Transient global amnesia. Recurrence factors.

This recent retrospective cohort study included the review of medical records of patients with isolated or recurrent transient global amnesia (TGA) who presented at the Mayo Clinic in Rochester, Minnesota, between August 1, 1992 and February 28, 2018. A total of 1491 cases were examined and 1044 met the diagnostic inclusion criteria for TGA, while the remainder were excluded due to indeterminate or alternative diagnoses or limited information available in the clinical history.

Of the 1044 patients included, 575 (55.1%) were male, and the mean age (SD) at the time of inclusion was 75.0 (11.5) years. A total of 901 patients (86.3%) had a single episode of TGA and 143 (13.7%) had recurrent episodes of TGA. The two groups were similar in age of inclusion, sex, identifiable triggers, and duration of antegrade amnesia. The number of recurrences ranged from 1 to 9, with 137 individuals (95.8%) having 3 or fewer recurrences. The mean age (SD) in the first episode of TGA was 65.2 (10.0) years for individuals with a single episode versus 58.8 (10.3) years for those with recurrent episodes (P < 0.001). There was a personal history of migraine in 180 individuals (20.0%) with a single episode of TGA and 52 individuals (36.4%) with recurrent episodes of AGT (P < .001), and a family history of migraine in 167 individuals (18.5%) with a single episode of AGT and 44 individuals (30.8%) with recurrent episodes of TGA (P = .001). There were no electroencephalographic findings associated with increased risk of TGA recurrence. Acute and subacute temporal lobe abnormalities in MRI results were rarely observed and did not require intervention. A family history of TGA was identified in 12 individuals (1.3%) with a single episode of TGA and 4 individuals (2.8%) with recurrent episodes of TFA.

This study suggests that, in this large cohort of TGA patients, recurrent TGA was associated with an earlier age at the time of the first TGA episode and a greater prevalence of personal and family history of migraine compared to isolated cases.

These results can be used to advise patients about the risks of recurrence and may have implications for understanding the pathophysiology of TGA.