Levodopa versus non-levodopa brain language fMRI in Parkinson's disease.

Objective: To identify the effect of levodopa in language areas in Parkinson's disease patients.

Methods: We evaluated 50 patients with mild to moderate Parkinson's disease, age and gender paired to 47 healthy volunteers. We selected two homogeneous groups of 18 patients taking levodopa and 7 no levodopa patients. The functional magnetic resonance imaging verbal fluency task, with low and high cognitive demands, was performed at a 3T magnetic resonance imaging equipment. Data was analyzed with XBAM software for group maps and ANOVA comparison.

Results: Patients without levodopa had more activation than the ones with levodopa in the medial frontal and in the left frontal and parieto-occipital areas. The striatal activation in patients taking levodopa had similar result of the activation detected in the healthy volunteer group. Parieto-occipital areas were less activated in the levodopa group than in the no levodopa one.

Conclusion: Parkinson's disease patients without levodopa replacement, during a verbal fluency effort, had more diffuse and intense cerebral activation in left hemisphere, mainly in the frontal and parieto-occipital areas. The striatal activation in verbal fluency of patients with levodopa intake was more similar to the activation found in healthy volunteers. These initial evidences suggested a role of levodopa inhibiting activation in parieto-occipital compensating areas.