Models of Transition

Without a structure to address healthcare transition, adolescents and young adults with neurological disorders are likely to have disruptions in their care that result in a higher need for emergency care and hospitalization. There are numerous obstacles to implementing the existing transition guidelines: adequate numbers of skilled and willing adult providers, patient and family anxiety about transfer, changes in health insurance, inadequate reimbursement, and inefficient communication systems to pave the path for a smooth transition. The aim of this article is to provide practical information about developing a transition program, as well as a potential clinical model for transitioning care.

PedsQL™ Cognitive Functioning Scale in youth with epilepsy: Reliability and validity

OBJECTIVE

The objective of the study was to report on the internal consistency reliability and discriminant, concurrent and construct validity of the Pediatric Quality of Life Inventory™ (PedsQL™) Cognitive Functioning Scale as a brief generic cognitive functioning measure in youth with epilepsy.

METHODS

The 6-item PedsQL™ Cognitive Functioning Scale and 23-item PedsQL™ 4.0 Generic Core Scales were completed by 221 pediatric patients ages 5-18 years with epilepsy and 336 parents of patients ages 2-18 years in a national field test study for the PedsQL™ Epilepsy Module. Parents also completed the 86-item Behavior Rating Inventory of Executive Function (BRIEF), a widely validated measure of executive functioning.

RESULTS

The PedsQL™ Cognitive Functioning Scale evidenced excellent reliability (patient self-report α = 0.88; parent proxy-report α = 0.96), distinguished between youth with epilepsy and an age, gender, and race/ethnicity-matched healthy sample supporting discriminant validity with large effect sizes (~20-30 point score differences, P < 0.001), and demonstrated concurrent and construct validity, respectively, through large effect size intercorrelations with the BRIEF (Behavioral Regulation Index, Metacognition Index, Global Executive Composite Summary Scores rs = 0.43-0.67, P < 0.001) and the PedsQL™ Generic Core Scales (Total Scale Scores rs = 0.67-0.74, P < 0.001). Minimal clinically important difference (MCID) scores ranged from 5.92 to 8.80.

CONCLUSIONS

The PedsQL™ Cognitive Functioning Scale demonstrated excellent internal consistency reliability, discriminant, concurrent, and construct validity in youth with epilepsy and may be suitable as a brief generic patient-reported outcome (PRO) measure for clinical research, clinical trials, and routine clinical practice in pediatric epilepsy.

Child neurology in the 21st century

In September 2017, the Child Neurology Society (CNS) convened a special task force to review the practice of child neurology in the United States. This was deemed a necessity by our membership, as our colleagues expressed discouragement and burnout by the increase in workload without additional resources; reliance on work relative value units (wRVUs) as the sole basis of compensation; a push by administrators for providers to see more patients with less allotted time; and lack of administrative, educational, and research support. The CNS Task Force designed and distributed a survey to multiple academic divisions of various sizes, as well as to private practices. Our findings were strikingly similar across different practices, demonstrating high workloads, lack of resources, poor electronic medical record support, and high provider symptoms of fatigue and burnout. From the results, the CNS Task Force has concluded that wRVUs cannot be the sole basis of compensation for child neurology. We have also made several specific recommendations for alleviating the current situation, including innovative ways to fund child neurology as well as ways to enhance job satisfaction.

Neurocognitive Comorbidities in Pediatric Epilepsy: Lessons in the Laboratory and Clinical Profile

Children with epilepsy are at risk for a variety of neurocognitive comorbidities. Animal models have increased our understanding about the neurobiological mechanisms underlying the association between seizures and these comorbidities. This article starts with an overview of the current data on animal model research, studying the influence of early-life seizures, followed by a summary of potential cellular and molecular mechanisms by which seizures can affect cognitive development. We then describe specific abnormal neuropsychological profiles that accompany specific pediatric epilepsy syndromes. Finally, we offer a potential guideline to the treatment and management of children with epilepsy and its neurocognitive comorbidities.

Therapeutic hypothermia for neonatal hypoxic ischemic encephalopathy is associated with short-term reduction of seizures after discharge from the neonatal intensive care unit

INTRODUCTION

Therapeutic hypothermia for the treatment of moderate to severe neonatal hypoxic ischemic encephalopathy has been shown to reduce death and disability, but the effects on seizures after discharge from the Neonatal ICU are not known.

METHODS

A retrospective cohort study was conducted involving 56 neonates admitted to the Neonatal ICU at Children's Hospital of Orange County, CA from January 1, 2007 to September 1, 2013 with hypoxic ischemic encephalopathy who met criteria for selective brain cooling. Fifteen patients received supportive care. Forty-one patients received cooling, of whom 25 were included for analysis. Sixteen patients from the hypothermia group and 12 from the no hypothermia group developed clinical seizures while inpatient. Up to 6 months, four patients (16%) had continued seizures in the therapeutic hypothermia group compared to eight (53%) patients who did not receive hypothermia.

DISCUSSION

Our study shows an association between therapeutic hypothermia and reduced seizures after discharge from the neonatal intensive care unit. The short duration of follow-up, 6 months, is a limitation of this study. Another limitation is its observational nature, where reasons for treatment selection and exclusions are unmeasurable confounding factors. Further studies are needed to determine long-term effects.

