Introduction

Traumatic brain injury remains a significant cause of morbidity and mortality throughout the world. In the United Kingdom more than 150,000 patients are admitted to hospital each year with a head injury. Of this group more than 80% are classified as having a mild head injury, as defined by the Glasgow Coma Scale (GCS). The GCS (Teasdale & Jennett 1974, 1976) provides a means of quantifying the level of consciousness after traumatic brain injury based on the clinical features of verbal performance, eye opening and motor response. Using this scale three levels of severity of head injury are defined; mild (score 13–15), moderate (score 9–12), and severe (score 3–8).

Approximately 1–2% of patients admitted to hospital after traumatic brain injury die as a consequence of their injuries. The majority of fatalities are within the severe head injury group, with 40% of the cases resulting in death at 6 months (Murray et al., 1999).

Among survivors of traumatic brain injury of all grades chronic disability may have a physical component although it is predominantly the cognitive and behavioural problems which provide the greatest challenge (Jennett et al., 1981). Outcome may be assessed by the Glasgow Outcome Scale (GOS) (Jennett & Bond 1975) which defines four outcome states; death/vegetative state, severe disability, moderate disability, and good recovery. The GOS is based predominantly on assessment of social reintegration after traumatic brain injury involving a structured questionnaire-based interview. This has recently been modified as the extended GOS (Teasdale et al., 1998).