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
- 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.