The ketogenic diet for the treatment of pediatric status epilepticus

BACKGROUND

Refractory status epilepticus carries a high risk of morbidity and mortality for children. Traditional treatment of status epilepticus consists of multiple anticonvulsant drugs and, if needed, induction of a medical coma. The ketogenic diet has been used for intractable epilepsy for many years. The purpose of this article is to report a case series of five patients with refractory status epilepticus successfully managed with the ketogenic diet.

METHODS

A summary of pediatric patients with refractory status epilepticus treated with diet was performed.

CONCLUSIONS

Ketogenic diet therapy should be considered as a treatment option in pediatric patients with refractory status epilepticus.

Corpus callosotomy in multistage epilepsy surgery in the pediatric population

OBJECT

The object of this study was to evaluate surgical outcome in a select group of patients with medically refractory epilepsy who had undergone corpus callosotomy combined with bilateral subdural electroencephalography (EEG) electrode placement as the initial step in multistage epilepsy surgery.

METHODS

A retrospective chart review of 18 children (ages 3.5-18 years) with medically refractory symptomatic generalized or localization-related epilepsy was undertaken. A corpus callosotomy with subdural bihemispheric EEG electrode placement was performed as the initial step in multistage epilepsy surgery. All of the patients had tonic and atonic seizures; 6 patients also experienced complex partial seizures. All of the patients had frequent generalized epileptiform discharges as well as multifocal independent epileptiform discharges on surface EEG monitoring. Most of the patients (94%) had either normal (44%) MR imaging studies of the brain or bihemispheric abnormalities (50%). One patient had a suspected unilateral lesion (prominent sylvian fissure).

RESULTS

Of the 18 patients who underwent corpus callosotomy and placement of subdural strips and grids, 12 progressed to further resection based on localizing data obtained during invasive EEG monitoring. The mean patient age was 10.9 years. The duration of invasive monitoring ranged from 3 to 14 days, and the follow-up ranged from 6 to 70 months (mean 35 months). Six (50%) of the 12 patients who had undergone resection had an excellent outcome (Engel Class I or II). There were no permanent neurological deficits or deaths.

CONCLUSIONS

The addition of invasive monitoring for patients undergoing corpus callosotomy for medically refractory epilepsy may lead to the localization of surgically amenable seizure foci, targeted resections, and improved seizure outcomes in a select group of patients typically believed to be candidates for palliative surgery alone.

Efficacy of felbamate in the treatment of intractable pediatric epilepsy

The antiepileptic drug felbamate has demonstrated efficacy against a variety of seizure types in the pediatric population, particularly seizures associated with Lennox-Gastaut syndrome. Postmarketing experience, however, revealed serious idiosyncratic adverse effects not observed during clinical trials, including aplastic anemia and liver failure. As a result, many physicians have been hesitant to prescribe felbamate. This retrospective study evaluated the efficacy of felbamate in a pediatric population with intractable epilepsy. Of 38 patients, 22 had Lennox-Gastaut syndrome (58%); 6 had myoclonic-astatic epilepsy of Doose (16%); 5 had symptomatic generalized epilepsy, not otherwise specified (13%); and 5 had symptomatic localization-related epilepsy (13%). Most patients had multiple seizure types and had been tried on a variety of antiepileptic medications. With felbamate treatment, 6 patients (16%) became seizure free, including 4 of the 6 patients with myoclonic-astatic epilepsy of Doose; 24 patients (63%) had a greater than 50% reduction in seizure frequency. In this population felbamate appeared to be safe, with minimal adverse effects. The study is limited by the small number of patients and by its retrospective nature, but nonetheless adds to the evidence that felbamate is an important antiepileptic drug for medically refractory epilepsy in children and is well tolerated with few adverse effects.

Epilepsy surgery outcomes: quality of life and seizure control

A consecutive, retrospective analysis of seizure control and quality of life was performed among 83 pediatric patients undergoing epilepsy surgery at Children's Hospital of Wisconsin. Seizure outcomes were generally favorable, with 68.7% class I outcomes; class II, 12%; and class III, 19.3%. Seizure freedom was highest among temporal lobectomies (84.2%) and hemispherectomies (76.2%). Outcomes among hemispherectomies were substantially superior to those of multilobar resections. Cortical dysplasia was associated with lower seizure freedom, at 57.5%. Among age groups, seizure-free outcomes in infants were lowest, at 50%. The lower infant seizure-free rate was likely attributable to frequency of multilobar resections and type of pathology (cortical dysplasia). Quality-of-life measures generally paralleled seizure outcomes. These results indicate that epilepsy surgery in children with intractable epilepsy can result in significant improvements in seizure control, quality of life, and development. Anticipated type of surgery, presumed location of epileptogenic site, absence of a defined lesion on magnetic resonance imaging scan of the brain, and patient's age should not prevent surgical evaluations of children with intractable epilepsy.

