Cross-validation of a method for predicting wechsler memory scale-revised index scores

Abstract

Equations for prorating Wechsler Memory Scale-Revised General Memory (GM) and Delayed Recall (DR) index scores (Woodward & Axelrod, 1995) were confirmed in clinical samples of patients who were seen for comprehensive neuropsychological testing with (1) moderate or severe closed-head injuries (n = 53); (2) mild head injury/concussion (n = 47); and (3) patients with intractible seizures who were seen for neuropsychological testing prior to neurosurgical resection (n = 24). Fifty-one of the closed-head injury (CHI) patients were involved in litigation related to their injury at the time of this evaluation. Predicted GM and DR index scores fell within 6 points of the obtained scores for 91% and 92%, respectively, of the CHI sample, and 100% of the seizure resection sample. This is well within the standard error of measurement of these index scores. There were no significant differences in accuracy of estimated index scores between litigants and non-litigants or between levels of head injury severity. These findings confirm the earlier cross-validation results reported by Axelrod et al. (1996) in a mixed sample of traumatic brain injury and other neurological insult.