Dissociation of structural and functional integrities of the motor system in amyotrophic lateral sclerosis and behavioral-variant frontotemporal dementia

Bae, Jong Seok, Ferguson, Michele, Tan, Rachel, Mioshi, Eneida, Simon, Neil, Burrell, James, Vucic, Steve, Hodges, John R., Kiernan, Matthew C. and Hornberger, Michael (2016) Dissociation of structural and functional integrities of the motor system in amyotrophic lateral sclerosis and behavioral-variant frontotemporal dementia. Journal of Clinical Neurology, 12 (2). pp. 209-217. ISSN 1738-6586

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Abstract

Background and Purpose: This study investigated the structural and functional changes in the motor system in amyotrophic lateral sclerosis (ALS; n=25) and behavioral-variant fronto-temporal dementia (bvFTD; n=17) relative to healthy controls (n=37). Methods: Structural changes were examined using a region-of-interest approach, applying voxel-based morphometry for gray-matter changes and diffusion tensor imaging for white-matter changes. Functional changes in the motor system were elucidated using threshold-tracking transcranial magnetic stimulation (TMS) measurements of upper motor-neuron excitability. Results: The structural analyses showed that in ALS there were more white-matter changes in the corticospinal and motor-cortex regions and more gray-matter changes in the cerebellum in comparison to controls. bvFTD showed substantial gray- and white-matter changes across virtually all motor-system regions compared to controls, although the brainstem was affected less than the other regions. Direct comparisons across patient groups showed that the gray- and white-matter motor-system changes inclusive of the motor cortex were greater in bvFTD than in ALS. By contrast, the functional integrity of the motor system was more adversely affected in ALS than in bvFTD, with both patient groups showing increased excitability of upper motor neurons compared to controls. Conclusions: Cross-correlation of structural and functional data further revealed a neural dissociation of different motor-system regions and tracts covarying with the TMS excitability across both patient groups. The structural and functional motor-system integrities appear to be dissociated between ALS and bvFTD, which represents useful information for the diagnosis of motor-system changes in these two disorders.

Item Type: Article
Additional Information: This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Faculty \ School: Faculty of Medicine and Health Sciences > School of Health Sciences
Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Pure Connector
Date Deposited: 22 Mar 2016 09:19
Last Modified: 28 Apr 2020 23:50
URI: https://ueaeprints.uea.ac.uk/id/eprint/57710
DOI: 10.3988/jcn.2016.12.2.209

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