Assessment of the brain rate parameter in three protocol-dependant groups of epileptic patients.

Aim: It has been shown that the EEG spectrum gravity (i.e. spectrum weighted frequency named as "brain rate") is related to the level of consciousness. On the other hand, the influence of some anti-epileptic drugs over the background EEG activity, thus affecting the level of mental arousal, is also well documented. The aim of this study is to assess the brain rate parameter in three protocol dependant groups of epileptic patients, in order to estimate whether it can be used as an indicator of the therapeutic efficacy of the anti-epileptic treatment. Methods: Thirty patients, selected over a period of 3 years (2006-2009) and diagnosed with epilepsy were divided in 3 equal groups. The first group of patients (6M/4F) were free from anti-epileptic medications; the second group (4M/6F) were treated with Lamotrigine only, whereas the third group (3M/7F) received only Carbamazepine. The EEG data was obtained under the same conditions and electrodes were applied according to International 10/20 system using standard bipolar montage. For each patient, 40 artefact-free baseline EEG epochs (4 seconds each during eyes closed) were selected for further analysis. The sampling rate was 256 Hz. Low-cut frequency was 0.53 Hz, whereas high-cut was 30 Hz. Results: Visual analysis of the raw EEG data was performed before obtaining the results. The final assessment resulted in power spectra values, calculated within 6 frequency bands: delta (1 - 4 Hz), theta (4 - 8 Hz), alpha (8 - 12 Hz), SMR (12.00 Hz - 16 Hz), beta1 (16 - 20 Hz) and beta2 (20 - 24 Hz) in 14 equivalent locations, based on which the brain rate values were calculated. Conclusion: The results have shown that the conscious relaxation is much greater in the patients free from medication, while the level of consciousness is slightly decreased in the patients treated with Carbamazepine and increased in the group under Lamotrigine treatment.