Effect of age and disease duration on parkinsonian motor scores under levodopa therapy.

One hundred and fifty patients suffering from Parkinson's disease were analysed for the expression of the motor symptoms during optimum response to levodopa therapy (subscale III of the Unified-Parkinson's Disease Rating Scale). Patients were grouped according to age (< or = 64, 65-74, > or = 75 years). Disease duration and daily levodopa dosage were similar in the three groups. Pooled residual scores for posture and gait impairment (PGI), tremor (T), rigidity (R) and distal motor impairment (DMI; hand and foot movements) increased with age (Kruskal-Wallis ANOVA). The parkinsonian scores were significantly higher than the scores of 150 age-matched normal controls (Mann-Whitney U test). The differences between the patients' scores and the scores of the age-matched controls increased with age. In spite of a significant increase in the daily levodopa dosage with disease duration (linear regression), PGI aggravated age-dependently, and DMI age-independently with symptom duration (Spearman rank correlation). In contrast, T and R did not increase with disease duration.