Women and epilepsy

Women with epilepsy face additional challenges when compared to their peers. Hormonal influences may increase seizure activity, alter endocrine function, and affect fertility. In this population, antiepileptic drugs (AEDs) reduce the efficacy of contraception methods and increase the risk of fetal malformations. Other pertinent issues to women with epilepsy include breastfeeding as well as bone mineral health. This article summarizes our current, collective knowledge of these issues and makes specific recommendations with respect to management.

Clinical evaluation and diagnosis of severe epilepsy syndromes of early childhood

The developing brain is particularly susceptible to seizures. Diffuse central nervous system pathology or injury in early infancy, when the brain is most vulnerable, may lead to catastrophic epilepsies such as Ohtahara's epileptic encephalopathy and early myoclonic epileptic encephalopathy. These epileptic encephalopathies are difficult to treat and have poor prognoses. As the brain undergoes programmed synaptogenesis, apoptosis, and myelination, the epilepsy phenotypes and electroencephalography (EEG) findings change, producing age-dependent epileptic encephalopathies. Specifically, as they grow older, 40% to 60% of infants with infantile spasms and a concomitant hypsarrhythmia on EEG will develop Lennox-Gastaut syndrome with tonic and atonic seizures, associated with a synchronous, generalized 1.5- to 2-Hz spike and slow wave discharges on EEG. In the context of age-dependent epileptic encephalopathies, as an epilepsy syndrome is evolving, it is often difficult to accurately diagnose the specific epilepsy syndrome in a young child who presents with seizures. It is the clinical evolution of the seizure types and the EEG that helps the clinician make an accurate diagnosis. As more is known about the underlying pathophysiology for the various epilepsy syndromes, not only the clinical picture and EEG but also a genetic blood test will be used to accurately diagnose a specific epilepsy syndrome. A case in point would be severe myoclonic epilepsy of infancy (classically known as Dravet syndrome) and severe myoclonic epilepsy of infancy-borderland/ borderline, which are associated with specific mutations in the sodium ion channel gene SCN1A.

Magnetic resonance imaging abnormalities associated with vigabatrin in patients with epilepsy

PURPOSE

Vigabatrin used to treat infantile spasms (IS) has been associated with transient magnetic resonance imaging (MRI) abnormalities. We carried out a retrospective review to better characterize the frequency of those abnormalities in IS and in children and adults treated with vigabatrin for refractory complex partial seizures (CPS).

METHODS

Medical records and 332 cranial MRIs from 205 infants (aged <or=24 months) with IS treated at 10 sites in the United States and Canada were collected. Similarly, 2,074 images from 668 children (aged 2-16 years) and adults (aged >16 years) with CPS were re-reviewed. Prespecified MRI abnormalities were defined as any hyperintensity on T(2)-weighted or fluid-attenuated inversion-recovery (FLAIR) sequences with or without diffusion restriction not readily explained by a radiographically well-characterized pathology. MRIs were read by two neuroradiologists blinded to treatment group. The incidence and prevalence of MRI abnormalities associated with vigabatrin were estimated.

RESULTS

Among infants with IS, the prevalence of prespecified MRI abnormalities was significantly higher among vigabatrin-treated versus vigabatrin-naive subjects (22% vs. 4%; p < 0.001). Of nine subjects in the prevalence population with at least one subsequent determinate MRI, resolution of MRI abnormalities occurred in six (66.7%)-vigabatrin was discontinued in four. Among adults and children treated with vigabatrin for CPS, there was no statistically significant difference in the incidence or prevalence of prespecified MRI abnormalities between vigabatrin-exposed and vigabatrin-naive subjects.

DISCUSSION

Vigabatrin is associated with transient, asymptomatic MRI abnormalities in infants treated for IS. The majority of these MRI abnormalities resolved, even in subjects who remained on vigabatrin therapy.

Felbamate: Consensus of current clinical experience

An expert panel convened to evaluate data and review current clinical practices regarding the novel antiepileptic drug (AED) felbamate. Felbamate has demonstrated efficacy against a variety of refractory seizures types, including seizures associated with Lennox-Gastaut syndrome, but postmarketing experience revealed serious idiosyncratic adverse effects that were not observed during clinical trials. Although felbamate is not indicated as first-line antiepileptic therapy, its utility in treating seizures that are refractory to other AEDs is undisputed, as shown by the number of patients who continue to use it. New exposures to felbamate number approximately 3200-4200 patients annually, and it is estimated that over the past 10 years, approximately 35,000 new starts have occurred. Recommendations by the American Academy of Neurology and a review of felbamate literature were evaluated in conjunction with the clinical experience of the expert panel to determine current medical opinion and practice regarding felbamate. The past 10 years of clinical experience have demonstrated that when used in accordance with existing recommendations and close clinical monitoring, felbamate is an effective treatment for some patients with seizures refractory to other AEDs. This review of clinical data and discussion of the current understanding of the risk:benefit of felbamate therapy supports its use as an important therapeutic option for some patients with refractory epilepsy.

