A study of intellectual recovery following closed head injury

Previous studies have utilized the WAIS and WAIS-R to assess the level of intellectual functioning after closed head injury, and have found that the Full Scale scores are depressed within the first year, and show a gradual improvement over time. The Verbal scale is usually higher that the Performance scale and exhibits a faster recovery rate. The present study focused on identifying subject variables (such as premorbid IQ and severity of injury) which contribute to the initial depression of IQ scores, and on determining the reasons for the VIQ-PIQ discrepancy. Results indicated that premorbid intellectual levels and severity of injury were correlated with change in IQ scores over time. Also, the interval between injury and readiness to be tested was significantly related to IQ at follow-up. The VIQ-PIQ discrepancy appeared to be an artefact of deficits in visual discrimination and motor programming at baseline. At follow-up there was no overall discrepancy, but visual discrimination was correlated with Performance IQ. Implications of these results will be discussed.