The value of EEG-Mapping in focal cerebral lesions

Summary In 148 patients with focal cerebral lesions the findings of EEG mapping, routine EEG and CT were compared. Regarding etiology 43 patients suffered from completed stroke (CS), 43 patients from transient ischemic attack (TIA), 33 patients had an intracerebral hemorrhage (ICH) and 29 an hemispheric tumor. In 37 patients with CS (86%) and 27 patients with TIA (63%) the EEG mapping revealed focal changes, but only in 28 patients with CS (65%) and in 11 patients (26%) with TIA using routine EEG alone. Thus the EEG mapping showed focal abnormalities significantly more often. In the remaining patient groups no significant difference in the results of EEG mapping or routine EEG could be demonstrated. Focal abnormalities corresponding to focal lesions seen in CT were obtained by means of EEG mapping in 27 patients (90%) with CS and 10 patients (77%) with TIA, but only in 17 patients (57%) with CS and 4 patients (31%) with TIA using routine EEG and in that way the EEG mapping could indicate focal lesions in CT significantly more often than routine EEG. In the remaining patient groups no significant difference in the number of focal changes corresponding to lesions in CT could be seen.