While amnesia literally means loss of memory, in clinical practice it has a more limited application. It refers to a person's verbal statement that he does not remember a particular event, person, place, or period of time. A further definition is that the situation is one with which the patient should be familiar as to where he lives, the kind of work he does, and why he came to the hospital. The term is not used to characterize poor performance on a memory test, or for loss of memory for actions (apraxia) or reading (alexia). Patients with amnesia may do well on standard memory tests and have no difficulty in reproducing previously learned acts.
In the literature, amnesia following injury to the brain has been attributed to many types of neural deficit representing thinking in various disciplines and emphasizing certain aspects of the clinical picture.