Transient Global Amnesia and Its Aeromedical Implications

Abstract

Transient global amnesia (TGA) is an episode of severe anterograde amnesia of sudden onset, characteristically lasting 4 to 6 h. Patients become disorientated in time and place, but not in person. Automated motor tasks are preserved; however, the retention of new information is impaired, with clear implications to a pilot's fitness to fly. This study examines the United Kingdom Civil Aviation Authority (UK CAA) experience of pilots with TGA and compares it to the medical literature. The UK CAA medical records database was searched for subjects who had reported a history of TGA between the years 1990 and 2010. Subject age and gender, the frequency and duration of episodes, the follow-up period, precipitants, and associated features were recorded. A literature search for papers with similar information was undertaken. The UK CAA database showed 29 subjects who had held a UK CAA medical certificate with a history of TGA. There were 28 male individuals and 1 female. The mean age was 59 yr. The mean follow-up period was 3.4 yr. The average duration of an episode was 2.8 h. Activity, stress, or exposure to cold water were reported as possible precipitants by 16 subjects (55%). There were 6 subjects (21%) who had a history of migraine and 10 (34%) who had a history of hypertension. From the literature, 10 papers were reviewed and compared to our study group. The aeromedical implications of TGA, including its etiology, associations, misdiagnosis, and recurrence risk are considered. A policy for the certification of pilots following TGA is proposed.