Multiple sclerosis (MS) is a neurodegenerative disease characterized by neuronal and synaptic loss, resulting in an imbalance of excitatory and inhibitory synaptic transmission and potentially cognitive impairment. Current methods for measuring the excitation/inhibition (E/I) ratio are mostly invasive, but recent research combining neurocomputational modeling with measurements of local field potentials has indicated that the slope with which the power spectrum of neuronal activity captured by electro- and/or magnetoencephalography rolls off, is a non-invasive biomarker of the E/I ratio. A steeper roll-off is associated with a stronger inhibition. This novel method can be applied to assess the E/I ratio in people with multiple sclerosis (pwMS), detect the effect of medication such as benzodiazepines, and explore its utility as a biomarker for cognition. We recruited 44 healthy control subjects and 95 pwMS who underwent resting-state magnetoencephalographic recordings. The 1/f spectral slope of the neural power spectra was calculated for each subject and for each brain region. As expected, the spectral slope was significantly steeper in pwMS treated with benzodiazepines (BZDs) compared to pwMS not receiving BZDs (p = .01). In the sub-cohort of pwMS not treated with BZDs, we observed a steeper slope in cognitively impaired pwMS compared to cognitively preserved pwMS (p = .01) and healthy subjects (p = .02). Furthermore, we observed a significant correlation between 1/f spectral slope and verbal and spatial working memory functioning in the brain regions located in the prefrontal and parietal cortex. In this study, we highlighted the value of the spectral slope in MS by quantifying the effect of benzodiazepines and by putting it forward as a potential biomarker of cognitive deficits in pwMS.
Akbarian, F, Rossi, C, Costers, L, D'hooghe, MB, D'haeseleer, M, Nagels, G & Van Schependom, J 2023, 'The spectral slope as a marker of excitation/inhibition ratio and cognitive functioning in multiple sclerosis', Human Brain Mapping, vol. 44, no. 17, pp. 5784-5794. https://doi.org/10.1002/hbm.26476
Akbarian, F., Rossi, C., Costers, L., D'hooghe, M. B., D'haeseleer, M., Nagels, G., & Van Schependom, J. (2023). The spectral slope as a marker of excitation/inhibition ratio and cognitive functioning in multiple sclerosis. Human Brain Mapping, 44(17), 5784-5794. https://doi.org/10.1002/hbm.26476
@article{f188c3b833fc414e8f0560a63e52bf7b,
title = "The spectral slope as a marker of excitation/inhibition ratio and cognitive functioning in multiple sclerosis",
abstract = "Multiple sclerosis (MS) is a neurodegenerative disease characterized by neuronal and synaptic loss, resulting in an imbalance of excitatory and inhibitory synaptic transmission and potentially cognitive impairment. Current methods for measuring the excitation/inhibition (E/I) ratio are mostly invasive, but recent research combining neurocomputational modeling with measurements of local field potentials has indicated that the slope with which the power spectrum of neuronal activity captured by electro- and/or magnetoencephalography rolls off, is a non-invasive biomarker of the E/I ratio. A steeper roll-off is associated with a stronger inhibition. This novel method can be applied to assess the E/I ratio in people with multiple sclerosis (pwMS), detect the effect of medication such as benzodiazepines, and explore its utility as a biomarker for cognition. We recruited 44 healthy control subjects and 95 pwMS who underwent resting-state magnetoencephalographic recordings. The 1/f spectral slope of the neural power spectra was calculated for each subject and for each brain region. As expected, the spectral slope was significantly steeper in pwMS treated with benzodiazepines (BZDs) compared to pwMS not receiving BZDs (p = .01). In the sub-cohort of pwMS not treated with BZDs, we observed a steeper slope in cognitively impaired pwMS compared to cognitively preserved pwMS (p = .01) and healthy subjects (p = .02). Furthermore, we observed a significant correlation between 1/f spectral slope and verbal and spatial working memory functioning in the brain regions located in the prefrontal and parietal cortex. In this study, we highlighted the value of the spectral slope in MS by quantifying the effect of benzodiazepines and by putting it forward as a potential biomarker of cognitive deficits in pwMS.",
keywords = "1/f spectral slope, aperiodic exponent, aperiodic, excitation/inhibition balance, magnetoencephalography, Resting state, Spectral power",
author = "Fahimeh Akbarian and Chiara Rossi and Lars Costers and D'hooghe, {Marie B} and Miguel D'haeseleer and Guy Nagels and {Van Schependom}, Jeroen",
note = "{\textcopyright} 2023 The Authors. Human Brain Mapping published by Wiley Periodicals LLC. This study was supported by the VUB Steunfonds Wetenschappelijk Onderzoek and the Brussels Capital Region-Innoviris. The MEG data collection was enabled by a grant from the Belgian Charcot Foundation and an unrestricted research grant by Genzyme-Sanofi awarded to Guy Nagels. CR and LC are holders of a PhD grant awarded by the Fonds Wetenschappelijk Onderzoek (FWO) and GN is supported by an FWO “Fundamenteel Klinisch mandate”, grant/award numbers: 11K2823N, 11B7218N, 1805620N. Funding Information: This study was supported by the VUB Steunfonds Wetenschappelijk Onderzoek and the Brussels Capital Region‐Innoviris. The MEG data collection was enabled by a grant from the Belgian Charcot Foundation and an unrestricted research grant by Genzyme‐Sanofi awarded to Guy Nagels. CR and LC are holders of a PhD grant awarded by the Fonds Wetenschappelijk Onderzoek (FWO) and GN is supported by an FWO “Fundamenteel Klinisch mandate”, grant/award numbers: 11K2823N, 11B7218N, 1805620N. Publisher Copyright: {\textcopyright} 2023 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.",
year = "2023",
month = dec,
day = "1",
doi = "10.1002/hbm.26476",
language = "English",
volume = "44",
pages = "5784--5794",
journal = "Human Brain Mapping",
issn = "1065-9471",
publisher = "Wiley-Liss Inc.",
number = "17",
}