Contributions
Abstract: P580
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Introduction: Disability in multiple sclerosis (MS) is mediated by dysfunction of a number of brain structures. Cortical dysfunction, as measured by transcranial magnetic stimulation (TMS); and corticospinal tract (CST) diffusivity correlates with disability in MS patients.
Objective: To assess the structure and function of the corticospinal tract and motor cortex in a cohort of patients with relapsing remitting MS (RRMS), and examine correlations of each to disability.
Methods: 16 patients with RRMS and 17 healthy controls (HCs) were assessed. EDSS, Pyramidal FSS (pFSS), 9-hole peg test (9HPT) and 25-foot walk test (25FWT) were performed in the MS group. The CST was delineated using probabilistic tractography from diffusion weighted tensor imaging (DTI) acquired on 3T-MRI; and the primary motor cortex parcellated with Freesurfer. Mean diffusivity along the CST; CST T2 lesion volume (T2LV); and precentral gyrus volume and thickness were measured. Threshold tracking TMS (TT-TMS) values included resting motor threshold (RMT), short interval intracortical inhibition (SICI), average intracortical facilitation (Avg ICF), cortical silent period (CSP) and central motor conduction time (CMCT). Patients were grouped according to their worse side by clinical examination. Independent T-test analysed differences between the groups and associations were explored by Pearson's correlation.
Results: Mean DTI metrics along the CST did not differ between patients and controls (p range 0.30-0.75). The cortical silent period (CSP) was reduced (mean difference -24.738ms) in MS patients vs HCs (p=0.016). Within the MS group, CST T2LV correlated with 25FTW (0.907, p=0.001), EDSS (0.685, p=0.019) and 9HPT (0.687, p=0.02). CST T2LV also correlated with mean FA (-0.660, p=0.027) and RD (0.689, p=0.019) along the CST. Average SICI (0.803, p=0.003) and peak SICI (0.821, p=0.002) correlated with precentral gyrus thickness, however no TT-TMS metrics correlated with either clinical outcomes or CST DTI parameters.
Conclusion: Pathology within the CST contributed more to motor disability than cortical injury, as measured by structural MRI and TMS, in patients with RRMS. Shortening of the CSP suggests a degree of cortical dysfunction in this cohort of patients with RRMS, but did not contribute to disability. Mean CST diffusivity is insensitive to variation in clinical motor outcomes, and regional/lesional CST DTI should be further explored as a biomarker of disability.
Disclosure:
Justin Y Garber has received funding for a multiple sclerosis fellowship from Sanofi-Genzyme, Merck and Teva.
Chenyu Wang has nothing to disclose.
Heidi N Beadnall has received compensation for education travel, speaker honoraria and consultant fees from Biogen, Novartis, Merck and Sanofi-Genzyme.
Todd A Hardy has received honoraria for talks and advisory boards, and support for scientific meeetings from Novartis, Biogen Idec, Merck-Serono and Genzyme.
Jose M Matamala has nothing to disclose.
James Howells has nothing to disclose.
Stephen Reddel has received payments for grant support from Biogen, CSL, Novartis and Sanofi-Genzyme, travel support from Merck, Sanofi-Genzyme and Teva, membership on advisory councils from Biogen, Merck, Sanofi-Genzyme and Teva, speaker's bureau from Biogen, Novartis, and Sanofi-Genzyme.
Matthew C Kiernan is Editor-in-Chief Journal of Neurology, Neurosurgery & Psychiatry.
Michael H Barnett has received institutional support for research, speaking and/or participation in advisory boards (Biogen, Novartis, and Sanofi Genzyme); research consultant (Medical Safety Systems)
Abstract: P580
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Introduction: Disability in multiple sclerosis (MS) is mediated by dysfunction of a number of brain structures. Cortical dysfunction, as measured by transcranial magnetic stimulation (TMS); and corticospinal tract (CST) diffusivity correlates with disability in MS patients.
Objective: To assess the structure and function of the corticospinal tract and motor cortex in a cohort of patients with relapsing remitting MS (RRMS), and examine correlations of each to disability.
Methods: 16 patients with RRMS and 17 healthy controls (HCs) were assessed. EDSS, Pyramidal FSS (pFSS), 9-hole peg test (9HPT) and 25-foot walk test (25FWT) were performed in the MS group. The CST was delineated using probabilistic tractography from diffusion weighted tensor imaging (DTI) acquired on 3T-MRI; and the primary motor cortex parcellated with Freesurfer. Mean diffusivity along the CST; CST T2 lesion volume (T2LV); and precentral gyrus volume and thickness were measured. Threshold tracking TMS (TT-TMS) values included resting motor threshold (RMT), short interval intracortical inhibition (SICI), average intracortical facilitation (Avg ICF), cortical silent period (CSP) and central motor conduction time (CMCT). Patients were grouped according to their worse side by clinical examination. Independent T-test analysed differences between the groups and associations were explored by Pearson's correlation.
Results: Mean DTI metrics along the CST did not differ between patients and controls (p range 0.30-0.75). The cortical silent period (CSP) was reduced (mean difference -24.738ms) in MS patients vs HCs (p=0.016). Within the MS group, CST T2LV correlated with 25FTW (0.907, p=0.001), EDSS (0.685, p=0.019) and 9HPT (0.687, p=0.02). CST T2LV also correlated with mean FA (-0.660, p=0.027) and RD (0.689, p=0.019) along the CST. Average SICI (0.803, p=0.003) and peak SICI (0.821, p=0.002) correlated with precentral gyrus thickness, however no TT-TMS metrics correlated with either clinical outcomes or CST DTI parameters.
Conclusion: Pathology within the CST contributed more to motor disability than cortical injury, as measured by structural MRI and TMS, in patients with RRMS. Shortening of the CSP suggests a degree of cortical dysfunction in this cohort of patients with RRMS, but did not contribute to disability. Mean CST diffusivity is insensitive to variation in clinical motor outcomes, and regional/lesional CST DTI should be further explored as a biomarker of disability.
Disclosure:
Justin Y Garber has received funding for a multiple sclerosis fellowship from Sanofi-Genzyme, Merck and Teva.
Chenyu Wang has nothing to disclose.
Heidi N Beadnall has received compensation for education travel, speaker honoraria and consultant fees from Biogen, Novartis, Merck and Sanofi-Genzyme.
Todd A Hardy has received honoraria for talks and advisory boards, and support for scientific meeetings from Novartis, Biogen Idec, Merck-Serono and Genzyme.
Jose M Matamala has nothing to disclose.
James Howells has nothing to disclose.
Stephen Reddel has received payments for grant support from Biogen, CSL, Novartis and Sanofi-Genzyme, travel support from Merck, Sanofi-Genzyme and Teva, membership on advisory councils from Biogen, Merck, Sanofi-Genzyme and Teva, speaker's bureau from Biogen, Novartis, and Sanofi-Genzyme.
Matthew C Kiernan is Editor-in-Chief Journal of Neurology, Neurosurgery & Psychiatry.
Michael H Barnett has received institutional support for research, speaking and/or participation in advisory boards (Biogen, Novartis, and Sanofi Genzyme); research consultant (Medical Safety Systems)