The MSLT is repeatable in narcolepsy type 1 but not narcolepsy type 2: A retrospective patient study

Chad Ruoff, Fabio Pizza, Lynn Marie Trotti, Karel Sonka, Stefano Vandi, Joseph Cheung, Swaroop Pinto, Mali Einen, Narong Simakajornboon, Fang Han, Paul Peppard, Sona Nevsimalova, Giuseppe Plazzi, David Rye, Emmanuel Mignot

Research output: Contribution to journalArticlepeer-review

Abstract

Study Objectives: To examine repeatability of Multiple Sleep Latency Test (MSLT) results in narcolepsy type 1 (NT1) and narcolepsy type 2 (NT2) according to the criteria of the International Classification of Sleep Disorders, Third Edition (ICSD-3). Methods: Repeatability of the MSLT was retrospectively evaluated in NT1 (n = 60) and NT2 (n = 54) cases, and controls (n = 15). All subjects had documented HLA-DQB1. 06:02 status and/or hypocretin-1 levels from cerebrospinal fluid. All subjects had undergone 2 MSLTs (≥ 1 meeting ICSD-3 criteria for narcolepsy). Repeatability was explored in children versus adults and in those on versus not on medication(s). Subsample and multivariate analysis were performed. Results: Both MSLTs in unmedicated patients were positive for narcolepsy in 78%, 18%, and 7% of NT1, NT2, and controls, respectively. NT2 cases changed to idiopathic hypersomnia or to a negative MSLT 26% and 57% of the time, respectively. Although NT1 cases were 10 to 14 times more likely to demonstrate a second positive MSLT compared to NT2 cases (P < 10-5) and controls (P < 10-4), respectively, NT2 cases were not significantly different from controls (P = .64). Medication use (P = .009) but not adult versus children status (P = .85) significantly decreased the likelihood of a repeat positive MSLT. Conclusions: In a clinical setting, a positive MSLT for narcolepsy is a more reproducible and stable feature in NT1 than NT2. The retrospective design of this study hinders interpretation of these data, as there are many different, and possibly opposing, reasons to repeat a MSLT in NT1 versus NT2 (ie, ascertainment bias). Additional systematic MSLT repeatability studies independent of confounds are ideally needed to confirm these findings.

Original languageEnglish
Pages (from-to)65-74
Number of pages10
JournalJournal of Clinical Sleep Medicine
Volume14
Issue number1
DOIs
Publication statusPublished - Jan 15 2018

Keywords

  • 06:02
  • Cataplexy
  • HLA-DQB1
  • Hypocretin-1
  • ICSD-3
  • Idiopathic hypersomnia
  • MSLT
  • Narcolepsy type 1
  • Narcolepsy type 2

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Neurology
  • Clinical Neurology

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