title: Central fatigue in multiple sclerosis: a review of the literature.
abstract: Fatigue is a major concern for patients with multiple sclerosis (MS). A clear definition of MS-related fatigue is a prerequisite for appropriate instruments for fatigue assessment. In turn, accurate assessment of fatigue in MS will enhance exploration of plausible mechanisms underlying this common and distressing symptom. Content/Objectives: To provide an integrative review of the current literature on theoretical models used to study fatigue in MS, instruments used to assess fatigue and other factors that impact fatigue during the various phases of MS.
  
  
  
  
  
  
  
  PUBMED, OVID, Ovid Health Star, Ovid MEDINE, CINAHL, Health and Psychosocial Instruments (HaPI), and PsycINFO. Seventeen articles fit the inclusion criteria and were included in the review.
  
  
  
  Definitions of MS-related fatigue are reviewed. Several studies found a link with neurotransmitter dysfunction, circadian rhythm, and the timing of fatigue. Central fatigue in MS is associated with neurotransmitters disruptions as well as circadian rhythm disorders, but the evidence is not strong. Perceptions of fatigue or fatigability may arise as either a primary or secondary manifestation of disease. Based on findings from the literature review, a theoretical model of fatigue in MS is proposed.
  
  
  
  Future research on MS-related fatigue may consider a longitudinal design with a carefully selected self-report instrument to advance understanding of the underlying pathological mechanisms.
authors.affiliation: a Office of Nursing Research, Goldfarb School of Nursing at Barnes Jewish College , St. Louis , MO , USA.
authors.forename: Pamela
authors.initials: P
authors.lastname: Newland
authors.affiliation: b Center for Advancement of Managing Pain, University of Connecticut School of Nursing , Storrs , CT , USA.
authors.forename: Angela
authors.initials: A
authors.lastname: Starkweather
authors.affiliation: c DePaul University School of Nursing , Chicago , IL , USA.|d Department of Physical Medicine and Rehabilitation , Northwestern University Feinberg School of Medicine , Chicago , IL , USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Sorenson
mesh_terms: D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D009103:Multiple Sclerosis / Q000150:complications* / Q000175:diagnosis
keywords: Central fatigue; Demyelination; Electroencephalogram; Multiple sclerosis