Early onset Alzheimer's disease is associated with a distinct neuropsychological profile

J Alzheimers Dis. 2012;30(1):101-8. doi: 10.3233/JAD-2012-111934.

Abstract

Alzheimer's disease (AD) in younger patients is associated with a higher prevalence of atypical symptoms. We examined neuropsychological performance according to age-at-onset. We assessed cognition in 172 patients with AD (81 early and 91 late onset) in five cognitive domains (memory, language, visuo-spatial functioning, executive functioning, attention). Dementia severity was assessed using the Mini-Mental State Examination (MMSE) and global cognitive decline using Cambridge Cognitive Examination (CAMCOG). Analyses of variance were performed with age-at-onset as between-subjects factor, and gender and education as covariates. Analysis was repeated after stratification for dementia severity (based on median MMSE). In early onset AD, age (mean ± SD) was 60 ± 4 years; 44 (54%) were female. In late onset AD, age was 72 ± 5 years; 47 (52%) were female. Dementia severity and global cognitive decline did not differ between groups (early onset: MMSE: 20 ± 5, CAMCOG: 69 ± 15, late onset: MMSE: 21 ± 5, CAMCOG: 70 ± 15; p > 0.05). Early onset patients performed worse than late onset patients on visuo-spatial functioning (p < 0.01), executive functioning (p < 0.001), and attention (p < 0.01). Late onset patients performed worse on memory, although not significantly (p = 0.11). Stratification for dementia severity showed that in mildly demented early onset patients, memory function was remarkably preserved compared to late onset patients (p < 0.01). In moderate AD, differences in memory function disappeared, but early onset patients performed worse on visuo-spatial functioning (p < 0.01), executive functioning (p < 0.001), and attention (p < 0.01) than late onset patients. Adjustment for APOE left results unchanged. In conclusion, early onset AD presents with a different cognitive profile and the disease course seems different. Relative sparing of memory function in early stages stresses the need to adequately test other cognitive domains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age of Onset
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / complications*
  • Alzheimer Disease / epidemiology
  • Alzheimer Disease / genetics
  • Alzheimer Disease / psychology*
  • Apolipoproteins E / genetics
  • Attention / physiology
  • Cognition Disorders / complications*
  • Cognition Disorders / diagnosis*
  • Cognition Disorders / epidemiology
  • Dementia / epidemiology
  • Executive Function / physiology
  • Female
  • Humans
  • Language
  • Male
  • Memory / physiology
  • Mental Status Schedule
  • Mutation / genetics
  • Neuropsychological Tests
  • Presenilin-1 / genetics
  • Retrospective Studies
  • Space Perception / physiology

Substances

  • Apolipoproteins E
  • PSEN1 protein, human
  • Presenilin-1