Neuropsychological assessment of moderate to severe traumatic brain injury

Abstract

Individuals are usually deemed to have sustained a moderate or severe traumatic brain injury (TBI) when their Glasgow Coma Scale (GCS) (Teasdale and Jennett, 1974) a few hours postinjury falls between 9 and 12 or between 3 and 8, respectively. However, criteria for moderate TBI have occasionally been expanded to include GCS scores of 13-15 if intracranial mass lesions are present (e.g., Williams et al., 1990). Posttraumatic amnesia (PTA) between 1 and 24 hours or lasting more than 24 hours also suggests moderate and severe TBI, respectively. PTA is defined as the period postinjury before a person is able to reliably, consistently, and accurately recall ongoing events. Within the forensic setting, neuropsychologists are typically called upon to testify regarding issues of diagnosis, causation, prognosis, and functional impairment. Doing so requires a thorough evaluation, consideration of all factors potentially contributing to a person's neuropsychological presentation, and knowledge of the recent neuropsychological literature as it pertains to moderate and severe TBI. These issues will be the focus of this chapter, with particular emphasis on neuropsychological findings in the area of TBI.