A probabilistic approach for lateralization of seizure onset zone in drug-resistant epilepsy with bilateral cerebral pathology

BACKGROUND

Lateralization of seizure-onset zone (SOZ) during electroencephalography (EEG) monitoring in people with bilateral potentially epileptogenic lesions is important to facilitate clinical decision making for resective surgery.

METHODS

We develop two Bayesian approaches for estimating the number of consecutive ipsilateral seizures required to lateralize the SOZ to a given lower limit of 95% credible interval (LLI, assuming continuous prior distribution), or to a given posterior probability (assuming mixture of discrete and continuous prior probabilities).

RESULTS

With estimation approach, if both the cerebral hemispheres are a priori equi-probable to contain SOZ, then using Jeffrey's prior, a minimum of 9, 18, and 38 consecutive ipsilateral seizures will yield an LLI of 0.81, 0.90, and 0.95 respectively. If one of the hemisphere is a priori more likely to have SOZ, then prior beta distributions with α=3, β=2, and α=4, β=3 will require a minimum of 18 and 24 consecutive ipsilateral seizures to yield an LLI of 0.80. Contrariwise, the testing approach allows approximation of the number of consecutive ipsilateral seizures to lateralize the SOZ depending on an estimate of prior probability of lateralized SOZ, to a desired posterior probability. For a prior probability of 0.5, using uniform prior, mixture model will require 7, 17, and 37 consecutive ipsilateral seizures to lateralize the SOZ with a posterior probability of 0.8, 0.9, and 0.95 respectively.

CONCLUSION

While the reasoning presented here is based on probability theory, it is hoped that it may help clinical decision making and stimulate further validation with actual clinical data.

Constipation in Duchenne Muscular Dystrophy: Prevalence, Diagnosis, and Treatment

OBJECTIVES

To determine the prevalence and clinical characteristics of constipation among patients with Duchenne muscular dystrophy (DMD).

STUDY DESIGN

This cross-sectional prospective study included 120 patients (age range 5-30 years old) with an established diagnosis of DMD. Participants filled out the constipation section of a validated Questionnaire on Pediatric Gastrointestinal Symptoms based on Rome-III Criteria (QPGS-RIII) for the diagnosis of functional constipation as part of a routine clinic visit. We evaluated several potential screening methods for constipation: the Bristol stool form scale, routine physical examination, and fecal load on abdominal radiograph. These methods were compared with the QPGS-RIII in diagnosing functional constipation. Risk factors for the development of functional constipation were determined.

RESULTS

Based on the QPGS-RIII, 46.7% of patients with DMD in this cohort were diagnosed with functional constipation. Prevalence was not affected by age or functional status. None of the screening methods tested were sensitive enough to diagnose functional constipation. Among patients with constipation, only 43.6% received specific treatment for constipation and only one-half of these treated patients reported resolution of constipation.

CONCLUSIONS

This study systematically examined constipation among patients with DMD and provides evidence that constipation among patients with DMD is highly prevalent, underdiagnosed, and undertreated. QPGS-RIII is easy to administer and is an efficient tool to diagnose functional constipation in patients with DMD in a clinic setting.

Increased expression of the PI3K catalytic subunit p110δ underlies elevated S6 phosphorylation and protein synthesis in an individual with autism from a multiplex family

Background

Dysfunctions in the PI3K/mTOR pathway have gained a lot of attention in autism research. This was initially based on the discovery of several monogenic autism spectrum disorders with mutations or defects in PI3K/mTOR signaling components. Recent genetic studies corroborate that defective PI3K/mTOR signaling might be a shared pathomechanism in autism disorders of so far unknown etiology, but functional molecular analyses in human cells are rare. The goals of this study were to perform a functional screen of cell lines from patients with idiopathic autism for defects in PI3K/mTOR signaling, to test if further functional analyses are suitable to detect underlying molecular mechanisms, and to evaluate this approach as a biomarker tool to identify therapeutic targets.

