Attacks of Loss of Consciousness and Disturbance of Memory

Abstract

Consciousness is the state of awareness of self and surroundings and is normally associated with the recording of memory. Thus concussive head injury will lead initially to unrousable unconsciousness followed by a drowsy state where there is diminished awareness. Consciousness can only be said to have fully recovered after concussion when the patient is able to record continuous memory. The duration of loss of consciousness in concussion is measured by the time from the head injury to the recovery from post-traumatic amnesia, and the duration of post-traumatic amnesia correlates well with the severity of the head injury. Disturbance of consciousness may, therefore, be without any discernible drowsiness. But specific defects of memory-the amnesic states—should be classified separately from conditions causing disturbance of consciousness because they imply a focal disturbance of brain function. In this chapter we will consider the causes of blackouts and the amnesic states, since these are seen relatively commonly in the elderly population.