Ten milligrams (mg) per day of deprenyl (selegiline), a relatively new selective monoamine oxidase inhibitor (MAOI) type B is believed to reduce the rate at which motor symptoms in idiopathic Parkinson's Disease (IPD) progress (Parkinson's study group, 1989). It has also been suggested to have a positive impact on cognitive deficits in persons with IPD. This claim was investigated in a double-blind placebo controlled trial with 23 dementia-free mild to moderate IPD subjects, eight of whom had established IPD requiring levodopa therapy. The remaining 15 subjects formed a second group of more recently diagnosed early IPD. Ten control subjects were used for comparative purposes on the baseline cognitive and affective measures. Subjects with IPD were significantly more depressed than controls, and demonstrated impairment on the Wisconsin Card Sorting Test, and a trend towards reduced immediate recall of prose. The results of this study indicated that eight weeks of deprenyl therapy did not result in improved motor, cognitive or affective functioning. The lack of improvement is consistent with Heitanen (1991), but conflicts with claims made by Lees (1991) and Partin & Rinnie (1983) who suggest that deprenyl improves cognitive functioning in IPD. Instead, deprenyl's effect may be to delay cognitive deterioration in early untreated IPD (Como, 1990)
