Developmental analysis of the Wechsler Memory Scale

Memory functions commonly decline with age. All dimensions of memory functioning may not change equally with age. Some studies have shown declines in visual-spatial memory tasks, others in remembering stories, and another in learning pairs of associated words. The purpose of this study was to determine which dimensions deteriorate with increasing age. In addition, this study examines the construct validity of the Wechsler Memory Scale (WMS), for which previous reports note two-, three- and four-factor solutions. WMS data from 1264 males and 1141 females at six age intervals, 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years, were compared on seven subtests to assess age trends. Visual-spatial memory tasks, remembering stories, and learning pairs of associated words proved more difficult with advanced age. Using theoretical, psychometric and statistical criteria, a one-factor (cluster) solution in both sexes across all age groups shows that the WMS measures only one construct, memory. This was shown by using principal component analyses, hierarchical cluster analyses, and very simple structure.