The value of magnetic resonance imaging in the detection of hippocampal sclerosis has been controversial. We studied 10 patients aged 22.5 +/- 6.0 years with intractable temporal lobe epilepsy selected because of a history of a prolonged childhood convulsion, which is characteristic of a group of patients in whom hippocampal sclerosis is a constant finding. All 10 patients showed reduction in size of one hippocampus associated with increased signal intensity on T2-weighted magnetic resonance images. These changes were reliably detected on coronal spin-echo images, perpendicular to the long axis of the hippocampus. Appreciation of the normal imaging anatomy of the hippocampus allowed correct interpretation of the relative changes in signal intensities of the hippocampus and adjacent temporal horn on sequential echo images. The side of the abnormal hippocampus on magnetic resonance imaging accorded with the electroencephalographic localization in all 10 patients, and with the lateralization of the early convulsions in all 6 patients where this was known. Temporal lobectomy was performed in all 10 patients. Hippocampal sclerosis was confirmed in the 3 patients in whom hippocampal tissue was available for histological examination. The value of this technique was reinforced by the excellent postoperative results, with 80% being seizure free at a mean follow-up time of 33 +/- 4 months.

Adolescent↗

PubMed1991

In vivo magnetic resonance spectroscopy of brain and muscle in a type of mitochondrial encephalomyopathy (MERRF).

Phosphorus magnetic resonance spectroscopy allows noninvasive measurement of the intracellular phosphate-containing metabolites and intracellular pH in localized volumes of human muscle and brain in vivo. This technique was used to study 8 patients with a mitochondrial cytopathy (myoclonus epilepsy with ragged red fibers). Phosphorus magnetic resonance spectroscopy of resting gastrocnemius muscle demonstrated significantly increased relative intracellular inorganic phosphate concentrations (p less than 0.0005) and decreased phosphocreatine to inorganic phosphate concentration ratios (p less than 0.01) in the patients, although only 3 had myopathic signs or symptoms. We propose, therefore, that phosphorus magnetic resonance spectroscopy of resting skeletal muscle is a useful clinical test in evaluation of progressive myoclonus epilepsy. In contrast to results from muscle, however, the relative phosphate metabolite concentrations and intracellular pH in central volumes of the brains of these patients were normal, despite evidence from our previous positron emission tomography studies suggesting that there is diffuse impairment of cerebral oxidative metabolism.

Brain↗

PubMed1991

Mitochondrial dysfunction in multiple symmetrical lipomatosis.

Multiple symmetrical lipomatosis is a striking clinical finding associated with a variety of peripheral and central nervous system abnormalities. We describe 4 unrelated patients with evidence of mitochondrial dysfunction in skeletal muscle. Multiple symmetrical lipomatosis is an additional, albeit unusual, manifestation of the expanding clinical spectrum of mitochondrial diseases.

Adult↗

PubMed1991

Anterior callosotomy in the treatment of medically intractable epilepsies: a study of 43 patients with a mean follow-up of 39 months.

We studied the effectiveness of anterior callosotomy in 43 patients whose follow-up period averaged 39 months. These patients had intractable generalized seizures, characterized by a combination of seizure patterns, most frequently drop attacks with generalized tonic-clonic, generalized tonic, and absence seizures. Overall, drop attacks were the most frequent (31/43 or 72%) and the most disabling seizure pattern (27/43 or 63%); they were also the most likely to benefit from anterior callosotomy (70%). Patients with lateralized changes tended to have a better result than did those without lateralization, but patients with synchronous and symmetrical spike and wave discharges also benefited. The preoperative intelligence quotient and the etiological factors were not predictors of outcome. There was a correlation between the extent of section and the results; patients with section of the anterior two thirds had a better result, compared with those who had section of the anterior half.

Adolescent↗

PubMed1991

Focal neuronal migration disorders and intractable partial epilepsy: a study of 30 patients.

