title: Clinical features distinguishing large cohorts with possible AD, probable AD, and mixed dementia.
abstract: OBJECTIVE
  To determine whether clinical features and rate of cognitive and functional decline differed in cohorts of possible AD (poAD), probable AD (prAD), and mixed dementia (MIX) patients.
  
  
  METHODS
  Cohort study with 1-year follow-up examination, comparing three groups of subjects.
  
  
  METHODS
  Outpatient evaluation at nine California Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC).
  
  
  METHODS
  There were 1701 elderly patients who presented for evaluation of memory complaints.
  
  
  METHODS
  Historical, physical, and neurological variables for cross-sectional comparisons and 1-year rate of change on the Mini-Mental State Examination (MMSE), Blessed Information-Memory-Concentration test (BIMC), and Blessed Dementia Scale (BDS).
  
  
  RESULTS
  Mean initial MMSE scores for poAD (n = 279), prAD (n = 928) and MIX (n = 430) were 17.9 (+/- 7.4), 13.9 (+/- 7.5), and 15.4 (+/- 7.1). Delusions and psychosis occurred in about one-third of each group, most often in those with moderate dementia (MMSE 11-20). PoAD were distinguished from prAD by significantly more alcohol abuse, physical health problems, and focal motor or sensory findings. MIX differed from AD alone by increased prevalence of cardiovascular disease, hypertension, stroke, TIA, and exposure to general anesthesia, and by a greater frequency on exam of depressed mood, focal motor or sensory findings, and gait disorder. All groups declined by about 2.8 points on the BIMC, 2.9 points on the MMSE, and 1.8 points on the BDS, a functional scale, over 1 year. Neither extrapyramidal signs nor psychosis predicted a more rapid rate of decline.
  
  
  CONCLUSIONS
  Various features help to distinguish poAD, prAD, and MIX in a large cohort of patients, but do not predict the rate of progression.
authors.affiliation: Neurology Service, Veteran's Affairs Medical Center, San Diego, California 92161.
authors.forename: J
authors.initials: J
authors.lastname: Corey-Bloom
authors.forename: D
authors.initials: D
authors.lastname: Galasko
authors.forename: C R
authors.initials: CR
authors.lastname: Hofstetter
authors.forename: J E
authors.initials: JE
authors.lastname: Jackson
authors.forename: L J
authors.initials: LJ
authors.lastname: Thal
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D002140:California / Q000453:epidemiology; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D015897:Comorbidity; D003704:Dementia / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D003937:Diagnosis, Differential; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008403:Mass Screening; D008487:Medical History Taking; D008609:Mental Status Schedule; D009460:Neurologic Examination; D010044:Outpatient Clinics, Hospital; D015995:Prevalence; D012017:Referral and Consultation / Q000706:statistics & numerical data; D012307:Risk Factors