Incidence and Risk Factors of Transient Global Amnesia

Abstract

<b><i>Introduction:</i></b> Transient global amnesia (TGA) is a spontaneously resolving, anterograde amnesia that lasts mostly &lt;24 h and often occurs with retrograde amnesia. The etiology of TGA remains unclear, although in recent decades, many risk factors and preceding events have been identified. There are few up-to-date reports on the TGA incidence in Northern Europe. In this study, we report the incidence and risk factors associated with TGA in Finland. <b><i>Materials and Methods:</i></b> The study included all patients with suspected TGA that were referred to Kuopio University Hospital (KUH) in 2017. The hospital catchment area included 246,653 individuals. Risk factors and demographic data were collected from medical records. The TGA incidence rates were calculated as the number of patients with TGA divided by the number of individuals at risk in different age groups. <b><i>Results:</i></b> In 2017, 56 patients were treated for TGA at KUH. Of these, 46 had a first-ever TGA. The most common event preceding TGA was physical effort (<i>n</i> = 28, 50%), followed by emotional stress (<i>n</i> = 11, 19.6%) and water contact or a temperature change (<i>n</i> = 11, 19.6%). The most common comorbidities were hypercholesterolemia (<i>n</i> = 22, 39.3%), hypertensive disease (<i>n</i> = 21, 37.5%), hypothyroidism (<i>n</i> = 11, 19.6%), coronary artery disease (<i>n</i> = 8, 14.3%), and migraine (<i>n</i> = 7, 12.5%). TGA occurred most often in December (<i>n</i> = 9, 16.0%), March (<i>n</i> = 8, 14.3%), or October (<i>n</i> = 8, 14.3%), and least often in November and May (<i>n</i> = 2, 3.6% in both months). The crude incidence of a first TGA in Eastern Finland was 18.6/100,000 inhabitants, and when standardized to the European population in 2010, it was 14.3/100,000 inhabitants. Therefore, the TGA incidence was higher than previously reported in European countries. <b><i>Discussion:</i></b> The most common precipitating factors for TGA were physical effort, emotional stress, and water contact/temperature change. The incidence of TGA was high in the Eastern Finnish population.