Cerebral blood flow study using SPECT in patients with memory disorders

Introduction. Global amnesia (AG) is a dysfunction of memory, in which there is a sudden incapacity to remember recent events and assimilate new information. The aetiology is currently under discussion. The main hypotheses under consideration are an ischemic mechanism and an epileptic mechanism. Objective. To study the cerebral blood flow in patients with temporary global amnesia (AGT) or permanent global amnesia (AGP) using functional neuroimaging techniques. Material and methods. Four patients were studied. Two had severe alterations of fixation memory which had been present for months. The other two had a sudden loss of recent memory, although space-person orientation and immediate memory remained normal. In all cases the cerebral blood flow (FSC), was assessed by single photon emission tomography (SPECT), using Tc-HMPAO as the radio tracer. Results. We describe 4 patients, 2 men and 2 women aged between 42 and 64,2 with AGT and the others with AGP. On SPECT there was temporally hypoperfusion in all 4 patients. In 2 cases there was associated parietal hypoperfusion and in 1 case there was frontal hypoperfusion. Conclusions. These findings suggest that AGT and AGP are of vascular origin and that SPECT is a useful diagnostic technique in patients with AG.