title: Parkinson's disease-related fatigue: A case definition and recommendations for clinical research.
abstract: Fatigue is one of the most common and disabling symptoms in Parkinson's disease (PD). Since fatigue was first described as a common feature of PD 20 years ago, little progress has been made in understanding its causes or treatment. Importantly, PD patients attending the 2013 World Parkinson Congress voted fatigue as the leading symptom in need of further research. In response, the Parkinson Disease Foundation and ProjectSpark assembled an international team of experts to create recommendations for clinical research to advance this field. The working group identified several areas in which shared standards would improve research quality and foster progress including terminology, diagnostic criteria, and measurement. Terminology needs to (1) clearly distinguish fatigue from related phenomena (eg, sleepiness, apathy, depression); (2) differentiate subjective fatigue complaints from objective performance fatigability; and (3) specify domains affected by fatigue and causal factors. We propose diagnostic criteria for PD-related fatigue to guide participant selection for clinical trials and add rigor to mechanistic studies. Recommendations are made for measurement of subjective fatigue complaints, performance fatigability, and neurophysiologic changes. We also suggest areas in which future research is needed to address methodological issues and validate or optimize current practices. Many limitations in current PD-related fatigue research may be addressed by improving methodological standards, many of which are already being successfully applied in clinical fatigue research in other medical conditions (eg, cancer, multiple sclerosis). © 2016 International Parkinson and Movement Disorder Society.
authors.affiliation: Department of Neurology, University of Colorado School of Medicine, Aurora, Colorado, USA.
authors.forename: Benzi M
authors.initials: BM
authors.lastname: Kluger
authors.affiliation: Department of Neurology, Sorlandet Hospital Arendal, Norway.
authors.forename: Karen
authors.initials: K
authors.lastname: Herlofson
authors.affiliation: Departments of Neurology and Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Kelvin L
authors.initials: KL
authors.lastname: Chou
authors.affiliation: Department of Neurology, University of North Dakota School of Medicine and Health Science, Department of Neurology, Sanford Health, Fargo, North Dakota, USA.
authors.forename: Jau-Shin
authors.initials: JS
authors.lastname: Lou
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Goetz
authors.affiliation: Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Lang
authors.affiliation: Departments of Psychiatry and Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.|Parkinson's Disease and Mental Illness Research, Education and Clinical Centers (PADRECC and MIRECC), Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weintraub
authors.affiliation: Department of Neurology, Butler Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Friedman
mesh_terms: D035843:Biomedical Research / Q000592:standards*; D005221:Fatigue / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D010300:Parkinson Disease / Q000150:complications*
keywords: Parkinson's disease; case definition; clinical research; fatigue