Influences of dopaminergic treatment on motor cortex in Parkinson disease: A MRI/MRS study

Abstract

The objective of this study was to investigate neurochemical and metabolic changes in the motor cortex in a group of de novo Parkinson's disease (PD) patients before and after 6 mo treatment with the dopamine agonist pergolide. Proton magnetic resonance spectroscopy (1H-MRS) has been used to study striatal and cortical metabolism in PD and other parkinsonisms. So far, no studies evaluating possible brain metabolic changes in PD patients before and after dopaminergic therapy have been reported. De novo PD patients (11) and controls (11) underwent clinical evaluation (UPDRS-III motor evaluation) and a first single-voxel 1H-MRS of the motor cortex. 1H-MRS studies were performed using the PROBE-SV System implemented on a 1.5 Tesla Scanner (GE Medical System, Milwaukee, WI). Pergolide was administered up to a dose of 1 mg t.i.d. After 6 mo follow-up, all patients were clinically evaluated and a second single-voxel 1H-MRS was performed. Lower values of Cho/Cr and NAA/Cr ratios were observed in the motor cortex of PD patients compared with controls (P < 0.02 and P < 0.01, respectively). After 6 mo therapy with pergolide (1 mg t.i.d), PD patients showed an improvement in motor performances (P < 0.05) and an increase in Cho/Cr ratios in the motor cortex at the second 1H-MRS evaluation (P < 0.05) was reported. In conclusion, cortical NAA/Cr and Cho/Cr ratios may be impaired in de novo PD. Dopaminergic therapy capable of improving motor function may restore the Cho/Cr ratio in the motor cortex.