Clinical and electroencephalographic characteristics of midline parasagittal foci.

We report the clinical and electroencephalographic (EEG) characteristics of 14 patients with midline parasagittal epileptogenic foci. Montages not including the vertex electrodes demonstrated the abnormal activity poorly or not at all. The clinical manifestations were diverse and included tonic-clonic, atypical absence, and partial seizures. In the majority, no cause could be established. The interictal EEG abnormality did not predict the pattern of clinical attack. Half the patients had evidence of structural brain disease. Four patients had no history of seizures.