Ruben Kuzniecky

Classification system for malformations of cortical development Update 2001

The many recent discoveries concerning the molecular biologic bases of malformations of cortical development and the discovery of new such malformations have rendered previous classifications out of date. A revised classification of malformations of cortical development is proposed, based on the stage of development (cell proliferation, neuronal migration, cortical organization) at which cortical development was first affected. The categories have been created based on known developmental steps, known pathologic features, known genetics (when possible), and, when necessary, neuroimaging features. In many cases, the precise developmental and genetic features are uncertain, so classification was made based on known relationships among the genetics, pathologic features, and neuroimaging features. A major change since the prior classification has been the elimination of the separation between diffuse and focal/multifocal malformations, based on the recognition that the processes involved in these processes are not fundamentally different; the difference may merely reflect mosaicism, X inactivation, the influence of modifying genes, or suboptimal imaging. Another change is the listing of fewer specific disorders to reduce the need for revisions; more detail is added in other smaller tables that list specific malformations and malformation syndromes. This classification is useful to the practicing physician in that its framework allows a better conceptual understanding of the disorders, while the component of neuroimaging characteristics allows it to be applied to all patients without necessitating brain biopsy, as in pathology-based classifications.

Patient‐Validated Content of Epilepsy‐Specific Quality‐of‐Life Measurement

Summary: Purpose: To study the effects of epilepsy from the patients’perspective and assist determination of content validity of health‐related quality‐of‐life (HRQOL) measures.

Congenital bilateral perisylvian syndrome: study of 31 patients

Advances in neuroimaging techniques have enabled the recognition of developmental malformations of the brain during life. Careful correlation of clinical and imaging features has identified several new syndromes. We have studied 31 patients with a congenital neurological syndrome characterised by pseudobulbar palsy, cognitive deficits, and bilateral perisylvian abnormalities on imaging studies. All patients had diplegia of the facial pharyngeal, and masticatory muscles, of variable severity. Some patients had slight dysarthria, whereas others were unable to speak. 85% of patients had mental retardation, ranging from mild to severe. Epilepsy was present in 27 (87%) and commonly consisted of atypical absence, atonic/tonic, tonic-clonic seizures, and, less frequently, partial attacks. Seizures were poorly controlled in 55%. Magnetic resonance imaging showed bilateral perisylvian cortical malformations consistent with polymicrogyria, confirmed at necropsy. Division of the corpus callosum in several patients resulted in seizure improvement. This congenital bilateral perisylvian syndrome can be clinically diagnosed and confirmed by imaging studies. Further studies are necessary to elucidate its cause.

A Comparison of Rectal Diazepam Gel and Placebo for Acute Repetitive Seizures

BACKGROUND Acute repetitive seizures are readily recognizable episodes involving increased seizure frequency. Urgent treatment is often required. Rectal diazepam gel is a promising therapy. METHODS We conducted a randomized, double-blind, parallel-group, placebo-controlled study of home-based treatment for acute repetitive seizures. Patients were randomly assigned to receive either rectal diazepam gel, at a dosage varying from 0.2 to 0.5 mg per kilogram of body weight on the basis of age, or placebo. Children received one dose at the onset of acute repetitive seizures and a second dose four hours later. Adults received three doses -- one dose at onset, and two more doses 4 and 12 hours after onset. Treatment was administered by a care giver, such as a parent, who had received special training. The number of seizures after the first dose was counted for 12 hours in children and for 24 hours in adults. RESULTS Of 125 study patients (64 assigned to diazepam and 61 to placebo) with a history of acute repetitive seizures, 91 (47 children and 44 adults) were treated for an exacerbation of seizures during the study period. Diazepam treatment was superior to placebo with regard to the outcome variables related to efficacy: reduced seizure frequency (P<0.001) and improved global assessment of treatment outcome by the care giver (frequency and severity of seizures and drug toxicity) (P<0.001). Post hoc analysis showed diazepam to be superior to placebo in reducing seizure frequency in both children (P<0.001) and adults (P=0.02), but only in children was it superior with regard to improvement in global outcome (P<0.001). The time to the first recurrence of seizures after initial treatment was longer for the patients receiving diazepam (P<0.001). Thirty-five patients reported at least one adverse effect of treatment; somnolence was the most frequent. Respiratory depression was not reported. CONCLUSIONS Rectal diazepam gel, administered at home by trained care givers, is an effective and well-tolerated treatment for acute repetitive seizures.

