Defining mild cognitive impairment in Parkinson's disease.
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.
Caviness
John N
JN
Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA. jcaviness@mayo.edu
Driver-Dunckley
Erika
E
Connor
Donald J
DJ
Sabbagh
Marwan N
MN
Hentz
Joseph G
JG
Noble
Brie
B
Evidente
Virgilio Gerald H
VG
Shill
Holly A
HA
Adler
Charles H
CH
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