To assess the test-retest reliability of the polysomnography-multiple sleep latency test (PSG-MSLT) diagnostic classification and measures and to study the determinants of its variability in patients with narcolepsy type 1 (NT1) or with noncataplectic central disorders of hypersomnolence (NCHS): type 2 (NT2), idiopathic hypersomnia (IH), and unspecified hypersomnolence (unspecified excessive daytime sleepiness [UnsEDS]).
Well-controlled longitudinal studies with high quality data on cataplexy and hypocretin status are needed to understand where the PSG SOREMP phenomenon falls on the hypersomnolence spectrum and to establish which comorbidities share variance with and/or potentially mask narcolepsy.