Dopamine levels after repetitive transcranial magnetic stimulation of motor cortex in patients with Parkinson's disease: Preliminary results

Background: Repeated sessions of repetitive transcranial magnetic stimulation (rTMS) over motor cortex have been reported to produce significant improvement of motor performance in patients with Parkinson's disease (PD). In addition, it is known that a single session of rTMS over motor cortex transiently increases DA in striatum. Here, we test whether repeated sessions of rTMS increase serum dopamine in PD patients and whether this correlates with changes in clinical rating scales. Material and Methods: Twenty untreated PD patients with moderate to severe symptoms (Hoehn & Yahr stage III-V 1967) were assessed on the Unified Parkinson's Disease Rating Scale (UPDRS), and with an enzyme immunoassay for quantitative determination of plasma dopamine before and after six daily sessions of 25 Hz rTMS with 3,000 stimuli over the right and left hand and leg motor cortex. Results: There was significant improvement in UPDRS compared with the baseline. Serum dopamine level also was significantly elevated ever the same interval. There was a significant correlation between UPDRS and serum dopamine level before and after treatment. Conclusion: Improved motor performance in PD after repeated sessions of rTMS may be related to an elevation of serum dopamine concentration. (C) 2007 Movement Disorder Society.