Antiepileptic drugs and hormonal contraceptives in adolescent women with epilepsy

Both estrogen and progesterone influence seizure activity in women with epilepsy, with estrogen generally demonstrating proconvulsant and progesterone anticonvulsant effects. Women with epilepsy exhibit a variety of endocrine disturbances, probably due to a combination of factors, including the epilepsy syndrome and the effect of interictal and ictal epileptic discharges in the brain. The direct effects of some antiepileptic drugs (AEDs) further increase this risk, apparently related to a specific drug's effect on hepatic microsomal enzymes of the cytochrome P-450 system. AEDs that induce hepatic microsomal enzymes also interact with hormonal contraception to increase estrogen's metabolism and progesterone's protein binding, decreasing concentrations of both hormones and thus reducing contraceptive efficacy. Some evidence indicates that concurrent use of hormonal contraceptives and lamotrigine significantly decreases the plasma concentration of lamotrigine, suggesting that close monitoring is warranted. Nevertheless, hormonal contraception confers comparable or superior efficacy compared with such other contraceptives as the intrauterine device and barrier methods and remains an appropriate option in women with epilepsy. Importantly, concurrent use of hormonal contraception and AEDs does not adversely affect seizure control. Careful patient management, including the use of increased estrogen doses (> or =50 microg) in patients receiving enzyme-inducing AEDs, may further minimize the risk for unintended pregnancy. Special considerations in women of childbearing age include decreased compliance and disease prevention. Although adequate seizure control is the critical requirement of an AED, the potential for interactions with hormonal contraception and the increased risk for endocrine disturbances caused by drugs that alter hepatic microsomal enzymes suggest additional potential advantages for AED treatment that does not affect these enzymes. Both the constellation of physicians treating women with epilepsy and the patients themselves have a poor understanding of the spectrum of reproductive health issues involved, and increased awareness is needed to improve patient management.

Neurodevelopmental outcomes of children born to mothers with epilepsy

Most children born to women with epilepsy are normal, but there is an increased risk of abnormal functional neurodevelopment in these children. Although there are many contributing factors, antiepileptic drugs (AEDs) may play a role. Most women with epilepsy must take AEDs during pregnancy because the potential for injury from seizures to both mother and fetus is a greater risk. AEDs are also used to treat other disorders, including depression and pain. Thus, an understanding of the effects of AEDs on the unborn child is relevant to physicians who treat nonepileptic mothers as well. This review discusses animal and human studies of the neurodevelopmental effects of AEDs and briefly reviews the possible mechanisms underlying these effects. Flaws in the methodology of some studies of these effects require that the results be interpreted cautiously and highlight the need for well-designed studies to explore this issue further.

Ketogenic diet: outpatient initiation, without fluid, or caloric restrictions

Although the ketogenic diet has been used for more than 80 years, the optimal methods of initiating the diet and its maintenance have not been clearly defined. This retrospective study was performed to review our experience with initiation of the ketogenic diet in the outpatient and inpatient settings and maintenance of the diet without fluid or caloric restriction. We analyzed 54 patients who had medically intractable epilepsy of whom 44% manifested some degree of mental retardation, 80% had multiple seizure types, and failed on average 4.8 antiepileptic drugs. Forty-four patients underwent induction of the ketogenic diet on an outpatient basis and 21 as inpatients. Three patients in each group were fasted at the initiation of the diet. No significant differences were observed with regard to seizure control in that 62% and 71% had greater than 50% improvement in the outpatient and inpatient groups, respectively. Both groups manifested improvement in alertness and social interaction. The efficacy of a ketogenic diet in the symptomatic epilepsies was confirmed, and benefit for medically refractory childhood absence epilepsy was documented. We conclude that a prospective, randomized trial is necessary to compare outpatient vs inpatient initiation of the ketogenic diet and the utility of fluid and caloric restriction.

Progressive myoclonic epilepsy

Progressive myoclonic epilepsies (PMEs) are a group of rare disorders characterized by the occurrence of seizures, myoclonus, and progressive neurological dysfunction. This article discusses epidemiology, genetics, pathology, clinical manifestations, EEG characteristics, methods of diagnosis and treatment of the most common causes of PME, including Unverricht-Lundborg Disease (Baltic Myoclonus), MERRF, neuronal ceroid lipofuscinosis, dentatorubropallidoluysan atrophy, Gaucher disease, Lafora disease, and sialidosis. The aim of this paper is to provide clinicians with useful clinical information in order to facilitate the diagnosis and treatment of these rare diseases.

Neonatal seizures

Neonatal seizures typically indicate significant underlying disease.They are poorly classified, under-recognized, and often difficult to treat. Recognition of etiology is often helpful in prognosis and treatment; the most common is hypoxic-ischemic encephalopathy. Patients generally have a poor prognosis, with most developing a severe encephalopathy and epilepsy. Studies suggest that neonatal seizures and their etiology have a significant impact on the developing brain; it is critical to recognize seizures early and initiate immediate antiepileptic therapy. Continuous computerized simultaneous video electroencephalograph monitoring is imperative;at-risk infants will frequently have electrographic seizures without clinical manifestations. Although there are antiepileptic therapies for neonatal seizures, they are ineffective in over 35% of cases. The goal of research should be the development of more effective therapies for neonatal seizures, regardless of etiology.

