Contributions
Abstract: P609
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 23 Neurophysiology
Background: Neurophysiological measures of brain function, such as magnetoencephalography (MEG), are widely used in clinical neurology and have strong relations with cognitive impairment and dementia, but are presently still underdeveloped in multiple sclerosis (MS). This study aims to assess the value of clinically applicable quantitative MEG measures of neuronal activity in evaluating and predicting cognitive impairment in MS.
Methods: Eyes-closed resting-state MEG measurements of 83 patients with long-standing, clinically definite MS and 34 healthy controls (HC) were analyzed and related to neuropsychological evaluations, based on an expanded brief repeatable battery of neuropsychological tests (BRB-N). “Cognitive impairment” (CI) was defined as Z-scores (using HC as reference) of ≤-2 on two or more domains; Z-scores > -1.5 on all domains as “cognitively preserved” (CP) and all scores in between as “mildly cognitively impaired” (MCI). Time series were estimated using a beamforming approach, for 78 cortical regions of interest (ROIs) based on an automated anatomical labelling atlas (AAL). For each subject five artifact-free epochs (~13 seconds, sample frequency 1250Hz) were selected; peak frequencies and relative power were calculated for each of six frequency bands and each ROI. Subsequently, global relative power and peak frequency were averaged over all 78 ROIs. Associations with cognitive impairment were performed using linear modelling correcting for age, gender and educational level where appropriate.
Results: Of all 83 patients, 37 were labeled as CP, 18 as MCI, and 28 as CI. The CI-MS group had a significantly lower peak frequency (β-0,266,P=0.049) than HCs, indicating higher relative alpha1-power and overall slowing of neuronal activity. Increased global relative alpha1-power was associated with impaired overall cognitive performance (β-0.304;P=0.005) but specifically with attention (β-0.408;P< .001), working memory (β-0.388;P< .001 and verbal memory (β-0.257;P=0.020). Increased global relative theta-power was associated with worse performance on verbal memory tasks (β-0.333;P=0.003).
Conclusion: These findings indicate a clinically relevant global slowing of neuronal activity in MS patients, affecting cognition, and hold promise for the application of resting-state MEG in a clinical setting as a biomarker for cognitive disturbances. Future studies are warranted to assess the prognostic value of these neurophysiological changes in MS.
Disclosure: E.M.M. Strijbis, D. Schoonhoven, B.M.J. Uitdehaag, A. Hillebrand and C.J. Stam have nothing to disclose.
M. Fraschini and P. Tewarie received funding from the Neuroscience Campus Amsterdam from a grant for the scientific excellence program.
M. Schoonheim receives research support from the Dutch MS Research Foundation, grant number 13-820.
Abstract: P609
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 23 Neurophysiology
Background: Neurophysiological measures of brain function, such as magnetoencephalography (MEG), are widely used in clinical neurology and have strong relations with cognitive impairment and dementia, but are presently still underdeveloped in multiple sclerosis (MS). This study aims to assess the value of clinically applicable quantitative MEG measures of neuronal activity in evaluating and predicting cognitive impairment in MS.
Methods: Eyes-closed resting-state MEG measurements of 83 patients with long-standing, clinically definite MS and 34 healthy controls (HC) were analyzed and related to neuropsychological evaluations, based on an expanded brief repeatable battery of neuropsychological tests (BRB-N). “Cognitive impairment” (CI) was defined as Z-scores (using HC as reference) of ≤-2 on two or more domains; Z-scores > -1.5 on all domains as “cognitively preserved” (CP) and all scores in between as “mildly cognitively impaired” (MCI). Time series were estimated using a beamforming approach, for 78 cortical regions of interest (ROIs) based on an automated anatomical labelling atlas (AAL). For each subject five artifact-free epochs (~13 seconds, sample frequency 1250Hz) were selected; peak frequencies and relative power were calculated for each of six frequency bands and each ROI. Subsequently, global relative power and peak frequency were averaged over all 78 ROIs. Associations with cognitive impairment were performed using linear modelling correcting for age, gender and educational level where appropriate.
Results: Of all 83 patients, 37 were labeled as CP, 18 as MCI, and 28 as CI. The CI-MS group had a significantly lower peak frequency (β-0,266,P=0.049) than HCs, indicating higher relative alpha1-power and overall slowing of neuronal activity. Increased global relative alpha1-power was associated with impaired overall cognitive performance (β-0.304;P=0.005) but specifically with attention (β-0.408;P< .001), working memory (β-0.388;P< .001 and verbal memory (β-0.257;P=0.020). Increased global relative theta-power was associated with worse performance on verbal memory tasks (β-0.333;P=0.003).
Conclusion: These findings indicate a clinically relevant global slowing of neuronal activity in MS patients, affecting cognition, and hold promise for the application of resting-state MEG in a clinical setting as a biomarker for cognitive disturbances. Future studies are warranted to assess the prognostic value of these neurophysiological changes in MS.
Disclosure: E.M.M. Strijbis, D. Schoonhoven, B.M.J. Uitdehaag, A. Hillebrand and C.J. Stam have nothing to disclose.
M. Fraschini and P. Tewarie received funding from the Neuroscience Campus Amsterdam from a grant for the scientific excellence program.
M. Schoonheim receives research support from the Dutch MS Research Foundation, grant number 13-820.