Objective:

Electroencephalography (EEG) is a non-invasive method frequently used in neurological practice. To know the anatomic distribution of abnormal waves will help to assess EEG more rapidly and accurately as well as the diagnosis, classification and treatment of the patients. In this study, anatomical localizations of spike, sharp and slow wave activities reported in our EEG recordings were assessed.

Material and Methods:

In this study, 3459 cases examined in our EEG laboratory between May 2007 and June 2010 was evaluated. EEG recordings were done by Nihon Kohden EEG 9100 instrument under required conditions for minimum 20 minutes. Within all these cases, data of 389 cases reported as pathological, were evaluated statistically (p<0.05).

Results:

This study consisted of 389 pathological EEG cases (11,2 % with 56,3% (n=219) female and 43,7% (n=170) male subjects. Age range was between 7-96 years (31,76±20,63). Spike, sharp and slow wave activities were frequently observed in the temporal and frontal regions although no statistically significant difference was observed regarding the other brain areas (p<0,05). Evaluation of the waves according to the age groups, spike and sharp wave activities were more frequent in right frontal and temporal area regarding the other areas, in the younger than 40 year-old groups. Below 20 year-old and above 40 year-old cases, spike and sharp wave activities in the left temporal area were found significantly higher. Diffuse primary generalized discharge rates of 21-40 year-old cases were significantly higher than the other age groups (p>0,05). Frontal regions and diffuse slow waves in old age groups were more frequent as compared to the other epileptiform abnormalities.

Conclusion:

Sharp and spike wave activities were more frequently localized in frontal and temporal areas, however slow wave activities were commonly observed in frontal areas, in our EEG recordings. Information of cerebral anatomical distribution of epileptiform abnormalities according to the age groups, will contribute to easier, faster and accurate evaluation for diagnosis, classification and treatment of the patients.

Keywords: Electroencephalography, epilepsy, epileptiform abnormalities