Do the WAIS-IV Tests Measure the Same Aspects of Cognitive Functioning in Adults Under and Over 65?

One of the important questions that needs to be considered when evaluating cognitive functioning in older adults is whether the scores on the tests have the same meaning as they do in young and middle-aged adults. While it is generally agreed that crystallized intelligence (Gc) measures such as those derived from vocabulary subtests tend to ‘‘hold’’ well with age, barring neurological complications arising from, for example, Alzheimer’s disease, traumatic brain injury (TBI), or stroke, other areas commonly tapped by intelligence tests such as abstract reasoning, working memory, and processing speed tend to show decline with normal aging. Thus two questions come to the fore when evaluating the results of a test such as the fourth edition of the Wechsler Adult Intelligence Scale (WAIS-IV; Wechsler, 2008); specifically, do the cognitive abilities of adults change quantitatively or qualitatively with age, and do the scores obtained from them reflect the same constructs in people of different ages? These questions are relevant to the clinical evaluation of older adults because the test scores may not have the same interpretation at different ages if the meanings are different for adults under and over 65 years of age. The major