retrograde amnesia

amnesia /am·ne·sia/ (am-ne´zhah) pathologic impairment of memory.

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anterograde amnesia  amnesia for events occurring subsequent to the episode precipitating the disorder.

dissociative amnesia  a dissociative disorder characterized by a sudden loss of memory for important personal information and which is not due to the direct effects of a psychogenic substance or a general medical condition.

psychogenic amnesia  dissociative a.

retrograde amnesia  amnesia for events occurring prior to the episode precipitating the disorder.

transient global amnesia  a temporary episode of short-term memory loss without other neurological impairment.

visual amnesia  alexia.

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retrograde amnesia

n.

A condition in which events that occurred before the onset of amnesia cannot be recalled.

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retrograde amnesia,

the loss of memory for events occurring before a particular time in a person's life, usually before the event that precipitated the amnesia. The condition may result from disease, brain injury or damage, or a traumatic emotional incident. Compare anterograde amnesia.

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amnesia [am-ne´zhah]

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.

localized amnesia circumscribed amnesia.

lacunar amnesia.

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.

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retrograde amnesia

Neurology Amnesia that extends to before the trauma or events that caused the loss of memory. See Amnesia. Cf Anterograde amnesia.