Comparing methods for estimating-premorbid intellectual functioning

Efforts to determine premorbid intellectual functioning for a patient prior fb their current evaluation has been attempted using demographic informati on, current performance data, or a combination of both. Five of these premo rbid intellectual prediction methods were assessed in a sample of 104 neuro logical patients referred for neuropsychological evaluation and a matched c ontrol sample. Predicted Full-Scale Intelligence Quotient (FSIQ) scores of patients did not differ from the true FSIQ scores of the matched controls. Logistic regression analyses found no difference in classification accuracy among the prediction methods. The findings of this study found combined de mographic and performance methods developed by Vanderploeg and Schinka (199 5), Vanderploeg, Schinka, and Axelrod (1996), Krull, Scott, and Sherer (199 5) and Williamson, Krull, and Scott (1996) to be accurate estimates of prem orbid functioning. This study found estimates of premorbid functioning base d on demographic data alone (Barona, Reynolds, & Chastain, 1984) not to dif fer from the other methods, which is at odds with prior studies. Prospectiv e studies employing all of these methods are recommended to clarify the uti lity of demographically based estimates. (C) 1999 National Academy of Neuro psychology. Published by Elsevier Science Ltd.