title: Neuropsychological syndromes associated with Alzheimer's/vascular dementia: a latent class analysis.
abstract: BACKGROUND
  Epidemiologic autopsy studies show mixed Alzheimer's disease (AD)/vascular pathology in many patients. Moreover, clinical research shows that it is not uncommon for AD and vascular dementia (VaD) patients to be equally impaired on memory, executive, or other neurocognitive tests. However, this clinical heterogeneity has not been incorporated into the new diagnostic criteria for AD (Dubois et al., 2010; McKhann et al., 2011).
  
  
  OBJECTIVE
  The current research applied Latent Class Analysis (LCA) to a protocol of six neuropsychological parameters to identify phenotypic subtypes from a large group of AD/VaD participants. Follow-up analyses examined difference between groups on neuroradiological parameters and neuropsychological measures of process and errors.
  
  
  METHODS
  223 AD/VaD patients were administered a comprehensive neuropsychological protocol. Measures of whole brain and hippocampal volume were available for a portion of the sample (n = 76).
  
  
  RESULTS
  LCA identified four distinct groups: moderate/mixed dementia (n = 54; 24.21%), mild/mixed dementia (n = 91; 40.80%); dysexecutive (n = 49, 21.97%), and amnestic (n = 29, 13.00%). Follow-up analyses comparing the groups on neuropsychological process and error scores showed that the dysexecutive group exhibited difficulty sustaining mental set. The moderate/mixed group evidenced pronounced impairment on tests of lexical retrieval/naming along with significant amnesia. Amnestic patients also presented with gross amnesia, but showed relative sparing on other neuropsychological measures. Mild/mixed patients exhibited milder memory deficits that were intermediary between the amnestic and moderate/mixed groups.
  
  
  CONCLUSIONS
  There are distinct neuropsychological profiles in patients independent of clinical diagnosis, suggesting that the two are not wholly separate and that this information should be integrated into new AD diagnostic paradigms.
authors.affiliation: Department of Neurology, Drexel University, College of Medicine, Philadelphia, PA, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Libon
authors.affiliation: Department of Psychology, Temple University, Philadelphia, PA, USA.
authors.forename: Deborah A G
authors.initials: DA
authors.lastname: Drabick
authors.affiliation: Department of Psychology, Temple University, Philadelphia, PA, USA.
authors.forename: Tania
authors.initials: T
authors.lastname: Giovannetti
authors.affiliation: Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA.
authors.forename: Catherine C
authors.initials: CC
authors.lastname: Price
authors.affiliation: Department of Psychiatry, University of California San Diego, School of Medicine, San Diego, CA, USA and The Psychology Service VA San Diego Healthcare System, San Diego, CA, USA.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Bondi
authors.affiliation: Department of Neurology, Drexel University, College of Medicine, Philadelphia, PA, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Eppig
authors.affiliation: Department of Psychology, Temple University, Philadelphia, PA, USA.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Devlin
authors.affiliation: Department of Neurology, Drexel University, College of Medicine, Philadelphia, PA, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Nieves
authors.affiliation: Department of Psychiatry, University of Illinois, Chicago, IL, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Lamar
authors.affiliation: Department of Psychiatry, University of California San Diego, School of Medicine, San Diego, CA, USA and The Psychology Service VA San Diego Healthcare System, San Diego, CA, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Delano-Wood
authors.affiliation: Department of Psychology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Nation
authors.affiliation: Department of Neurology, Drexel University, College of Medicine, Philadelphia, PA, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Brennan
authors.affiliation: Department of Neurology, Boston University and the Framingham Heart Study, Boston, MA, USA.
authors.forename: Rhoda
authors.initials: R
authors.lastname: Au
authors.affiliation: Department of Neuroscience, North Dakota Medical School, Fargo, ND, USA.
authors.forename: Rod
authors.initials: R
authors.lastname: Swenson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications*; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D015140:Dementia, Vascular / Q000150:complications*; D056344:Executive Function; D005260:Female; D005500:Follow-Up Studies; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007859:Learning Disabilities / Q000175:diagnosis / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012660:Semantics; D012720:Severity of Illness Index
keywords: Alzheimer's disease; latent class analysis; mixed dementia; vascular dementia