Clinical significance of nocturnal sleep onset REM periods in narcolepsy diagnosis and diagnostic stability
摘要
Narcolepsy diagnosis relies on polysomnography (PSG) and the Multiple Sleep Latency Test (MSLT), though concerns remain regarding their diagnostic accuracy and reliability. Nocturnal sleep-onset rapid eye movement periods (SOREMPs) are a known feature of narcolepsy. This study investigated the clinical significance of nocturnal SOREMP in narcolepsy diagnosis and its association with test–retest reliability.
MethodsWe retrospectively reviewed 109 patients who underwent at least two MSLTs. Patients were categorized into nocturnal SOREMP (n = 40) and non-nocturnal SOREMP (n = 69) groups based on PSG findings. Only MSLT-identified SOREMPs were used for diagnosis. Group comparisons and follow-up changes were analyzed using t-tests, chi-square tests, or Wilcoxon signed-rank tests.
ResultsThe nocturnal SOREMP group had more SOREMPs (3.50 vs. 2.23), shorter mean sleep latency (1.99 vs. 4.77), and higher initial narcolepsy diagnosis rates (92.5% vs. 63.8%). Diagnostic stability was significantly higher in the nocturnal group (90.0% vs. 50.7%). Among narcolepsy type 2 (NT2) patients, those with nocturnal SOREMP showed complete diagnostic retention (100%), whereas only 27.3% of those without nocturnal SOREMP did. In a subgroup analysis, patients who had a nocturnal SOREMP on at least one of the two PSGs exhibited significantly higher diagnostic stability (93.9%) than those without nocturnal SOREMP on either test (50.0%). Similarly, NT2 retention was 100% in the former versus 16.7% in the latter.
ConclusionsNocturnal SOREMP may serve as a specific marker for narcolepsy, suggesting potential utility in supporting diagnostic consistency. Its presence appears to be associated with improved diagnostic reliability, particularly in NT2.