[Long latency auditory evoked potentials in schoolchildren and adolescents with epilepsy].

INTRODUCTION

Long latency auditory evoked potentials, especially P300, are a clinically relevant method for evaluation of the cognitive function. They are an objective and non-invasive procedure and a recommended standard for clinical evaluation of mental processing.

AIM OF THE STUDY

In order to evaluate the results of epilepsy treatment in children and adolescents the influence of two antiepileptic drugs (AED) carbamazepine (CBZ) and valproates (VPA) on cognitive functions of epileptic children and adolescents was analyzed.

MATERIALS AND METHODS

The examination of P300 component was performed in 30 newly diagnosed patients 8 to 18 years old before AED therapy and in 62 patients to whom both formulations of CBZ or VPA was administered in monotherapy. They were diagnosed as suffering from general tonic-clonic fits and partial seizures (simplex or complex), both with and without secondary generalization. Neuropediatric status as well as the neuroimaging in the examined groups were unremarkable. Control group for neurophysiological examinations consisted of 66 healthy children and adolescents of the same age. All examined persons showed normal mentality measured by psychological tests. The following factors were taken into consideration in statistical evaluation: age, duration of the disease and the type of epileptic seizures in relation to the values of examined latencies and amplitudes of P300 component. Criteria were also established to include and exclude patients from clinical and neurophysiological examinations. According to the International Federation of Clinical Neurophysiology (IFCN) standards, we applied the oddball paradigm to elicit P300. They were performed with a Multiliner (Toennies, Germany) equipment. The reception of potentials was completed by unipolar method with far-field recording (Fz, Cz, Pz and 10, EOG, in 10-20 system). The latencies of the first negative wave N1, next positive P2, the following N2 negative and positive component P300 were evaluated. Moreover, the amplitude differences N1-P2, P2-N2 and N2-P3 were analysed.

RESULTS

Significant prolongation of P300 and N2 latency was observed and the increase of N1- P2, P2 - N2 and N2 -P3 amplitude values in all epileptic patients in comparison to healthy controls was detected. There were also significant changes of N1 and P2 latency recorded in children receiving CBZ. P300 latency was longer in patients with newly diagnosed epilepsy than in control group. These changes were accompanied by the increase of P2-N2 amplitude. It was also shown that patients with partial seizures demonstrated longer P300 and N2 latency than recorded in case history as well as N2-P3 amplitude was higher than in patients with generalized seizures. There was not any statistically significant relation between parameters of P300 and the age of the child at the moment of epilepsy being diagnosed, the duration of the disease and the level of AED in blood serum.

CONCLUSIONS

There were significant differences indicated in parameters of P300 in epileptic children and adolescents in comparison to control group. The type of epileptic seizures and the choice of AED influence their values significantly.