Features:
(1) antegrade and retrograde amnesia
(2) preserved personal identity
(3) preserved level of consciousness, alertness and awareness
(4) may or may not be able to identify a precipitating event (see below)
(5) resolution with 24 hours (usually 4 to 6 hours), often with a small degree of retrograde amnesia
(6) absence of focal neurological signs and symptoms
(7) absence of seizures or traumatic brain injury
Events that may precipitate the amnesia:
(1) emotional stress
(2) migraine headache
(3) drugs
(4) medical procedure
(5) physical exertion
(6) environmental stimulus (immersion in hot or cold water)
(7) severe pain
(8) sexual intercourse
Common clinical findings:
(1) disorientation to time and/or place
(2) repetitive questioning as the person tries to become reoriented
(3) ability to perform complex motor tasks
The diagnosis is more certain if the episode was observed by at least one reliable witness.
Differential diagnosis:
(1) post-concussion amnesia (see chapter on physical activity)
(2) transient amnesia following a seizure (see above)
