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The truth behind amnesia: Is it harmless or a sign of something more serious?

Created date

March 31st, 2009
Most people think memories are made on vacations and family reunions, but if you ask a neurologist, memories are made in the frontal and temporal areas of the brain. Because memory involves so many interwoven brain functions, virtually any type of damage or disease anywhere in your brain can cause amnesia. "Amnesia is memory loss," says James L. Bicksel, M.D., a neurologist in McLean, Va. "It can be memory loss of the present anterograde or of the past, which is retrograde. With anterograde amnesia, you are unable to form new memories. According to Bicksel, when a new memory is formed, a neurological circuit or chain of events takes place. "If that doesn t take place, you won t remember anything," he says. If the brain is in the process of making memories and something interrupts it, the memory doesn t fully get made. "If you have a head injury, concussion, stroke, or seizure, it s common to not remember the five to ten minutes before that because the memory of it was never properly formed," he adds. Symptom or sickness? "Amnesia can be a symptom of many different conditions," says Mary Gonzales, Ph.D., A.P.R.N., B.C., a mental health specialist at Ann s Choice, an Erickson-developed community in Warminster, Pa. "It can be caused by migraines, seizures, or a transient ischemic attack." Transient ischemic attack.Also known as a warning stroke or mini stroke, a transient ischemic attack (TIA) occurs when a blood clot temporarily clogs an artery and part of the brain doesn t get the blood it needs. A TIA produces stroke-like symptoms but no lasting damage. But, TIAs are important predictors of stroke, so you should not ignore them. Epilepsy."Amnesia may be seen in people with epilepsy," says Austin Welsh, M.D. "Seizure activity blocks the making of any new memories in the brain." With seizures, there is a loss of oxygen. With a loss of oxygen, you won t make memories. Transient epileptic amnesia is a medical condition that involves a mix of anterograde and retrograde amnesia. Severe emotional trauma."Amnesia can also be seen in people with severe emotional trauma people who have lived through a war or witnessed horrific things," Welsh says. Dissociative amnesia, also called psychogenic amnesia, can be triggered by a stressful life event. The memories are buried deep within the person s mind and cannot be recalled. "With psychogenic amnesia, people have made a memory of the event, but with transient global amnesia, memories are never imprinted. They just aren t there," Gonzales adds. Frightful, yet harmless Each year, transient global amnesia (TGA) affects about 23 of 100,000 Americans over age 50. TGA is a sudden, temporary loss of memory that cannot be attributed to a more common neurological condition such as a head injury, epilepsy, TIA, or stroke. On average, TGA lasts between four and eight hours and resolves within 24 hours. About half of all TGA starts just after a physically or emotionally stressful incident. Among the triggering events commonly reported are sudden immersion in cold or hot water, strenuous physical activity, sexual intercourse, medical procedures, or emotional distress. If you have migraines, your risk of TGA is significantly higher than someone without migraines. "When transient global amnesia happens, people suddenly can t form new memories and can t remember where they were. People will feel confused and ask questions like, What am I supposed to be doing today? and Why am I here? Usually, it only happens one time in a person s life. Less than 25% of people will have a recurrence," Bicksel says. "When people have sudden memory loss, my job is to rule out a stroke or seizure," he adds. "If someone experiences amnesia, you want to go to the emergency room to rule out the things that wouldn t be as harmless as TGA." Bicksel stresses the fact that TGA is unique in that it happens suddenly. "It s different from the slow onset of Alzheimer s, and it s not related in any way," he says. "You are not more likely to get dementia or have a stroke if you have an episode of TGA." If you or someone you love suddenly can t remember basic things, you should see a doctor immediately. "Many different things need to be examined in order to figure out what actually occurred," says Gonzales. After getting this checked out, you can get back to making more memories you won t want to lose.