The effect of dopamine agonists on cognitive functions in non-demented early-mild Parkinson's disease patients.

The effect of dopamine agonists (DAs) on cognition in Parkinson's disease (PD) is not yet completely established. Previous papers reported a worsening effect on some cognitive functions with some DAs, but not with others, suggesting that DAs may differently affect cognition in PD patients according to their pharmacological characteristics. We set out to test the effect of rotigotine and cabergoline on cognitive functions in a group of forty non-demented early-mild PD patients (H &Y <2). Subjects were randomly divided into two groups and evaluated in a randomized cross-over study using neuropsychological tests; at the same time, motor function was monitored under three different treatment conditions: DA (rotigotine or cabergoline), L-dopa, and off therapy. Rotigotine and cabergoline were chosen because while they share a mixed D1 and D2 receptor profile, the former is non-ergolinic and the latter ergolinic. No significant differences were found in cognitive function between the basal condition and the DA treatments. On the basis of the present data, which we compare with previous findings regarding pramipexole IR and pergolide, we hypothesize that combined stimulation of both dopamine receptor families, as occurs with rotigotine, cabergoline, L-dopa and pergolide, may preserve cognitive functions more than pure D2 family stimulation.