Transient Global Amnesia


Transient global amnesia (TGA) is a syndrome of amnesia where there is a brief loss of the ability to form new memories and to recall recent events. It usually lasts for no more than a few hours.

A diagnosis of TGA requires:

  • Clear loss of the ability to form new memories which resolve within a 24 hour period during the attack
  • Epileptic symptoms must be absent and patients with recent head injury or active epilepsy are excluded

Clinical Features

  • Abrupt onset in middle to old age
  • No impairment of consciousness or other cognitive functions besides memory
  • Dense anterograde amnesia
  • Rare recurrence (rate approximately 3% per year)
  • Attacks last for 4-10 hours
  • Often triggered by acute emotional or physical stress
  • Repetitive questioning; usually related to self-orientation e.g. “where am I?”
  • Sometimes non-specific symptoms of nausea and headaches present


TGA has a very stereotypical presentation, thus; a single, uncomplicated episode requires minimal investigation. TGA requires no specific treatment as episodes rarely reoccur.