METHODS OF ESTIMATING PREMORBID FUNCTIONING

Clinical neurophysiological assessment frequently requires the compari son of obtained scores against estimate of premorbid level of function ing, but only recently has significant attention been turned to object ive methods to accomplish this objective. Clinical judgment, although useful in some circumstances, is generally insufficient. Other methods of estimating premorbid function include demographic regression formu lae, such as the Barona formula, subtest scatter methods, such as that suggested by Lezak, and the use of current scores on tests of presuma bly spared abilities, such as the National Adult Reading Test (NART). Almost all methods predict to some general level of intellectual funct ioning rather than to specific neuropsychological skills. This pater r eviews the suggested methods in terms of the underlying assumptions an d the available empirical evidence. Suggestions for future research in clude the development of skill specific predictors as well as investig ations regarding the relation between predictor accuracy and character istics of the subject, such as high versus low premorbid functioning i n the subject. Additionally, there is a great need for methods to pred ict premorbid functioning in children. (C) 1997 National Academy of Ne uropsychology. Published by Elsevier Science Ltd.