Brain electrical activity mapping [BEAM] in the diagnosis of primary generalised epilepsy

ABSTRACT

This study was carried out on 45 children. Their ages ranged from 7 to 12 years [mean = 9 +/- 1.8 yr.]. They were divided into two groups; [1] control group which comprised 20 normal children [10 males and 10 females] and [2] epileptic group which comprised 25 children [15 females and 10 males]. 17 patients of group [2] had only absence attacks and 8 patients had both absence attacks and generalised tonic clonic fits. All patients of bothgroups were subjected to history, clinical examination, EEG and BEAM. Interictal neurologic examination was normal for group [2]. In the control group, BEAM showed four classical frequency bands [delta, theta, beta and alpha]. As regards the percentage activity, during eye closed state; the delta frequency band showed frontal maximum that might extend to the temporal area, the theta band was maximum in the bitemporal and central areas, the beta band was maximum in the bitemporal area and might extend to the central or frontal areas; whereas the alpha band showed occipital maximum that might extend in the middle line to time frontal area. On time other hand in all patients of group [2], EEG showed; [1] normal back ground [alpha wave], [2] 3 C/S Spike Wave Discharge [SWD] mainly in the frontal region, and [3] an occipital alpha rhythm before and after 3 C/S SWD. As regards BEAM, the following were found during SWD; [1] percentage activity in delta and theta range increased with occipital maximum, [2] percentage activity in alpha frequency band reduced in numerical value and became maximum frontally, [3] percentage beta activity showed a sudden increase all over the scalp with frontal maximum, and [4] full band power increased in numerical value with frontal maximum. In conclusion, brain mapping is an essential tool for supporting time diagnosis of primary generalised epilepsy. It can extend time usefulness of EEG through quantitation and extraction of more information that can be obtained from visual analysis of conventional EEG