Turning and Sitting in Early Parkinsonism: Differences Between Idiopathic Normal Pressure Hydrocephalus Associated with Parkinsonism and Parkinson's Disease

BackgroundDifferential diagnosis between idiopathic normal pressure hydrocephalus (iNPH) associated with parkinsonism (iNPH-P) and Parkinson's disease (PD) may prove difficult when evaluating patients with early parkinsonism. The objective of this study was to evaluate differences in mobility during standardized tasks between iNPH-P and PD. MethodsWe selected 21 iNPH-P and 21 pharmacologically untreated PD patients. They all performed the instrumented Timed Up and Go test at the time of diagnosis. ResultsTurning tasks showed longer duration and lower speed in iNPH-P than in PD. Vertical variation in acceleration during the sit-to-stand phase was lower in iNPH-P patients, whereas the duration of the stand-to-sit phase was longer. On walking, iNPH-P showed smaller stride length and a longer gait cycle duration. In multivariate analysis adjusting for age and cognitive status as potential confounders, average angular speed on turning before sitting was the discriminating parameter between the two groups. ConclusionsPatients with iNPH-P showed specific abnormal mobility performances with respect to untreated PD, specifically during the turning-to-sitting transition.