The electroencephalogram in neonatal maple syrup urine disease: a case report

Untreated maple syrup urine disease (MSUD) leads to encephalopathy in neonates and causes abnormalities on the electroencephalogram (EEG). A case is presented of MSUD with unique features consisting of a comb-like rhythm before the therapy and its disappearance with therapy is presented. This case illustrates the potential use of the EEG in the identification of this specific cause of a neonatal encephalopathy.

Update on the newer antiepileptic drugs in child neurology: advances in treatment of pediatric epilepsy

The goal of epilepsy treatment is the prevention of recurrent seizures, and antiepileptic drugs (AEDs) are the mainstay. Uncontrolled seizures may cause medical, developmental, and psychologic disturbances. Treatment advances include 1) identification of the basic mechanisms of epilepsy and action of AEDs, 2) the introduction of many new AEDs, and 3) the use of neurostimulation, starting with vagus nerve stimulation. We must balance the efficacy of an AED versus its side effects, which if persistent, lead to patient discontinuation of the AED. Although all AEDs have a proven efficacy, they are differentiated by their efficacy for a given seizure type or epilepsy syndrome versus the side effects or tolerability. The many new AEDs give us a larger armamentarium for epilepsy treatment. We refer to studies and expert opinion consensus.

Education of the child neurologist: pediatric neurocritical care

Neurocritical care (NCC) is now an essential field in child neurology that requires dedicated training. NCC applies the basic principles of neuroresuscitation to all situations, integrates this with modern technology. and emphasizes that brain protection is not limited to the intensive care unit. We outline the essential competencies needed and how to obtain these.

Intraoperative monitoring of motor evoked potentials in very young children

OBJECT

Neurophysiological monitoring of motor evoked potentials (MEPs) during complex spine procedures may reduce the risk of injury by providing feedback to the operating surgeon. While this tool is a well-established surgical adjunct in adults, clinical data in children are sparse. The purpose of this study was to determine the reliability and safety of MEP monitoring in a group of children younger than 3 years of age undergoing neurosurgical spine procedures.

METHODS

A total of 10 consecutive spinal procedures in 10 children younger than 3 years of age (range 5-31 months, mean 16.8 months) were analyzed between January 1, 2008, and May 1, 2010. Motor evoked potentials were elicited by transcranial electric stimulation. A standardized anesthesia protocol for monitoring consisted of a titrated propofol drip combined with bolus dosing of fentanyl or sufentanil.

RESULTS

Motor evoked potentials were documented at the beginning and end of the procedure in all 10 patients. A mean baseline stimulation threshold of 533 ± 124 V (range 321-746 V) was used. Six patients maintained MEP signals ≥ 50% of baseline amplitude throughout the surgery. There was a greater than 50% decrease in intraoperative MEP amplitude in at least 1 extremity in 4 patients. Two of these patients returned to baseline status by the end of the case. Two patients had a persistent decrement or variability in MEP signals at the end of the procedure; this correlated with postoperative weakness. There were no complications related to the technique of monitoring MEPs.

CONCLUSIONS

A transcranial electric stimulation protocol monitoring corticospinal motor pathways during neurosurgical procedures in children younger than 3 years of age was reliably and safely implemented. A persistent intraoperative decrease of greater than 50% in this small series of 10 pediatric patients younger than 3 years of age predicted a postoperative neurological deficit. The authors advocate routine monitoring of MEPs in this pediatric age group undergoing neurosurgical spine procedures.

Seizure detection using digital trend analysis: Factors affecting utility

BACKGROUND

EEG monitoring is important for the early detection of seizures during the course of critical illness. However, the logistics of real time EEG interpretation is challenging for the neurophysiology and critical care medicine teams. This study evaluated factors affecting the utility of digital trend analysis (DTA) for rapid seizure identification in children.

METHODS

digital EEG files of seizures in critically ill children were retrieved for DTA. The envelop trend (ET) and compressed spectral array (CSA) were applied to the raw EEG data and presented to an experienced and inexperienced user for interpretation who were blinded to conventional EEG findings. The EEG findings with and without presence of seizures and features of seizures were analyzed.

