Normal multiple sleep latency test values in adults: A systematic review and meta-analysis.

Area of Science:

• Sleep Medicine
• Neuroscience
• Clinical Research

Background:

• Mean sleep latency (MSL) quantifies time to fall asleep, crucial for diagnosing excessive daytime sleepiness and narcolepsy.
• Normative MSL values in healthy adults using the Multiple Sleep Latency Test (MSLT) are not well-established, hindering clinical interpretation.
• Understanding MSL variability is essential for accurate diagnosis and research in sleep disorders.

Approach:

• A comprehensive review synthesized data from 110 healthy adult cohorts undergoing the MSLT.
• Investigated the influence of demographic (age, sex, BMI) and methodological (sleep onset definitions, MSLT protocols) variables on MSL.
• Examined associations between MSL and sleep architecture, sleep-disordered breathing (e.g., apnea-hypopnea index), and prior night polysomnography.

Key Points:

• The average MSL was 11.7 min (earlier sleep onset definition) and 11.8 min (later definition).
• No significant associations were found between MSL and demographic or methodological variables.
• A negative association was observed between MSL and apnea-hypopnea index, suggesting shorter sleep latency with increased breathing disturbances.

Conclusions:

• Updated normative ranges for MSL in healthy adults are proposed based on this extensive data synthesis.
• Findings may aid clinical decision-making for sleep pathologies and guide future research on sleepiness and disorders.
• The study highlights the importance of considering sleep-disordered breathing when interpreting MSL values.