title: Residual decline in cognition after adjustment for common neuropathologic conditions.
abstract: OBJECTIVE
  Neurodegenerative and cerebrovascular conditions are common in old age and are associated with cognitive decline. However, considerable heterogeneity remains in residual decline (i.e., person-specific trajectories of cognitive decline adjusted for these common neuropathologic conditions). The present study aimed to characterize profiles of residual decline in late life cognition.
  
  
  METHODS
  Up to 19 waves of longitudinal cognitive data were collected from 876 autopsied participants from 2 ongoing clinical-pathologic cohort studies of aging. Uniform neuropathologic examinations quantified measures of Alzheimer's disease, cerebral infarcts, Lewy body disease, and hippocampal sclerosis. Random effects mixture models characterized latent profiles of residual decline in global cognition.
  
  
  RESULTS
  We identified 4 latent groups, and each group demonstrated distinct residual decline profiles. On average, 44% of the participants had little or no decline, 35% showed moderate decline, 13% showed severe decline and the rest (8%) had substantial within-subject fluctuation of longitudinal cognitive measures. These latent groups differed in psychological, experiential and neurobiologic factors that have been previously shown to be associated with cognitive decline. Specifically, compared with nondecliners, decliners had more depressive symptoms, were more socially isolated; were less engaged in cognitive or physical activities; and had lower density of noradrenergic neurons in locus ceruleus.
  
  
  CONCLUSIONS
  After controlling for common dementia related pathologies, considerable residual variability remains in cognitive aging trajectories and this variability is not random but rather is related to markers of cognitive and neural reserve. The mixture modeling approach provides a powerful tool to identify latent groups with distinct cognitive trajectories.
authors.affiliation: Rush Alzheimer's Disease Center.
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.affiliation: Rush Alzheimer's Disease Center.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Boyle
authors.affiliation: Department of Medical Social Sciences, Feinberg School of Medicine, Northwestern University.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Segawa
authors.affiliation: Rush Alzheimer's Disease Center.
authors.forename: Sue
authors.initials: S
authors.lastname: Leurgans
authors.affiliation: Rush Alzheimer's Disease Center.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Schneider
authors.affiliation: Rush Alzheimer's Disease Center.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Wilson
authors.affiliation: Rush Alzheimer's Disease Center.
authors.forename: David A
authors.initials: DA
authors.lastname: Bennett
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology / Q000523:psychology*; D001921:Brain / Q000473:pathology*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000473:pathology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000473:pathology / Q000523:psychology*; D009483:Neuropsychological Tests