Transient global amnesia:: a review.: I.: Clinical aspects

Introduction. Transient global amnesia (TGA) is a neuropsychological syndrome in which a sudden, temporary loss of the capacity of creating new memories and a retrograde amnesia of variable intensity occur whereas consciousness, personal identity and attention are preserved. Aim. To review different clinical aspects about TGA. Development. Accordingly, the following topics will be reviewed: definition and diagnosis criteria, types of amnesias which should be ruled out and their peculiarities and differences with TGA, epidemiological data such as incidence, age, sex, educational level of the patients and number of TGA episodes, most frequent scene where TGA appears, and most common triggering events. Additionally, classical proposals about its possible etiology (epilepsy, vascular disease and migraine) and other new theories (Leao's spreading depression or influence of stress) will be revised. Finally, different data about neuroimaging studies in patients with TGA will be reviewed. Conclusions. There are data and arguments in favour and against the hypotheses regarding etiology of TGA, but there is no current consensus on a theory which explains in a satisfactory way the nature of this kind of amnesia.