Generalizability of Two Methods of Estimating Premorbid Intelligence in the Elderly

Two methods for estimating premorbid WAIS-R IQ (Barona Reynolds & Chastain, 1984; Barona & Chastain, 1986) were compared in a sample of normal elderly and a sample of neurologically impaired persons. The normals consisted of 75 males with a mean age of 80.48 (SD = 4.57) years and the neurological group consisted of 20 males averaging 78.65 (SD = 5.62) years of age. For the normals, the percent of obtained IQs that fell within one standard error of estimate of the formula-estimated IQs demonstrated adequate agreement of both methods for the Full Scale IQ, but relatively poor prediction for the Performance Scale. The Verbal IQ was adequately predicted by the 1984 method, but not the 1986 procedure. As expected, both estimation procedures overestimated the obtained IQs of the brain-damaged subjects.