Factors Associated With Risk of Recurrent Transient Global Amnesia

Abstract

IMPORTANCETransient global amnesia (TGA) is usually considered a benign event with a low recurrence rate. However, recurrence rates vary considerably among studies and there are no known risk factors for TGA. OBJECTIVE To examine risk factors for the recurrence of TGA. DESIGN, SETTING, AND PARTICIPANTSThis retrospective cohort study involved medical record review of patients with isolated or recurrent TGA presenting to the Mayo Clinic in Rochester, Minnesota, between August 1, 1992, and February 28, 2018. A total of 1491 cases were reviewed and 1044 met diagnostic inclusion criteria for TGA, with the remainder excluded owing to indeterminate or alternate diagnoses or limited information available in the medical record.EXPOSURES Single vs recurrent episodes of TGA.MAIN OUTCOMES AND MEASURES Demographics, precipitating factors, migraine history, imaging and electrodiagnostic findings, and family history of TGA were collected. The main outcome measure was TGA recurrence. RESULTSOf 1044 included patients, 575 (55.1%) were male, and the mean (SD) age at 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 2 groups were similar in age at inclusion, sex, identifiable triggers, and duration of anterograde amnesia. The number of recurrences ranged from 1 to 9, with 137 individuals (95.8%) having 3 or fewer recurrences. The mean (SD) age at first episode of TGA was 65.2 (10.0) years for individuals with a single episode vs 58.8 (10.3) years for those with recurrent episodes (P < .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 TGA (P < .001), and a family history of migraine in 167 individuals (18.5%) with a single episode of TGA 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 on results of magnetic resonance imaging were seen rarely 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 TGA.CONCLUSIONS AND RELEVANCE This study suggests that, in this large cohort of patients with TGA, recurrent TGA was associated with earlier age at the time of first TGA episode and higher prevalence of both personal and family history of migraine compared with isolated cases. These results can be used to counsel patients about risks of recurrence and may have implications for the understanding of TGA pathophysiology.

Transient Global Amnesia (TGA): Younger Age and Absence of Cerebral Microangiopathy Are Potentially Predisposing Factors for TGA Recurrence

“…In our study, there was no difference between patients with versus without subsequent recurrence in the presence and number (unilateral vs. bilateral) of hippocampal DWI lesions. This result is consistent with other previous studies ( 8 , 27 , 28 ).…”

“…Compared to the previously reported studies, a strength of our study is the large collective and the long follow-up period. Only two reported collectives were larger ( 8 , 30 ) and had a longer period of follow-up ( 6 , 8 ).…”

“…The recurrence rate of our study is very consistent with the rate of 13.5% ascertained from a recent review from nine different cohort studies involving 1,989 patients ( 4 ). An overview of studies on recurrence rates in TGA is displayed in Table 2 ( 6 – 8 , 16 – 29 ). The recurrence rates varied between these studies, which might be explained by the diagnostic accuracy of the patients investigated.…”

“…For example, a disclosure of a TIA as a potential alternative diagnosis was not guaranteed in all cases ( 17 ). Furthermore, the duration of the follow-up period ranged widely from 16.5 months ( 7 ) to 15.0 years ( 8 ).…”

“…A recent systematic review, evaluating nine cohort studies with a total of 1,989 patients, reported an overall recurrence rate of 13.5% ( 4 ), although single studies showed a wide variation (from 5.4 to 27.1%) ( 6 , 7 ). Interestingly, patients with TGA recurrence were found to be younger ( 8 ). There is also evidence for an association between TGA recurrence and a family or personal history of migraine, as well as a personal history of depression ( 4 ).…”