Frontal intermittent rhythmic delta activity. A comparative study of EEG and CT scan findings

26 cases with frontal intermittent rhythmic delta activity (FIRDA) in the EEG are presented and compared to the corresponding results in computerized axial tomography (CT) of the brain. Selection was undertaken randomly without reference to special diagnostic aspects. Only 3 cases showed a deviation of the cerebral midline structures in the CT, because of a cerebral tumor. No deviation of the midline structures in the CT could be found in the other 23 cases, where FIRDA was the outstanding finding in the EEG. Thus, the conclusion may be drawn that FIRDA in the EEG is by no means indicative of subcortical lesions, especially tumors, with alteration of midline structures.