Methods

We performed phospho-S6- and S6-specific ELISA experiments on 21 lymphoblastoid cell lines from the AGRE collection and on 37 lymphoblastoid cell lines from the Simons Simplex Collection and their healthy siblings. Cell lines from one individual with increased S6 phosphorylation and his multiplex family were analyzed in further detail to identify upstream defects in PI3K signaling associated with autism diagnosis.

Results

We detected significantly increased S6 phosphorylation in 3 of the 21 lymphoblastoid cell lines from AGRE compared to a healthy control and in 1 of the 37 lymphoblastoid cell lines from the Simons Simplex Collection compared to the healthy sibling. Further analysis of cells from one individual with elevated S6 phosphorylation showed increased expression of the PI3K catalytic subunit p110δ, which was also observed in lymphoblastoid cells from other autistic siblings but not unaffected members in his multiplex family. The p110δ-selective inhibitor IC87114 reduced elevated S6 phosphorylation and protein synthesis in this cell line.

Conclusions

Our results suggest that functional analysis of PI3K/mTOR signaling is a biomarker tool to identify disease-associated molecular defects that could serve as therapeutic targets in autism. Using this approach, we discovered impaired signaling and protein synthesis through the PI3K catalytic subunit p110δ as an underlying molecular defect and potential treatment target in select autism spectrum disorders. Increased p110δ activity was recently associated with schizophrenia, and our results suggest that p110δ may also be implicated in autism.

Electronic supplementary material

The online version of this article (doi:10.1186/s13229-015-0066-4) contains supplementary material, which is available to authorized users.

Efficacy of nonvenous medications for acute convulsive seizures: A network meta-analysis

OBJECTIVE

This is a network meta-analysis of nonvenous drugs used in randomized controlled trials (RCTs) for treatment of acute convulsive seizures and convulsive status epilepticus.

METHODS

Literature was searched according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines for RCTs examining treatment of acute convulsive seizures or status epilepticus with at least one of the study arms being a nonvenous medication. After demographic and outcome data extraction, a Bayesian network meta-analysis was performed and efficacy results were summarized using treatment effects and their credible intervals (CrI). We also calculated the probability of each route-drug combination being the most clinically effective for a given outcome, and provided their Bayesian hierarchical ranking.

RESULTS

This meta-analysis of 16 studies found that intramuscular midazolam (IM-MDZ) is superior to other nonvenous medications regarding time to seizure termination after administration (2.145 minutes, 95% CrI 1.308-3.489), time to seizure cessation after arrival in the hospital (3.841 minutes, 95% CrI 2.697-5.416), and time to initiate treatment (0.779 minutes, 95% CrI 0.495-1.221). Additionally, intranasal midazolam (IN-MDZ) was adjudged most efficacious for seizure cessation within 10 minutes of administration (90.4% of participants, 95% CrI 79.4%-96.9%), and persistent seizure cessation for ≥1 hour (78.5% of participants, 95% CrI 59.5%-92.1%). Paucity of RCTs produced evidence gaps resulting in small networks, routes/drugs included in some networks but not others, and some trials not being connected to any network.

CONCLUSIONS

Despite the evidence gaps, IM-MDZ and IN-MDZ exhibit the best efficacy data for the nonvenous treatment of acute convulsive seizures or status epilepticus.

Cytochrome c oxidase deficit is associated with the seizure onset zone in young patients with focal cortical dysplasia Type II

