Probing the Brain-Body Connection Using Transcranial Magnetic Stimulation (TMS): Validating a Promising Tool to Provide Biomarkers of Neuroplasticity and Central Nervous System Function

Overview

Journal Brain Sci

Publisher MDPI

Date 2021 Apr 3

PMID 33803028

Citations 13

Authors

Arthur R Chaves

Nicholas J Snow

Lynsey R Alcock

Michelle Ploughman

Affiliations

Soon will be listed here.

Abstract

Transcranial magnetic stimulation (TMS) is a non-invasive method used to investigate neurophysiological integrity of the human neuromotor system. We describe in detail, the methodology of a single pulse TMS protocol that was performed in a large cohort of people ( = 110) with multiple sclerosis (MS). The aim was to establish and validate a core-set of TMS variables that predicted typical MS clinical outcomes: walking speed, hand dexterity, fatigue, and cognitive processing speed. We provide a brief and simple methodological pipeline to examine excitatory and inhibitory corticospinal mechanisms in MS that map to clinical status. Delayed and longer ipsilateral silent period (a measure of transcallosal inhibition; the influence of one brain hemisphere's activity over the other), longer cortical silent period (suggestive of greater corticospinal inhibition via GABA) and higher resting motor threshold (lower corticospinal excitability) most strongly related to clinical outcomes, especially when measured in the hemisphere corresponding to the weaker hand. Greater interhemispheric asymmetry (imbalance between hemispheres) correlated with poorer performance in the greatest number of clinical outcomes. We also show, not surprisingly, that TMS variables related more strongly to motor outcomes than non-motor outcomes. As it was validated in a large sample of patients with varying severities of central nervous system dysfunction, the protocol described herein can be used by investigators and clinicians alike to investigate the role of TMS as a biomarker in MS and other central nervous system disorders.

Citing Articles

MacKenzie E, Bray N, Raza S, Newell C, Murphy H, Ploughman M Physiol Rep. 2025; 13(4):e70223.

PMID: 39985143 PMC: 11845323. DOI: 10.14814/phy2.70223.

Robotic Rigor: Validity of the Kinarm End-Point Robot Visually Guided Reaching Test in Multiple Sclerosis.

Bray N, Raza S, Avila J, Newell C, Ploughman M Arch Rehabil Res Clin Transl. 2025; 6(4):100382.

PMID: 39822195 PMC: 11733819. DOI: 10.1016/j.arrct.2024.100382.

Lowered ratio of corticospinal excitation to inhibition predicts greater disability, poorer motor and cognitive function in multiple sclerosis.

Chaves A, Tremblay S, Pilutti L, Ploughman M Heliyon. 2024; 10(15):e35834.

PMID: 39170378 PMC: 11337054. DOI: 10.1016/j.heliyon.2024.e35834.

Disrupted hemodynamic response within dorsolateral prefrontal cortex during cognitive tasks among people with multiple sclerosis-related fatigue.

Baldasso B, Raza S, Islam S, Burry I, Newell C, Hillier S PLoS One. 2024; 19(6):e0303211.

PMID: 38837991 PMC: 11152297. DOI: 10.1371/journal.pone.0303211.

Transcranial magnetic stimulation enhances the specificity of multiple sclerosis diagnostic criteria: a critical narrative review.

Snow N, Murphy H, Chaves A, Moore C, Ploughman M PeerJ. 2024; 12:e17155.

PMID: 38563011 PMC: 10984191. DOI: 10.7717/peerj.17155.

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