We studied 30 patients with partial epilepsy and a radiological or pathological diagnosis of localized neuronal migration disorders, with a view to surgical treatment. Eight patients had identifiable prenatal etiological factors. The frequency of complex partial, partial motor, and secondarily generalized seizures was approximately 70% each. Drop attacks were present in 27%: Their presence usually correlated with a lesion involving the central region. Partial motor or generalized convulsive status epilepticus occurred in 30%, and was most frequently associated with extensive structural abnormalities involving two or more lobes. A full-scale intelligence quotient of less than 80 was found in 44%. Magnetic resonance imaging (MRI) was superior to computed tomography for identification of the dysplastic cortical lesions. In one third, MRI showed only subcortical abnormalities. It did not allow distinction between true pachygyria, focal cortical dysplasia, or the forme fruste of tuberous sclerosis. The epileptogenic area was usually more extensive than the lesion; it was multilobar in more than 70% of patients. Of 26 surgically treated patients, a histological diagnosis of the type of neuronal migration disorder was possible in 22: 12 had focal cortical dysplasia and 10 the forme fruste of tuberous sclerosis. In the remaining 4, no definite histological diagnosis was made, since the maximally abnormal tissue could not be examined. In the latter, and in the 4 nonoperated patients, the diagnosis of neuronal migration disorder was based on imaging findings. The presence of the forme fruste of tuberous sclerosis correlated with delayed psychomotor development and more extensive epileptogenic areas.

Adolescent↗

PubMed1991

Focal neuronal migration disorders and intractable partial epilepsy: results of surgical treatment.

Twenty-six patients with focal or lateralized neuronal migration disorders and intractable partial epilepsy were treated surgically. Twenty-four had reliable follow-up ranging from 1 to 15 years (mean, 5.0). Pathologically, they fell into two categories: focal cortical dysplasia (12 patients) and forme fruste of tuberous sclerosis (8 patients). In the remaining 4 patients, the material was inadequate for histological analysis. Outcome regarding seizure control was assessed according to a classification most sensitive to variations in frequency of major attacks. Ten (42%) of the 24 patients achieved good or excellent outcome, 6 (25%) had a worthwhile decrease in seizure frequency, and 8 (33%) had only discrete improvement. The variable most strongly correlated with surgical outcome was the amount of lesion removed. Seventy-seven percent of patients in whom a complete excision or excision of 50% or more of the lesion was accomplished achieved excellent or good surgical outcome. Conversely, no patient with less than 50% of the lesion removed attained the same result. There was no correlation between other clinical, radiological, or electrographic variables and outcome regarding seizure control. Specifically there was no significant correlation between the amount of excision of the epileptogenic area as judged by scalp electroencephalography and electrocorticography studies, and surgical outcome. In patients with neuronal migration disorders and intractable partial epilepsy, removal of the structural abnormality takes precedence over removal of epileptogenic tissue as the main surgical strategy to achieve seizure control.

Adolescent↗

PubMed1991

Neuronal migration disorders: a contribution of modern neuroimaging to the etiologic diagnosis of epilepsy.

Computed tomography and magnetic resonance imaging enable the identification of neuronal migration disorders during life. Several specific syndromes have been identified and early diagnosis of previously unrecognized entities is now possible. We report 51 patients with imaging. Thirty-two had a single widespread cortical dysplastic lesion. Twenty-eight had focal corticectomies. From a pathological standpoint, these encompassed focal cortical dysplasia (14 cases) and forme fruste of tuberous sclerosis (10 cases). These two groups of patients were indistinguishable from the clinical and radiological standpoint. In only two was the MRI examination normal. In addition, there were 10 with bilateral perisylvian dysplasia, four with diffuse cortical dysplasia or the "double cortex" syndrome, three with hemimegalencephaly, one with megalencephaly, and one with nodular neuronal heterotopia. The electroclinical and imaging findings led to the development of specific surgical strategies for the alleviation of the intractable seizures in each of these radiologically-defined syndromes.

Adolescent↗

PubMed1991

Surgical treatment of intractable epilepsy associated with schizencephaly.

With the advent of magnetic resonance imaging, there has been an increased recognition of schizencephaly during life, especially in epileptic patients. We report our experience with the assessment and treatment of three patients with medically intractable seizures associated with this condition. The three men were aged 24 to 37 years. Two had delayed developmental milestones and hemiparesis or hemiplegia. One had normal development and a normal neurological examination. Seizures began between the ages of 15 and 19 years and lasted for 5 to 22 years before surgery. All had partial simple or generalized seizures with predominant electroencephalographic and electrocorticographic epileptic activity localized to temporal and frontal lobes on the side of the lesion. Neuropsychological assessment indicated widespread dysfunction maximal at the areas of predominant electroencephalographic abnormality. Magnetic resonance imaging demonstrated anterior parasagittal, parietal, and Rolandic cerebral clefts, with ventricular diverticuli, gray matter heterotopia, polymicrogyria, and a true agenesis of the corpus callosum in individual patients. The patients underwent temporal (one patient) and frontotemporal (two patients) lobectomies without additional neurological deficits or neuropsychological deterioration. Postoperative follow-up showed reduction in seizure frequency. We conclude that the surgical treatment of epilepsy is well tolerated in such patients, and their seizures can be alleviated by resection of epileptogenic areas.

