Transient global amnesia, the sudden temporary and total loss of memory for no known medical reason, is said to have no aftereffects. The Mayo Clinic’s information on transient global amnesia (TGA) is posted on other websites far and wide. The 2009 article claims that TGA is seemingly harmless and unlikely to reoccur. Mayo says that TGA is short-lived and doesn’t result in impaired memory afterward. The Mayo Clinic reports that no treatment is necessary for TCG and that it has no confirmed aftereffects other than emotional distress over the event. However, some researchers claim they have found aftereffects in patients with transient global amnesia in follow-up studies: brain lesions, impaired cognitive function and continued memory problems.
Causes of TGA
The Mayo Clinic reports that transient global amnesia can often be linked to emotionally or physically stressful events, such as sudden immersion in cold or hot water, strenuous physical activity or sexual intercourse, medical procedures or acute emotional distress.
The Mayo Clinic also reports that migraines have some unknown connection with TGA, and that people older than 50 seem at higher risk of suffering from transient global amnesia.
Lesions and Memory
In 2001, German researcher Joseph Kessler and his colleagues tested 14 people who had suffered from transient global amnesia. Although memory is thought to return quickly following a TGA episode, these researchers found that three to four days later, the impairments in verbal and nonverbal long-term memory and ability to speak fluently were still dramatically evident.
In 2004, Dr. Oliver L. Sedlaczek and his fellow scientists found that while TGA sufferers are usually screened for medical problems at the time of the attack, lesions in the brain can appear over the course of following days. Using a type of MRI imaging, the scientists found that lesions began to appear in the hippocampus, a region of the brain associated with memory, two to three days after the TGA episodes.
A 2010 study published in the journal “Science” by German researchers T. Bartsch and his colleagues tested patients with TGA with lesions in the hippocampus. They found that the size of the lesions and the duration of the transient global amnesia attack correlated with reduced cognitive performance.
Kessler believes that stress and stress hormones are involved in TGA onset and in the continued problems with cognition.
Sedlaczek points out that emotional arousal can affect metabolic rate, disturbing blood flow to the hippocampus.
Dr. David Tong of Stanford University believes that anti-platelet therapy could help prevent patients with vascular risk factors from being stricken with TGA.
Although transient global amnesia is said to have no known medical cause, the Life Extension Foundation says many illicit and prescription drugs can trigger TGA. Prescription medications that could be at fault include: aminophylline, barbiturates, bromide, digoxin, diuretics, isoniazid, methyldopa and tricyclic antidepressants.
Three erectile dysfunction drugs have had reports of TGA: Cialis, Levitra and Viagra. The drugs now have this information on their labels, reports Miranda Hitti of “MedicineNet,” but not as a precaution or warning; the information is listed in the “Post-Marketing” section of the labels.
Recurring Transient Global Amnesia
Probably the worst after-effect of TGA is experiencing another episode of the memory loss. Former astronaut and family physician Duane Graveline experienced two episodes of TGA, both related to the statin drug Lipitor.
Graveline writes of his experience in his book “Lipitor: Thief of Memory.” He was prescribed Lipitor for his rising cholesterol levels and five weeks later experienced his first episode of global transient amnesia. Although his examining doctors did not believe the drug was at fault; Graveline stopped taking it.
A year later, NASA doctors reassured Graveline that Lipitor was not the cause of his TGA and represcribed the drug to him. Within six weeks he had another attack of TGA with retrograde memory loss.
Graveline explains that it has been discovered that cholesterol is important for the transmission of impulses along nerve cells, and that statins may interfere with this essential process.