Transient Global Amnesia and Neurological Events: The Framingham Heart Study

Abstract

Background/objective: Transient global amnesia (TGA) is a temporary amnestic syndrome characterized by lack of other focal neurological deficits. Cerebrovascular disease, migraine and seizures have been suggested as underlying mechanisms. TGA may be a risk factor for cerebrovascular or other neurological events. We studied the relation of TGA, vascular risk factors, brain magnetic resonance imaging (MRI) indices of subclinical ischemia and neurological events in a community-based sample.Design/setting: A total of 12 TGA cases were ascertained using standard criteria by experienced neurologists, and matched to 41 stroke- and seizure-free controls. Vascular risk factors, brain MRI findings, and subsequent cerebrovascular or seizure events were compared in cases and controls.Participants: Framingham Heart Study (FHS) original and offspring cohort participants were included.Results: No significant differences between the groups were observed in the prevalence of vascular risk factors, or brain MRI measures. Few incident stroke/transient ischemic attacks (TIA) (one event among the cases and four in controls) or subsequent seizures occurred in either group. Head CT during the acute event (n = 11) and brain MRI (n = 7) were negative for acute abnormalities. Electroencephalograms (EEG) (n = 5) were negative for epileptiform activity. Extracranial vascular studies were negative for significant stenosis in all cases.Conclusion: In our community-based study TGA was not related to traditional vascular risk factors, or cerebrovascular disease. However, our study is limited by small sample size and power, and larger studies are required to exclude an association.

No Signs of Intracranial Arterial Vasoconstriction in Transient Global Amnesia

“…[25][26][27] However, only a minority of our TGA patients were migraneurs (less than 30%) and did not show any difference with regard to intracranial hemodynamics, casting further doubts on the migraine-induced vasoconstriction/depolarization hypotheses of TGA. Considering the cerebrovascular hypothesis, similarly to a recent study by the Framingham group, 24 no significant differences between TGA and control patients were observed regarding the incidence of hypertension, diabetes, smoking, hypercholesterolemia, atrial fibrillation, and ischemic heart disease. Furthermore, the prevalence of extracranial and intracranial arterial stenosis among TGA patients was low and US, ultrasound; IMT, intima-media thickness; R.I., resistance index; PSV, peak systolic velocity; EDV, end diastolic velocity; MFV, mean flow velocity; VM, Valsalva maneuver; P.I., pulsatility index; MCA, middle cerebral artery; PCA, posterior cerebral artery; ACA, anterior cerebral artery; VA, vertebral artery; BA, basilar artery; N.S., not significant.…”

Stress-related factors in the emergence of transient global amnesia with hippocampal lesions

“…The prevalence of risk factors in the large cohort corresponds to the distribution within the healthy, age-matched population (Quinette et al, 2006 ; Enzinger et al, 2008 ; Romero et al, 2013 ; Mangla et al, 2014 ). This applies to transient ischemic attacks, arterial hypertension, coronary heart disease, cardiac arrhythmia, subcortical arteriosclerotic encephalopathy, preexisting insults, lacunar stroke and diabetes.…”

Transient Global Amnesia

“…18,51,52 Also, in a subset of 12 individuals from the Framingham Heart Study who had an episode of TGA, the investigators noted that these patients had a similar vascular risk factor profile and risk of future cerebrovascular events as stroke-free and seizurefree controls matched for Framingham Heart Study cohort, sex, and year of birth. 64 Recently, a study using a state registry including 4299 patients with TGA demonstrated that the stroke risk after the diagnosis of TGA (0.54%) was similar to that after the diagnosis of migraine (0.22%), was lower than the risk after the diagnosis of seizure (0.90%), and was much lower than that after the diagnosis of TIA (4.72%). 65 Risk of seizures in patients with TGA has not been demonstrated to be increased compared with other populations.…”