Speed and memory in WAIS-R-NI Digit Symbol performance among healthy olderadults

Although roles have been proposed for both graphomotor speed and learning i n the execution of Digit Symbol, few data have been available concerning pe rformance across the adult lifespan on the Symbol Copy, paired associates, or free recall measures derived from Digit Symbol and recommended in the WA IS-R-NI. We report findings on 177 healthy older adults (ages 50-90), provi ding normative data by age group, education level, and gender. As previousl y reported, Digit Symbol scores decline steeply with age (r = -.64). Symbol Copy speed declines almost as steeply (r = -.58). Incidental learning, how ever, declines only modestly (r = -.26 on both measures). Symbol Copy is a far stronger correlate of Digit Symbol (r- =.72) than are paired associates or free recall (r =.26 and r- =.28, respectively). The 2 incidental learni ng measures do, however, offer valuable supplementary information as part o f a comprehensive individual assessment. When low Digit Symbol scores are p roduced by slowing on Symbol Copy, further evaluation of perceptual and mot or speed and dexterity are indicated. When low incidental learning scores a re obtained, further evaluation of memory is warranted. Qualitative analysi s of errors (e.g., rotations) made on the incidental learning procedures ma y also be valuable.