- : An impairment or lack of memory. Amnesia after a trauma event can be either antegrade (lack of memory related to events occurring after the event) or retrograde (lack of memory related to events occurring before the event).
* * *A disturbance in the memory of information stored in long-term memory, in contrast to short-term memory, manifested by total or partial inability to recall past experiences. [G. a., forgetfulness]- anterograde a. a. in reference to events occurring after the trauma or disease that caused the condition.- posthypnotic a. selective forgetting, after a hypnotic state, of events occurring during hypnosis or of information stored in long-term memory, such as one's name, address, and names of relatives.- retrograde a. a. in reference to events that occurred before the trauma or disease that caused the condition.- transient global a. a memory disorder seen in middle aged and elderly persons characterized by an episode of a. and bewilderment that persists for several hours; during the episode the patient has a memory defect for present and recent past events, but is fully alert, oriented, capable of high-level intellectual activity, and has a normal neurological examination. Typically, these amnesic episodes occur spontaneously, and most patients experience only one; of uncertain etiology—probably ischemic, but not due to atherosclerosis.- traumatic a. the loss or disturbance of memory following an insult or injury to the brain of the type that accompanies a head injury, or excessive use of alcohol, or following the cessation of alcohol ingestion or other psychoactive drugs; or loss or disturbance of memory of the type seen in hysteria and other forms of dissociative disorders.
* * *am·ne·sia am-'nē-zhə n1) loss of memory sometimes including the memory of personal identity due to brain injury, shock, fatigue, repression, or illness or sometimes induced by anesthesia <a period of \amnesia after the wreck>2) a gap in one's memory <an \amnesia concerning her high-school years>
* * *n.total or partial loss of memory following physical injury, disease, drugs, or psychological trauma (see confabulation, fugue, repression). Anterograde amnesia is loss of memory for the events following some trauma; retrograde amnesia is loss of memory for events preceding the trauma. Some patients experience both types.
* * *am·ne·sia (am-neґzhə) [Gr. amnēsia forgetfulness] lack or loss of memory; inability to remember past experiences.
Medical dictionary. 2011.