Algorithmic complexity of EEG for prognosis of neurodegeneration in idiopathic rapid eye movement behavior disorder (RBD)

Abstract

Objectives: Idiopathic REM sleep behavior disorder (RBD) is a serious risk factor for neurodegenerative processes such as Parkinson's disease (PD). We investigate the use of EEG algorithmic complexity derived metrics for its prognosis. Methods:We analyzed resting state EEG data collected from 114 idiopathic RBD patients and 83 healthy controls in a longitudinal study forming a cohort in which several RBD patients developed PD or dementia with Lewy bodies.Multichannel data from ∼5 minute recordings was converted to spectrograms and their algorithmic complexity estimated using Lempel-Ziv-Welch compression (LZW).Results: Complexity measures and entropy rate displayed statistically significant differences between groups. Results are compared to those using the ratio of slow to fast frequency power, which they are seen to complement by displaying increased sensitivity even when using a few EEG channels.Conclusions: Poor prognosis in RBD appears to be associated with decreased * Corresponding author, giulio.ruffini@neuroelectrics.com, +1 617-899 6911 Preprint submitted to Clinical NeurophysiologyDecember 10, 2017. CC-BY-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/200543 doi: bioRxiv preprint first posted online Oct. 9, 2017; complexity of EEG spectrograms stemming in part from frequency power imbalances and cross-frequency amplitude coupling.Significance: Algorithmic complexity metrics provide a robust, powerful and complementary way to quantify the dynamics of EEG signals in RBD with links to emerging theories of brain function stemming from algorithmic information theory.

Frequency-dependent Alterations in Complexity in Parkinson’s Disease and Prodromal Parkinson’s Disease: A Resting-State fMRI Study

“…Our results reveal lower complexity in PPD patients compared to NCs (especially in CAU.L in slow-2 and SFGmed.L in both slow-2 and slow-3), which is similar to previous study that RBD patients have diminished complexity compared to NCs (RBD is a state of PPD) (Holtbernd et al, 2021;Ruffini et al, 2019). Lesion of cortical surface in SFGmed.L would result in declined control of eye movements (Deng et al, 2016).…”

“…Previous studies have noted abnormal complexity of PD (C. X. Han, Wang, Yi, & Che, 2013) and rapid-eye-movement sleep behavior disorder (RBD) (Holtbernd et al, 2021;Ruffini et al, 2019) patients in electroencephalography (EEG) signals (RBD is a state of prodromal Parkinson's disease [PPD]).…”