Affiliations: [a] Département de psychologie, Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, Canada, H3C3J7 | [b] Centre de Recherche du Centre Hospitalier Universitaire de l’Hôpital Sainte Justine, 3175 Chemin de la Côte Ste-Catherine, Montréal, Canada, H3T1C5 | [c] Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, USA, 02215
Correspondence:
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Corresponding author: Hugo Théoret, PhD, Département de Psychologie, Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, QC, H3C 3J7, Canada. Tel.: +1 514 343 6362; Fax: +1 514 343 5787; hugo.theoret@umontreal.ca
Note: [1] These authors contributed equally to this work.
Abstract:
Purpose: Recent studies investigating the effects of mild traumatic brain injury (mTBI) suggest the presence of unbalanced excitatory and inhibitory mechanisms within primary motor cortex (M1). Whether these abnormalities are associated with impaired synaptic plasticity remains unknown.
Methods: The effects of continuous theta burst stimulation (cTBS) on transcranial magnetic stimulation-induced motor evoked potentials (MEPs) were assessed on average two weeks and six weeks following mTBI in five individuals.
Results: The procedure was well-tolerated by all participants. Continuous TBS failed to induce a significant reduction of MEP amplitudes two weeks after the injury, but response to cTBS normalized six weeks following injury, as a majority of patients became asymptomatic.
Conclusions: These preliminary results suggest that cTBS can be used to assess M1 synaptic plasticity in subacute phase following mTBI and may provide insights into neurobiological substrates of symptoms and consequences of mTBI.
Keywords: Traumatic brain injury, concussion, transcranial magnetic stimulation, plasticity, motor cortex
