Transient Global Amnesia
DEFINITION
Transient global amnesia is a sudden, temporary episode of memory loss that can’t be attributed to a more common neurological condition, such as epilepsy or stroke.
During an episode of transient global amnesia, your recall of recent events simply vanishes, so you can’t remember where you are or how you got there. In addition, you may not remember anything about what’s happening in the here and now. Consequently, you may keep repeating the same questions because you don’t remember the answers you’ve just been given. You may also draw a blank when asked to remember things that happened a day, a month or even a year ago.
With transient global amnesia, you do remember who you are, and recognize the people you know well. But that doesn’t make your memory loss less disturbing.
Fortunately, transient global amnesia is rare, seemingly harmless and unlikely to happen again. Episodes are usually short-lived, and afterward your memory is fine.
CAUSES
The underlying cause of transient global amnesia is unknown. There appears to be a link between transient global amnesia and a history of migraines, though the underlying factors that contribute to both conditions aren’t fully understood.
Some commonly reported events that may trigger transient global amnesia include:
- Sudden immersion in cold or hot water
- Strenuous physical activity
- Sexual intercourse
- Medical procedures, such as angiography or endoscopy
- Mild head trauma
- Acute emotional distress, as might be provoked by bad news, conflict or overwork
SYMPTOMS
Transient global amnesia is identified by its main symptom, which is the inability to form new memories and to recall the recent past. Once that symptom is confirmed, ruling out other possible causes of amnesia is important.
Necessary symptoms for diagnosis
Health care professionals base a diagnosis of transient global amnesia on the following signs and symptoms:
- Sudden onset of memory loss, verified by a witness
- Retention of personal identity despite memory loss
- Normal cognition, such as the ability to recognize and name familiar objects and follow simple directions
- Absence of signs indicating damage to a particular area of the brain, such as limb paralysis, involuntary movement or impaired word recognition
Additional symptoms and history on which a diagnosis for transient global amnesia is based:
- Duration of no more than 24 hours and generally shorter
- Gradual return of memory
- No evidence of seizures during the period of amnesia
- No history of active epilepsy
Along with these signs and symptoms, a common feature of transient global amnesia includes repetitive questioning, usually of the same question — for example, “What am I doing here?” or “How did we get here?”
When to see a doctor
Seek immediate medical attention for anyone who quickly goes from normal awareness of present reality to confusion about what just happened. If the person experiencing memory loss is too disoriented to call an ambulance, call one yourself.
Although transient global amnesia isn’t harmful, there’s no easy way to distinguish the condition from the life-threatening illnesses that can also cause sudden memory loss. In fact, sudden amnesia is much more likely to be caused by a stroke or a seizure than by transient global amnesia. A medical evaluation is the only way to determine the cause of sudden memory loss.
