Utility of the Barona demographic equations to estimate premorbid intelligence: information from the WAIS-R standardization sample.

The WAIS-R (Wechsler, 1981) and elderly WAIS-R standardization samples (Ryan, Paolo, & Brungardt, 1990) were combined to evaluate the utility of the Barona demographic regression equations (Barona, Reynolds, & Chastain, 1984) to estimate premorbid intelligence. The equations underestimated ability for persons with IQs less than 80 and overestimated ability of subjects with IQs greater than 119. The equations also overestimated the IQs of 247 persons with confirmed brain dysfunction. Because this overestimation occurred for impaired persons with IQs less than 90, it is difficult to determine whether the difference reflects true intellectual deterioration or statistical artifact. Abnormal cut-off scores at the 10% and 5% levels are provided to allow clinicians to detect abnormal discrepancies between the estimated and obtained IQs.