Clinical characteristics related to worsening of motor function assessed by the Unified Parkinson’s Disease Rating Scale in the elderly population

There is evidence that nigrostriatal pathology may at least partly underlie mild Parkinsonian signs. We evaluated whether an increase in the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III) could be predicted by the presence of risk and prodromal markers for neurodegenerative diseases in elderly individuals without those diseases. Therefore, we analyzed the UPDRS-III score and various risk and prodromal markers known to antecede neurodegenerative diseases in a population-based cohort comprising 807 individuals free of neurodegenerative diseases at baseline. After 5 years, eight persons (1.0 %) were diagnosed with Parkinson’s Disease (PD). Of those, seven (87.5 %) had motor worsening ≥3 points on the UPDRS-III from baseline to follow-up, one had two points increase. Of the 788 people without PD, 568 (72.1 %) showed no increase in the UPDRS-III scale, 220 (27.9 %) had ≥1 point increase and out of these 104 (13.2 %) had an increase of ≥3 points in the UPDRS-III score after 5 years. We identified an age >60 years (relative risk, RR = 1.7; confidence interval, CI 1.3–2.1) and the occurrence of ≥2 risk factors (RR = 1.5; CI 1.2-1.9) as possible predictors of motor progression. After 5 years, individuals with an increase in the UPDRS-III score had more often a one-sided reduced arm swing (p < 0.001) and identified less odors in the Sniffin’ sticks test (p < 0.041) than persons with stable motor performance. Our data support the assumption that progression of Parkinsonian signs assessed by the UPDRS-III parallels the development of prodromal markers for neurodegenerative diseases in the elderly population.