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Classification and external resources
ICD-10F04, R41.3
ICD-9294.0, 780.9, 780.93
  (Redirected from Memory loss)
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Classification and external resources
ICD-10F04, R41.3
ICD-9294.0, 780.9, 780.93

Amnesia (from Greek Ἀμνησία) is a condition in which one's memory is lost. The memory can be either wholly or partially lost due to the extent of damage that was caused.[1] The causes of amnesia have traditionally been divided into certain categories. Memory appears to be stored in several parts of the limbic system of the brain. Any condition that interferes with the function of this system can cause amnesia. Functional causes are psychological factors, such as mental disorder, post-traumatic stress or, in psychoanalytic terms, defence mechanisms. Amnesia may also appear as spontaneous episodes, in the case of transient global amnesia.[2] Patients with the amnesic syndrome have an unclouded sensorium and appear alert, able to concentrate and are cooperative.[3]

However, there are different types of memory, for example procedural memory (i.e. automated skills) and declarative memory (personal episodes or abstract facts), and often only one type is impaired. For example, a person may forget the details of personal identity, but still retain a learned skill such as the ability to play the piano.

In addition, the terms are used to categorize patterns of symptoms rather than to indicate a particular cause (etiology). Both categories of amnesia can occur together in the same patient, and commonly result from drug effects or damage to the brain regions most closely associated with episodic memory: the medial temporal lobes and especially the hippocampus.

An example of mixed retrograde and anterograde amnesia, may be a motorcyclist unable to recall driving his motorbike prior to his head injury (retrograde amnesia), nor can he recall the hospital ward where he is told he had conversations with family over the next two days (anterograde amnesia).

The most influential case on anterograde amnesia was H.M.. This patient had to undergo bi-lateral removal of the hippocampus and amygdala in order to treat his severe epilepsy. In fact, H.M. was reported having up to 10 seizures per day. Although the epilepsy was fixed through surgery H.M. ended up with anterograde amnesia.[7]

The effects of amnesia can last a long time even after the condition has passed. Some sufferers claim that their amnesia changes from a neurological condition to also being a psychological condition, whereby they lose confidence and faith in their own memory and accounts of past events.

Another effect of some forms of amnesia may be impaired ability to imagine future events. A 2006 study showed that future experiences imagined by amnesiacs with bilaterally damaged hippocampus lacked spatial coherence, and the authors speculated that the hippocampus may bind different elements of experience together in the process of re-experiencing the past or imagining the future.[8]


Discovery of amnesia

French psychologist named Theodule-Armand Ribot first observed that patients tend to lose recent memories because of retrograde amnesia. Because of this, medical experts started to call the gradients of memory loss as Ribot gradients. Aside from this particular type of amnesia, there is also anterograde amnesia, a medical condition where patients are unable to turn their immediate memory into long-term memory.[9]

Types and causes of amnesia


Many of the treatments of amnesia back in the 1990s, involved medication, behavioral modification, and the most used is psychotherapy, followed by closely watching physicians.[21]

See also


  1. ^ "Amnesia." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed. Vol. 1. Detroit: Gale, 2008. 182-184. Gale Virtual Reference Library.
  2. ^ "Transient Global Amnesia : Article by Roy Sucholeiki". eMedicine. Retrieved 28 November 2011. 
  3. ^ Ennio De Renzi. 2000. The Amnesic Syndrome. Chapter 8. P.164-p.186. Memory Disorders in Psychiatric Practice Edited by German E. Berrios, John R. Hodges. Cambridge University Press. Retrieved on Aug 2012. Web. :
  4. ^ Reed J.M, Squir L.R (1998) Retrograde Amnesia for Facts and Events: Findings from Four New Cases. J. Neurosci.18(10):3943–3954
  5. ^ Fast, Kristina; Fujiwara.,Esther (2001). "Isolated Retrograde Amnesia.". Neurocase 7: 2–3. 
  6. ^ R.B. Tattersall (1995) Hypoglacaemic amnesia. The Lancet, Vol. 345 No. 8958 p 1188
  7. ^ Memory for remote events in anterogradeamnesia: Recognition of public figures from newsphotographs, Neuropsychologia 13 (3): 353 - 364
  8. ^ Patients with hippocampal amnesia cannot imagine new experiences, Proceedings of the National Academy of Sciences.
  9. ^ "Who Discovered Amnesia?". Retrieved 2012-07-09. 
  10. ^ Carlson, N. R. (19992000). Memory. Psychology: the science of behaviour (Canandian ed., p. 250). Scarborough, Ont.: Allyn and Bacon Canada.
  11. ^ Masferrer R, Masferrer M, Prendergast V, Harrington TR (2000). "Grading Scale for Cerebral Concussions" ([dead link]). BNI Quarterly (Barrow Neurological Institute) 16 (1). ISSN 0894-5799
  12. ^ Dissociative Fugue. Retrieved 7 August 2012
  13. ^ The Merck Manuals Online[dead link]
  14. ^ Carlson, Neil (2007). Psychology the Science of Behaviour. Toronto: Pearson. p. 283. ISBN 978-0-205-64524-4. 
  15. ^ Harlene Hayne*, Fiona Jack, [1], Wiley Interdisciplinary Reviews: Cognitive Science, March/April 2011
  16. ^ "Types of Amnesia". uwaterloo. Retrieved 9 April 2012. 
  17. ^ Erdogan, Serap (2010). "Anterograde Amnesia". Current Approaches In Psychiatry 2 (2): 174–189. Retrieved 27 November 2011. 
  18. ^ Erdogan, Serap (2010). "Anterograde Amnesia". Psikiyatride Guncel Yaklasimlar 2 (2): 174–189. Retrieved 30 November 2011. 
  19. ^ Mastin, L. (2010). The human memory: Retrograde amnesia . Retrieved from
  20. ^ "memory abnormality." Encyclopædia Britannica. Encyclopædia Britannica Online Academic Edition. Encyclopædia Britannica Inc., 2012. Web. 21 Apr 2012.
  21. ^ Bruckheim, Allan, "Psychotherapy a frequent amnesia treatment: [NORTH SPORTS FINAL, CN Edition", Chicago Tribune (pre-1997 Fulltext),07 Sep 1990