title: A systematic review of the incidence and prevalence of sleep disorders and seizure disorders in multiple sclerosis.
abstract: BACKGROUND
  Several studies have suggested that comorbid neurologic disorders are more common than expected in multiple sclerosis (MS).
  
  
  OBJECTIVE
  To estimate the incidence and prevalence of comorbid seizure disorders and sleep disorders in persons with MS and to evaluate the quality of studies included.
  
  
  METHODS
  The PUBMED, EMBASE, Web of Knowledge, and SCOPUS databases, conference proceedings, and reference lists of retrieved articles were searched. Two reviewers independently screened abstracts to identify relevant articles, followed by full-text review of selected articles. We assessed included studies qualitatively and quantitatively (I² statistic), and conducted meta-analyses among population-based studies.
  
  
  RESULTS
  We reviewed 32 studies regarding seizure disorders. Among population-based studies the incidence of seizure disorders was 2.28% (95% CI: 1.11-3.44%), while the prevalence was 3.09% (95% CI: 2.01-4.16%). For sleep disorders we evaluated 18 studies; none were population-based. The prevalence ranged from 0-1.6% for narcolepsy, 14.4-57.5% for restless legs syndrome, 2.22-3.2% for REM behavior disorder, and 7.14-58.1% for obstructive sleep apnea.
  
  
  CONCLUSIONS
  This review suggests that seizure disorders and sleep disorders are common in MS, but highlights gaps in the epidemiological knowledge of these conditions in MS worldwide. Other than central-western Europe and North America, most regions are understudied.
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada/Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada rmarrie@hsc.mb.ca.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: Nadia
authors.initials: N
authors.lastname: Reider
authors.affiliation: Mellen Center for MS Treatment and Research, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Cohen
authors.affiliation: Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Trojano
authors.affiliation: Department of Neurology, Copenhagen University Hospital Rigshospitalet, Denmark.
authors.forename: Per Soelberg
authors.initials: PS
authors.lastname: Sorensen
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Cutter
authors.affiliation: Scientific and Clinical Review Associates, LLC, Salisbury, CT, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Reingold
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, TX, USA.
authors.forename: Olaf
authors.initials: O
authors.lastname: Stuve
mesh_terms: D015897:Comorbidity; D004827:Epilepsy / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D009103:Multiple Sclerosis / Q000150:complications / Q000453:epidemiology*; D015995:Prevalence; D012893:Sleep Wake Disorders / Q000453:epidemiology* / Q000209:etiology
keywords: Multiple sclerosis; comorbidity; epilepsy; incidence; prevalence; seizures; sleep