Transient Global Amnesia (TGA) is a relatively newly-recognized condition, first identified in 1956. It only occurs among people over 50 years-old, usually older. For reasons not at all understood, a person loses their ability to form new memories. They know their name and who they are, but don’t know how they got to wherever they are, and are confused about why they are doing whatever they’re doing, since they don’t recall what they’d just begun to do.
They also lose recent memories, and ask questions over and over, trying to understand what’s going on. But older memories are preserved, so the patient retains all their previously-learned vocabulary. They can dress, perform math, drive, play an instrument – anything they’d learned in the past. The condition is extremely frightening; patients seek help however they can.
Patients are invariably taken to an ER, where all sorts of tests are done (see the mnemonic Vowel TIPS for how an ER addresses the symptom of “altered mental status,” i.e. confusion). Everything is normal. An MRI may detect various small findings, but none are diagnostic, so they can’t be interpreted.
TGA lasts from 1 to 12 hours (average is 6, by definition it’s <24). Then it resolves on its own. It would seem off-hand to be a form of stroke, seizure, migraine (without headache), or psychiatric phenomenon, but none of those causes are found. The condition almost never recurs, so no treatment is available nor necessary. Since we can’t help but wonder if such older persons might be at more risk of stroke, we make sure that any other diseases like diabetes or hypertension are well-controlled. But we don’t even recommend aspirin, and we don’t restrict driving or other activities.