Repetitive Transcranial Magnetic Stimulation Helpful for Depression in Parkinson's Disease
Laurie Barclay, MD
Aug. 13, 2004 — Repetitive transcranial magnetic stimulation (rTMS) is as effective as fluoxetine for the treatment of depression in patients with Parkinson's disease, according to the results of a placebo-controlled trial published in the August issue of the Journal of Neurology, Neurosurgery and Psychiatry.
"[rTMS] is a non-invasive, well tolerated technique for stimulating the brain," write F. Fregni, from Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, Massachusetts, and colleagues. "rTMS may have an antidepressant effect by the enhancing the serotoninergic system and increasing monoamine levels. Furthermore, previous studies showed that rTMS applied to the prefrontal area led to an improvement in motor function in patients with Parkinson's disease."
In this double-blind study, 42 patients with Parkinson's disease and depression received active rTMS (15 Hz for 10 days) and oral placebo; or sham rTMS using a specially designed sham coil and 20 mg of fluoxetine per day.
After two weeks of treatment, the Hamilton Rating Scale for Depression and Beck Depression Inventory were similarly improved in both groups (38% and 32% for active rTMS; 41% and 33% for fluoxetine, respectively). At week 8, activities of daily living were improved only in the active rTMS group, and there was a nonsignificant trend for worse scores in the motor function section of the Unified Parkinson's Disease Rating Scale in the fluoxetine group. Although scores on the Mini-Mental State Examination improved with both treatments, it improved faster in the active rTMS group. There were fewer adverse effects with active rTMS than with fluoxetine.
Study limitations include lack of a placebo group due to ethical constraints and possible methodological problems involving the sham coil.
"rTMS has the same antidepressant efficacy as fluoxetine and may have the additional advantage of some motor improvement and earlier cognitive improvement, with fewer adverse effects," the authors write. "The drawbacks of each treatment have to be considered, as rTMS involves higher costs (TMS equipment, trained people to apply) and inconveniences (dislocation to treatment centre), and fluoxetine has some adverse effects, being associated with worsening of the motor symptoms of Parkinson's disease, although this is still controversial."
The authors note that more information is needed concerning optimal stimulation parameters, including number of stimuli per session, number of sessions per week, and optimum length of a course of stimulation. They recommend testing a longer period of rTMS treatment in a similar population.
J Neurol Neurosurg Psychiatry, 2004;75:1171-1174