Transient global amnesia (TGA) is a very frightening condition. Suddenly, you feel confused and disoriented. You don’t know where you are, what time it is, what you are supposed to be doing. You can’t remember what you were just told and keep asking, what time it is, where you are, what is going on. Fortunately, it is a benign condition and tends to last four to six hours.
A study published last year by the Mayo Clinic researchers analyzed records of over one thousand patients who experienced TGA. The majority (86%) had a single episode and 14% had more than one. The mean age was 65. History of migraines was present in 20% of people with a single episode and in 36% in those with multiple attacks. Family history of migraines was found in 19% and 31% respectively.
TGA is a benign disorder. MRI scan and EEG were abnormal only in a small number of patients. The authors speculate that a similar mechanism may be responsible for TGA and migraines. This may apply to those with a personal or family history of migraines, but the majority of patients did not have either. It is not clear why TGA tends to occur in older people and why a family history of TGA is uncommon.
A review of several prior studies that looked at the incidence of TGA in large groups of migraine patients was published last month. This meta-analysis showed that people who suffer from migraines are 2.5 times more likely to have an episode of TGA.
A study from Taiwan showed that patients with an attack of TGA are more likely to develop dementia, but mostly in those who were older and suffered from diabetes. People with a history of TGA are not at an increased risk of a stroke.
Despite the low yield, most people who experience a TGA undergo an MRI scan for a possible tumor or a stroke. An EEG, or brain wave test is done because some types of epileptic seizures can present with confusion.
