Executive dysfunction, severity of traumatic brain injury, and IQ in workers with disabilities.

OBJECTIVE: To study whether severity of traumatic brain injury and the intelligence quotient are related to executive dysfunction. PARTICIPANTS: Sixty-two adults with brain injury who were referred for a work capacity evaluation.
METHODS: Retrospective review of severity of traumatic brain injury, intelligence quotient from a previously-conducted neuropsychological evaluation, determination of executive function status from the neuropsychological evaluation, and both self-report and informant-report executive dysfunction scores from the Behavior Rating Inventory of Executive Function.
RESULTS: Executive dysfunction and the intelligence quotient are related to severity of traumatic brain injury, but executive dysfunction and the intelligence quotient are not related to each other. Executive dysfunction as determined by a neuropsychological evaluation was not consistent with clients' self-reports but was consistent with informant-reported executive dysfunction. Five types of executive dysfunction were reported by knowledgeable informants, with significant elevations on the Shift, Plan/Organize, Task Monitor, Organization of Materials, and Working Memory BRIEF clinical scales.
CONCLUSIONS: The intelligence quotient is not a useful indicator of executive dysfunction. Informant-report executive dysfunction is a reliable and potentially useful adjunct to a neuropsychological evaluation. Working memory is the most severe type of executive dysfunction and may not be adequately measured by current neuropsychological evaluation methods.