Journal: Brain Stimulation (2017)
Authors: Kedzior KK, Müller C, Gellersen HM
Background:
Various non-invasive repetitive transcranial magnetic stimulation (rTMS) methods have been approved for treatment-resistant unipolar depression.
Objective:
To compare the efficacy of two rTMS coils (H1-coil vs. F8-coil) using a systematic review and meta-analysis.
Methods:
Following a systematic search of PsycInfo and Medline (until July, 2016), 17 studies using similar stimulation parameters with either H1-coil (k=6, n=80 patients) or F8-coil (k=11, n=155) were included in this review. The inclusion criteria were: high-frequency (18-20 Hz) stimulation of the left dorsolateral prefrontal cortex, ≥5 patients with unipolar major depression (according to DSM or ICD), open-label or randomized-controlled design (RCT; single- or double-blind), depression assessment using Hamilton Depression Rating Scale (HDRS) at baseline and after the same number of sessions (session 10 in all studies). Data from only the active stimulation groups from RCTs were included in the analysis.
Results:
HDRS scores were expressed as standardized mean paired differences (baseline – session 10). According to random-effects meta-analysis with inverse-variance weights HDRS scores were significantly more reduced after 10 sessions of rTMS with H1-coil than F8-coil. This effect did not depend on add-on antidepressants, study design (open-label or RCT), or percent female patients/study. However, studies with H1-coil used presumably less focal but more intense stimulation (at 120% of the resting motor threshold, MT). In contrast, studies with F8-coil used more focal but less intense stimulation (at 80-110% MT). Furthermore, the antidepressant effect of either coil tended to be lower in studies with older patients.
Conclusions:
The acute efficacy of high frequency rTMS might depend on a combination of focality and intensity of stimulation and patient age in unipolar major depression. Head-to-head trials are necessary to compare the efficacy of different rTMS coils and to find the most optimal stimulation protocols for long-lasting antidepressant effects.
