Age Effects on Subtest and Composite Scores of the Wechsler Abbreviated Scale of Intelligence-Second Edition.

We evaluated age effects in the Wechsler Abbreviated Scale of Intelligence-Second Edition (WASI-II) standardization sample. This extends work completed using previous editions of the Wechsler Adult Intelligence Scales. Of the four subtests, Vocabulary (VC) and Similarities (SI) were most resistant to aging. VC showed minimal variation regardless of age; SI peaked at 30 to 54 years followed by a decline. Block Design (BD) and Matrix Reasoning (MR) showed substantial drops from the younger to older groups. BD peaked at 17 to 44 years and then declined; MR peaked at 20 to 29 years and then consistently deteriorated. The WASI-II Verbal Comprehension Index peak at 30 to 44 years was followed by a maximum drop at 85 to 90 years. The Perceptual Reasoning Index peaked at 20 to 29 years, with a marked decline by 65 to 69 years. The Full Scale IQ was average until age 65 years followed by a decline. Minor changes in points of peak performance and subsequent decline were seen as a function of Full Scale IQ level. Results were consistent with crystallized and fluid intelligence theory.