Neurophysiological MEG markers of cognitive impairment and performance validity in multiple sclerosis

Abstract

Background: Suboptimal performance during neuropsychological testing frequently occurs in multiple sclerosis (MS), leading to unreliable cognitive outcomes. Neurophysiological alterations correlate with MS-related cognitive impairment, but studies have not yet considered performance validity. Objectives: To investigate neurophysiological markers of cognitive impairment in MS, while explicitly addressing performance validity. Methods: Magnetoencephalography recordings, neuropsychological assessments, and performance validity testing were obtained from 90 MS outpatients with cognitive complaints. Spectral and resting-state functional connectivity (rsFC) properties were compared between cognitively impaired (CI), cognitively preserved (CP), and suboptimally performing (SUB) patients using regression models and permutation testing. Results: CI had higher power in low-frequency bands and lower power in high bands compared to CP, indicating neuronal slowing. CI also showed lower beta power compared to SUB. Overall power spectra visually differed between CI and CP, and SUB showed overlap with both groups. CI had lower rsFC than CP and SUB patients. CP and SUB patients showed no differences. Conclusion: Neuronal slowing and altered rsFC can be considered cognitive markers in MS. Patients who performed suboptimally showed resemblance with patients with and without cognitive impairments, and although their overall neurophysiological profile was more similar to patients without impairments, it suggests heterogeneity regarding their pathophysiology.

Stimulus-related modulation in the 1/f spectral slope suggests an impaired inhibition during a working memory task in people with multiple sclerosis

“…While the exact mechanisms underlying cognitive dysfunction in MS remain incompletely understood, evidence suggests a potential link between synaptic loss, particularly in inhibitory synapses, and cognitive impairment. 2 Previous in vivo studies in MS 5,6 using magnetoencephalography/electroencephalography (MEG/EEG) have primarily focused on investigating the relationship between oscillatory biomarkers and cognitive performance during resting state and while performing a task. Nevertheless, it has also been shown that the non-oscillatory component of neuronal activity contains functionally relevant information.…”