This study was conducted to identify the patterns of regional cerebral blood flow (rCBF) in TGA patients via longitudinal SPECT scans. Most of studies have focused on the acute phase of attack and reported normalization with follow-up SPECT studies based on a few case observations, but longitudinal follow-up SPECT examinations using voxel-based whole brain analysis are rare. This variability may be derived from the differences in the study designs, including imaging protocol and the latency of scanning. Previous studies of cerebral hypoperfusion using single photon emission computed tomography (SPECT) have shown inconclusive results, as some describe medial temporal flow change and others report decreased or increased flow changes in various structures. Therefore, the question remains as to how cerebral ischemia or hypoperfusion is related to the occurrence of TGA. However, such findings have also been thought of as ‘innocent bystanders’ due to the higher prevalence of jugular valve insufficiency without evidence of jugular venous reflux. Instead of arterial ischemia, recent studies have reported venous congestion or venous reflux with subsequent ischemia combined with jugular valve insufficiency. Among them, cerebral ischemia in terms of thromboembolic etiology or hemodynamics was investigated via several studies, but a definite association between TGA and arterial ischemia was not identified. Several etiological factors, such as migraine, epilepsy, cerebral ischemia, venous flow abnormalities, have been proposed as possible explanations. TGA was first described more than 50 years ago, but the exact pathophysiological mechanism remains unknown. All rights reserved.Transient global amnesia (TGA) refers to the sudden onset of anterograde and retrograde amnesia, which lasts up to 24 hours with no other cognitive impairment. Our findings indicate that having an episode of TGA does not increase the risk of subsequent cerebrovascular events, seizures, or cognitive impairment.Ĭopyright © 2016 Mayo Foundation for Medical Education and Research. Modified Rankin scale and death rates at last follow-up were also similar between both groups.
The TGA recurrence occurred in 5.4% of patients after a median interval of 4.21 years (interquartile range, 2.82-8.44).
There was no statistically significant difference between survival curves for the TGA group and the control group using time to any type of cerebrovascular event (log-rank P=.30), time to seizures event (log-rank P=.55), and time to cognitive impair event (log-rank P=.88) as end points.
Previous migraine was more common in the TGA group (42 patients vs 12 patients P<.001). Prevalence of vascular risk factors and history of seizures were similar between both groups. The mean duration of follow-up was 12 years in both groups (range, 0.07-29.93). End points were studied using Kaplan-Meier survival plots and log-rank test.Ī total of 221 patients with TGA were identified and 221 age- and sex-matched controls were included in the analysis. End points were cerebrovascular event (stroke or transient ischemic attack), seizure, or cognitive impairment (mild cognitive impairment or dementia) during follow-up.
Transient global amnesia was defined clinically. To study the long-term risk of cerebrovascular events, seizures, and cognitive impairment in patients with transient global amnesia (TGA).ĭata for all patients diagnosed with possible TGA in Olmsted County, Minnesota, between January 1, 1985, through December 31, 2010, were retrieved from the Rochester Epidemiology Project database.
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