Comparison of predicted-difference, simple-difference, and premorbid-estimation methodologies for evaluating IQ and memory score discrepancies

Research output: Contribution to journalArticlepeer-review

Abstract

Discrepancies between WAIS-III and WMS-III scores for a group of 39 males and 48 females with a history of TBI were examined using three methodologies: Predicted-difference, Simple-difference, and Premorbid-estimation methods. Overall, the Predicted-difference method tended to classify the fewest individuals as impaired based on statistical rarity of discrepancies (11-16% classified as impaired), while the regression-based Premorbid method tended to classify the fewest individuals as impaired based on clinical rarity of discrepancies (4-8% classified as impaired). Degree of agreement is reported and was substantial. The only comparison between methods to reach statistical significance was the Predicted-difference method classifying subjects as impaired at a higher rate than other methods for Auditory Delayed memory index (Cochran's Q=7.00, P<.05). Findings suggest a combination of estimates of premorbid functioning and regression-based predicted scores is optimal for interpreting IQ/memory score discrepancies. Clinical implications are discussed.

Original languageEnglish
Pages (from-to)363-374
JournalArchives of Clinical Neuropsychology
Volume19
StatePublished - 2004

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