Infantile spasms

Infantile spasms is a catastrophic form of epilepsy found only in infants and young toddlers, with the peak incidence between 4 - 7 months of age. Estimated prevalence is 1 in 2000 - 6000 live births. There are many causes of infantile spasms, including tuberous sclerosis, hypoxic-ischaemic injury, congenital infectious diseases, inborn errors of metabolism, malformations of cortical development, genetic syndromes such as Aicardi's syndrome and chromosomal abnormalities. A small percentage of patients have idiopathic infantile spasms, with normal growth and development prior to the onset of infantile spasms and no known aetiology. Because of the poor prognosis of infantile spasms, treatment is usually aggressive and immediate, with the hopes of altering the natural history of the disease. The majority of patients with infantile spasms have a poor prognosis with intractable epilepsy, severe developmental delays and/or significant cognitive impairments. Of all patients with infantile spasms, 70 - 90% have mental retardation. Furthermore, 20 - 50% of patients with infantile spasms develop Lennox-Gastaut syndrome with multiple seizure types, cognitive impairments and a markedly abnormal electroencephalogram, arguably one of the most difficult epilepsy syndromes to treat. Infantile spasms are resistant to most of the standard antiepileptic drugs. Adrenocorticotropin hormone (ACTH) or oral steroids result in a significant reduction of seizures, as well as an improvement in the electroencephalogram. Some studies have indicated that infants treated with ACTH within the first month of onset have a more favourable prognosis. Vigabatrin has also been shown to be effective in the treatment, although it is not yet FDA-approved in the US. Valproate has also been used in the treatment of infantile spasms, with an efficacy of approximately 25 - 40%. However, in the very young infant, it does carry a high risk of fatal hepatotoxicity. Surgical resection may be the treatment of choice for those infants with focal cortical dysplasia and intractable infantile spasms. Emerging therapeutic possibilities include topiramate, felbamate, lamotrigine, zonisamide and perhaps levetiracetam. With the advancements in molecular biology, genetics and neuroimaging, there is the hope of novel therapies in the future.

Infantile Spasms

Infantile spasm is a catastrophic form of epilepsy found only in infants and young toddlers. Onset is before one year of age, with a peak incidence occurring between 4 to 7 months of age. The prevalence is difficult to calculate, but previous reviews have estimated between 1 per 2000 to 6000 live births. There are many causes of infantile spasms, including tuberous sclerosis, malformations of cortical development, hypoxic-ischemic injury, congenital infectious diseases, inborn errors of metabolism, genetic syndromes such as Aicardi's syndrome, and chromosomal abnormalities. A small percentage of patients have idiopathic infantile spasms, with no identifiable cause and premorbid normal growth and development. In order to prevent an ongoing epileptic encephalopathy with its concomitant consequences of cognitive impairment and intractable seizures, treatment should be aggressive and immediate. It is not enough to control the clinical infantile spasms. The underlying "interictal" hypsarrhythmia pattern must also be abolished if the prognosis is to be improved. Otherwise, the immature brain appears to remain hyperexcitable.

Alternating hemiplegia of childhood: clinical manifestations and long-term outcome

We present our analysis of 44 patients with alternating hemiplegia of childhood. The clinical course usually consisted of three phases. The first was dominated by abnormal eye movements and dystonic episodes, the second by hemiplegic spells and psychomotor regression, and the third by persistent developmental delay and fixed neurologic deficits. The age of onset was 0-54 months (mean = 7.9 +/- 13 months). The presenting signs included abnormal ocular movements in 65%, dystonia in 60%, and hemiplegia in 32%. Patients with an early onset of the disorder and an early appearance of hemiplegic spells faired the poorest developmentally. Developmental delay was present in 91%, ataxia in 68%, choreoathetosis in 50%, and seizures in 18%. Laboratory investigations suggested mitochondrial abnormalities and cerebrovascular dysfunction in several patients. Numerous therapies were largely ineffective. Flunarizine reduced the duration, severity, and frequency of the hemiplegic attacks in 78%. Patients who received flunarizine did not differ developmentally from those who did not. Our data suggest that flunarizine does not adversely affect and may favorably influence the outcome in patients with alternating hemiplegia of childhood. Additionally, the occurrence of autosomal-dominant cases of the syndrome, although rare, suggests that, in addition to mitochondrial dysfunction, genetic factors may be important.

Violent recurrent ballism associated with infections in two children with static encephalopathy

A variety of cerebral insults can result in static encephalopathy with developmental delays and relatively fixed motor and cognitive deficits. We describe two boys with static encephalopathy who experienced recurrent episodes of generalized, violent ballism seemingly provoked by relatively minor infectious illnesses or surgical procedures. These episodes first began at ages 14 and 9 years, respectively. The baseline clinical states included relatively mild choreoathetosis plus cognitive impairment, as well as spasticity and/or ataxia. These episodes of ballism developed over hours, remained for weeks, and ultimately returned to baseline. Neuroleptics, anticonvulsants, and benzodiazepines were only partially beneficial; responses corresponded to the degree of sedation. Potential for self-injury or rhabdomyolysis/myoglobinuria led to the use of general anesthetics or neuromuscular blocking agents during selected episodes. Blood, urine, and cerebrospinal fluid studies, magnetic resonance imaging head scans, and electroencephalography revealed no diagnostic clues as to the precise causative factor precipitating these episodes.

