Time trends, frequency, characteristics and prognosis of short-duration transient global amnesia.
Romoli M., Tuna MA., Li L., Paciaroni M., Giannandrea D., Tordo Caprioli F., Lotti A., Eusebi P., Mosconi MG., Pellizzaro Venti M., Salvadori N., Gili A., Ricci S., Stracci F., Sarchielli P., Parnetti L., Rothwell PM., Calabresi P.
BACKGROUND: Transient global amnesia (TGA) is characterised by a sudden onset of anterograde amnesia lasting up to 24 hours. One major differential for TGA is transient epileptic amnesia (TEA), which typically lasts<1h. However TGA can also be short in duration and little is known about the time-trends, characteristics and prognosis of TGA cases lasting<1h. METHODS: We compared the clinical features of TGA ascertained in two independent cohort studies in Oxfordshire, UK (Oxford cohort 1977-1987 vs. Oxford Vascular Study- OXVASC 2002-2018) to determine the time-trends of clinical features of TGA. Results were validated in another independent contemporary TGA cohort in Italy (Northern Umbria registry-NU 2002-2018). We compared the risk factors, clinical features and long-term prognosis (major cardiovascular events-MaCE, recurrent TGA and seizure/epilepsy) of patients presenting with episodes lasting <1h vs. those ≥1h. RESULTS: Overall 639 TGA patients were included (114 Oxford cohort, 100 OXVASC, 425 NU). Compared to the original Oxford cohort, there were more cases with TGA lasting <1 hour in OXVASC (n/% 32/32.0% vs. 9/8.8%), and in NU (11.8% vs 8.8% in Oxford cohort). In both OXVASC and NU, patient age, vascular risk factors and clinical features were largely comparable between those with TGA<1h vs. those lasting ≥1h. Moreover, there was no difference in the long-term risk of seizure/epilepsy or MaCE between TGA<1h vs. TGA≥1h. CONCLUSIONS: Short-duration TGA episodes (<1h) are not uncommon and are more frequent now than in earlier studies. The clinical features and long-term prognosis of short-duration TGA did not differ from more typical episodes lasting≥1h.