IQ and Ability Across the Adult Life Span

Abstract

The experience of cognitive decline can be a potent source of anxiety and concern for many people. While an IQ consistent with estimated optimal levels or previously recorded scores may indicate no significant change in cognitive function, the patient may be accurately reporting a normal age-related deterioration in actual ability. The aim of this article is to chart the age-related changes in intellectual abilities evident on the Wechsler Adult Intelligence Scales-Fourth Edition (WAIS-IV). The norms from the WAIS-IV manual were examined to plot the age-related changes in Full-Scale IQ (FSIQ) and composite scores across the adult life span, while holding actual ability level constant across the age groups. Here we present a graphical representation of the normal cognitive developments and declines in FSIQ, Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed across the adult life span. This graphical representation provides a rational basis for the identification of atypical profiles/complaints of cognitive deterioration that may require further specialist neuropsychological evaluation. These graphs can be used to provide reassurance for healthy adults with concerns of cognitive decline and as an educative tool for their referring agencies.

Key words:

• aging
• cognitive decline
• intelligence
• IQ
• WAIS-IV

ACKNOWLEDGEMENTS

Thanks to Dr. Heidi Adshead, Dr. Karen Long, and the Learning Disabilities Team at the Roselands Clinic, Kingston Upon Thames, Surrey, for their help in the preparation of this study. This work was undertaken at UCLH/UCL, who received a proportion of funding from the Department of Health's NIHR Biomedical Research Centres funding scheme.