Effective treatment of minor head injury and understanding its neurological consequences.

Minor head injury (MHI) is typically associated with coma and posttraumatic amnesia of short duration. Resulting impairment has been found in neurological and cognitive functioning, although these deficits tend to be brief in duration. A review of the literature reveals that although considerable research has been done on MHI, there remain a few critical issues that require resolution. First, one of the more noticeable problems relates to the fact that MHI does not have well-defined lower limits, which can lead to individuals being categorized as having an MHI despite never enduring trauma to the brain. The second problem relates to the failure of researchers to differentiate between cognitive deficits and postconcussion symptoms (PCS) when assessing outcome. Because PCS can occur in the absence of head injury and are often present beyond the period of cognitive recover from MHI, the two clearly result from different factors. Finally, many preinjury factors (age, personality) and postinjury factors (stress, neurological complications) interact with cognitive functioning and significantly affect recovery, which confounds the study of outcome. These problems are reviewed and discussed.