TRANSIENT GLOBAL AMNESIA AND TRANSIENT ISCHEMIC ATTACK - NATURAL-HISTORY, VASCULAR RISK-FACTORS, AND ASSOCIATED CONDITIONS

Background and Purpose The purpose of the present study was to make an attempt to ascertain the etiology of transient global amnesia (TGA), which is still disputed more than 30 years after the first description of this clinical entity. Methods In a case-control study, we compared the prevalence of vascular risk factors in 64 TGA patients with 64 fi rst-ever transient ischemic attack (TIA) control subjects and 108 norm al community-based control subjects matched for age and sex. We prospe ctively studied the vascular events and mortality rates of the TGA cas es and of the TIA control subjects. Then we compared the outcome of th e two groups using actuarial analysis based on survival curves. Result s We did not find evidence of an increased risk of TGA associated with any vascular risk factor. In contrast to TIA control subjects, no TGA patient suffered stroke, myocardial infarction, or TIA during the fol low-up period. Migraine was more common in TGA patients than in both n ormal and TIA control subjects. In three patients (4.5%), the TGA was eventually considered to be of epileptic origin. Conclusions The resul ts of our case-control and longitudinal studies point to the conclusio n that TGA and TIA do not share the same etiology, Since half of our p atients had a precipitating event in their history, it is reasonable t o hypothesize that spreading depression may play a role in TGA. The si gnificant positive association between migraine and TGA may support th is hypothesis. Epilepsy may mimic TGA in a minority of cases.