Antisaccadic effects of a dopamine agonist as add-on therapy in advanced Parkinson's patients

We wanted to compare clinical neurological and antisaccadic behavior before and after addition of a dopamine agonist to the usual antiparkinsonian drugs in advanced Parkinson's disease. Parkinson's patients in stage 3 and 4 of Hoehn and Yahr not yet taking a dopamine agonist were selected. In 20 patients, the treating neurologist decided to add pergolide. The dose of pergolide was adjusted by the treating neurologist according to clinical response. Antisaccades were studied by infrared oculography before and after addition of pergolide. Antisaccades are voluntary saccades in the opposite direction of an unanticipated visual target. The patients made more errors, i.e. they glanced to the target or they made no eye movement at all. In contradistinction to the global neurological improvement and the better motor scores, antisaccadic disturbances did not improve significantly with pergolide, except in younger patients. These findings suggest that antisaccadic alterations in patients with advanced Parkinson's disease could be multifaceted. Not only depletion of dopamine, but also non-dopaminergic dysfunctions could contribute. Cortical frontal lesions must also be taken into account.