Dynamic strength in Parkinson's disease. Quantitative measurements following withdrawal of medication

This study examined the influence of pharmacological treatment on muscle strength in Parkinson's disease (PD). Twelve patients, 7 men and 5 women, were tested with modified Cybex II equipment. Peak torques in isometric, concentric and eccentric contraction at 30, 120 and 180 degrees/s in ankle dorsiflexors were recorded before and after the withdrawal of medication. EMG were recorded during contraction. Clinical assessment was done according to Webster's and Hoehn and Yahr's rating scales. Clinical scores were significantly increased (p < 0.05). Peak torques in isometric, concentric and eccentric contraction (p < 0.05) decreased at almost all velocities after withdrawal of medication. Correlations were found between changes in clinical score and strength. Strength production in PD was influenced by medication, and the results correlated with changes in clinical ratings. Strength measurement may be used in the evaluation of pharmacological therapy.