Amnesia topográfica transitoria: descripción de una serie de ocho casos

Abstract

Impaired memory, and more particularly spatial orientation, occurs in pathologies such as dementia, cerebrovascular accidents or traumatic brain injuries. Less frequently it also appears as a transient disorder in healthy people with no apparent brain damage, in which case it is known as transient topographical amnesia (TTA). The aim of this work is to report on a series of eight cases of TTA that were evaluated in a neurology unit. We study the cases of eight patients diagnosed with TTA over the period 2002-2008. Patients were considered to fulfil eligibility criteria if they had presented at least one episode of spatial disorientation, with no loss of memory or consciousness, and were able to describe the events that had taken place, without any previous cognitive impairment and with a normal neurological examination. The demographic characteristics taken into account in the study were: predominance of females (75%) and a mean age of 69.13 +/- 8.79 years. The mean number of episodes was 1.75 (range: 1-3), which lasted an average of 24.5 minutes. Three of the eight patients had associated vascular risk factors. Neuroimaging studies did not reveal any relevant findings in any of the eight patients, except one case of a bilateral frontal porencephalic area resulting from a traumatic brain injury suffered in the past. Simple single-photon emission tomography and Doppler ultrasound imaging scans of the brain, as well as an electroencephalogram, were performed on two patients, the results being normal in all cases. Follow-ups were performed on all the patients, without any kind clinical change being observed, except for one patient who developed dementia at six years after the episode of amnesia. TTA is possibly an underdiagnosed condition which we believe should be included in the differential diagnosis of patients who are referred owing to suspected cognitive impairment.