Cortical neurodynamics changes mediate the efficacy of a personalized neuromodulation against multiple sclerosis fatigue

Carlo Cottone,Camillo Porcaro,Giancarlo Zito,Andrea Cancelli,Franca Tecchio,Paolo M Rossini

doi:10.1038/s41598-019-54595-z

Abstract

The people with multiple sclerosis (MS) often report that fatigue restricts their life. Nowadays, pharmacological treatments are poorly effective accompanied by relevant side effects. A 5-day transcranial direct current stimulation (tDCS) targeting the somatosensory representation of the whole body (S1) delivered through an electrode personalized based on the brain MRI was efficacious against MS fatigue (FaReMuS treatment). This proof of principle study tested whether possible changes of the functional organization of the primary sensorimotor network induced by FaReMuS partly explained the effected fatigue amelioration. We measured the brain activity at rest through electroencephalography equipped with a Functional Source Separation algorithm and we assessed the neurodynamics state of the primary somatosensory (S1) and motor (M1) cortices via the Fractal Dimension and their functional connectivity via the Mutual Information. The dynamics of the neuronal electric activity, more distorted in S1 than M1 before treatment, as well as the network connectivity, altered maximally between left and right M1 homologs, reverted to normal after FaReMuS. The intervention-related changes explained 48% of variance of fatigue reduction in the regression model. A personalized neuromodulation tuned in on specific anatomo-functional features of the impaired regions can be effective against fatigue.

Highlights

The people with multiple sclerosis (MS) often report that fatigue restricts their life
Shapiro-Wilk test indicated that none of the fractal dimension (FD) among the four primary sensorimotor cortical sources (FSSL1, FSSR1, FSML 1, FSMR1) either before or after FaReMuS differed from a Gaussian distribution (p > 0.300 consistently)
A strong interaction effect FaReMuS Treatment * Cortical District [F(1,17) = 12.066, p = 0.003] indicated that the intervention had a distinct impact on FSS1 and FSM1

Summary

Introduction

The people with multiple sclerosis (MS) often report that fatigue restricts their life. A 5-day transcranial direct current stimulation (tDCS) targeting the somatosensory representation of the whole body (S1) delivered through an electrode personalized based on the brain MRI was efficacious against MS fatigue (FaReMuS treatment). This proof of principle study tested whether possible changes of the functional organization of the primary sensorimotor network induced by FaReMuS partly explained the effected fatigue amelioration. By the present proof of concept study, we tested the working hypothesis that FaReMuS modifies the functional organization of the brain networks involved in MS-related fatigue contributing to its efficacy In this way, we aim at deepen the understanding of the phenomena subtending fatigue and its relief. Is there a correlation between such changes and the extent of amelioration of fatigue symptoms?

Methods

Results

Discussion

Conclusion