Journal: BMC Psychiatry 19(1) (2019)
Authors: H.M Gellersen and K.K Kedzior
Although repetitive transcranial magnetic stimulation (rTMS) with figure-of-8 (F8)-coil and deep transcranial stimulation (dTMS)with H1-coil are promising treatments for unipolar major depressive disorder (MDD), the head-to-head comparisons in efficacy of both methods are lacking so far.
The current study aims to systematically assess and compare the antidepressant outcomes of rTMS F8-coil and dTMS with the H1-coil in studies matched on stimulation frequency in unipolar MDD.
Electronic search of Medline and PsycInfoidentified 19 studies with stimulation frequency of 18–20 Hz using F8-coil (k = 8 randomised sham-controlled trials, RCTs, k = 3 open-label; n = 168 patients) or H1-coil (k = 1 RCT, k = 7 open-label; n = 200). Depression severity (the primary outcome) andresponse/remission rates (the secondary outcomes) were assessed at session 10.
Effects pooled with random-effects meta-analysis showed a large reduction in depression severity, 29% response, and 15% remission rates after 10 sessions of active stimulation with either coil relative to baseline. Reduction in depression severity was greater in studies with younger patients using either coil. The comparison between coils showed a larger reduction in depression severity in H1-coil vs. F8-coil studies(independent of the study design or the concurrent pharmacotherapy) and a trend towards higher remission rates in F8-coil vs. H1-coils studies. These effects are based on a low volume of studies, are not controlled for placebo, and may not be clinically relevant. The stimulation protocols differed systematically because stimulation was more focal but less intense (80–110% of the resting motor threshold, MT) in the F8-coil studies and less focal but more intense (120% MT) in the H1-coil studies. Two seizures occurred in the H1-coil studies relative to none in the F8-coil studies.
When matched on frequency, the higher-intensity and less focal stimulation with the H1-coil reduces depression more than the lower-intensity and more focal stimulationwith the F8-coil. Head-to-head trials should compare the antidepressant outcomes of F8-coil and H1-coil to identify the most optimal stimulation protocols for acute and longer-lasting efficacy.