Transient global amnesia is a sudden, temporary disturbance of memory in which the patient cannot retain new information and has a period of retrograde amnesia, while remaining alert, oriented to person, and otherwise neurologically normal. Diagnostic criteria focus on a witnessed, isolated episode of amnesia that resolves within 24 hours, without seizures, head trauma, or other major neurologic deficits.^[1][2][3]

• Attack is witnessed
  • The episode is seen by someone who can describe how it began and evolved^[2][3].
• Clear anterograde amnesia
  • The patient cannot lay down new memories.
  • Often asks repetitive, stereotyped questions (e.g., “Where am I?”, “What happened?”)^[1][2][3].
• Disturbance limited to memory
  • Dysfunction is confined to repetitive queries and amnesia^[2][3].
  • No clouding of consciousness^[2][3].
  • No general cognitive defect aside from memory disturbance on bedside testing^[1].
  • No loss of personal identity (the patient knows who they are and recognizes familiar people, except for events within the retrograde gap)^[2][3].
• No other major neurologic signs
  • No focal neurologic signs during or after the attack^[2][3].
  • No major neurologic symptoms suggesting stroke or other focal brain disease^[1][2].
• No seizure or recent head trauma
  • No epileptic features^[2][3].
  • No recent head injury^[2][3].
  • No active epilepsy^[2][3].
• Transient course
  • Memory loss is transient, typically lasting several hours^[4].
  • The episode resolves within 24 hours^[1][2][3].
  • A permanent gap in memory remains for the episode itself and for a period before onset^[1].