Corpus callosotomy for seizures associated with band heterotopia.

Band heterotopia is a severe form of neuronal migration disorder associated with intractable epilepsy and neurologic impairment. Surgical treatment of seizures associated with this malformation has not been reported previously. We report a patient with band heterotopia and poorly controlled atonic seizures causing falls and injury. The patient was treated with anterior corpus callosotomy, with significant postoperative decrease in seizure frequency. Corpus callosotomy is a reasonable alternative to consider in management of patients with cortical heterotopia and intractable seizures.

Temporal lobectomy for seizures associated with unilateral schizencephaly.

Schizencephaly is characterized by unilateral or bilateral cerebral clefts associated with neurologic deficits and epilepsy. Most commonly schizencephaly is attributed to abnormal neuronal migration, and these malformations are well visualized by current neuroimaging techniques. This report describes a patient with unilateral schizencephaly and poorly controlled complex partial seizures who was found to have a temporal lobe seizure focus; anterior temporal lobectomy produced nearly complete control of the seizures. Despite the extensive malformation, relatively restricted resection was of significant benefit. The principles of seizure focus localization and resection are applicable to the management of patients with schizencephaly.

Preoperative electroencephalographic localization of large epileptogenic zones in the frontal and temporal lobes.

The concept of epileptogenic zone is defined as a large area of cortical neurons arranged in concentric circles of variable degrees of epileptogenicity. This is particularly so in frontal lobe epilepsy since the interictal and ictal epileptic abnormalities are poorly localized, often absent and at times misleading in terms of localization. In temporal lobe epilepsy, the epileptogenic zones may be more restricted.

Clinical significance of periodic lateralized epileptiform discharges: relationship with status epilepticus.

A retrospective study was carried out in 147 patients who had been found to have periodic lateralized epileptiform discharges (PLEDs). Clinical, laboratory, radiological, and pathological correlation was performed for all patients. As in previously published works, we found a high correlation with cerebrovascular accidents in our population. A large number of patients, however, had no evidence of focal central nervous system pathology. An attempt was made to find a temporal relationship between the onset of seizure activity (or neurological dysfunction in those patients without seizure activity) and the recording of an EEG with PLEDs. We found that most of the EEGs with PLEDs were obtained within the first 4 days of seizure activity or status epilepticus condition. We postulate that the EEG phenomenon of PLEDs could be considered a part of the status epilepticus condition. Suggestive of this was the fact that the first EEG record obtained in one-third of our patients showed electrographic partial status epilepticus. In a small percentage of our patients, a transitional record showed first status epilepticus and then PLEDs. We found that PLEDs usually disappeared from the EEG tracing within 9 days post-ictus flash status. They were most frequently replaced by focal slowing or random spike activity.

Experimental studies on different thresholds for epileptiform activity.

This investigation was carried out to clarify the mechanisms for production of different seizure threshold. To study this problem changes of a single cell activity were examined by means of penicillin iontophoretical application to a single cell of both low seizure threshold hippocampus and the high seizure threshold olfactory bulb, and also topical application to the surface of hippocampus and olfactory bulb. Penicillin was applied iontophoretically using five barrel glass micropipettes. Extracellular recordings from 58 hippocampal pyramidal cells and 68 olfactory bulb mitral cells were analyzed. Penicillin increased the firing rate in most of both hippocampal pyramidal and olfactory bulb mitral cells. This suggests that penicillin finally had an excitatory effect on both cells. The results from the experiments of intermittent and continuous GABA application on a cell during penicillin iontophoresis revealed that GABA inhibitory action was reduced by penicillin in both cells. A progressively shortened duration of the post-discharge inhibition during penicillin iontophoresis also suggested that penicillin may reflect a decrease of GABA inhibitory action. No obvious seizure activity and/or no change of firing pattern were observed even after long penicillin iontophoresis. There was no significant different responses to penicillin iontophoresis in the hippocampus and the olfactory bulb single cell. Extracellular activity from 64 hippocampal pyramidal cells and 32 olfactory bulb mitral cells was recorded. The effects of penicillin topical application on single cell function were examined. From hippocampus surface, paroxysmal activity begun to appear within 6 min after topical application, and became more regular and stereotyped in form. The firing rate initially decreased in the majority of cells, with no increase prior to interictal or ictal events. The unit responses to both intermittent and continuous GABA iontophoresis was suppression in unit firing incidence, except for the burst patterns associated with the surface interictal or ictal discharges. Post-discharge inhibition was not significantly different either before or after the onset of the surface interictal discharges. These results indicate the firing rate and inhibitory function of the hippocampal pyramidal cells were not significantly changed during and following the development of interictal and/or ictal epileptiform activity. Olfactory bulb surface activity was not significantly changed and no epileptiform activity was observed even several hours after topical penicillin application.(ABSTRACT TRUNCATED AT 400 WORDS)

Radionuclide cerebral perfusion scintigraphy in determination of brain death in children.

We evaluated a radionuclide scintigraphic technique for imaging relative cerebral perfusion in 18 children who had no evidence of cortical and brainstem function. Patients without scintigraphic evidence of cerebral perfusion all later met criteria for diagnosis of brain death. Patients who failed to satisfy brain-death criteria had persistent scintigraphic evidence of cerebral perfusion. Seven patients with normal scintigraphic studies were being treated with barbiturates and hypothermia at levels that attenuated or completely suppressed EEG activity. Four patients without scintigraphic evidence of cerebral perfusion had mean arterial pressures (MAP) higher than (54.8 +/- 7.6 torr) intracranial pressures (ICP) at the time of scintigraphic study, suggesting that ICP in excess of MAP is not the sole explanation for the absence of cerebral perfusion. Radionuclide cerebral perfusion scintigraphy (RCPS) is a rapid, portable, accurate test that appears to be useful in the diagnosis of brain death in the pediatric population.

Electroencephalographic findings in Gaucher disease.

The electroencephalographs (EEGs) of 26 patients with Gaucher disease were reviewed. Eleven cases with abnormal EEGs or neurologic complications are reported, and the findings of the abnormal recordings are discussed.