The Effects of Repetitive Transcranial Magnetic Stimulation on Cognitive Performance in Treatment-Resistant Depression. A Systematic Review

Abstract

Background: Major depressive disorder (MDD) is a disabling illness associated with significant functional and psychosocial impairment. Although many psychopharmacological agents are currently available for its treatment, many MDD patients suffer from treatment-resistant depression (TRD). Methods: A systematic review of the current literature (Pubmed/Medline, Scopus and ScienceDirect search) has been conducted with the primary aim to investigate the role of repetitive transcranial magnetic stimulation (rTMS) in improving neurocognition in patients with TRD. Studies were included according to the following criteria: (a) being an original paper in a peer-reviewed journal and (b) having analyzed the effect of rTMS on neurocognitive functioning in TRD. Results: The combined search strategy yielded a total of 91 articles, of which, after a complete analysis, 22 fulfilled our inclusion criteria. Based on the main findings, most of the selected studies suggested the existence of a trend towards improvements in the neurocognitive profile using rTMS. Negative findings have also been reported. However, most studies were limited by their small sample size or included mixed samples, or the adopted single-blind designs potentially biased the blinding of the study design. Conclusion: rTMS is a noninvasive brain stimulation that may be considered a valuable and promising technique for cognitive enhancement in TRD.

Cognitive enhancing effects of rTMS administered to the prefrontal cortex in patients with depression: A systematic review and meta-analysis of individual task effects

“…We conducted a literature search in the following databases: PubMed/MEDLINE, EMBASE (Ovid), and PsychINFO (Ovid). In addition, the published systematic review bibliographies of the cognitive effects of rTMS were searched for additional studies (Guse, Falkai, & Wobrock, 2010;Serafini et al, 2015). The search terms included "repetitive transcranial magnetic stimulation" or "rTMS," and "neurocognition" or "neurocognitive performance" or "cognitive effects" or "cognitive" or "neuropsychological," and "randomized controlled trial" or "randomized controlled trial" or "controlled clinical trial" or "RCT" or "sham controlled."…”

Does Therapeutic Repetitive Transcranial Magnetic Stimulation Cause Cognitive Enhancing Effects in Patients with Neuropsychiatric Conditions? A Systematic Review and Meta-Analysis of Randomised Controlled Trials

“…These specific search terms were chosen to be broad enough to capture studies of rTMS conducted in clinical populations, regardless of diagnosis or site of stimulation, and specific enough to limit results to randomised controlled trials where cognitive outcomes were examined. Further, the bibliographies of published systematic reviews of the cognitive effects of rTMS were searched for additional studies (i.e., Guse et al 2010; Dougall et al 2015; Serafini et al 2015), and we contacted study authors as needed to attain additional data. Results were limited to studies in humans and those published in English language.…”

“…Given that the site of stimulation (i.e., DLPFC) frequently used for therapeutic rTMS is known to subserve multiple higher level cognitive functions including executive function, learning and memory, and working memory, and that repeated daily administration to this same region over several weeks has proven therapeutic effects, the possibility of cognitive enhancement following repeated rTMS administration remains an open question. Recent systematic reviews conducted in both mixed (Guse et al 2010) and depressed samples (Serafini et al, 2015) indeed have suggested that rTMS has promising cognitive enhancing effects.…”

Transcranial magnetic stimulation for treatment of major depression during pregnancy: a review

“…Unlike ECT, TMS appears to improve cognitive function. 48 On the other hand, the response of depressive symptoms to ECT is presumed to be more general and robust. 49…”