Sudden memory loss is not always the same disorder. Transient epileptic amnesia (TEA) and transient global amnesia (TGA) can both cause episodes in which a person cannot form normal memories, but their causes, typical patterns and treatment are different.
What is transient epileptic amnesia?
TEA is a form of epilepsy in which recurrent episodes of amnesia are the main seizure manifestation. Large case series describe attacks that often last around 15–30 minutes, recur over time and frequently occur on waking.
What is transient global amnesia?
TGA is a clinical syndrome characterised by sudden, prominent anterograde amnesia with variable retrograde amnesia. People commonly repeat the same questions because they cannot retain new information. Episodes usually resolve within 24 hours.
Why the two can be confused
During either condition, the person may appear awake, converse and perform familiar actions while repeatedly forgetting what has just happened.
Recurrence is an important clue
TEA is typically recurrent. TGA can recur, but repeated brief episodes, especially on waking and lasting well under an hour, can raise suspicion for TEA.
Duration can help, but it is not absolute
TEA attacks are often shorter than classic TGA episodes. TGA commonly lasts several hours, while TEA often lasts minutes. There is overlap.
Other seizure features
Smell or taste sensations, brief unresponsiveness, automatisms or other focal temporal-lobe seizure symptoms can support TEA when present.
Interictal memory problems
TEA is associated in some patients with accelerated long-term forgetting, autobiographical memory loss and topographical memory difficulty.
EEG and MRI
EEG may help identify epileptiform activity, but a normal routine EEG does not exclude TEA. MRI is used to assess other causes. In TGA, MRI can sometimes show small hippocampal diffusion-weighted lesions, although timing affects detection.
Why the distinction matters
TEA is generally responsive to antiseizure treatment. TGA is not treated as epilepsy simply because amnesia occurred.
Sudden amnesia still needs proper assessment
Stroke, TIA, head injury, intoxication, metabolic disturbance, functional amnesia and other causes can also produce acute memory disturbance.
Related reading
- Postictal Amnesia and Memory Gaps
- Memory and Cognition
- Temporal Lobe Epilepsy
- A Normal EEG Does Not Rule Out Epilepsy
Sources and further reading
- The syndrome of transient epileptic amnesia: a combined series of 115 cases and literature review. 2021. PMID: 33884371.
- Clinical differences between transient epileptic amnesia and recurrent transient global amnesia. 2024. PMID: 39416713.
- Cognitive deficits and course of recovery in transient global amnesia: a systematic review. 2024. PMID: 39090229.
Evidence checked: September 2026.