ARE THERE DEFICITS IN ANTICIPATORY POSTURAL ADJUSTMENTS IN PARKINSONS-DISEASE

WE studied anticipatory postural adjustments in patients with Parkinso n's disease who dropped a load from extended arms while standing. Anti cipatory postural adjustments were seen when load dropping was induced by a fast, bilateral shoulder abduction but not when it was induced b y pressing a trigger with the right thumb. We conclude that anticipato ry postural adjustments in patients with Parkinson's disease can chang e with the magnitude of an action which is used to trigger a predictab le postural perturbation. Thus, the described deficits in anticipatory postural adjustments in patients with Parkinson's disease are likely to be of quantitative rather than qualitative nature.