Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Neuropsychology. 2005 Jul;19(4):520-31.

Cognitive impairment in preclinical Alzheimer's disease: a meta-analysis.

Author information

  • 1Aging Research Center, Division of Geriatric Epidemiology, Neurotec, Karolinska Institute, Stockholm, Sweden. lars.backman@neurotec.ki.se

Abstract

To determine the size of the impairment across different cognitive domains in preclinical Alzheimer's disease (AD), a meta-analysis based on 47 studies involving 9,097 controls and 1,207 preclinical AD cases was conducted. There were marked preclinical deficits in global cognitive ability, episodic memory, perceptual speed, and executive functioning; somewhat smaller deficits in verbal ability, visuospatial skill, and attention; and no preclinical impairment in primary memory. Younger age (< 75 years) and shorter follow-up intervals (< 3 years) were associated with larger effect sizes for both global cognitive ability and episodic memory. For global cognitive ability, studies that used population-based sampling yielded larger effect sizes; for episodic memory, larger differences were seen in studies that preidentified groups in terms of baseline cognitive impairment. Within episodic memory, delayed testing and recall-based assessment resulted in the largest effect sizes. The authors conclude that deficits in multiple cognitive domains are characteristic of AD several years before clinical diagnosis. The generalized nature of the deficit is consistent with recent observations that multiple brain structures and functions are affected long before the AD diagnosis.

((c) 2005 APA, all rights reserved).

PMID:
16060827
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for American Psychological Association
    Loading ...
    Write to the Help Desk