Contributions
Abstract: P808
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - MRI and PET
Introduction: The majority of Multiple Sclerosis (MS) patients report fatigue as one of their most debilitating symptoms1,8. MRI studies have shown differences in both structural2 and functional connectivity (FC)6 in MS compared to healthy controls (HC). The current study aims to explore network measures of FC in a motor-alertness task and how these measures correlate with fatigue scores in MS.
Methods:
Participants: 40 female participants with MS (mean age 48.9), with clinical fatigue, assessed by the Fatigue Severity Scale3 (FSS) and 40 age matched, within 3 years, female healthy volunteers (mean age 49.8) were recruited.
Paradigm: A simple alertness-motor paradigm modified from Perin et al., (2010)5 consisted of three distinct tasks, a sensorimotor task, an intrinsic attention task and an extrinsic attention task.
Data acquisition: 3T Siemens Skyra scanner, 32 channel head coil. fMRI scans were T2*-weighted multi-band accelerated EPI images10, TR of 0.906s, 3mm ³ voxels, 39 slices covering the whole brain. A T1-weighted inversion recovery MPRAGE giving 1mm³ voxels, 192 slices was also acquired.
Analysis: performed in MATLAB2013a. FC between ROIs was measured using Pearson's correlations, resulting in a 116x116 connectivity matrix for each individual. A fisher z-transform was applied to the matrices to increase normality. Network measures of modularity7, small world propensity4 (SWP) and efficiency7 were computed from the weighted connectivity matrices. T-tests to compare between MS and healthy participants. Bivariate correlations were used to correlate modularity, SWP and efficiency with FSS scores.
Results: No statistical differences between MS and HC groups on any network measures across any of the three tasks. In the HC group the effect of mental effort is inconsistent, but they show increased basal ganglia network FC in the intrinsic alertness task, which is associated with no effect of mental effort. In MS the finding is more robust and during both intrinsic and extrinsic alertness tasks the groups that showed no effect of mental effort also show increased FC of the basal ganglia network.
Conclusions: Both the HC and MS groups exhibited efficient small-world properties in a whole brain network during an alertness-motor task. Furthermore, there is strong evidence to suggest that increased FC of the basal ganglia mitigates the effect of mental effort. However, this cannot overcome the impact of latent fatigue, suffered by the MS group.
Disclosure: Christelle van Antwerpen: Nothing to disclose
N. Jade Thai: Nothing to disclose
Simon Godwin: Nothing to disclose
Giovanni DeMarco: Nothing to disclose
Angela Davies-Smith: Nothing to disclose
, Rosemary Jones: Nothing to disclose
Naoki Masuda: Nothing to disclose
Abstract: P808
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - MRI and PET
Introduction: The majority of Multiple Sclerosis (MS) patients report fatigue as one of their most debilitating symptoms1,8. MRI studies have shown differences in both structural2 and functional connectivity (FC)6 in MS compared to healthy controls (HC). The current study aims to explore network measures of FC in a motor-alertness task and how these measures correlate with fatigue scores in MS.
Methods:
Participants: 40 female participants with MS (mean age 48.9), with clinical fatigue, assessed by the Fatigue Severity Scale3 (FSS) and 40 age matched, within 3 years, female healthy volunteers (mean age 49.8) were recruited.
Paradigm: A simple alertness-motor paradigm modified from Perin et al., (2010)5 consisted of three distinct tasks, a sensorimotor task, an intrinsic attention task and an extrinsic attention task.
Data acquisition: 3T Siemens Skyra scanner, 32 channel head coil. fMRI scans were T2*-weighted multi-band accelerated EPI images10, TR of 0.906s, 3mm ³ voxels, 39 slices covering the whole brain. A T1-weighted inversion recovery MPRAGE giving 1mm³ voxels, 192 slices was also acquired.
Analysis: performed in MATLAB2013a. FC between ROIs was measured using Pearson's correlations, resulting in a 116x116 connectivity matrix for each individual. A fisher z-transform was applied to the matrices to increase normality. Network measures of modularity7, small world propensity4 (SWP) and efficiency7 were computed from the weighted connectivity matrices. T-tests to compare between MS and healthy participants. Bivariate correlations were used to correlate modularity, SWP and efficiency with FSS scores.
Results: No statistical differences between MS and HC groups on any network measures across any of the three tasks. In the HC group the effect of mental effort is inconsistent, but they show increased basal ganglia network FC in the intrinsic alertness task, which is associated with no effect of mental effort. In MS the finding is more robust and during both intrinsic and extrinsic alertness tasks the groups that showed no effect of mental effort also show increased FC of the basal ganglia network.
Conclusions: Both the HC and MS groups exhibited efficient small-world properties in a whole brain network during an alertness-motor task. Furthermore, there is strong evidence to suggest that increased FC of the basal ganglia mitigates the effect of mental effort. However, this cannot overcome the impact of latent fatigue, suffered by the MS group.
Disclosure: Christelle van Antwerpen: Nothing to disclose
N. Jade Thai: Nothing to disclose
Simon Godwin: Nothing to disclose
Giovanni DeMarco: Nothing to disclose
Angela Davies-Smith: Nothing to disclose
, Rosemary Jones: Nothing to disclose
Naoki Masuda: Nothing to disclose