The prognosis of transient global amnesia. Results of a multicenter study.

In a Danish multicenter study, 74 patients 20 to 75 years of age (mean age, 58.8 years) with transient global amnesia (TGA) without accompanying major neurological signs were studied. Over a follow-up period ranging from seven to 210 months (mean, 66.6 months) the observed rates of death and cerebrovascular morbidity were similar to those expected in the Danish population, matched for age and sex. Sixteen patients (22%) had further TGAs occurring one month to nine years after the original episode; the mean annual recurrence rate was 4.7%. We concluded that TGA without associated major neurological deficits is a benign clinical phenomenon, probably caused by a functional cerebral disturbance unrelated to cerebrovascular disease in general. Furthermore, the observed temporal pattern of recurrence suggests that, although TGA is in principle a recurrent disorder, the annual risk of recurrence is so low that most of the elderly patients are likely to experience only one attack.