The remains of the day: neuropsychological findings in postacute transient global amnesia.

Abstract

Current clinical diagnostic criteria of transient global amnesia (TGA) require the episode to completely resolve within 24h. Small case series investigating the neuropsychological profiles obtained during the first days after TGA are inconclusive, with some suggesting the persistence of memory deficits. In this retrospective observational study, neuropsychological data of 185 TGA patients obtained during the first days following an attack were analysed. Data of cognitive functions assessed in at least 50 patients were evaluated and dichotomised according to z-values as "impaired" or "unimpaired". Moreover, the results of magnetic resonance imaging (MRI) were collected. Neuropsychological assessment was performed within the first 3days after TGA in 158 (85.4%) of all patients. The majority of patients showed no significant neuropsychological sequelae in the postacute phase of TGA. However, Mini-Mental Status Examination showed impairment in 22.6% of 159 patients, and we found subtle reductions of patients' performance in tests of verbal long-term memory and executive function in 16.3-24.6% of patients. Patients with hippocampal diffusion-weighted imaging (DWI) lesions performed significantly worse in a verbal recognition task than those without DWI lesions. Our findings reflect subtle performance reductions in different cognitive domains in a small subgroup of TGA patients. This implies that the gradual resolution of subclinical symptoms may take longer than the 24h required as maximum episode duration by current diagnostic criteria.