Transient global amnesia

Introduction
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By Alfredo Ardila PhD

Transient global amnesia represents an episode of acute onset of transient global anterograde amnesia, with a variable degree of impairment of retrograde memory, which is not associated with any other major neurologic signs or symptoms. Resolution is gradual, with subjective recovery occurring in two thirds of patients within 2 to 12 hours and, in almost all, within 24 hours. In this clinical article, Dr. Alfredo Ardila explains that the etiology is still controversial and could be explained by an ischemic event due to arterial thromboembolic ischemia in a subgroup of patients with increased vascular risk factors. PET studies usually show hypometabolism in the hippocampi and mesial temporal lobes. An acute effect on hippocampal cornu ammonis neurons has been proposed as the functional correlate of amnesia, reflecting a transient disruption in the hippocampus memory circuits. It has been suggested that not only is memory affected, but executive functions are diminished as well.

Key Points

  • Transient global amnesia is characterized by acute onset of transient global anterograde amnesia that is not associated with any other major neurologic signs or symptoms.
  • Amnesia resolves gradually, usually within about 2 to 12 hours.
  • Recurrence is low, about 2.5% to 5% per year.
  • In a significant percentage of cases, a precipitant factor (physical or psychological) can be identified.

In This Article

Introduction
Historical note and nomenclature
Clinical manifestations
Clinical vignette
Etiology
Pathogenesis and pathophysiology
Epidemiology
Prevention
Differential diagnosis
Diagnostic workup
Prognosis and complications
Management
References cited
Contributors