Long-term seizure outcome in 74 patients with Lennox-Gastaut syndrome: effects of incorporating MRI head imaging in defining the cryptogenic subgroup

PURPOSE

To determine if using more stringent criteria for cryptogenic Lennox-Gastaut syndrome (LGS) would result in an improved prognosis for that group. Cryptogenic, symptomatic, and non-cryptogenic LGS patients without etiology (indeterminate) were compared with respect to seizure and cognitive outcome.

METHODS

Retrospective chart review was performed on 245 patients seen at the Mayo Clinic Rochester from 1976 to 1997, with a diagnosis of either LGS or slow spike wave on EEG. LGS was confirmed in 107 (64 male, 43 female) patients. This group was divided into cryptogenic, symptomatic, and indeterminate groups containing 23, 47, and 37 patients, respectively. In this study, cryptogenic patients all had normal development before onset of LGS, absence of dysmorphic features, normal neurologic examination, and normal magnetic resonance (MRI) brain imaging. Of the 107 patients, 74 had >/=3 years of follow-up.

RESULTS

LGS onset in the 107 patients occurred at a median age of 4.0 years (range, 0.6-28.9 years). When last seen, 63% of those with symptomatic LGS had more than three seizures a day compared with 50% of cryptogenic and 34% of indeterminate patients. The most common seizure types were tonic (77%), atypical absence (61%), and generalized tonic-clonic (56%). Only three patients, all part of the indeterminate group, were seizure free at last follow-up.

CONCLUSIONS

Using stringent criteria in defining the cryptogenic subgroup resulted in no significant difference in seizure outcome. Individuals with a normal cognitive outcome did not segregate into one etiologic subgroup, but did have LGS onset at an older age.

Unusual presentation and MRI findings in Rasmussen's syndrome

Rasmussen's syndrome is a chronic disorder characterized by uncontrollable focal seizures and eventually epilepsia partialis continua, ipsilateral hemiparesis, developmental arrest, and cerebral inflammation. Viral and autoimmune etiologies have been postulated. A patient is presented who illustrates the wide variability of clinical and radiographic presentations in this disorder. The patient is an 8-year-old female who developed intermittent facial twitching at 2 years of age that eventually progressed to epilepsia partialis continua. Electroencephalography demonstrated clinical seizures that emanated from the right parasagittal area. Cranial magnetic resonance imaging revealed pronounced atrophy of the right caudate nucleus, globus pallidus, and putamen, with mild increased T2-weighted signal in the right striatum, without accompanying cortical atrophy. Ictal single-photon emission computed tomography revealed markedly reduced uptake in the right hemisphere that was maximum in the right basal ganglia. Cerebrospinal fluid, blood, and urine collected for metabolic and immunologic screening and DNA testing for a wide variety of disorders were all unremarkable. Neuropsychologic testing demonstrated difficulties in memory, attention, and calculation. Brain biopsy revealed mild microglial activation, rare glial nodules, and collections of lymphocytes and histiocytes, consistent with the clinical diagnosis of Rasmussen's syndrome. After a modified hemispherectomy, she demonstrated marked clinical improvement.

The practical utility of performing peri-ictal SPECT in the evaluation of children with partial epilepsy

Peri-ictal brain single-photon emission computed tomography (SPECT) is increasingly being established as a useful test in localizing partial epilepsy in adults. However, obtaining an ictal injection and acquiring the SPECT images poses a greater challenge in pediatric patients, and few reports have specifically addressed the practical use of this technique in children. The Mayo Clinic experience of peri-ictal SPECT in the evaluation of children with partial epilepsy is reported here. Peri-ictal SPECT was attempted during 71 admissions involving 59 patients (median age 12 years, range 1 year 6 months-17 years). A peri-ictal SPECT injection was performed on 48 (67.6%) of these admissions in 43 (72.9%) patients, and only two patients could not be scanned. Of the 46 peri-ictal images successfully obtained, 30 (65.2%) were from ictal injection and 16 (34.8%) from post-ictal injections. Forty-two (91.3%) of the successfully obtained SPECT images, in 38 patients (92.3%), were classified as localizing (15 temporal, 24 extratemporal). We conclude that, with the appropriate unit setup and well-trained staff, peri-ictal SPECT scans can be obtained in most pediatric partial epilepsy patients. Moreover, the procedure provides specific localizing information in a high proportion of these patients.

