title: Measurement of narcolepsy symptoms: The Narcolepsy Severity Scale.
abstract: OBJECTIVE
  To validate the Narcolepsy Severity Scale (NSS), a brief clinical instrument to evaluate the severity and consequences of symptoms in patients with narcolepsy type 1 (NT1).
  
  
  METHODS
  A 15-item scale to assess the frequency and severity of excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, sleep paralysis, and disrupted nighttime sleep was developed and validated by sleep experts with patients' feedback. Seventy untreated and 146 treated adult patients with NT1 were evaluated and completed the NSS in a single reference sleep center. The NSS psychometric properties, score changes with treatment, and convergent validity with other clinical parameters were assessed.
  
  
  RESULTS
  The NSS showed good psychometric properties with significant item-total score correlations. The factor analysis indicated a 3-factor solution with good reliability, expressed by satisfactory Cronbach α values. The NSS total score temporal stability was good. Significant NSS score differences were observed between untreated and treated patients (dependent sample, 41 patients before and after sleep therapy; independent sample, 29 drug-free and 105 treated patients). Scores were lower in the treated populations (10-point difference between groups), without ceiling effect. Significant correlations were found among NSS total score and daytime sleepiness (Epworth Sleepiness Scale, Mean Sleep Latency Test), depressive symptoms, and health-related quality of life.
  
  
  CONCLUSIONS
  The NSS can be considered a reliable and valid clinical tool for the quantification of narcolepsy symptoms to monitor and optimize narcolepsy management.
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France. ydauvilliers@yahoo.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Dauvilliers
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Severine
authors.initials: S
authors.lastname: Beziat
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Carole
authors.initials: C
authors.lastname: Pesenti
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Regis
authors.initials: R
authors.lastname: Lopez
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Barateau
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Carlander
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Gianina
authors.initials: G
authors.lastname: Luca
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Tafti
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Morin
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Michel
authors.initials: M
authors.lastname: Billiard
authors.affiliation: From CHU Montpellier (Y.D., S.B., C.P., R.L., L.B., B.C., M.B.), Hôpital Gui-de-Chauliac, Service de Neurologie, Unité du Sommeil, Centre National de Référence pour la Narcolepsie, Montpellier, France; Center for Integrative Genomics (G.L., M.T.), University of Lausanne; Centre Neuchâtelois de Psychiatrie (G.L.), Neuchâtel; Center for Investigation and Research in Sleep (M.T.), Lausanne University Hospital, Switzerland; Department of Psychology (C.M.M.), Université Laval, Quebec City, Quebec, Canada; Inserm (Y.D., S.B., C.P., R.L., I.J.), U1061; and Université Montpellier (Y.D., S.B., C.P., R.L., I.J.), France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Jaussent
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy*; D000068797:Orexins / Q000134:cerebrospinal fluid; D017063:Outcome Assessment, Health Care; D017286:Polysomnography; D011594:Psychometrics; D011788:Quality of Life; D012720:Severity of Illness Index; D012894:Sleep Stages
chemical_list: D000068797:Orexins