RESULTS

we found that a number of factors affected accurate seizure detection including factors related to interpreter's experiences, display size and type of DTA methods used for analysis in addition to baseline EEG findings. ET was more dependent on user experience, furthermore, display size and multimodal DTA application (CSA and ET combined) increased the sensitivity of seizure detection for the experienced user compared to inexperience users. The artifacts were reported as seizures regardless of experience without presence of conventional EEG recording. The maximum spike amplitude, seizure duration, and seizure frequency were other important determinants for accuracy. Electrographic seizures with shorter duration were better detected by ET, and the maximum spike amplitude was important for both the ET and CSA. Repetitive seizures are readily detected by both digital trending methods. Artifacts may be reported as seizures regardless of experience if conventional EEG recording is not available for the interpretation.

CONCLUSION

DTA applied to the raw EEG data does produce a graphic display that facilitates identification of seizures. The actual characteristics of the electrographic seizure may predict which DTA method is better and the overall accuracy of seizure detection may increase when multimodal trending is used simultaneously. Application of DTA alone with display of conventional EEG is beneficial for rapid interpretation of EEG findings regardless of experience.

Neuropathology of a fatal case of posterior reversible encephalopathy syndrome

The pathology of posterior reversible encephalopathy syndrome (PRES) is undefined, since it is rarely fatal and is biopsied in only exceptional circumstances. We describe rapidly progressive PRES following stem cell transplant for acute lymphoblastic leukemia. After development of altered mental status, this 8-year-old girl had T2 prolongation of the white matter in a posterior-dominant distribution, eventually developing cerebellar edema, hemorrhage, hydrocephalus, and herniation. Despite surgical and medical management, she died 36 hours later. At autopsy, the occipital and cerebellar white matter and focal occipital cortical gray matter showed a spectrum of microvascular changes, including dilated perivascular spaces containing proteinaceous exudates and macrophages, as well as fibrinoid necrosis and acute hemorrhage, in a distribution corresponding to the neuroimaging abnormalities and reminiscent of those seen in patients with acute hypertensive encephalopathy. Of note, similar microvascular changes were not seen in the kidney or other systemic sites. Thus, the findings indicate a brain-specific microvascular compromise as the substrate of PRES, at least in the rare instance of cases progressing to fatal outcome.

In-session seizures during low-frequency repetitive transcranial magnetic stimulation in patients with epilepsy

Low-frequency repetitive transcranial magnetic stimulation (rTMS) is emerging as a therapeutic tool for patients with intractable epilepsy. Although seizures during treatment have been reported as adverse events in some patients, the nature and severity of seizures that may be provoked by low-frequency rTMS in patients with epilepsy have not been extensively studied. Accordingly, this article documents seizures in patients (n=5) with intractable epilepsy and average seizure frequency greater than one per day who underwent 1-Hz rTMS for seizure suppression. We report three observations in the present case series: (1) in each instance the in-session seizure was typical in semiology to the patient's habitual seizures, (2) the duration of each documented seizure was either the same as or shorter than the patients' baseline seizures, and (3) the overall neurological outcome on follow-up was not affected by the in-session seizures. More data will be required for valid conclusions with respect to safety and tolerability of low-frequency rTMS in patients with epilepsy, but it is noteworthy from our perspective that seizures during rTMS in this series were similar to the patients' habitual seizures, occurred in patients with epilepsy with baseline seizure frequency exceeding one per day, and did not correlate with a poor neurological outcome or with absence of clinical response to rTMS.

Seizure suppression by EEG-guided repetitive transcranial magnetic stimulation in the rat

OBJECTIVE

To test the anticonvulsive potential of a range of repetitive transcranial magnetic stimulation (rTMS) frequencies by novel methods for simultaneous EEG and rTMS in a rat seizure model.

