Seizure threshold and excess dietary amino acids.
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Age Factors↗
Biomedical subjects
B B Gallagher
Publications and source records attributed to B B Gallagher.
Corpus callosotomy for the treatment of intractable epilepsy.
Twenty-five patients underwent anterior corpus callosotomy (ACC) for treatment of uncontrolled seizures. Two patients died, and 6 patients experienced perioperative complications which resolved. A statistically significant reduction of generalized tonic-clonic seizures (17 patients; P less than 0.05) and complex partial seizures (11 patients; P less than 0.05) occurred following ACC. A single patient with atonic seizures became free of atonic seizures. Two patients had a greater than 50% reduction in seizures resulting in falls, a single patient became free of episodes of status epilepticus, and in 2 patients the seizures changed from generalized tonic-clonic seizures to hemiconvulsive seizures. Thus ACC appears to decrease the severity and frequency of disabling seizures in some patients with uncontrolled seizures.
Adolescent↗
Spectral analysis of sphenoidal evoked potentials predicts epileptic focus.
Sphenoidal evoked potentials (SpEPs) were recorded in 14 patients with intractable temporal lobe epilepsy. Twelve patients had electrographically proven unilateral seizure onset (five left, seven right). Two patients had partial complex seizures and unilateral mesial temporal lobe lesions shown by magnetic resonance imaging (MRI). Thirteen patients subsequently underwent temporal lobectomy. SpEPs were recorded using the P3 tonal oddball paradigm from sphenoidal electrodes referenced to scalp electrodes (i.e., T3, T4, C3, C4, Cz) and were subjected to spectral analysis for whole band (1-12.6 Hz) power. A significant relationship was found for side of seizure focus and reduced spectral power of the sphenoidal-temporal target SpEPs. In 10 of 14 patients, SpEP spectral power was less from the "epileptogenic" than from the "nonepileptogenic" temporal lobe. Of the remaining 4 patients, 2 had bilaterally equal spectral power, and 2 had lower SpEP power from the nonepileptogenic side. Postoperatively, all 13 patients are seizure-free except for the 2 patients with reduced SpEP power opposite to the ictal onset and 1 patient with fluctuations in SpEP asymmetries. Spectral analysis of SpEPs appears to have utility in the assessment of temporal lobe dysfunction and thus in the preoperative evaluation for epilepsy surgery.
Adolescent↗
Genetically epilepsy-prone rats are characterized by altered tissue trace element concentrations.
Since trace element abnormalities have been found in the human epileptic population, trace element concentrations were determined in blood and tissues of genetically epilepsy-prone rats both exposed to an unexposed to seizure-inducing stimuli and in genetically related epilepsy-resistant rats. Half of the epilepsy-prone group were exposed to seizure-inducing sound twice daily for 3 weeks. Food intake and weight gain were monitored for each animal. Genetically epilepsy prone rats with induced seizures consumed significantly less food and gained less weight than did the epilepsy resistant group. Seizure prone rats without seizures consumed the same amount of food as the resistant rats but gained less weight than the resistant strain but more than the seizure-induced animals. Epilepsy-prone animals had significantly altered trace element concentrations in tissues as compared with the resistant animals independent of seizure induction. Brain and liver iron, liver copper, and brain and heart manganese levels were all significantly lower in the seizure-prone rats as compared with the seizure-resistant rats. In the seizure-prone rats, induction of seizures resulted in an increase in brain and heart zinc levels and a decrease in whole blood manganese levels. These results demonstrate that both genetic factors relevant to susceptibility to seizures and the seizures themselves are associated with changes in trace element concentrations.
Acoustic Stimulation↗
Manganese and epilepsy: brain glutamine synthetase and liver arginase activities in genetically epilepsy prone and chronically seizured rats.
Low blood manganese (Mn2+) concentration is associated with epilepsy in humans and rats. The low Mn2+ concentration is attributed by some investigators to the seizure activity associated with the epilepsy, whereas others propose that the low Mn2+ concentration may be secondary to genetic mechanisms underlying the epilepsy. To begin to differentiate between these possibilities, Mn(2+)-binding enzymes of liver and brain (i.e., arginase and glutamine synthetase, respectively) were assayed in rats exposed to chronically induced seizures and in genetically epilepsy-prone rats (GEPRs). Chronic seizures caused a decrease in whole blood Mn2+ levels but did not affect brain Mn2+ concentrations. Arginase activity was increased in livers of rats with chronic seizure as compared with controls, but this difference was eliminated when Mn2+ was added to the assay. Brain glutamine synthetase activity was unaffected by chronic seizures, but the activity of this enzyme was significantly lower in GEPR brain than in control brain. Liver arginase activity tended to be lower in GEPRs, although the difference was not statistically significant. These data indicate that seizures affect liver arginase activity through changes in liver Mn2+ concentration, but GEPRs show abnormalities in Mn(2+)-dependent enzymes apparently independent of seizure activity.
Animals↗
Amnesia after unilateral temporal lobectomy: a case report.
We report a mixed handed (L > R) patient with exclusive right cerebral language representation who developed a permanent anterograde amnestic syndrome after right anterotemporal lobectomy. Preoperative neuropsychological performance consisted of impaired verbal memory and normal nonverbal memory. Wada memory performance was asymmetrical for objects presented soon after amobarbital injection in conjunction with no memory asymmetry for items presented later in the Wada evaluation. Pre- and postoperative magnetic resonance imaging (MRI) scans showed no structural lesions; however, postoperative MRI hippocampal volume measurements suggested decreased hippocampal volume for the nonresected temporal lobe. These results confirm the risk of anterograde amnesia after unilateral temporal lobectomy and demonstrate that baseline neuropsychological testing may falsely literalize material-specific memory functions in patients with atypical cerebral language dominance.
Adult↗
Endocrine abnormalities in human temporal lobe epilepsy.
Patients with temporal lobe epilepsy secrete ACTH at higher rates and in greater amounts than normal subjects. Temporal lobectomy restores ACTH secretion to normal amounts and rates. The ACTH secretion in temporal lobe epilepsy is independent of anticonvulsant drug effect and seizure frequency. Electrical stimulation of medial temporal lobe structures in patients with temporal lobe epilepsy affected ACTH secretion in a manner consistent with the hypothesis that ACTH secretion is regulated by tonic inhibition. A defect in the excitatory and/or inhibitory components of this regulatory process appears to exist in temporal lobe epilepsy.
Adrenocorticotropic Hormone↗
Modified CT techniques in the evaluation of temporal lobe epilepsy prior to lobectomy.
The outcome of temporal lobectomy performed for seizure control is improved by preoperative identification of structural lesions. We used cranial CT, modified to improve visualization of mesial temporal structures, as a means of preoperative evaluation in 48 patients with partial complex seizures. The axial views, parallel to the temporal fossa, improved visualization of five lesions, including two that were not diagnosed by routine cranial CT. In 12 patients, intrathecal metrizamide was used; the rest received intravenous contrast. These modified techniques could not reliably predict mesial temporal herniation; however, modified axial CT with intravenous contrast is recommended for evaluation of suspected temporal lobe pathology.
Brain Neoplasms↗