The role of pre-injury IQ in the determination of intellectual impairment from traumatic head injury.

The subjects were 17 head trauma patients whose pre-injury IQ and post-injury IQ scores on the Chinese Revised Version of the Wechsler Adult Intelligence Scale (WAIS-RC) were collected and analyzed. All patients had a neuroradiological imaging study. Changes in IQ scores were compared with neuroradiological findings and clinical determinations on the presence or absence of intellectual impairment from head trauma that were made by neuropsychiatrists without knowledge of pre-injury IQ scores. Thirteen patients were clinically determined not to have suffered intellectual impairment, primarily because their post-injury IQs on the WAIS-RC were higher than 70. However, 3 of the 13 had significantly higher pre-injury IQ scores, and they also showed brain damage on CT or MRI. Consideration of pre-injury IQ can improve the determination of intellectual impairment from head injury.