Influence of a Slight Damage to the Mesial Temporal Lobe Visible on Positron Emission Tomography on Severity of Cognitive Impairment and Course of Epilepsy

Aim: The study on the influence of minor lesions of the mesial temporal lobe visible on positron emission tomography on the severity of cognitive disorders and the course of epilepsy.

Material and Methods: A group of thirty one patients with mesial temporal lobe epilepsy of unknown cause, mild course and positive response to treatment was divided into a group of fifteen patients with reduced uptake of the 18F-fluorodeoxyglucose tracer and a group of sixteen patients with normal uptake of this tracer from mesial temporal lobe shown on positron emission tomography. Then, the two groups were compared in terms of the severity of cognitive impairment and the course of epilepsy. The group of fifteen patients with reduced uptake of the 18F-fluorodeoxyglucose tracer from the mesial temporal lobe, was later divided into a group of five patients who had indistinct mesial temporal sclerosis shown on magnetic resonance imaging and a group of ten patients who had visible changes only on positron emission tomography. They again underwent the above mentioned comparison.

Results: In the first comparison, there were significantly bigger cognitive impairments in the range of functions of attention p=0,037 and the sum of individual cognitive functions was p=0,032. In the second comparison bigger cognitive impairments were noticed in the range of verbal memory p=0,032, the overall Behavioral Assessment of the Dysexecutive Syndrome-score was p=0,015 and executive functions were p=0,011. There were no significant differences in the course of epilepsy.

Conclusions: A slight damage to the mesial temporal lobe visible on positron emission tomography or slightly larger damage to the mesial temporal lobe cause significantly bigger cognitive impairment, without a clear impact on the severity of epilepsy. The obtained results contradict the characteristics of benign mesial temporal lobe epilepsy