Quantitative EEG effects of carbamazepine, oxcarbazepine, valproate, lamotrigine, and possible clinical relevance of the findings.

UNLABELLED: Quantitative EEG (QEEG) effects of therapeutic doses of carbamazepine (CBZ), oxcarbazepine (OXC), valproate (VA) and lamotrigine (LA) monotherapy were investigated in patients with beginning epilepsy. Baseline waking EEG (EEG1) was recorded in the untreated state, the second EEG (EEG2) was done after 8 weeks of reaching the therapeutic dose. Left occipital data were used for analysis. QEEG target parameters were absolute band-power (delta: AD, theta: AT, alpha: AA, beta: AB), and alpha mean frequency (AMF). Group effects (untreated versus treated condition in the CBZ, VA, OXC, LA groups) were computed for each target parameter. One group with benign rolandic epilepsy remained untreated for clinical reasons and served to estimate the QEEG test-retest differences. In addition, the individual QEEG response to each drug was calculated as (EEG2-EEG1). RESULTS: statistically significant (p<0.05) group differences indicated the QEEG domain systematically affected by the drugs. CBZ caused AT increase and AMF decrease. OXC caused AMF decrease. VA and LA did not decrease AMF (LA even increased it), but reduced broad-band power. Individual power and AMF changes showed considerable variability in each group. >0.5 Hz AMF decrease (that was reported to predict cognitive impairment in prior studies) occurred in 10/41 patients in the CBZ group but never in the OXC, VA, LA groups. The results may be utilized in planning further studies addressing the relationship between antiepileptic drugs and their CNS effects. In addition, the relationship of AED-related cognitive impairment and AMF changes was discussed.

[Effect of flumazenil on the regional cerebral blood flow measured by [15O]-butanol PET scan and transcranial Doppler ultrasonography]. / Flumazenil hatása a regionális agyi perfusióra [15O]-butanol-PET- és transcranialis Doppler-UH-vizsgálatok alapján.

The authors investigated the role of the cBZD/GABA-A receptor-complex in the regulation of rCBF by simultaneously applying [15O]-butanol-PET and TCD in therapy-resistant TLE patients. It is known that the density of the cBZD/GABA-A-receptors is reduced in the epileptogenic area of the temporal lobe, but there are no data available about the impact of this phenomenon on rCBF. FMZ is a well-known BZD-receptor antagonist which can be used to inhibit the effect mediated by cBZD/GABA-A-receptors, offering a way to study the contribution of these receptors in the determination of rCBF. The authors examined the possible correlation between the rCBF values obtained by PET and the blood flow speed readings measured by TCD in MCAs. The results show that FMZ does not cause any change in rCBF on the side of the epileptogenic focus but it significantly raises rCBF (p < 0.001) in the intact brain tissue on the other side. The TCD measurements showed no significant differences between the blood flow in the MCAs supplying the affected and the contralateral lobe.