Progression of parkinsonian signs in Parkinson disease

Background: Current knowledge about the rate of progression of extrapyramid al signs (EPSs) in Parkinson disease (PD) is derived largely from cross-sec tional studies comparing subjects at various stages of illness rather than longitudinal studies in which the subjects were followed up over time. Objective: To longitudinally study the progression of EPSs in PD by quantif ying the rate of change of EPSs and by examining each EPS (rigidity, bradyk inesia, tremor, and postural instability) separately. Methods: A community based cohort of 237 patients with PD living in Washing ton Heights-Inwood in Manhattan, NY, was evaluated at baseline and at yearl y intervals. The EPSs were rated using the motor portion of the Unified Par kinson's Disease Rating Scale Motor Examination. Analyses of longitudinal d ata were performed by applying generalized estimating equations to regressi on analyses. Results: The total EPS score increased at an annual rate of 1.5 points (1.5 %), but, among those who died, the total EPS score increased at an annual r ate of 3.6 points (3.6%). Bradykinesia, rigidity, and gait and balance subs cores worsened at similar annual rates of 2.0% to 3.1%, whereas the tremor subscore did not clearly worsen with time. Patients with a shorter disease duration (less than or equal to 3 years) may have progressed more rapidly t han patients with longer disease duration (annual rate of change, 1.9% vs 1 .4%, respectively), although this did not leach statistical significance A high total EPS score was independently associated with dementia, low Activi ties of Daily Living score, and long disease duration at baseline. Conclusions: In this cohort, the progression of EPSs in PD occurred at a ra te of 1.5% per year and at twice that rate among those who died. Bradykines ia, rigidity, and gait and balance impairment worsened at similar rates, wh ereas tremor did not, suggesting that tremor may be relatively independent of these other cardinal manifestations of PD.