Normal memory function involves many parts of the brain, and any disease or injury that affects the brain can interfere with the intricacies of memory.
Amnesia can result from damage to brain structures that form the limbic system, which controls your emotions and memories. These structures include the thalamus, which lies deep within the center of your brain, and the hippocampal formations, which are situated within the temporal lobes of your brain.
Amnesia caused by brain injury or damage is known as neurological amnesia. Possible causes of neurological amnesia include:
- Brain inflammation (encephalitis) as a result of infection with a virus such as herpes simplex virus, as an autoimmune reaction to cancer somewhere else in the body (paraneoplastic limbic encephalitis), or as an autoimmune reaction in the absence of cancer
- Lack of adequate oxygen in the brain, for example, from heart attack, respiratory distress or carbon monoxide poisoning
- Long-term alcohol abuse leading to thiamin (vitamin B-1) deficiency (Wernicke-Korsakoff syndrome)
- Tumors in areas of the brain that control memory
- Degenerative brain diseases, such as Alzheimer's disease and other forms of dementia
- Certain medications, such as benzodiazepines
Head injuries that cause a concussion, whether from a car accident or sports, can lead to confusion and problems remembering new information. This is especially common in the early stages of recovery. But head injuries usually don't cause severe amnesia.
Another rare type of amnesia, called dissociative (psychogenic) amnesia, stems from emotional shock or trauma, such as being the victim of a violent crime. In this disorder, a person may lose personal memories and autobiographical information, but usually only briefly.
Sept. 04, 2014
- Amnesias. The Merck Manual for Health Care Professionals. http://www.merckmanuals.com/professional/neurologic_disorders/function_and_dysfunction_of_the_cerebral_lobes/amnesias.html. Accessed June 18, 2014.
- Aminoff MJ, et al. Clinical Neurology. 8th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=66. Accessed June 18, 2014.
- Longo DL, et al. Harrison's Online. 18th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4. Accessed June 18, 2014.
- Ropper AH, et al. Adams & Victor's Principles of Neurology. 9th ed. New York, N.Y.: The McGraw-Hill Companies; 2009. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=54. Accessed June 18, 2014.
- Woodruff BK (expert opinion). Mayo Clinic, Scottsdale, Arizona. June 19, 2014.