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A new angle on transcranial magnetic stimulation coil orientation: A targeted narrative review
Journal article   Open access   Peer reviewed

A new angle on transcranial magnetic stimulation coil orientation: A targeted narrative review

Andris Cerins, Elizabeth H.X. Thomas, Tracy Barbour, Joseph J. Taylor, Shan H. Siddiqi, Nicholas Trapp, Alexander McGirr, Kevin A. Caulfield, Joshua C. Brown and Leo Chen
Biological psychiatry : cognitive neuroscience and neuroimaging, Vol.9(8), pp.744-753
08/2024
DOI: 10.1016/j.bpsc.2024.04.018
PMCID: PMC12221855
PMID: 38729243
url
https://doi.org/10.1016/j.bpsc.2024.04.018View
Published (Version of record) Open Access

Abstract

Transcranial magnetic stimulation (TMS) is used to treat several neuropsychiatric disorders including depression, where it is effective in approximately half of patients for whom pharmacological approaches have failed. Treatment response is related to stimulation parameters such as the stimulation frequency, pattern, intensity, location, total number of pulses and sessions applied, as well as target brain network engagement. One critical but underexplored component of the stimulation procedure is the orientation or yaw angle of the commonly used figure-of-eight TMS coil, which is known to impact neuronal response to TMS. However, coil orientation has remained largely unchanged since TMS was first used to treat depression and continues to be based on motor cortex anatomy which may not be optimal for the dorsolateral prefrontal cortex treatment site. This targeted narrative review evaluates experimental, clinical, and computational evidence indicating that optimizing coil orientation may potentially improve TMS treatment outcomes. The properties of the electric field induced by TMS, the changes to this field caused by the differing conductivities of head tissues, and the interaction between coil orientation and the underlying cortical anatomy are summarized. We describe evidence that the magnitude and site of cortical activation, surrogate markers of TMS dosing and brain network targeting considered central in clinical response to TMS, are influenced by coil orientation. We suggest that coil orientation should be considered when applying therapeutic TMS and propose several approaches to optimizing this potentially important treatment parameter.
current direction dorsolateral prefrontal cortex gyral anatomy Repetitive transcranial magnetic stimulation rTMS coil orientation TMS targeting TMS treatment

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