Adult↗

PubMed1991

Diffuse cortical dysplasia, or the 'double cortex' syndrome: the clinical and epileptic spectrum in 10 patients.

Diffuse neuronal migration disorders associated with epilepsy can now be recognized by modern neuroimaging techniques, particularly high-resolution MRI. We report 10 patients with a recently described MRI picture of continuous or generalized band heterotopia underlying the cortical mantle, giving the appearance of a "double cortex." They have epilepsy, and almost all have mental retardation. The epileptic disorder varies in nature and degree of severity. Patients may present with infantile spasms, a Lennox-Gastaut syndrome, or other forms of secondary generalized or multifocal epilepsy. Response to medical treatment is variable. Callosotomy may lead to considerable reduction of drop attacks, present in 60%. Mental retardation is usually mild or moderate, and only rarely severe. It correlates with the type of epileptic syndrome, and is greater in patients with more disorganized cortex overlying the heterotopia. Recognition of this entity by MRI is important for appropriate diagnosis of the epileptic disorder, planning of therapeutic strategy, and prognosis.

Adolescent↗

PubMed1991

Complex partial seizures and small posterior temporal or extratemporal structural lesions: surgical management.

Twenty patients with small, indolent, relatively inaccessible posterior temporal or extratemporal lesions had complex partial seizures presumably related to anterior and inferomesial temporal lobe epileptic activity. All underwent anterior temporal corticectomies, and in six the resection was extended at a second operation. There was sclerosis of mesial temporal structures in seven of the surgical specimens. Two patients became seizure free for more than 2 years; three others showed more than 95% reduction in seizure frequency, and five had moderate (greater than 50%) reduction. While cessation of seizures or improved control may occur following this surgical strategy, the results are strikingly inferior to those obtained when the lesion, as well as the epileptogenic area, can be resected. Review of this group of patients suggests that the lesion should be included in the resection if at all possible.

Adolescent↗

PubMed1991

Functional hemispherectomy: EEG findings, spiking from isolated brain postoperatively, and prediction of outcome.

We reviewed the prognostic significance of preoperative EEG findings in 25 patients who underwent functional hemispherectomy. Bilateral independent epileptogenic foci, found in five patients, generally indicate a less satisfactory outcome, with only three of the five patients becoming seizure free following hemispherectomy. In contrast, abnormalities of background activity over the "good" hemisphere, multifocal epileptic activity confined to the side of operation, or bilaterally synchronous discharges were associated with a good outcome and should not be considered as contraindications to operation. Postoperatively, discharges may occur in the functionally isolated frontal and occipital cortex, which are benign, with no other clinical significance than showing that the isolated cortex remains viable and continues to generate epileptogenic potentials.

Action Potentials↗

PubMed1991

Phenytoin toxicity due to interaction with clobazam.

The benzodiazepine antiepileptic drug clobazam can be added to existing AED treatment, usually without clinical toxicity. We report 3 patients in whom the addition of clobazam led within several weeks to clinically obvious phenytoin (PHT) intoxication in patients who had been taking maximum tolerable PHT doses. Symptoms and high PHT levels resolved with lowering the PHT dose. Clobazam and norclobazam levels were not elevated. This interaction is probably related to interference with hepatic degradation of PHT. Clinicians should be aware of possible PHT intoxication in patients starting clobazam.

Adult↗

PubMed1991

Magnetic resonance imaging shows specific abnormalities in the MELAS syndrome.

The MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) can be difficult to identify. We report MRI abnormalities that we believe are specific to this disorder in three patients with complete or partial MELAS syndrome. The patients all showed an unusual pattern on T2-weighted MRI with multifocal areas of hyperintense signal confined to the cortex of the cerebrum, cerebellum, and adjacent white matter. Some images suggested selective cortical involvement of deeper layers only. Deep white matter was relatively spared, distinguishing this from usual cerebrovascular disease or the edema after status epilepticus. Specificity of these findings is further suggested by a good correlation of these findings with the previously described unique postmortem brain pathology of MELAS.

Acidosis, Lactic↗