Gait dysfunction in Parkinson's disease and normal pressure hydrocephalus: a comparative study.

Our objectives were to characterize gait dysfunction in Parkinson's disease (PD) and normal pressure hydrocephalus (NPH) patients, in a comparative analysis. We used a walking test to determine gait velocity (GV), stride length (SL), stride cadence and the presence of frontal (FG) and sub-cortical hypokinetic gait (SHG) features. Equilibrium was tested with the shoulder tug test (STT). These variables were used in cluster analysis, to classify subjects according to gait dysfunction. PD patients were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (HY) scale. NPH patients were reassessed after high volume lumbar puncture (LP). NPH (n = 35) and PD (n = 40) patients had lower SL, GV and STT scores than controls (n = 30). NPH patients had worse results in SL, GV and STT than PD and a higher frequency of both FG and SHG features, compared to PD and the control groups. We found a severe/moderate gait dysfunction cluster, formed by 33 NPH patients and 11 PD patients, and a normal/mild dysfunction cluster, comprising 2 NPH, 29 PD patients and all control subjects. PD patients in the first cluster had worse UPDRS (except for tremor) and HY scores. In NPH patients, all gait variables improved after LP, although not to the controls level. PD and NPH gait was similarly characterized by loss of balance, slowness and small steps, although NPH patients performed worse. In PD patients, gait dysfunction comparable to that of NPH patients was associated with worse motor stage and the akinetic-rigid variant.