DEAR DR. GOTT: Could you please talk about transient global amnesia? I have never seen this discussed in your column before. Thank you.

DEAR READER: Transient global amnesia (TGA) is a rare event that causes sudden, temporary loss of memory. It is often accompanied by repetitive questioning. It is not associated with the more common causes of amnesia such as stroke.

For a positive diagnosis, the patient must meet a set of criteria. He or she must retain knowledge of personal identity and have normal cognition (naming familiar objects, following simple instructions, etc.); the event must be verified by a witness; there cannot be a history of active epilepsy, a recent head injury or the presence of seizures during the episode; the event cannot last more than 24 hours; testing and examination will not reveal signs of brain damage; and, finally, the patient must experience a gradual return of memory.
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