The primary aim of this review was to evaluate the effectiveness of noninvasive brain stimulation to the dorsolateral prefrontal cortex (dlPFC) for modulating appetitive food cravings and consumption in laboratory (via meta-analysis) and therapeutic (via systematic review) contexts.
Keyword searches of electronic databases (PubMed, Scopus, Web of Science, PsychoInfo, and EMBASE) and searches of previous quantitative reviews were used to identify studies (experimental [single-session] or randomized trials [multi-session]) that examined the effects of neuromodulation to the dlPFC on food cravings (n = 9) and/or consumption (n = 7). Random-effects models were employed to estimate the overall and method-specific (repetitive transcranial magnetic stimulation [rTMS] and transcranial direct current stimulation [tDCS]) effect sizes. Age and body mass index were examined as potential moderators. Two studies involving multisession therapeutic stimulation were considered in a separate systematic review.
Findings revealed a moderate-sized effect of modulation on cravings across studies (g, −0.516; p = .037); this effect was subject to significant heterogeneity (Q, 33.086; p < .001). Although no statistically significant moderators were identified, the stimulation effect on cravings was statistically significant for rTMS (g, −0.834; p = .008) but not tDCS (g, −0.252; p = .37). There was not sufficient evidence to support a causal effect of neuromodulation and consumption in experimental studies; therapeutic studies reported mixed findings.
Stimulation of the dlPFC modulates cravings for appetitive foods in single-session laboratory paradigms; when estimated separately, the effect size is only significant for rTMS protocols. Effects on consumption in laboratory contexts were not reliable across studies, but this may reflect methodological variability in delivery of stimulation and assessment of eating behavior. Additional single- and multi-session studies assessing eating behavior outcomes are needed.
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From the Faculty of Applied Health Sciences (Lowe, Hall), University of Waterloo, Ontario, Canada; Faculty of Medicine (Vincent), University of Toronto, Toronto, Canada.
Cassandra J. Lowe, MSc and Corita Vincent, MSc contributed equally to this work.
Address correspondence and reprint requests to Peter A. Hall, PhD, Prevention Neuroscience Lab, Faculty of Applied Health Sciences, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1. E-mail: firstname.lastname@example.org
Received for publication February 2, 2016; revision received May 1, 2016.