The Clinical Usefulness of Electroencephalography: Comparison of Findings Electroencephalography with Findings of Brain Computed Tomography and Magnetic Resonance Imaging

Kang, D W; Lee, Y H; Choi, Y H; Chung, Y J

Abstract

To demonstrate the clinical usefulness of electroencephalography (EEG) and factors increasing the usefulness of EEG, the authors avaluated each relationship between EEG related factors and clinical variables, and neuroimaging studies(CT and MRI)-related factors, and factors which are related with routine neurological examination for 207 patients who had been evaluated with both of EEG and neuroimaging study(CT or/and MRI). The results were as follows: 1) Abnormality of EEG findings had significant relationships with chief complaints, diagnosis, medication use, seizure attack, pathological reflex, and level of consciousness. However there were no significant correlations between abnormality of EEG findings and neuroimaging studies (CT and MRI)-related factors. 2) Laterality of EEG findings had significant relationships with abnormality, laterality, and focality of CT findings, and also with abnormality of MRI findings. But there were no significant correlations between laterality of EEG findings and clinical variables, and neurological examination-related factor. 3) Anterior-posterior distribution of EEG findings was significantly related with medication use. 4) Focality of EEG findings had significant relationships with sex, sensory dysfunction sign, and cerebellar dysfunction sign. But there were no significant correlations between focality of EEG findings and neuroimaging studies(CT and MRI) related factors. 5) Abnormal EEG pattern had significant correlations with various factors, such as age, chief complaints, duration from onset of symptom to taking MRI, seizure attack, abnormality and nature of lesion in CT findings, cortical atrophy in MRI findings, motor dysfunction sign, sensory dysfunction sign, and pathological reflex. 6) With abnormality on sleep activation, age, age of onset, seizure attack, ventricular enlargement in CT findings, and abnormality of MRI findings were significantly correlated. 7) With abnormality on sleep activation, duration of illness and laterality of MRI findings were significantly correlated. Above results may suggest that abnormality of EEG findings is more closely related with functional change of the brain than structural changes of the brain and laterality of EEG findings is vice versa. And also that medication use has an influenc on anterior versus posterior distribution of EEG findings and focaliy of EEG findings is not related with structural changes of the brain. Activation with sleep may be effective to show age differences and provocation of seizure activity and hyperventilation may be effective to detect the abnormal EEG findings by cerebrovascular insufficiency.