean age 52.0 (SD 12.0), 14 men). Sensitivity to sensory perturbations was evaluated using the displacement of the centre of pressure during tendon vibration (proprioception score), optokinetic (visual score) and galvanic perturbations (vestibular score) while standing on a force-platform a mean of 2 months after stroke, and 1 month later. Balance and independence were evaluated using the Berg Balance Scale (BBS), Timed Up and Go test (TUG) and Barthel Index (BI). Results: Global sensitivity to perturbations decreased (p = 0.001). Patients remained more sensitive to visual perturbation than did controls (p = 0.033). The Vestibular Score was correlated with BBS (Rs = -0.576, p = 0.006), TUG (Rs = 0.408, p = 0.045), BI (Rs = -0.481, p = 0.016); the Visual Score was correlated with BBS (Rs = -0.500, p = 0.019), TUG (Rs = 0.401, p = 0.049). Conclusion: The initial months following stroke appear to be a period of individual perceptual motor adaptation. Sensory re-weighting is likely to be a major component of that process.