Technical challenges in REM sleep microstructure classification: A study of patients with REM sleep behaviour...

Area of Science:

• Neuroscience
• Sleep Medicine
• Biomedical Engineering

Background:

• Rapid eye movement (REM) sleep is often treated uniformly, but comprises distinct phasic and tonic microstructures.
• Accurate classification of these microstructures is crucial for understanding sleep disorders, particularly REM sleep behavior disorder (RBD).
• Existing visual classification methods face challenges in inter-rater reliability due to subjective interpretations and technical interferences.

Purpose of the Study:

• To identify technical challenges in the visual classification of REM sleep microstructures.
• To propose and evaluate solutions for enhancing inter-rater reliability in REM sleep microstructure scoring.
• To develop guidance for consistent classification of phasic and tonic REM sleep.

Main Methods:

• Fifty-seven sleep recordings were scored by three raters from different institutions.
• A novel REM sleep scoring schematic graph was developed to standardize microstructure classification.
• The schematic graph incorporated strategies for handling microstructure transitions and artefacts.
• Inter-rater reliability was assessed using Cohen's kappa, with a third rater acting as an arbitrator.

Main Results:

• Inter-rater variance was primarily caused by microstructure transitions and moderate-to-severe artefacts.
• The developed schematic graph significantly improved inter-rater agreement.
• After applying the schematic graph, 27 out of 34 recordings achieved a Cohen's kappa score above 0.8, indicating almost perfect agreement.

Conclusions:

• Technical challenges in REM sleep microstructure classification can be overcome with standardized protocols.
• The proposed schematic graph offers practical solutions to enhance reliability in scoring phasic and tonic REM sleep.
• This study provides valuable guidance for improving the consistency and accuracy of REM sleep analysis in clinical and research settings.