METHODS

Seizures were triggered by intraperitoneal kainic acid (KA; 10mg/kg). Rats (n=21) were divided into three groups in which individual seizures were treated with rTMS trains at one of three frequencies: 0.25, 0.5 or 0.75 Hz. EEG was continuously viewed by an operator who identified each seizure onset. Consecutive seizures in each animal were (1) treated with active rTMS, (2) treated with sham rTMS, or (3) were untreated. EEG was re-analyzed post hoc by visual inspection, and seizure durations were compared within and between treatment groups.

RESULTS

KA-induced seizures were abbreviated by 0.75 Hz (P=0.019) and 0.5 Hz (P=0.033) active EEG-guided rTMS. In contrast, neither active 0.25 Hz rTMS nor the control conditions affected seizure duration (P>0.2).

CONCLUSIONS

We demonstrate that EEG-guided rTMS can suppress seizures in the rat KA epilepsy model, and that the effect is frequency dependent, with 0.75 and 0.5 Hz rTMS being superior to 0.25 Hz rTMS.

SIGNIFICANCE

These data support the use of rat seizure models in translational research aimed at evaluation and development of effective rTMS anticonvulsive protocols. We also offer a proof of principle that real-time analysis of EEG can be used to guide rTMS to suppress individual seizures.

Oxcarbazepine in children with nocturnal frontal-lobe epilepsy

Nocturnal frontal-lobe epilepsy is characterized by paroxysmal arousals, motor seizures with dystonic or hyperkinetic features, and episodic nocturnal wanderings. Carbamazepine is effective for seizure control in some of these patients, but seizures may be refractory to multiple antiepileptic drugs. We report on eight children between ages 4-16 years with nocturnal frontal-lobe epilepsy who had a dramatic response to oxcarbazepine at standard recommended doses, some of whom were refractory to previous antiepileptic medications. Brain magnetic resonance imaging, routine electroencephalogram, and prolonged, continuous video-electroencephalogram telemetry were performed in all children. Nocturnal frontal-lobe epilepsy was diagnosed by demonstrating ictal electroencephalogram changes originating from the frontal lobes. The children were followed for response of seizures to oxcarbazepine, side effects, and routine blood tests, including serum 10-monohydroxide derivative levels. The mean oxcarbazepine dose was 30.4 mg/kg/day +/- 11.7 (mean +/- SD); the mean 10-monohydroxide level was 23.1 microg/mL +/- 8.6 (mean +/- SD). Seizures improved within 4 days of oxcarbazepine initiation in six children, whereas two children required higher doses. Their follow-up has ranged from 12 to 24 months, without seizure recurrence or serious side effects. Our patients demonstrate the efficacy of oxcarbazepine for nocturnal hyperkinetic seizures in children with nocturnal frontal-lobe epilepsy.

Safety and tolerability of repetitive transcranial magnetic stimulation in patients with epilepsy: a review of the literature

Repetitive transcranial magnetic stimulation (rTMS) is emerging as a new therapeutic tool in epilepsy, where it can be used to suppress seizures or treat comorbid conditions such as mood disorder. However, as rTMS carries a risk of inducing seizures among other adverse events, its safety and tolerability in the population with epilepsy warrant distinct consideration, as this group is especially seizure-prone. Accordingly, we performed a review of the literature to estimate the risk of seizures and other adverse events associated with rTMS in patients with epilepsy. We performed an English-language literature search, and reviewed all studies published from January 1990 to February 2007 in which patients with epilepsy were treated with rTMS, and complemented the literature search with personal correspondence with authors when necessary. We identified 30 publications that described patients with epilepsy who underwent rTMS, and noted total number of relevant subjects, medication usage, incidence of adverse events, and rTMS parameters including stimulus frequency, number of stimuli, train duration, intertrain interval, coil type, and stimulation sites. The data were analyzed for adverse events related to rTMS. Crude per-subject risk, as well as per-subject mean risk weighted by sample size and risk per 1000 stimuli weighted by number of stimuli in each study, were computed for seizures and for other adverse events. Adverse events or lack thereof was reported in 26 studies (n=280 subjects). Adverse events attributed to rTMS were generally mild and occurred in 17.1% of subjects. Headache was most common, occurring in 9.6%. The most serious adverse event was seizure during treatment, which occurred in four patients (1.4% crude per-subject risk). All but one case were the patients' typical seizures with respect to duration and semiology, and were associated with low-frequency rTMS. A single case of an atypical seizure appearing to arise from the region of stimulation during high-frequency rTMS is reported. No rTMS-related episodes of status epilepticus were reported. We cautiously conclude that the risk of seizure in patients with epilepsy undergoing rTMS is small, and the risk of other mild adverse events is comparable to that seen when rTMS is used to treat other diseases. Status epilepticus or life-threatening seizures have not been reported in patients undergoing rTMS treatment. rTMS thus appears to be nearly as safe in patients with epilepsy as in nonepileptic individuals, and warrants further investigation as a therapy in this population.

