title: Time to redefine PD? Introductory statement of the MDS Task Force on the definition of Parkinson's disease.
abstract: With advances in knowledge disease, boundaries may change. Occasionally, these changes are of such a magnitude that they require redefinition of the disease. In recognition of the profound changes in our understanding of Parkinson's disease (PD), the International Parkinson and Movement Disorders Society (MDS) commissioned a task force to consider a redefinition of PD. This review is a discussion article, intended as the introductory statement of the task force. Several critical issues were identified that challenge current PD definitions. First, new findings challenge the central role of the classical pathologic criteria as the arbiter of diagnosis, notably genetic cases without synuclein deposition, the high prevalence of incidental Lewy body (LB) deposition, and the nonmotor prodrome of PD. It remains unclear, however, whether these challenges merit a change in the pathologic gold standard, especially considering the limitations of alternate gold standards. Second, the increasing recognition of dementia in PD challenges the distinction between diffuse LB disease and PD. Consideration might be given to removing dementia as an exclusion criterion for PD diagnosis. Third, there is increasing recognition of disease heterogeneity, suggesting that PD subtypes should be formally identified; however, current subtype classifications may not be sufficiently robust to warrant formal delineation. Fourth, the recognition of a nonmotor prodrome of PD requires that new diagnostic criteria for early-stage and prodromal PD should be created; here, essential features of these criteria are proposed. Finally, there is a need to create new MDS diagnostic criteria that take these changes in disease definition into consideration.
authors.affiliation: Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Center of Neurodegenerative Diseases, Tuebingen, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Berg
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Postuma
authors.forename: Bastiaan
authors.initials: B
authors.lastname: Bloem
authors.forename: Piu
authors.initials: P
authors.lastname: Chan
authors.forename: Bruno
authors.initials: B
authors.lastname: Dubois
authors.forename: Thomas
authors.initials: T
authors.lastname: Gasser
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Goetz
authors.forename: Glenda M
authors.initials: GM
authors.lastname: Halliday
authors.forename: John
authors.initials: J
authors.lastname: Hardy
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Lang
authors.forename: Irene
authors.initials: I
authors.lastname: Litvan
authors.forename: Kenneth
authors.initials: K
authors.lastname: Marek
authors.forename: José
authors.initials: J
authors.lastname: Obeso
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Oertel
authors.forename: C Warren
authors.initials: CW
authors.lastname: Olanow
authors.forename: Werner
authors.initials: W
authors.lastname: Poewe
authors.forename: Matthew
authors.initials: M
authors.lastname: Stern
authors.forename: Günther
authors.initials: G
authors.lastname: Deuschl
mesh_terms: D026683:Advisory Committees; D039721:Diagnostic and Statistical Manual of Mental Disorders; D006801:Humans; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis* / Q000473:pathology
keywords: MDS diagnostic criteria; disease heterogeneity; gold standard; nonmotor prodrome; redefinition of PD; subtypes