Simultaneous fMRI-EEG-Based Characterisation of NREM Parasomnia Disease: Methods and Limitations

Abstract

Functional magnetic resonance imaging (fMRI) techniques and electroencephalography (EEG) were used to investigate sleep with a focus on impaired arousal mechanisms in disorders of arousal (DOAs). With a prevalence of 2–4% in adults, DOAs are significant disorders that are currently gaining attention among physicians. The paper describes a simultaneous EEG and fMRI experiment conducted in adult individuals with DOAs (n=10). Both EEG and fMRI data were validated by reproducing well established EEG and fMRI associations. A method for identification of both brain functional areas and EEG rhythms associated with DOAs in shallow sleep was designed. Significant differences between patients and controls were found in delta, theta, and alpha bands during awakening epochs. General linear models of the blood-oxygen-level-dependent signal have shown the secondary visual cortex and dorsal posterior cingulate cortex to be associated with alpha spectral power fluctuations, and the precuneus with delta spectral power fluctuations, specifically in patients and not in controls. Future EEG–fMRI sleep studies should also consider subject comfort as an important aspect in the experimental design.

Alterations of sleep initiation in NREM parasomnia after sleep deprivation – A multimodal pilot study

“…Two of our participants actually did not want to continue the study after 40 min of recording due to unpleasant feelings in the scanner, 1 participant terminated the recording while not sleeping for many minutes). The technical aspects of the procedure as well as statistical analysis were in a great detail described by (Piorecky et al ,2020) who focused on the method of simultaneous EEG and fMRI recording along with its specific technical features and complications [ 30 ] and they are also further specified in following subsections.…”

“…Significant correlations between EEG and BOLD fluctuations were found using the general linear model implemented in the SPM toolbox [ 35 ]. More detailed description of the EEG informed fMRI analysis can be found in our previous methodological paper [ 30 ].…”

Violent and Complex Behaviors and Non-Restorative Sleep Are the Main Features of Disorders of Arousal in Adulthood: Real Picture or a More Severe Phenotype?

“…On the left, neurophysiologic studies directly analyzing DoA episodes are illustrated [15][16][17][18][19][20][22][23][24][25][26]30,32,34,36,[40][41][42]. On the right are neurophysiologic studies that analyzed DoA patients independently of the episodes (nocturnal sleep detached from episodes/wakefulness) [21,27,29,31,33,35,37,38,43,44]…”

“…On the left, neurophysiologic studies directly analyzing DoA episodes are illustrated[15][16][17][18][19][20][22][23][24][25][26]30,32,34,36,[40][41][42]. On the right are neurophysiologic studies that analyzed DoA patients independently of the episodes (nocturnal sleep detached from episodes/wakefulness)[21,27,29,31,33,35,37,38,43,44].Listed studies are circled by either blue or red discs, respectively indicating if performed during sleep or wakefulness. "*" and "**", respectively, indicate studies performed under sleep deprivation or with a specific cognitive load.…”