Focal cortical malformations can show asymmetrically higher uptake on interictal fluorine-18 fluorodeoxyglucose positron emission tomography (PET)

Interictal fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a component of the presurgical evaluation of patients with medically intractable epilepsy, including patients with malformations of cortical development. The authors describe 3 cases of focal cortical malformations that displayed asymmetrically higher uptake on FDG-PET performed in the interictal state in patients undergoing evaluation for possible focal resection for refractory localization-related epilepsy. The evaluation included routine and prolonged video electroencephalography (EEG), magnetic resonance imaging (MRI), interictal FDG-PET with concurrent EEG, and single-photon emission computed tomography (SPECT). All 3 patients had focal cortical malformations on MRI corresponding to regions of asymmetrically higher uptake on FDG-PET. EEG confirmed that the FDG-PET studies were performed in the interictal state. The lesions included a large region of subcortical heterotopia in the right frontal lobe, a left temporal lobe dysplasia, and a region of subcortical heterotopia in the right occipital lobe. In both patients with subcortical heterotopia, there were other focal regions of cortical malformation that were not associated with abnormal or asymmetric uptake on FDG-PET. Previous reports describe decreased uptake on interictal PET in most cases of focal cortical malformations. Normal to increased uptake has been reported with band heterotopia. The authors demonstrate that other types of focal malformations of cortical development, including focal subcortical heterotopia and lobar dysplasia, can be associated with asymmetrically higher uptake on interictal FDG-PET.

Practice parameter: diagnostic assessment of the child with status epilepticus (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society

OBJECTIVE

To review evidence on the assessment of the child with status epilepticus (SE).

METHODS

Relevant literature were reviewed, abstracted, and classified. When data were missing, a minimum diagnostic yield was calculated. Recommendations were based on a four-tiered scheme of evidence classification.

RESULTS

Laboratory studies (Na(++) or other electrolytes, Ca(++), glucose) were abnormal in approximately 6% and are generally ordered as routine practice. When blood or spinal fluid cultures were done on these children, blood cultures were abnormal in at least 2.5% and a CNS infection was found in at least 12.8%. When antiepileptic drug (AED) levels were ordered in known epileptic children already taking AEDs, the levels were low in 32%. A total of 3.6% of children had evidence of ingestion. When studies for inborn errors of metabolism were done, an abnormality was found in 4.2%. Epileptiform abnormalities occurred in 43% of EEGs of children with SE and helped determine the nature and location of precipitating electroconvulsive events (8% generalized, 16% focal, and 19% both). Abnormalities on neuroimaging studies that may explain the etiology of SE were found in at least 8% of children.

