Neural effects of fatigue on cognition in relapsing multiple sclerosis detected by magnetoencephalography: Towards an imaging biomarker (P11-3.007)

Abstract

<h3>Objective:</h3> Determining functional differences in MS patients during a task, compared to controls. <h3>Background:</h3> Fatigue affects 80% of patients with MS. Fatigue can also have adverse effects on cognitive abilities. MEG is a noninvasive functional brain imaging technique that measures the magnetic brain waves arising from neuronal activity during rest or during a cognitive task. MEG may help detect functional changes that happen in MS patients with fatigue and cognitive difficulties. <h3>Design/Methods:</h3> This study examined the effects of fatigue on cognition in patients with MS using the modified fatigue impact scale(MFIS) and symbol digits modalities test(SDMT) before and during MEG study respectively. MEG data from 6 patients with MS were compared to 3 control subjects. MEG data were filtered into 4 different frequency bands: theta, alpha, beta, and gamma. Network brain activity for each frequency band was mapped for the strength of connectivity across 27 regions in each hemisphere, resulting in 1431 pairings in the brain. The false discovery rate was used to adjust for multiple testing. Only the most statistically significant connections were based on a p-value of less than 0.05. <h3>Results:</h3> MS patients had most coherent beta and gamma connectivity in the fusiform and frontal regions respectively. The control subjects had more coherent connections in the frontal-parietal, frontal-temporal, and frontal-occipital regions. Individual MFIS scores in MS-patients were higher than the controls and correlated with lower SDMT scores in the MS patients. <h3>Conclusions:</h3> MEG was able to detect clear differences in active networks during SDMT tasks in patients with MS compared to controls. Slow processing speed has been associated with reduced frontal lobe activation in younger adults. Our study cohort supported the lack of coherent beta activity in the frontal lobe. The limitation of our study is a small sample size. The complete data analysis of 10 patients will be presented at AAN-2023. <b>Disclosure:</b> Dr. Memon has nothing to disclose. Mr. Hammami has nothing to disclose. Mr. Memon has nothing to disclose. Dr. Bowyer has nothing to disclose.