Document Type
Article
Language
eng
Publication Date
4-2017
Publisher
Lippincott, Williams & Wilkins, Inc.
Source Publication
Alzheimer Disease and Associated Disorders
Source ISSN
0893-0341
Abstract
Objective: Characterize the onset and timing of cognitive decline in Parkinson disease (PD) from the first recognizable stage of cognitively symptomatic PD-mild cognitive impairment (PD-MCI) to PD dementia (PDD). Thirty-nine participants progressed from PD to PDD and 25 remained cognitively normal.
Methods: Bayesian-estimated disease-state models described the onset of an individual’s cognitive decline across 12 subtests with a change point.
Results: Subtests measuring working memory, visuospatial processing ability, and crystalized memory changed significantly 3 to 5 years before their first nonzero Clinical Dementia Rating and progressively worsened from PD to PD-MCI to PDD. Crystalized memory deficits were the hallmark feature of imminent conversion of cognitive status. Episodic memory tasks were not sensitive to onset of PD-MCI. For cognitively intact PD, all 12 subtests showed modest linear decline without evidence of a change point.
Conclusions: Longitudinal disease-state models support a prodromal dementia stage (PD-MCI) marked by early declines in working memory and visuospatial processing beginning 5 years before clinical diagnosis of PDD. Cognitive declines in PD affect motor ability (bradykinesia), working memory, and processing speed (bradyphrenia) resulting in PD-MCI where visuospatial imagery and memory retrieval deficits manifest before eventual development of overt dementia. Tests of episodic memory may not be sufficient to detect and quantify cognitive decline in PD.
Recommended Citation
Johnson, David K.; Langford, Zachary; Garnier-Villarreal, Mauricio; Morris, John C.; and Galvin, James E., "Onset of Mild Cognitive Impairment in Parkinson Disease" (2017). College of Nursing Faculty Research and Publications. 529.
https://epublications.marquette.edu/nursing_fac/529
Comments
Accepted version. Alzheimer Disease & Associated Disorders, Vol. 30, No. 2 (April-June 2016): 127-133. DOI. © 2019 Ovid Technologies, Inc. Used with permission.