Improved health care resource utilization following video-EEG-confirmed diagnosis of nonepileptic psychogenic seizures

The economic burden of epilepsy is well recognized. However, empirical investigation establishing costs associated with the diagnosis and treatment of non-epileptic psychogenic seizures (NEPS) is lacking. We studied 20 patients with video/EEG monitoring-confirmed NEPS to determine the effect of definitive diagnosis and treatment on medical costs and utilization. A medical resource utilization questionnaire and inpatient medical chart review were employed to calculate utilization information. Medication usage, outpatient visits, emergency room admissions, and diagnostic testing over a 6-month pre-diagnosis and a 6-month post-diagnosis period were compared. There was an 84% average reduction in total seizure-related medical charges in the 6 months following NEPS diagnosis. Average diagnostic testing charges declined 76%, average medication charges decreased 69%, outpatient clinic visits declined 80%, and emergency room visits reduced by 97%. A majority of patients obtaining a definitive inpatient video/EEG-seizure-monitoring-confirmed NEPS diagnosis experience substantial reductions in health care utilization and dollar costs.

Gelastic seizures and hypothalamic hamartomas Evaluation of patients undergoing chronic intracranial EEG monitoring and outcome of surgical treatment

We retrospectively studied 12 consecutive patients with gelastic seizures and hypothalamic hamartomas who, because of intractable epilepsy, underwent chronic intracranial EEG monitoring or epilepsy surgery. All patients had medically refractory seizures that included laughter as an ictal behavior (gelastic seizures). The hypothalamic hamartomas were identified with neuroimaging studies (12 of 12) and by pathologic verification (four of 12). Associated clinical features included behavioral disorders (n = 5), developmental delay (n = 4), and precocious puberty (n = 2). Interictal extracranial EEG predominantly showed bihemispheric epileptiform changes suggesting a secondary generalized epileptic disorder. Intracranial EEG recordings, performed in eight patients, indicated the apparent focal onset of seizure activity (anterior temporal lobe [n = 7] and frontal lobe [n = 1]). None of the seven patients who underwent a focal cortical resection, however, experienced a significant reduction in seizure tendency. An anterior corpus callosotomy, performed in two patients with symptomatic generalized epilepsy, resulted in a worthwhile reduction in drop attacks. Results of this study may modify the surgical strategies in patients with gelastic seizures and hypothalamic hamartomas.

Vagus Nerve Stimulation for Treatment of Partial Seizures: 3. Long‐Term Follow‐Up on First 67 Patients Exiting a Controlled Study

Summary: Vagus nerve stimulation (VNS) has demonstrated a significant anticonvulsant effect in preclinicalstudies, in pilot studies in humans, and in the acute phaseof a multicenter, double‐blinded, randomized study. After completion of a 14–week, blinded, randomized study, with 31 receiving high (therapeutic) VNS and 36 receiving low (less or noneffective) VNS, 67 patients elected tocontinue in an open extension phase. During the extension phase, all 67 patients received high VNS. Seizurefrequency during the 3‐month treatment blocks was compared with a 12–week baseline. For both groups, all periods of high VNS demonstrated a significant decrease inseizure frequency (p < 0.01 level) as compared with baseline. For the 16–18–month period of VNS, data wereavailable for 26 of the 31 patients randomized to highVNS. This group achieved a 52.0% mean seizure frequency percentage réduction as compared with baseline. For those converted from low to high VNS, data wereavailable for 24 of the 36 patients at the 16–18‐month timeperiod. This group reported a mean seizure frequency percentage reduction of 38.1% as compared with baseline. No significant change in the safetyhde effect profilewas reported during longterm followup. The previouslyreported side effects of hoarsenesslvoice change, coughing, and paresthesia (sensation in neck and jaw) continued to occur during VNS. These side effects were well tolerated. During the follow‐up period, 1 patient died of thrombotic thrombocytopenic purpura (TTP) and 5 patients discontinued treatment because of unsatisfactory efficacy.