It has been postulated that mitochondrial dysfunction may be an important factor in epileptogenesis of intractable epilepsy. The current study tests the hypothesis that mitochondrial Complex IV (CIV) or cytochrome c oxidase dysfunction is associated with the seizure onset zone (SOZ) in patients with focal cortical dysplasia (FCD). Subjects were selected based on: age <19y; epilepsy surgery between May, 2010 and October, 2011; pathological diagnosis of isolated focal cortical dysplasia Type I (FCDI) or Type II (FCDII); and sufficient residual cortical tissue to conduct analysis of electron transport chain complex (ETC) activity in SOZ and adjacent cortical regions. In this retrospective study, patients were identified who had sufficient unfixed, frozen brain tissue for biochemical analysis in tissue homogenates. Specimens were subtyped using ILAE classification for FCD, and excluded if diagnosed with FCD Type III or dual pathology. Analysis of ETC activity in resected tissues was conducted independently and without knowledge of the identity, diagnosis, or clinical status of individual subjects. Seventeen patients met the inclusion criteria, including 6 FCDI and 11 FCDII. Comparison of adjacent cortical resections showed decreased CIV activity in the SOZ of the FCDII group (P = 0.003), but no significant CIV difference in adjacent tissues of the FCDI group. Because of the importance of CIV as the terminal and rate-limiting complex in the mitochondrial electron transport chain, these authors conclude that 1) a deficit of CIV is associated with the SOZ of patients with FCDII; 2) CIV deficiency may contribute to the spectrum of FCD neuropathology; and 3) further investigation of CIV in FCD may lead to the discovery of new targets for neuroprotective therapies for patients with intractable epilepsy.

Diagnoses in Pediatric Patients With Magnetic Resonance Imaging (MRI) Lesions Suspicious for Demyelination

Magnetic resonance imaging (MRI) studies of the brain in pediatric patients frequently show abnormal white matter lesions, which may be concerning for demyelinating disease. This study aimed to determine the proportion of pediatric patients who have MRI lesions concerning for demyelinating disease at presentation and ultimately are diagnosed with a primary central nervous system demyelinating disease. A retrospective chart review was performed on MRI reports of patients who underwent imaging evaluation at a single tertiary pediatric hospital. Of 299 patients identified, 192 presented with acute neurologic complaints. In this group, ≥ 5 discrete lesions, African American race, and having brain stem, thalamic, cerebellar, or optic nerve lesions was associated with the patient being diagnosed with a disease that required further treatment. The other 107 patients underwent MRI for other indications. Among these subjects, having lesions within the corpus callosum or cerebellum was associated with being diagnosed with a disease requiring further treatment.

Autonomic Imbalance as a Predictor of Metabolic Risks, Cardiovascular Disease, Diabetes, and Mortality

CONTEXT

Identifying novel early predictors of metabolic disorders is essential to improving effective primary prevention.

OBJECTIVES

The objectives were to examine the contribution of two measures of autonomic imbalance, resting heart rate (RHR) and heart rate variability (HRV), on the development of five metabolic risk outcomes, and on cardiovascular disease, diabetes, and early mortality.

DESIGN

This study was a secondary analysis of prospective data from Offspring Cohort participants (N = 1882) in the Framingham Heart Study (FHS).

PARTICIPANTS

Participants at FHS Exam 3 (1983-1987) with 1) age years 18 or older, and 2) data on RHR, HRV, and five measures of metabolic risk (blood pressure, fasting glucose, triglycerides, high-density lipoprotein [HDL] cholesterol, and body mass index [BMI]) at three follow-up visits over 12 years. We conducted a backward elimination variable selection procedure on a logistic regression model, using baseline RHR, HRV, age, sex, and smoking status to predict the odds of developing a specific metabolic risk.

OUTCOMES

Measures included hyperglycemia, high blood pressure, high triglycerides, low HDL cholesterol, and high BMI over 12 years; incident diabetes, cardiovascular disease, and early mortality over 20 years.

RESULTS

RHR and HRV, along with sex, age, and smoking were significant predictors of high blood pressure, hyperglycemia, and a diagnosis of diabetes within 12 years. RHR and HRV also predicted the development of cardiovascular disease and early mortality for most of the sample.

CONCLUSIONS

In this community sample two measures of autonomic imbalance predicted multiple poor metabolic outcomes and mortality, making autonomic imbalance a potentially worthy target for intervention studies to reduce risks for cardiovascular disorders, diabetes, and early death.