RECOMMENDATIONS

Although common clinical practice is that blood cultures and lumbar puncture are obtained if there is a clinical suspicion of a systemic or CNS infection, there are insufficient data to support or refute recommendations as to whether blood cultures or lumbar puncture should be done on a routine basis in children in whom there is no clinical suspicion of a systemic or CNS infection (Level U). AED levels should be considered when a child with treated epilepsy develops SE (Level B). Toxicology studies and metabolic studies for inborn errors of metabolism may be considered in children with SE when there are clinical indicators for concern or when the initial evaluation reveals no etiology (Level C). An EEG may be considered in a child with SE as it may be helpful in determining whether there are focal or generalized epileptiform abnormalities that may guide further testing for the etiology of SE, when there is a suspicion of pseudostatus epilepticus (nonepileptic SE), or nonconvulsive SE, and may guide treatment (Level C). Neuroimaging may be considered after the child with SE has been stabilized if there are clinical indications or if the etiology is unknown (Level C). There is insufficient evidence to support or refute routine neuroimaging in a child presenting with SE (Level U).

Brain-derived neurotrophic factor and autoantibodies to neural antigens in sera of children with autistic spectrum disorders, Landau-Kleffner syndrome, and epilepsy

BACKGROUND

Brain derived neurotrophic factor (BDNF) elevation in newborn sera predicts intellectual/social developmental abnormalities. Other autoantibodies (AAs) to endothelial cells (ECs) and myelin basic protein (MBP) are also elevated in some children. We tested relationships between BDNF, BDNF AAs, and other AAs in children with these disorders.

METHODS

BDNF levels and IgG/IgM autoantibodies to BDNF, ECs, MBP, and histones were measured in children with autism, childhood disintegrative disorder (CDD), pervasive developmental delay-not otherwise specified (PDD-nos), acquired epilepsy, Landau-Kleffner syndrome (LKS); healthy children (HC), and children with non-neurological illnesses (NNI).

RESULTS

Mean BDNF levels were elevated in children with autism and CDD, (p < or = 0.0002) compared to HC or NNI. Mean IgG and IgM BDNF AAs were elevated in children with autism, CDD and epilepsy (p < or = 0.0005) compared to HC but not to NNI. Mean IgM AA EC titers detected by immunocytochemistry were higher in autism, PDD-NOS, epilepsy, and LKS (p < or = 0.005) compared to HC and NNI. While mean ELISA IgG EC AAs were higher in autism and PPD-NOS (p < 0.005) compared to HC but not NNI, ELISA IgM EC AAs were higher in children with autism, CDD, PDD-NOS, and epilepsy compared to both HC and NNI (p < 0.0005). Mean anti-MBP IgG and IgM titers were higher in all study groups (p < 0.005) except for LKS compared to both HC and NNI.

CONCLUSION

Children with developmental disorders and epilepsy have higher AAs to several neural antigens compared to controls. The presence of both BDNF AAs and elevated BDNF levels in some children with autism and CDD suggests a previously unrecognized interaction between the immune system and BDNF.

A distinct asymmetrical pattern of cortical malformation: large unilateral malformation of cortical development with contralateral periventricular nodular heterotopia in three pediatric cases

PURPOSE

To describe a distinct asymmetrical pattern of cortical malformation with large focal malformations of cortical development (MCDs) and contralateral periventricular nodular heterotopia (PNH).

METHODS

We identified three patients with epilepsy and focal EEG abnormalities. Each patient underwent 1.5-Tesla magnetic resonance imaging (MRI) to obtain sagittal T1-weighted, axial fluid-attenuated inversion recovery (FLAIR), fast spin-echo (FSE) T2-weighted, and coronal fast spin-echo inversion recovery (FSEIR) T2-weighted images; coronal spoiled gradient recalled (SPGR) T1-weighted images were obtained in two cases.

RESULTS

Patient 1, an 18-year-old right-handed man, had a 4-year history of intractable seizures. MRI revealed a right frontal subcortical heterotopia (SH) and a single left anterior PNH. Patient 2, a 10-year-old left-handed boy, had a 4-year history of epilepsy. MRI revealed a large region of SH in the left temporal, parietal, and occipital lobes and three right-sided PNH. Patient 3, a 16-month-old girl, had medically refractory infantile spasms. MRI revealed a large MCD in the left parietal lobe with contiguous underlying periventricular heterotopia as well as a small contralateral PNH.

