Electroencephalography in intracranial space occupying lesions and a comparison of it with other investigative procedures

Summary

Electroencephalographic studies in 100 cases of intracranial space occupying lesions are reported and the value of EEG is compared with other investigative procedures. With cerebral hemisphere lesions good localisation was possible in 82.5% and lateralisation alone was possible in a further 13.9%. In 66% of the cases of third ventricle and posterior fossa tumours the EEGs were abnormal but definite localisation was not possible. With posterior fossa, third ventricle and sellar or suprasellar tumours, and with subdural haematomas, neuroradiological contrast studies gave better localisation than did EEGs. With meningiomas the brain scan proved to be a more reliable investigative procedure than electroencephalography. With astrocytomas Grs. III and IV, even though EEG was always abnormal, good localisation was possible in only 77.8%. However, with low grade gliomas EEG gave positive results more often than did the brain scan. An EEG pattern suggestive of an acutely destructive lesion was noted in 94.5% of the cases of astrocytoma Grs. III and IV, in 100% of the cases of cerebral abscess, and in 66% of the cases of cerebral metastasis. An EEG pattern suggestive of a slow growing lesion was noted in 83.3% of the granulomas, 77% of the less malignant gliomas, and 71.5% of the meningiomas.