Effect of 30 Hz theta burst transcranial magnetic stimulation on the primary motor cortex in children and adolescents

Fourteen healthy children (13.8 ± 2.2 years, range 10–16; M:F = 5:9) received 30 Hz intermittent theta burst transcranial magnetic stimulation (iTBS) with a stimulation intensity of 70% of resting motor threshold (RMT) with a total of 300 (iTBS300) pulses. All volunteers were free of neurologic, psychiatric and serious medical illnesses, not taking any neuropsychiatric medications, and did not have any contraindications to transcranial magnetic stimulation. Changes in the mean amplitudes of motor-evoked potentials from baseline following iTBS were expressed as a ratio and assessed from 1 to 10 min (BLOCK1) and 1–30 min (BLOCK2) using repeated-measures analysis of variance. All 14 subjects completed iTBS300 over the dominant primary motor cortex (M1) without any clinically reported adverse events. ITBS300 produced significant M1 facilitation [F_{(5, 65)} = 3.165, p = 0.01] at BLOCK1 and trend level M1 facilitation at BLOCK2 [F_{(10, 129)} = 1.69, p = 0.089]. Although iTBS300 (stimulation duration of 92 s at 70% RMT) delivered over M1 in typically developed children was well-tolerated and produced on average significant facilitatory changes in cortical excitability, the post-iTBS300 neurophysiologic response was variable in our small sample. ITBS300-induced changes may represent a potential neuroplastic biomarker in healthy children and those with neuro-genetic or neuro-psychiatric disorders. However, a larger sample size is needed to address safety and concerns of response variability.

Safety and tolerability of theta burst stimulation vs. single and paired pulse transcranial magnetic stimulation: a comparative study of 165 pediatric subjects

Background: Although single- and paired-pulse (sp/pp) transcranial magnetic stimulation (TMS) studies are considered minimal risk in adults and children, the safety profile for theta-burst TMS (TBS) is unknown.

Objective: In this comparative analysis, we explored the rate, severity, and specific symptoms of TMS-related adverse effects (AEs) between sp/ppTMS and TBS in subjects between ages 6 and 18 years.

Method: Data from 165 participants from 2009 to 2014 were analyzed. Assessment of AEs was performed based on baseline and post-TMS administration of a symptom-based questionnaire that rated AEs on a 5-level ordinal scale (minimal, mild, moderate, marked, severe). AE rates and severity were compared using Chi Square or Fisher’s Exact Test depending on data characteristics.

Result: Overall, no seizures or severe-rated AEs were reported by 165 pediatric participants. The rate of AE in all TBS sessions was 10.5% (n = 76, 95% CI: 4.7–19.7%), whereas the rate of AE in all sp/ppTMS sessions was 12.4% (n = 89, 95% CI: 6.3–21.0%). There was no statistical difference in AE rates between TBS and sp/ppTMS (p = 0.71). In all sp/ppTMS and TBS sessions, 20 subjects reported a total of 35 AEs, among these 31 (~88.6%) were rated as “minimal” or “mild”. There was no difference in the severity of AE between TBS and sp/ppTMS (p = 1.0). Only one of 76 TBS participants reported an AE rated as more than minimal/mild.

Conclusion: Our comparative analysis showed that TBS appears to be as safe as sp/ppTMS in terms of AE rate and severity. This report supports further investigation of TBS in children.

Melatonin improves sleep in children with epilepsy: a randomized, double-blind, crossover study

OBJECTIVE

Insomnia, especially maintenance insomnia, is widely prevalent in epilepsy. Although melatonin is commonly used, limited data address its efficacy. We performed a randomized, double-blind, placebo-controlled, crossover study to identify the effects of melatonin on sleep and seizure control in children with epilepsy.

METHODS

Eleven prepubertal, developmentally normal children aged 6-11 years with epilepsy were randomized by a software algorithm to receive placebo or a 9-mg sustained release (SR) melatonin formulation for four weeks, followed by a one-week washout and a four-week crossover condition. The pharmacy performed blinding; patients, parents, and study staff other than a statistician were blinded. The primary outcomes were sleep onset latency and wakefulness after sleep onset (WASO) measured on polysomnography. The secondary outcomes included seizure frequency, epileptiform spike density per hour of sleep on electroencephalogram (EEG), and reaction time (RT) measures on psychomotor vigilance task (PVT). Statistical tests appropriate for crossover designs were used for the analysis.

