Base Rates of WAIS-R Qualitative Information for Persons 75 Years and Older

Base rates of WAIS-R qualitative errors for normal persons 75 years and older were provided for Picture Arrangement, Block Design, and Digit Symbol subtests. A second sample of cognitively impaired elderly was used for comparison. Most errors were rare and occurred in less than 5% of the normal subjects. In contrast, some errors such as placing the Picture Arrangement cards vertically and skipping numbers on Digit Symbol were manifested relatively frequently. Although persons with cognitive dysfunction tended to commit more qualitative errors, only four errors occurred significantly more frequently for persons with brain dysfunction. Interpretation of qualitative errors for elderly persons must be done cautiously and they should not be considered pathognomonic of chronic, diffuse brain impairment.