XIV, Vol.14, Number 4/2010 269 QEEG: RELATIVE POWER FINDINGS IN EPILEPSY 1. Pharmacology Department, “Iuliu Haţieganu” University of Medicine and Pharmacy 2. Neurology Department, “Iuliu Haţieganu” University of Medicine and Pharmacy 3. First Intensive Care Unit, Cluj County Emergency Hospital Z. Z. Major 1 , Anca Dana Buzoianu 1 , Lăcrămioara Perju-Dumbravă 2 , I. Mărginean 2 , Ioana Corina Bocşan 1 , Kinga Andrea Major 3 herapeutics, Pharmacology and Clinical Toxicology Vol XIV, Number 4, December 2010 Pages 269-273 © Copyright reserved 2010 Abstract. he objectives of this study were to compare the distribution of spectral power in a heteroge- neous idiopathic epilepsy group, under antiepileptic treatment, versus healthy controls. Methods: Relative power values were calculated from EEGs obtained in wakefulness using Fast Fourier Transformation. he patient group was compared to an age-matched group of healthy controls, derivation by derivation, then regarding asymmetry, and considering the inluence of epilepsy on the topographic distribution of the main frequency bands. Results: here are highly signiicant diferences between the two groups: the spectral power of the slow frequencies is increased in epileptics versus controls, and for the fast domains there is a reduction of the relative power. No asymmetries were observed between the two hemispheres. Gross topography-dependent power changes did not interfere signiicantly with the epilepsy-induced power spectrum of the investigated domains, although a tendency was recorded for the delta band. Conclusion: Relative power indings were interpreted as a difusely increased neuronal synchrony in the theta and delta frequency range, as an efect of the idiopathic epilepsy, inluenced also probably by the efect of the concomitant antiepileptic drug therapy. Idiopathic epilepsy produces no asymmetries of the qEEG data. Idiopathic epilepsy shows no interference with the topographic distribution of qEEG markers, excepting such a tendency for the slow activities. Further research is needed to evaluate these changes, also compared with newly diagnosed, untreated epilepsy. Keywords: qEEG, epilepsy, relative power, frequency bands ORIGINAL PAPERS Major Zoltan Zsigmon 10 Negoiu Str., 400676 Cluj-Napoca, Romania e-mail: majorzsiga@yahoo.com INTRODUCTION qEEG analyses, in order to deine the spectral power of the main frequency domains of the EEG frequencies, are a valuable tool to investigate the reduction or increase of neuronal synchrony in a deined topographic area, or over the entire cerebral surface [1]. he power spectrum analysis of epileptic pa- tients was already investigated several times by many research groups, to determine regional cor- tical dysfunction [2] or the efect of antiepileptic drugs [3]. Considering the topographic sensitivity of the qEEG, one can assume that its role is restricted to focal cerebral disturbances, characterized for instance by secondary epileptic seizures. But there is already a vast literature regarding the use of the qEEG in idiopathic epilepsies also, by investigating minor cerebral dysfunctions, or the so-called “mild difuse epileptogenic state” [4]. his state, as it is already well deined, is produced by the disturbances of electrical current generation and propagation. hese disturbances are consequences of the lack of balance in neurotransmitter production and interaction. Newer theories even deine some of the involved neurotransmitters, especially GABA [5] and the particular cellular population also, fast spiking neurons, mainly the chandelier cells [6]. he EEG relects the interaction of these electro- chemical processes, but still has a great limitation given by the subjective manner of its interpreta- tion. Since the availability of the qEEG, and after its remarkable reliability [7] was tested, there is