Background: Although depression is highly prevalent in Parkinson disease (PD), little is known about the neural correlates associated with depression and antidepressant treatment in PD.
Objective: To examine the effects of fluoxetine and repetitive transcranial magnetic stimulation (rTMS) on regional cerebral blood flow (rCBF) using SPECT in patients with PD and depression.
Methods: Twenty-six patients were enrolled into two groups: One received active rTMS and placebo medication and the other sham rTMS and fluoxetine 20 mg/day. Brain SPECT was performed at baseline and after 2 and 8 weeks. Changes in rCBF were compared across timepoints and correlated with clinical scores. In addition, baseline rCBF of these patients was compared with that of 29 healthy, age-matched subjects.
Results: At baseline, patients with PD and depression showed significantly lower rCBF in the left prefrontal cortex, posterior cingulate gyrus, left insula, and right parietal cortex when compared with healthy controls. Both treatments induced significant clinical improvement and increases in rCBF in the posterior cingulate gyrus and decreases in rCBF in the right medial frontal gyrus. These changes were significantly correlated to the clinical outcome. Furthermore, the comparison between these two treatments revealed that whereas rTMS treatment was associated with an increased perfusion in the right and left prefrontal cortex, fluoxetine treatment was associated with a relative rCBF increase in the occipital lobe.
Conclusion: Depression in patients with Parkinson disease is correlated with a dysfunction of the frontal-limbic network that can be modulated by two different antidepressant therapies.