Retrograde amnesia

Retrograde amnesia is a form of amnesia where someone will be unable to recall events that occurred before the development of amnesia. The term is used to categorise patterns of symptoms, rather than to indicate a particular cause or etiology.

Both retrograde amnesia and anterograde amnesia can occur together in the same patient.

Classification

Retrograde amnesia can also be divided into two categories: temporally graded retrograde amnesia^[1] and stable, temporally ungraded retrograde amnesia.^[2]

Causes

Retrograde amnesia commonly results from damage to the brain regions most closely associated with episodic/declarative memory: the temporal lobes^[3] and especially the hippocampus.^[4]

Retrograde amnesia is caused by trauma that results in brain injury. Critical details of the physical changes in the brain that cause retrograde amnesia are still unknown. Retrograde amnesia is often temporally graded, meaning that remote memories are more easily accessible than events occurring just prior to the trauma (Ribot's Law).^[5] Events nearest in time to the event that caused memory loss may never be recovered.

Presentation

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A person who has suffered this injury will often feel as if the time (1–4 hours) before the injury were a dream. If someone informs the injured person of the events just before the trauma, they will most likely recollect some of the happenings.

The memory loss may just affect specific “classes” of memory. For instance, the victim, a concert pianist before, may still remember what a piano is after the onset of retrograde amnesia, but may forget how to play. The relearning rate for often used skills such as typing and math is typically faster than if they had never learned it before. While there is no cure for retrograde amnesia, “jogging” the victim’s memory by exposing them to significant articles from their past will speed the rate of recall.

The victim of retrograde amnesia may feel embarrassed or stressed that they no longer remember key people and significant events. Typically the victim may be overwhelmed by the rush of well-wishers who seek to reacquaint themselves. It is important to let the amnesic go at his or her “own pace,” so they are not overly stressed. Forgotten relations forget that they are effectively meeting the victim for the “first time” and may make the victim uncomfortable through displays of friendship such as kissing or slapping on the back that, while appropriate for longtime relationships, are not appropriate for "first time" meetings.

See also

• Anterograde amnesia
• Benjaman Kyle - Retrograde amnesia victim
• Samantha Who? - American comedy-drama television show of which retrograde amnesia is the subject

References

External links

• Journal of Neuroscience
• Jakten på hukommelsen (Norwegian)