Neuroimaging in the evaluation of children and adolescents with intractable epilepsy: II. Neuroimaging and pediatric epilepsy surgery

The costs of epilepsy encompass all aspects of life, including medical, educational, and psychosocial. Adults with intractable epilepsy who undergo epilepsy surgery and have seizure-free outcomes still have significant barriers in the attainment of improved quality of life. For this reason, there is increasing interest in the recognition of children and adolescents with intractable epilepsy who might be epilepsy surgery candidates. This is Part II of an article on the role of neuroimaging in the evaluation of children and adolescents with intractable epilepsy. Part I addressed the role of MRI in detecting the substrates of epilepsy (Pediatr Neurol 1997;17: 19-26); Part II elaborates on the selection process of pediatric patients who might benefit from epilepsy surgery. Although EEG remains the cornerstone of the evaluation process, MRI, SPECT, and PET can play a pivotal role in the identification of the underlying epileptogenic focus and minimize the need for invasive EEG monitoring. Magnetic resonance spectroscopy and magnetoencephalography are also innovative, noninvasive techniques which may aid in the localization of the epileptogenic focus. Functional MRI scans may soon replace invasive technologies in the identification of eloquent cortex that should not be a part of the surgical resection.

Neuroimaging in the evaluation of children and adolescents with intractable epilepsy: I. Magnetic resonance imaging and the substrates of epilepsy

Recent advances in neuroimaging, particularly the magnetic resonance imaging (MRI) scan, have greatly enhanced our ability to visualize intraparenchymal anatomy. With the linkage between intracranial pathology and epilepsy now clearly established, the MRI data provides detailed information for the clinician treating patients with epilepsy. This article supplies the reader with an overview of the new techniques in MRI brain imaging that allow us to identify intracranial abnormalities, and a survey of some of the MRI-identified substrates of epilepsy.

Update on epilepsy in pediatric patients

Epilepsy is a common condition that affects 0.5 to 1% of all children. Although most children with epilepsy have well-controlled seizures with use of one antiepileptic drug (AED), some children have medically refractory seizures. This situation can be the result of inaccurate classification of the paroxysmal event, use of an inappropriate AED, of a truly medically refractory seizure disorder. Paramount to the initial assessment of a child with presumed epilepsy is the appropriate classification of the paroxysmal event. Several nonepileptic conditions, such as motor tics or breath-holding spells, can cause paroxysmal abnormalities in children, which can be confused with epilepsy. The common pediatric epileptic and nonepileptic conditions are reviewed, and the standard and new AEDs and their side effects are discussed. When a child's seizure disorder is intractable despite adequate trials of AEDs, surgical treatment is increasingly becoming an effective option. Such procedures should ideally be performed at centers with extensive experience in this area and with a multidisciplinary team approach. With improved magnetic resonance imaging technology, increasing numbers of children with medically intractable localization-related epilepsy are being found to have underlying focal cortical dysplasia, tumors, or hippocampal atrophy. These abnormalities can often be surgically resected with excellent results. A generalized epilepsy may also be remediable with surgical treatment. Specifically, preliminary data suggest that infantile spasms, when triggered by an underlying focal cortical dysplasia, may be effectively treated by surgical resection. Patients with certain catastrophic seizure disorders, such as Sturge-Weber syndrome or hemimegalencephaly, require prompt intervention with hemispherectomy. The presurgical evaluation relies heavily on the magnetic resonance imaging, positron emission tomography, and single-photon emission computed tomography scan data as well as the electroencephalogram in identifying the area of epileptogenic abnormality.

Routine EEG and temporal lobe epilepsy: relation to long-term EEG monitoring, quantitative MRI, and operative outcome

PURPOSE

To investigate the relation among routine EEG, long-term EEG monitoring (LTM), quantitative magnetic resonance imaging (MRI), and surgical outcome in temporal lobe epilepsy (TLE).

METHODS

We evaluated 159 patients with intractable TLE who underwent an anterior temporal lobectomy between 1988 and 1993. The epileptogenic temporal lobe was determined by ictal LTM. A single awake-sleep outpatient EEG with standard activating procedures was performed before LTM. EEGs were analyzed by a blinded investigator.

RESULTS

MRI scans showed unilateral medial temporal atrophy (109 patients) or symmetrical hippocampal volumes (50 patients). The surgically excised epileptogenic brain tissue revealed mesial temporal sclerosis, gliosis, or no histopathologic alteration. Routine EEG revealed temporal lobe epileptiform discharges in 123 patients. Routine EEG findings correlated with the temporal lobe of seizure origin (p < 0.0001) and the results of MRI volumetric studies (p < 0.0001). Interictal epileptiform discharges were seen only during LTM in 24 patients. Routine EEG was disconcordant with interictal LTM in another 20 patients. MRI-identified unilateral medial temporal lobe atrophy was a strong predictor of operative success (p < 0.0001). There was no significant relation between the routine EEG findings and operative outcome (p > 0.20).

CONCLUSIONS

Results of this study modified our approach in patients with TLE. Interictal epileptiform discharges localized to one temporal lobe on serial routine EEGs or during LTM may be adequate to identify the epileptogenic zone in patients with MRI-identified unilateral medial temporal lobe atrophy.

Potential pharmacokinetic interaction between felbamate and phenobarbital

OBJECTIVE

To report a case of a potential pharmacokinetic interaction between felbamate and phenobarbital in a patient with epilepsy.

