title: Do patients with young onset Alzheimer's disease deteriorate faster than those with late onset Alzheimer's disease? A review of the literature.
abstract: BACKGROUND
  Young onset Alzheimer's disease (YOAD; onset before 65 years of age) is thought to have a more rapid course and increased rate of progression compared to late onset Alzheimer's disease (LOAD). This assumption appears partly due to important clinical, structural, neuropathological, and neurochemical differences suggesting YOAD is a separate entity to LOAD. The aim in this review was to systematically identify and examine appropriate studies comparing rate of cognitive decline between patients with YOAD and patients with LOAD.
  
  
  METHODS
  A computer-based literature search was initially undertaken, followed by citation tracking and search of related papers. Primary research studies specifically focused on the rate of cognitive decline between people with YOAD and LOAD were included. Studies were described, critically analyzed, presented, and discussed in the review.
  
  
  RESULTS
  Four studies were included, of which three were longitudinal and one was a case-control study. Three of the included studies found a faster rate of decline in patients with YOAD, and one found no difference in rate of decline between the two groups.
  
  
  CONCLUSIONS
  The findings of the review are mixed and conflicting, and limited by the heterogeneity of the included studies. There is a need for future research to design systematic studies that include sufficient sample sizes and follow-up periods, and control for possible confounding factors such as education level, baseline cognitive impairment, and vascular risk factors. This will help to validate the findings so far and improve our understanding of the rate of cognitive decline in people with YOAD and LOAD.
authors.affiliation: North Essex Partnership Foundation Trust,St Margaret's Hospital,The Plain,Epping,Essex CM16 6TN,UK.
authors.forename: Karen
authors.initials: K
authors.lastname: Stanley
authors.affiliation: Department of Mental Health Services,University College London,Gower Street,London WC1E 6BT,UK.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Walker
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000523:psychology; D003071:Cognition; D018450:Disease Progression; D006801:Humans; D007361:Intelligence Tests; D016743:Mental Competency; D008875:Middle Aged