ABSTRACT
In neurological clinics, the durations of unconsciousness and post-traumatic amnesia are recognized as useful pointers to the severity of the underlying brain injury. In addition, doctors have developed guidelines for assessing a patient’s level of consciousness at any given time. The most widely adopted terminology distinguishes different overall impairments ranging from delirium via stupor and coma to vegetative state (Bates and Cartlidge, 1994). Formal assessments are often based on the Glasgow Coma Scale (Teasdale and Jennett, 1974), which looks separately at three easily determined behavioural indices; eye opening, verbal responses and motor responses. Each of these is rated on a scale measuring an increasing degree of dysfunction; for example, eye opening may occur spontaneously, in response to speech, in response to pain, or not at all. The advantage of this scale is that it covers a wide range, from full consciousness to deep coma, simply and reliably. However, even in patients who are obviously awake, significant disorientation or other cognitive changes can be observed. A quick evaluation of the cognitive status of patients who are clearly awake can be achieved with the Mini-Mental State examination (Folstein et al., 1975).
