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. (c) 2007 Movement Disorder Society.
Defining mild cognitive impairment in Parkinson's disease. Publishing Authors By Initials
