POSITIVE EPILEPTIFORM DISCHARGES IN CHILDREN WITH NEURONAL MIGRATION DISORDERS

Most epileptiform abnormalities show a negative polarity on EEG, Focal positive spike waves have rarely been identified in seizure disorders and are generally associated with physiological and neurological impa irment. Results of EEG, computed tomography, MRI, and pathologic studi es of 15 children with focal neuronal migration disorders who underwen t surgery for refractory localization-related epilepsy were compared t o examine the association between positive discharges and other findin gs, Subjects were studied both ictally and interictally by scalp EEG w ith the International 10-20 system and zygomatic or sphenoidal electro des, and video EEG telemetry, The 5 children with positive discharges were significantly more likely to develop hemiparesis during the preop erative period (P less than or equal to.025). Correlations were observ ed between positive discharges and lesions apparent on MRI situated ar ound the rolandic fissure (P less than or equal to.025). Children with positive discharges had a significantly less favorable outcome after surgical treatment (P less than or equal to.025), Positive epileptifor m discharges in children with neuronal migration disorders may signal a more dysfunctional cortex leading to a focal neurological deficit or a more extended lesion than is detected on MRI. This would explain th e less favorable outcome of seizures after surgery, since the epilepto genic areas and neuronal migration lesions cannot be completely resect ed. (C) 1997 by Elsevier Science Inc.