title: Defining mild cognitive impairment in Parkinson's disease.
abstract: Our purpose was to characterize a state of mild cognitive impairment (MCI) in Parkinson's disease (PD) (PD-MCI) that would be analogous to the MCI that is posited as a precursor of Alzheimer's disease (AD). We categorized 86 PD subjects in a brain bank population as either cognitively normal (PD-CogNL), PD-MCI using criteria that included a 1.5 standard deviation or greater deficit upon neuropsychological testing consistently across at least one cognitive domain without dementia, and PD dementia (PD-D) using DSM-IV criteria. Twenty-one percent of our PD sample met criteria for PD-MCI, 62% were PD-CogNL, and 17% had PD-D. The mean duration of PD and MMSE scores of the PD-MCI group were intermediate and significantly different from both PD-CogNL and PD-D. The cognitive domain most frequently abnormal in PD-MCI was frontal/executive dysfunction followed by amnestic deficit. Single domain PD-MCI was more common than PD-MCI involving multiple domains. We conclude that a stage of clinical cognitive impairment in PD exists between PD-CogNL and PD-D, and it may be defined by applying criteria similar to the MCI that is posited as a precursor of AD. Defining PD-MCI offers an opportunity for further study of cognitive impairment in PD and targets for earlier therapeutic intervention.
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA. jcaviness@mayo.edu
authors.forename: John N
authors.initials: JN
authors.lastname: Caviness
authors.forename: Erika
authors.initials: E
authors.lastname: Driver-Dunckley
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Connor
authors.forename: Marwan N
authors.initials: MN
authors.lastname: Sabbagh
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Hentz
authors.forename: Brie
authors.initials: B
authors.lastname: Noble
authors.forename: Virgilio Gerald H
authors.initials: VG
authors.lastname: Evidente
authors.forename: Holly A
authors.initials: HA
authors.lastname: Shill
authors.forename: Charles H
authors.initials: CH
authors.lastname: Adler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D003704:Dementia / Q000150:complications / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010300:Parkinson Disease / Q000150:complications*; D012189:Retrospective Studies