CASE SUMMARY

A patient with a history of a mixed seizure disorder and static encephalopathy who was receiving sodium valproate 750 mg/d and phenobarbital 230 mg/d was initiated on felbamate (as part of a compassionate use program). Upon instituting felbamate, valproate dosage was reduced to 500 mg/d and phenobarbital to 200 mg/d. Felbamate dosage was titrated to approximately 50 mg/kg/d over three weeks. In this patient, plasma phenobarbital concentrations increased from 48 micrograms/mL to 68 micrograms/mL, at which point the patient was hospitalized because of clinically significant neurotoxicity. Phenobarbital dosage was subsequently reduced to 150 mg/d; this resulted in phenobarbital trough concentrations of 60 micrograms/mL.

CONCLUSIONS

Felbamate has been shown previously to interact with multiple other anticonvulsant medications, including valproate, phenytoin, and carbamazepine. Felbamate appears to decrease the clearance of valproate, phenytoin, and carbamazepine epoxide to a significant extent, an effect that may be the result of inhibition of the metabolism of these compounds. Carbamazepine plasma concentrations have been demonstrated to decrease following administration of felbamate, suggesting metabolic induction. It is reasonable to suggest that based on these findings and the observations in our patient, felbamate comedication may result in clinically significant increases in plasma phenobarbital concentrations. It would seem prudent, therefore, when initiating or adjusting felbamate therapy in patients receiving this drug combination, to monitor phenobarbital plasma concentrations.

Deletion of mitochondrial DNA in patients with combined features of Kearns-Sayre and MELAS syndromes

A 9-year-old girl and an 11-year-old boy had ptosis, progressive external ophthalmoplegia, pigmentary retinopathy, and sensorineural hearing loss. The girl had diabetes mellitus and the boy had hypoparathyroidism. Both children also developed recurrent vomiting and cerebral infarcts with lactic acidosis. Muscle biopsy specimens showed ragged-red fibers and Southern analysis demonstrated a distinct heteroplasmic deletion of muscle mitochondrial DNA in each patient but no evidence of the point mutation in the transfer RNALeu(UUR) gene recently identified in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). These 2 children had combined features of Kearns-Sayre syndrome and MELAS, suggesting that mitochondrial DNA deletions occasionally can have pleomorphic clinical expression.

123I-iodoamphetamine SPECT brain imaging in alternating hemiplegia

Alternating hemiplegia of childhood is an unusual disorder characterized by early onset (occurring before 18 months of age); repeated attacks of hemiplegia involving both sides of the body; other paroxysmal phenomena, such as tonic stiffening, dystonic posturing, choreoathetoid movements, ocular motor abnormalities, and autonomic disturbances, in association with bouts of hemiplegia or occurring independently; and evidence of mental or neurologic deficits. A girl was examined because of left hemiplegia at the age of 16 months. The patient had begun exhibiting episodes of alternating hemiplegia at approximately 4 months of age. They consisted of tonic stiffening and dystonia of the right or left extremities, lasting from 30 min to several hours and followed by residual hemiparesis. They were invariably accompanied by ocular motor abnormalities. Magnetic resonance imaging, computed tomography, and angiography all were normal. Single proton emission computed tomography brain images during an acute episode of right hemiplegia demonstrated hypoperfusion of the left cerebral hemisphere. Following improvement of the hemiplegia, the patient was re-evaluated. The uptake of the radiotracer in the left hemisphere was increased. The scan did not demonstrate significant asymmetry in cerebral perfusion.

Rasmussen encephalitis: epilepsia partialis continua secondary to chronic encephalitis

Rasmussen encephalitis is a disease consisting of chronic encephalitis with progressive neurologic deficits and focal intractable seizure activity. The etiology is unknown, but pathologic specimens revealed changes consistent with viral encephalitis. Even though neuro-imaging techniques, such as positron emission tomography and magnetic resonance imaging, offer the prospect of specific, presurgical diagnostic criteria, the initial diagnosis usually is made on a clinical basis. Treatment modalities, including a wide variety of antiepileptic drug therapies and surgical interventions, may result in significant physical and mental impairments. We summarize the clinical presentation, diagnostic considerations, and different treatment protocols in a patient with this rare and debilitating disorder.

Osmiophilic deposits in cytosomes in Hallervorden-Spatz syndrome

A young child with Hallervorden-Spatz syndrome is presented. She was well until 8 years of age when she lost interest in activities and her school performance declined. At age 11 years, she began having episodes of blepharospasm, accompanied by bilateral ptosis and occasional episodes of oculogyric crisis. By age 12 years, her motor coordination had declined and she began to exhibit evidence of dementia, dystonia, dysarthria, and tremor. Motor incoordination, dystonia, and tremor progressed until the patient was wheel-chair-bound. Multiple tests were performed, including metabolic studies, magnetic resonance imaging, bone marrow biopsy, and electron microscopy of the buffy coat. Both bone marrow and buffy coat revealed inclusions in the cytosomes which were granular and osmiophilic. To our knowledge, this is the third case report of inclusion bodies found in patients with manifestations of Hallervorden-Spatz syndrome. These findings suggest that obtaining a buffy coat and bone marrow biopsy may aid in the diagnosis of Hallervorden-Spatz syndrome and ultimately provide information regarding etiology.