Transient Global Amnesia (TGA)

Transient global amnesia (TGA) is a sudden, temporary interruption of short-term memory. Although patients may be disoriented, not know where they are or be confused about time, they are otherwise alert, attentive and have normal thinking abilities.

Unlike patients experiencing dementia, TGA patients keep their personal identity, consciousness and the ability to perform complex routine tasks. During the episode, however, patients are unable to form new memories.

Episodes of TGA are generally brief and although the effects are temporary, the patient often does not remember anything from the episode.


The main identifiable symptom of transient global amnesia is the sudden, but temporary, loss of short-term memory and not being able to form new memories.

Symptoms include:

  • Anxiety and agitation
  • Repeatedly asking questions about what is happening
  • Retaining personal identity during the episode
  • Able to complete complex routine tasks during the episode
  • Absence of signs suggesting damage to the brain tissue
  • Episodes end in 1-8 hours, no more than 24

Causes and Risk Factors

The cause of transient global amnesia is unknown.

People older than 50 are more likely to experience TGA. Research suggests there also may be a link between patients who have a history of migraines and those who experience TGA.

In most cases, there is no activity that triggers a transient global amnesia episode. In rare cases, certain events can trigger an episode, including:

  • Hard physical activity
  • Sexual intercourse
  • Sudden exposure to very hot or very cold water
  • Emotional stress
  • Mild head trauma


Transient global amnesia goes away on its own within 24 hours.