Reduction of parkinsonian signs in patients with Parkinson's disease by dopaminergic versus anticholinergic single-dose challenges

We investigated the effect of an anticholinergic (biperiden) and a dopamine agonist (apomorphine) on tremor, rigidity, and akinesia in patients with i diopathic Parkinson's disease. In a standardized, crossover study design 17 patients received single-dose challenges of 5 mg biperiden intravenously a nd a previously determined dose of apomorphine subcutaneously on 2 consecut ive days. Resting (RT); postural (PT), and action tremor (AT) were assessed using spectral analysis of accelerometer data, and Unified Parkinson's Dis ease Rating Scale (UPDRS) scores for rigidity and akinesia were determined before and after administration of the study drug. Both single-dose challen ges significantly reduced the amplitude of RT, PT, and AT, but only apomorp hine significantly reduced UPDRS scores for rigidity and akinesia. In only one patient was tremor reduced by the dopamine agonist but not by the antic holinergic. We found that anticholinergic and dopaminergic agents are both effective in reducing tremor in IPD, and there was no evidence for a select ive anticholinergic responsiveness of parkinsonian tremor. Akinesia and rig idity, on the other hand, were not improved by biperiden. We therefore conc lude that dopaminergic substances are as effective as anticholinergics in p atients with parkinsonian tremor and additionally improve other parkinsonia n signs.