Magnetic resonance imaging in childhood intractable partial epilepsies: Pathologic correlations

We conducted a retrospective single-blind study assessing the value of MRI in 44 children surgically treated for partial epilepsy, and correlated the MRI findings with the pathology in all cases. MRI revealed abnormalities in concordance with the clinical and electroencephalographic data in 84% of patients. Developmental neuronal migration pathology was present in 25% of patients and was relatively more common in the sensorimotor cortex. There was hippocampal sclerosis in 50% of patients with temporal lobe resection; however, only two of the 10 children with hippocampal sclerosis were below the age of 12 years. Similarly, ganglioglial tumors were more common than astrocytomas in children below age 12. These results indicate that MRI is sensitive in the detection of pathologic abnormalities in most pediatric candidates for epilepsy surgery, and that the distribution and type of pathology appear to be age related in this population.

Felbamate monotherapy for partial-onset seizures: An active-control trial

We evaluated felbamate (FBM) monotherapy in 111 patients with uncontrolled partial-onset seizures in a multicenter, double-blind, parallel-group trial. During the 56-day baseline period, patients had at least eight partial-onset seizures and received one standard antiepileptic drug (AED) at a therapeutic level; a second AED was allowed if at a subtherapeutic level. Patients received either FBM 3,600 mg/d or valproate (VPA) 15 mg/kg/d. The baseline AED at therapeutic levels was discontinued by one-third decrements on study days 1, 14, and 28 and the subtherapeutic AED, if any, was discontinued completely on study day 1. Study endpoints were completion of 112 study days or fulfilling one or more escape criteria. Criteria for escape relative to baseline were (1) twofold increase in monthly seizure frequency, (2) twofold increase in highest 2-day seizure frequency, (3) single generalized tonic-clonic seizure (GTC) if none occurred during baseline, or (4) significant prolongation of GTCs. The primary efficacy variable was the number of patients in each treatment group who met escape criteria. Thirty-seven patients on VPA and 18 on FBM met escape criteria (p < 0.001). Even when we considered FBM dropouts to have fulfilled escape criteria and VPA dropouts to have completed the 112-day trial, the treatment difference remained statistically significant (p = 0.039) in favor of FBM. Adverse experiences with FBM were all mild or moderate in severity. The frequency of adverse experiences was much lower during monotherapy. FBM monotherapy was effective in the treatment of partial-onset seizures with or without secondarily generalized seizures and demonstrated a favorable safety profile.

Familial perisylvian polymicrogyria: a new familial syndrome of cortical maldevelopment

Two familial X‐linked dominant syndromes of cortical maldevelopment have recently been described: double cortex/lissencephaly syndrome and bilateral periventricular nodular heterotopia. We report on 12 kindreds with familial perisylvian polymicrogyria (FPP) presenting at 10 centers, examine the clinical presentation in these familial cases, and propose a possible mode of inheritance. The clinical and radiological pattern was variable among the 42 patients, with clinical differences among the families and even within members of the same family. Pseudobulbar signs, cognitive deficits, epilepsy, and perisylvian abnormalities on imaging studies were not found in all patients. When present, they displayed a spectrum of severity. The only clear correlation in this study was between bilateral imaging findings and abnormal tongue movements and/or pronounced dysarthria. Most of the families provided evidence suggestive of, or compatible with, X‐linked transmission. On the other hand, the pedigrees of 2 families ruled out X‐linked inheritance. The most likely mode of inheritance for these 2 families was autosomal dominant with decreased penetrance; however, autosomal recessive inheritance with pseudodominance could not be ruled out in 1 family. We conclude that FPP appears to be genetically heterogeneous. However, most of the families probably represent a third previously undescribed X‐linked syndrome of cortical maldevelopment. Ann Neurol 2000;48:39–48