A case-control study of transient global amnesia.

Abstract

ItalySUMMARY To evaluate risk factors and prognosis oftransient global amnesia (TGA), three groups of 30 subjects each affected respectively by: (1) first-ever TGA; (2) first-ever transient ischaemic attack (TIA); (3) depressive neurosis, were compared. Prevalence ofcerebrovascular risk factors was similar in patients with TGA and TIA, but significantly lower in the third group. CT showed more hypodense lesions in TIA patients than in those with TGA. In a mean follow-up of 36 months, five TGA patients experienced a TIA and three others had recurrence of TGA, but none suffered stroke or myocardial infarction. In the TIA group, four had recurrence of TIA, two suffered a stroke and two others a myocardial infarction, whereas none had TGA attacks. None of the patients of the third group had any ischaemic event during follow-up. The similar prevalence of risk factors, but the different prognosis between TGA and TIA patients, suggest that TGA is an ischaemic event, probably not triggered by thromboembolism but by a different, possibly vasospastic, mechanism.Although transient global amnesia may occur in association with several morbid conditions,'1 most authors have attributed this syndrome to reversible ischaemia affecting the inferomedial part of the temporal lobes.7"'0 This view is supported by the high prevalence of cerebrovascular risk factors often observed in these patients." 12 However, most studies lacked data from suitable control groups.A recent case study of TGA concluded that this condition is closely linked to cerebrovascular disease, but its results were probably influenced by the unusually frequent prevalence of previous cerebrovascular attacks in the series.'3The prognosis of TGA is generally considered benign as most authors report a favourable long-term outcome in these patients.' '6 This fact is at variance with the assumption that TGA is a manifestation of cerebrovascular ischaemia, which carries a serious prognosis.To determine the prevalence ofcerebrovascular risk factors and the prognosis of TGA, we studied a series of patients with this condition, and compared them with a group of patients with their first TIA and with another group with only minor psychiatric symptoms.

Association of diffusion weighted imaging abnormalities and recurrence in transient global amnesia

“…10,11,18,24 The previously reported observation that most precipitating events were Valsalva-like activities prompted the theory of venous back-pressure, causing transient venous congestion of the hippocampus. 9 Since these events comprise common daily activities such as coughing, swimming and bathing, we would expect TGA to be more common.…”

“…There should also be a much higher annual recurrence rate than the reported 1% to 3%. 10,11,18,[24][25][26][27][28][29] That most people do not have TGA in their lifetime suggests that the threshold for developing symptomatic TGA in ordinary people is very high. Therefore, only a few susceptible patients develop TGA.…”

Subclinical Impairment of Neuromuscular Transmission in Transient Global Amnesia

“…14 Some cases of TGA triggered during a migraine attack are also described in the relevant literature. 18,19 On the contrary, Schmidtke and Ehmsen 20 compared patients with TGA with controls and found no evidence of an association between TGA and migraine. The different age predilections of these 2 entities, the low incidence of migraine (only one-third of patients with TGA have migraine) and the low recurrence rate of around 8% in TGA were all put forward against a real relationship more than a coincidence of migraine as a pathogenic mechanism.…”

High-field, T2 reversed MRI of the hippocampus in transient global amnesia

“…Patients with TGA show rapid subsequent recovery of memory, and most exhibit no residual damage on conventional CT or MRI. [3][4][5][6] Various potential etiologic factors have been proposed for TGA, including ischemic, epileptic, and migrainous. There is similar prevalence in risk factors for TIAs and TGA.…”