Transient global amnesia triggered by mild head trauma.

In 9 patients, aged 11 to 28 years, minor head injury triggered an amnesic attack grossly disproportionate to the degree of trauma. During these attacks, patients were unable to form new memories for 2 to 24 hours, had extensive retrograde amnesia, voiced repetitive queries and were disorientated for time, but were otherwise intact neurologically. We suggest that these episodes were attacks of transient global amnesia triggered by the mild blows to the head. We also suggest that they constitute a previously unrecognized variety of traumatic migraine.