Process and outcome for international reliability in sleep scoring.

Area of Science:

• Sleep Medicine
• Neuroscience
• Medical Diagnostics

Background:

• Accurate sleep stage scoring is crucial for diagnosing sleep disorders.
• International multi-center sleep studies require reliable scoring protocols.
• Variability in scoring can impact research findings and clinical decisions.

Purpose of the Study:

• To evaluate the inter-rater reliability of sleep stage scoring between two international sleep laboratories (Germany and China).
• To compare scoring agreement for different sleep stages and patient groups (healthy controls, sleep apnea hypopnea syndrome, narcolepsy).

Main Methods:

• Polysomnography (PSG) data from 15 healthy controls and 15 sleep apnea hypopnea syndrome (SAHS) patients in Germany, and 15 narcolepsy patients in China were scored.
• Five experienced technologists scored PSGs following the 2007 AASM manual, using two EEG leads.
• Inter-scorer agreement was assessed using Cohen's kappa (epoch-by-epoch) and intra-class correlation coefficients (quantitative parameters).

Main Results:

• Moderate inter-laboratory epoch-by-epoch agreement was observed (mean kappa 0.54-0.58).
• REM sleep scoring agreement was significantly lower in both SAHS and narcolepsy patients compared to controls.
• Narcolepsy patients showed higher rates of scoring discrepancies, particularly between N1 and REM stages.

Conclusions:

• Low REM sleep scoring agreement highlights the need for disorder-specific scoring guidelines.
• International multi-center studies necessitate intensive, standardized training to improve sleep stage scoring reliability.