The effects of theta burst stimulation (TBS) targeting the prefrontal cortex on executive functioning: A systematic review and meta-analysis

Cassandra J Lowe; Felicia Manocchio; Adrian B Safati; Peter A Hall

doi:10.1016/j.neuropsychologia.2018.02.004

The effects of theta burst stimulation (TBS) targeting the prefrontal cortex on executive functioning: A systematic review and meta-analysis

Neuropsychologia. 2018 Mar:111:344-359. doi: 10.1016/j.neuropsychologia.2018.02.004. Epub 2018 Feb 10.

Authors

Cassandra J Lowe¹, Felicia Manocchio¹, Adrian B Safati¹, Peter A Hall²

Affiliations

¹ Prevention Neuroscience Lab, School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
² Prevention Neuroscience Lab, School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada N2L 3G1. Electronic address: pahall@uwaterloo.ca.

PMID: 29438672
DOI: 10.1016/j.neuropsychologia.2018.02.004

Abstract

Theta burst stimulation (TBS) is a highly efficient repetitive transcranial magnetic stimulation (rTMS) variant employed in experimental and clinical treatment paradigms. Despite widespread usage of TBS targeting the prefrontal cortex (PFC), there has been no systematic review of the evidence linking TBS protocols to changes in task performance on common measures of prefrontal function in general, and executive functions specifically. A systematic review of the literature was conducted using PsycINFO, PubMed, Web of Science and Scopus databases to identify articles examining the effects of TBS targeting the PFC on executive function task performance. Both the up-regulating (intermittent theta burst stimulation; iTBS) and down-regulating (continuous theta burst stimulation; cTBS) variants of TBS were considered. 32 (29 cTBS; 8 iTBS) studies met the inclusion criteria. Participants (n = 759; 51.41% female) were primarily young adults (M_age = 26), with one study examining the effects of cTBS and iTBS in older adults. Results from individual studies were converted to Hedge's g and random-effects models were used to estimate the overall effect size for each protocol. Age, biological sex, and control methodology were examined as potential moderators of the cTBS effect on executive function test performance. Findings indicated a- reliable attentuating effect of cTBS on executive function task performance (g = -.244, Z = -5.920, p < .001); this effect was relatively uniform across included studies (Q= 24.178, p = .838, I² = 0). Although no significant moderators of the cTBS effect were identified, laterality sub analyses indicated that the magnitude of the effect was significantly higher (M_diff = .213, Z_diff = 2.546, p = .011) for left-sided (g = -.358, Z = -5.816, p < .001) relative to right-sided (g = -.145, Z = -2.552, p = .011) PFC stimulation. A systematic review of iTBS studies revealed variability in reliability of effects though most were in the theorized direction. TBS protocols appear to be effective in modulating prefrontal cortical excitability in previously theorized directions.

Keywords: Executive function; Meta-analysis; Prefrontal cortex; Theta burst stimulation.

Publication types

Meta-Analysis
Systematic Review

MeSH terms

Executive Function / physiology*
Humans
Prefrontal Cortex / physiology*
Transcranial Magnetic Stimulation / methods*