transient global amnesia

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Related to transient global amnesia: transient ischemic attack


pathologic impairment of memory. Amnesia is usually the result of physical damage to areas of the brain from injury, disease, or alcoholism. Psychologic factors may also cause amnesia; a shocking or unacceptable situation may be too painful to remember, and the situation is then retained only in the subconscious mind. The technical term for this is repression. (See also dissociative disorders.)

Rarely is the memory completely obliterated. When amnesia results from a single physical or psychologic incident, such as a concussion suffered in an accident or a severe emotional shock, the victim may forget only the incident itself; the victim may be unable to recall events occurring before or after the incident or the order of events may be confused, with recent events imputed to the past and past events to recent times. In another form, only certain isolated events are lost to memory.

Amnesia victims usually have a good chance of recovery if there is no irreparable brain damage. The recovery is often gradual, the memory slowly reclaiming isolated events while others are still missing. Psychotherapy may be necessary when the amnesia is due to a psychologic reaction.
anterograde amnesia impairment of memory for events occurring after the onset of amnesia. Unlike retrograde amnesia, it is the inability to form new memories.
circumscribed amnesia loss of memory for all events during a discrete, specific period of time. Called also localized amnesia.
continuous amnesia loss of memory for all events after a certain time, continuing up to and including the present.
dissociative amnesia the most common of the dissociative disorders; it is usually a response to some stress, such as a threat of injury, an unacceptable impulse, or an intolerable situation. The patient suddenly cannot recall important personal information and may wander about without purpose and in a confused state.

Persons with a dissociative disorder may at times forget what they are doing or where they are; when they regain self-awareness, they cannot recall what has taken place. A less severe form than amnesia is sleepwalking. Dissociative disorders are very likely an attempt by the mind to shield itself from the anxiety caused by an unresolved conflict. The patient, upon encountering a situation that may be symbolic of this inner conflict, goes into a form of trance to avoid experiencing the conflict.
generalized amnesia loss of memory encompassing the individual's entire life.
lacunar amnesia partial loss of memory; amnesia for certain isolated experiences.
post-traumatic amnesia amnesia resulting from concussion or other head trauma. Called also traumatic amnesia. See also amnestic syndrome.
psychogenic amnesia dissociative amnesia.
retrograde amnesia inability to recall events that occurred prior to the episode precipitating the disorder. Unlike anterograde amnesia, it is the loss of memories of past events.
selective amnesia loss of memory for a group of related events but not for other events occurring during the same period of time.
transient global amnesia a temporary episode of short-term memory loss without other neurological impairment.
traumatic amnesia post-traumatic amnesia.

tran·sient glo·bal am·ne·si·a

a disorder that affects mainly old people who have not sustained a recent head injury and who do not have epilepsy; characterized by the abrupt onset of the inability to form memories (i.e., anterograde amnesia) and the resulting bewilderment; during the episode, which may last minutes to a few hours, the person is fully conscious, oriented, can perform complex activities, and has a normal result on neurologic examination; of uncertain etiology, but currently most often attributed to an ischemic episode affecting the mesial temporal lobe region.

transient global amnesia (TGA)

Etymology: L, transire, to go through, globus, ball; Gk, amnesia, forgetfulness
a temporary short-term memory loss followed by full recovery. The disorder tends to affect middle-aged adults and may be attributed to cerebral ischemia. It is usually not accompanied by other mental deficiencies.

transient global amnesia

Neurology The loss of memory largely attributable to ischemia, possibly vasospasms. See Amnesia.

tran·si·ent glo·bal am·ne·si·a

(tran'sē-ĕnt glō'băl am-nē'zē-ă)
A memory disorder seen in middle-aged and old people characterized by an episode of amnesia 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 result on neurologic examination.

transient global amnesia

A state, lasting for less than 24 hours, in which there is inability to form new memories and in which there is loss of memory for periods of up to years (retrograde amnesia) prior to the attack. After the attack there is permanent memory loss for the period of the attack. The condition may be brought on by emotional upset, physical exertion, sexual intercourse or the Valsalva manoeuvre.
References in periodicals archive ?
Our thorough search of the medical literature using the National Library of Medicine's MEDLINE database failed to reveal a single case of transient global amnesia (TGA) from acute marijuana intoxication in a young child.
The classic presentation of transient global amnesia includes pronounced memory loss for recent events in the absence of focal neurologic signs.
8) The second mechanism of interference postulates that transient global amnesia results from the action of cannabinoids at receptors located in the intermediate pyramidal cell layers of the hippocampus, the dentate gyrus, and layers I and VI of the cortex, where memory is stored.

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