The role of event related potentials in evaluation of subclinical cognitive dysfunction in epileptic patients

Cognitive dysfunction in epileptic patients may develop due to the neurophysiological changes related to seizures or antiepileptic drugs. The aim of this study was to evaluate the cognitive dysfunction in epileptic patients under antiepileptic drug therapy by the aid of event related potentials.

P300 latencies were obtained from Fz, Cz and Pz electrod positions from both epileptic patients (n=40) and age and sex matched control group (n=40). Epileptic patients were classified either idiopathic primary generalized (IPGE) (n=9) or secondary generalized epilepsy (SGE) (n=31) based on the ILAE classification. The effect of epilepsy type, treatment types (monotherapy/polytherapy), daily dosages and serum levels of antiepileptic drugs, age at onset and EEG abnormalities on P300 latencies were studied.

P300 latencies were longer in the epileptics when compared to controls (P < 0.05). Besides, our results pointed out that P300 latencies were longer in IPGE when compared to SGE (P < 0.05). No statistically significant difference was determined between ERP parameters neither in monotherapy nor in polytherapy groups (p > 0.05). Antiepileptic drug subgroups revealed variable effects on ERP latencies.

We believe P300 latencies may have an important role in the evaluation of subclinical cognitive dysfunction in epileptic patients treated with antiepileptic drugs.