(1) A selected group of 25 chronic psychiatric cases who manifested seizures after lobotomy and 46 chronic psychiatric cases who were seizure-free after lobotomy were studied clinically and electroencephalographically.(2) An analysis of the prelobotomy EEGs of the seizure and seizure-free group revealed only slightly increased abnormality in the seizure group (33% as compared to 24%), more slow dysrhythmia in the seizure group, and more fast dysrhythmia in the seizure-free group.(3) Considering only the cases who had electric shock treatments before lobotomy, those in the seizure group averaged approximately twice as many treatments as those in the seizure-free group (31 as compared to 15). However, the difference in amount of shock treatments given to the 2 groups was not reflected in the prelobotomy EEGs.(4) Immediately after lobotomy almost all patients exhibited a drowsy akinetic state accompanied by diffuse slow potentials of increased amplitude. When the patients were aroused by means of various types of stimuli, the slow waves in the posterior leads were temporarily replaced by alpha rhythm, but slow activity in the anterior leads remained. As the akinetic state gradually subsided, the occipital slow waves were replaced by normal alpha rhythm, but the frontal slow activity persisted for a longer period of time.(5) Following lobotomy, there was an extremely high incidence of very slow "rolling activity" which was observed in frontal, precentral, and to a lesser extent in motor and temporal leads.(6) Slow activity from leads about the injured area was at its height within the first 2 weeks after lobotomy and then began to decline. This decline was well marked in the seizure-free cases, but in the seizure cases slow wave abnormality tended to persist.(7) One month or more after lobotomy the incidence of abnormal EEGs was much higher in seizure cases than in seizure-free cases (76% as compared to 38%).(8) One month or more after lobotomy the incidence of focal EEGs was much higher in seizure cases than in seizure-free cases (41% as compared to 12%).(9) EEG abnormality in the seizure cases was in part dependent upon the interval between the seizure and the recording of the EEG. When the interval was short (days), the EEG was usually more abnormal than when the interval was long (months or years). However, the majority of EEGs recorded more than one year after a seizure were still abnormal.(10) Clinical analysis of cases with postlobotomy seizures revealed the following:(a) The interval between lobotomy and onset of seizures varied from days to years, with a peak at 3 months to 1 year.(b) During a follow-up period varying from 3 months to 4 years, the majority of patients experienced only 1 or 2 seizures. However, some patients had frequent convulsions, and status epilepticus occurred in 2 cases.(c) In the large majority of cases, attacks were of the grand mal type. Two patients had Jacksonian seizures in addition to grand mal, and 2 patients had tonic seizures. No petit mal or psychomotor seizures were observed.(11) Postlobotomy seizures did not negate the beneficial effect of lobotomy upon the mental disorder. The clinical follow-up study after lobotomy revealed that the seizure cases were doing as well as, or better than, the seizure-free cases.(12) There was no correlation between EEG findings (either before or after lobotomy) and the beneficial effect of lobotomy upon the mental disorder.(13) There were 4 patients with severe chronic postlobotomy headaches, all of whom had abnormal focal EEGs in addition to postlobotomy seizures.Abstract Teaser