Facility-measured sleep electroencephalographic microstructures in long COVID

Area of Science:

• Neuroscience
• Sleep Medicine
• Chronic Illness Research

Background:

• Sleep electroencephalographic (EEG) microstructures offer insights into brain function.
• Non-restorative sleep and fatigue are hallmark symptoms of long COVID (LC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).
• Understanding sleep EEG differences may elucidate the pathobiology of these conditions.

Purpose of the Study:

• To characterize sleep EEG microstructural differences in individuals with LC and ME/CFS compared to healthy controls (HC).
• To investigate specific EEG parameters such as spectral band powers, spindles, slow oscillations (SO), spindle-SO coupling, brain age index (BAI), alpha-delta patterns, and infraslow oscillation relative band power (ISO).

Main Methods:

• Utilized overnight polysomnography (PSG) in a laboratory setting.
• Analyzed sleep EEG data from 28 LC participants, 28 HC participants, and 19 ME/CFS participants.
• Extracted quantitative measures of sleep EEG microstructures, including spectral power, oscillatory activity, and coupling dynamics.

Main Results:

• LC patients showed higher SO power during wake and REM sleep, faster spindle frequency drop, and shorter SO peak duration compared to HC.
• LC exhibited widespread, early spindle-SO coupling, with early fast spindle-SO coupling linked to poorer sleep quality.
• ME/CFS patients displayed distinct patterns, including higher SO-uncoupled slow spindle densities, more alpha-delta patterns, and elevated ISO power.

Conclusions:

• Sleep EEG microstructural changes in LC and ME/CFS suggest plausible pathological alterations.
• These findings contribute to understanding the neurobiological impact of post-infectious processes on brain activity.
• The study highlights distinct yet overlapping sleep abnormalities in LC and ME/CFS, warranting further investigation.