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O1–05–02: Cognitive factors of dementia associated with Parkinson's disease and Alzheimer's disease
Author(s) -
Galvin James E.,
Johnson David K.,
Morris John C.
Publication year - 2006
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2006.05.053
Subject(s) - dementia , clinical dementia rating , cognitive decline , cognition , psychology , disease , parkinson's disease , cognitive test , working memory , psychiatry , audiology , medicine , clinical psychology
Background: Declines in executive function and visuospatial abilities have been suggested as specific cognitive features of dementia associated with Parkinson’s disease (PDD); however, characterization of cognitive deficits during transition between Parkinson’s disease (PD) and PDD have not been fully explored. Objective(s): To investigate different rates of cognitive decline in PDD compared to 1) nondemented PD and 2) Alzheimer’s disease (AD). Dementia groups were matched on dementia severity. Preclinical (prior to dementia diagnosis) versus post diagnosis epochs were determined from archival data. We hypothesized differential cognitive decline would reflect disease specific onset and progression as measured by Clinical Dementia Rating (CDR). Methods: 338 participants enrolled in a longitudinal study of aging and dementia and followed with annual clinical and cognitive assessments were studied (PD 66, PDD 136, AD 136). Dementia was rated using the CDR. A ninety-minute psychometric battery was administered annually. Factor analyses were used to characterize a 3-factor solution (verbal, visuospatial and working memory), indicating cross-sectional and longitudinal strengths and weaknesses by domain. Results/Conclusions: Compared to PD, patients with PDD begin with significantly lower scores on all cognitive indices and their rate of progression was significantly steeper throughout the study. Compared to AD, patients with PDD experienced similar rates of verbal memory decline, although AD performance was significantly worse at all points of assessment. Visuospatial and working memory abilities in AD patients were relatively preserved until time of dementia onset/diagnosis. In contrast, PDD visuospatial and working memory declines were steeper than AD prior to dementia diagnosis and then paralleled AD after diagnosis. PDD visuospatial and working memory performance were significantly worse than AD at all times or assessment. Further, variability in the preclinical phase of PDD, an index of disease severity, was significantly greater than in the AD group. It appears that visuospatial and working memory impairments are prominent features of preclinical PDD. After dementia onset, however, these features progress in a similar manner to AD. Controlling for motor slowing and depression did not change the overall pattern of results. These data support using domain specific testing strategies to diagnose early stage PDD.