CONCLUSIONS

These cases together illustrate a distinct asymmetrical pattern of a large focal MCD with small contralateral PNH. The asymmetrical involvement of the two hemispheres suggests that the stage of maximal disruption of cortical development may differ between the two hemispheres. Further study into the mechanisms underlying such asymmetrical patterns of cortical malformation should enhance our understanding of cortical development as well as hemispheric lateralization.

Bilateral volume reduction of the superior temporal areas in Landau-Kleffner syndrome

No specific anatomic abnormalities have been detected in typical Landau-Kleffner syndrome (LKS), an acquired epileptic aphasia with language regression in children. In four children with typical LKS without obvious anatomic abnormalities, the authors performed MRI volumetric analysis of various neocortical regions and subcortical substructures. Volume reduction was detected in bilateral superior temporal areas (26 to 51%), specifically in planum temporale (25 to 63%) and superior temporal gyrus (25 to 57%), where receptive language is localized.

Electroencephalographic correlate of juvenile Huntington's disease

The spectrum of clinical disease in juvenile Huntington's disease differs from that seen in adults. Younger patients often present with seizures, dystonia and rigidity. The mechanism and type of seizures, timing of onset and electrographic features have not been well characterized in either adults or children. We describe the electroencephalographic findings observed in a young child with Huntington's disease who presented with motor regression and seizures. Recordings demonstrated bilateral posterior quadrant epileptiform discharges and occipital intermittent rhythmic delta activity, generally considered a nonspecific abnormality. These findings have not been reported in adult or juvenile Huntington's disease. Its presence in proximity to bilateral posterior spikes suggests that occipital intermittent rhythmic delta activity is an epileptiform abnormality, on a continuum with the posterior spike-and-wave discharges. Intermittent rhythmic delta activity can occur secondary to either the subcortical gray-matter disease or the associated seizure disorder. Huntington's disease should be considered in the differential diagnosis of young children who present with seizures and developmental regression.

The treatment of status epilepticus

Status epilepticus (SE) is a life-threatening emergency that requires prompt treatment, including basic neuroresuscitation principles (the ABCs), antiepileptic drugs to stop the seizure, and identification of etiology. Symptomatic SE is more common in younger children. Treating the precipitating cause may prevent ongoing neurologic injury and facilitates seizure control. A systematic treatment regimen, planned in advance, is needed, including one for refractory status epilepticus (RSE). Here we emphasize definitions, clinical and electroencephalography stages, early treatment, special circumstances that may require immediate seizure control, and treatment of RSE. Because much clinical research in SE has been done in adults, we indicate the patient population studied.

Prolonged treatment for acute symptomatic refractory status epilepticus: outcome in children

High-dose suppressive therapy (HDST) is used to treat refractory status epilepticus (RSE). Prolonged therapy is required in some cases, and prognosis is important in making therapeutic decisions. The authors therefore studied the long-term outcome in previously normal children who survived prolonged HDST for acute symptomatic RSE. All have intractable epilepsy, and none returned to baseline.

Classification of seizures and epilepsy

The management of seizures and epilepsy begins with forming a differential diagnosis, making the diagnosis, and then classifying seizure type and epileptic syndrome. Classification guides treatment, including ancillary testing, management, prognosis, and if needed, selection of the appropriate antiepileptic drug (AED). Many AEDs are available, and certain seizure types or epilepsy syndromes respond to specific AEDs. The identification of the genetics, molecular basis, and pathophysiologic mechanisms of epilepsy has resulted from classification of specific epileptic syndromes. The classification system used by the International League Against Epilepsy is periodically revised. The proposed revision changes the classification emphasis from the anatomic origin of seizures (focal vs generalized) to seizure semiology (ie, the signs or clinical manifestations). Modified systems have been developed for specific circumstances (eg, neonatal seizures, infantile seizures, status epilepticus, and epilepsy surgery). This article reviews seizure and epilepsy classification, emphasizing new data.