Citation

Ansado J, Blunt A, Chen JK, Koski L, Ptito A. Brain Inj. 2019; 33(8): 1021-1031.

Affiliation

Department of Neurology and Neurosurgery , McGill University , Montreal , QC , Canada.

Copyright

(Copyright © 2019, Informa - Taylor and Francis Group)

DOI

10.1080/02699052.2019.1605620

PMID

31170014

Abstract

Background: We combined performance on working memory (WM) tasks with diffusion (dMRI) and functional (fMRI) magnetic resonance imaging in young adults who had suffered a concussion to better understand the inter-hemispheric effects of unilateral repetitive transcranial magnetic stimulation (rTMS). Methods: The article is presenting pilot data on 8 symptomatic patients with persistent post-concussion symptoms for over 6 months. They received 20 sessions of rTMS over the left dorsolateral prefrontal cortex. Fractional anisotropy and mean diffusivity of the corpus callosum (CC) and fMRI measurement of blood-oxygen-level dependent signal changes during WM tasks were carried out before and after rTMS stimulation. Results: After participants had completed the rTMS sessions, we observed three main results: (1) bilateralization of activation within the WM network; (2) shift from transcallosal inhibition to transcallosal activation of the right-sided WM network via the anterior callosal fibres; and (3) shift from transcallosal activation to transcallosal inhibition of the right-sided WM network via the posterior parts of the CC. More nuanced patterns of transcallosal mediation in the region of the right-sided WM network were observed via the medial part of the CC. Conclusion: Our preliminary results encourage trends of further research supporting the use of rTMS to restore inter-hemispheric balance within the bilateral WM network in young adults with a history of concussion.

Language: en

Keywords

Concussion; corpus callosum; dMRI; fMRI; rTMS intervention; transcallosal mediation; working memory network