Effect of repetitive TMS and fluoxetine on cognitive function in patients with Parkinson's disease and concurrent depression

Abstract

Previous studies show that cognitive functions are more impaired in patients with Parkinson's disease (PD) and depression than in nondepressed PD patients. We compared the cognitive effects of two types of antidepressant treatments in PD patients: fluoxetine (20 mg/day) versus repetitive transcranial magnetic stimulation (rTMS, 15 Hz, 110% above motor threshold, 10 daily sessions) of the left dorsolateral prefrontal cortex. Twenty-five patients with PD and depression were randomly assigned either to Group 1 (active rTMS and placebo medication) or to Group 2 (sham rTMS and fluoxetine). A neuropsychological battery was assessed by a rater blind to treatment arm at baseline and 2 and 8 weeks after treatment. Patients in both groups had a significant improvement of Stroop (colored words and interference card) and Hooper and Wisconsin (perseverative errors) test performances after both treatments. Furthermore, there were no adverse effects after either rTMS or fluoxetine in any neuropsychological test of the cognitive test battery. The results show that rTMS could improve some aspects of cognition in PD patients similar to that of fluoxetine. The mechanisms for this cognitive improvement are unclear, but it is in the context of mood improvement.

Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex enhances working memory

“…Despite mixed results for healthy participants, a number of promising rTMS studies have shown beneficial WM effects in neuropsychiatric patients, both for depression (O'Connor et al 2003;Fabre et al 2004;Hausmann et al 2004;Schulze-Rauschenbach et al 2005;Boggio et al 2005;Kuroda et al 2006;Bloch et al 2008;Vanderhasselt et al 2009;Guse et al 2010) and schizophrenia (Demirtas-Tatlidede et al 2013;Levkovitz et al 2011;Barr et al 2013). Compromised cortical activity of neuropsychiatric patients, associated with hypo-dopaminergic states (Stahl 2013) and neurophysiological inhibitory deficits (Radhu et al 2013), may explain these findings.…”

Neuromodulation approaches for the treatment of major depression: challenges and recommendations from a working group meeting

“…Fregni et al 161 found that high-frequency rTMS applied over the left DLPFC daily for ten days resulted in reduction of depressive symptoms. Boggio et al 162 found that this improvement extended to cognitive functions such as verbal fluency and executive functions. The same authors found that anodal tDCS (2 mA) applied over the left DLPFC of patients with Parkinson's disease resulted in an improvement in working memory task 163 .…”

Parkinson's disease treatments: focus on transcranial direct current stimulation (tDCS)

“…64 Indeed, anodal tDCS over the left DLPFC with the cathode over the right supraorbital region has been shown to improve working memory in healthy subjects, 65 as well as improve mood in patients with major depression. 66,67 In this context, several studies have documented the beneficial effects of TMS on cognitive symptoms in PD 68,69 without worsening motor symptoms. 70 These results support the idea that active stimulation of the DLPFC with tDCS could also have beneficial effects on both affective and cognitive domains in patients with PD.…”