WISC-III index growth curve characteristics following traumatic brain injury. Wechsler Intelligence Scale for Children--Third Edition.

Previous studies have replicated the four-factor structure of the WISC-III in children with traumatic brain injury (TBI) and demonstrated the sensitivity of WISC-III indexes to severity of injury. This archival study examined the growth curve characteristics of the indexes following traumatic brain injury. The primary hypothesis was that there is systematic variability in the components (e.g., slope) of the curves. Subjects included 40 children with documented loss of consciousness, age at injury 9.3 years (SD = 2.6), 68% severe TBI, evaluated with a full WISC-III a minimum of three times post-injury. Growth curve analyses with hierarchical linear modeling, conducted with factor scores recalculated as non-age-standardized z scores, indicated that although the intercept was reliable and could be predicted by injury characteristics, there was little systematic variation in index growth rates. Findings suggest that WISC-III indexes are of limited utility as repeated measures of recovery following TBI.