RESULTS

Data were analyzed from 10 subjects who completed the study. Melatonin decreased sleep latency (mean difference, MD, of 11.4 min and p = 0.02) and WASO (MD of 22 min and p = 0.04) as compared to placebo. No worsening of spike density or seizure frequency was seen. Additionally, slow-wave sleep duration and rapid eye movement (REM) latency were increased with melatonin and REM sleep duration was decreased. These changes were statistically significant. Worsening of headache was noted in one subject with migraine on melatonin.

CONCLUSION

SR melatonin resulted in statistically significant decreases in sleep latency and WASO. No clear effects on seizures were observed, but the study was too small to allow any conclusions to be drawn in this regard.

Long-term outcomes of resective epilepsy surgery after invasive presurgical evaluation in children with tuberous sclerosis complex and bilateral multiple lesions

OBJECT

Tuberous sclerosis complex (TSC) with medically refractory epilepsy is characterized by multifocal brain abnormalities, traditionally indicating poor surgical candidacy. This single-center, retrospective study appraised seizurerelated, neuropsychological, and other outcomes of resective surgery in TSC patients with medically refractory epilepsy, and analyzed predictors for these outcomes.

METHODS

Patients with multilesional TSC who underwent epilepsy surgery between 2007 and 2012 were identified from an electronic database. All patients underwent multimodality noninvasive and subsequent invasive evaluation. Seizure outcomes were classified using the International League Against Epilepsy (ILAE) scale. The primary outcome measure was complete seizure remission (ILAE Class 1). Secondary outcome measures included 50% responder rate, change in full-scale IQ, electroencephalography improvement, and reduction in antiepileptic drug (AED) burden.

RESULTS

A total of 37 patients with TSC underwent resective surgery during the study period. After a mean follow-up of 5.68 ± 3.67 years, 56.8% achieved complete seizure freedom (ILAE Class 1) and 86.5% had ILAE Class 4 outcomes or better. The full-scale IQ on follow-up was significantly higher in patients with ILAE Class 1 outcome (66.70 ± 12.36) compared with those with ILAE Class 2 or worse outcomes (56.00 ± 1.41, p = 0.025). In 62.5% of the patients with ILAE Class 2 or worse outcomes, the number of AEDs were found to be significantly reduced (p = 0.004).

CONCLUSIONS

This study substantiates the evidence for efficacy of resective epilepsy surgery in patients with bilateral multilesional TSC. More than half of the patients were completely seizure free. Additionally, a high proportion achieved clinically meaningful reduction in seizure burden and the number of AEDs.

Predictors of response to vagus nerve stimulation in childhood-onset medically refractory epilepsy

This study explored predictors of response to vagus nerve stimulation in childhood-onset epilepsy. This retrospective chart review included all patients with new vagus nerve stimulator insertion between January 1, 2006, and December 31, 2011. Primary outcome was change in seizure frequency classified on the International League Against Epilepsy scale. Overall, 67.4% (95% confidence limits 53.3%-81.6%) of the patients had outcome of class 4 or better, and 4 patients (9.3%, 95% confidence interval 0.5%-18.1%) achieved complete seizure freedom (mean follow-up 3.5 y). Absence of magnetic resonance imaging (MRI) lesion (odds ratio 6.068, 95% confidence interval 1.214-30.329, P = .028) and duration of epilepsy before implantation (odds ratio 1.291, 95% confidence interval 1.015-1.642, P = .038) were found to be statistically significant predictors of good outcome and provided a sufficient fit to the data (area under the receiver operating characteristic curve .80, Hosmer-Lemeshow goodness of fit P = .92). This study provides preliminary evidence that nonlesional patients are significantly more likely to have better outcome with vagus nerve stimulation.

Corpus callosotomy for childhood-onset drug-resistant epilepsy unresponsive to vagus nerve stimulation

PURPOSE

Corpus callosotomy and vagus nerve stimulation are common palliative options for people with drug-resistant epilepsy when resective epilepsy surgery is not feasible. Because most of the published corpus callosotomy experience comes from a period before vagus nerve stimulation was approved and widely used, there is a paucity of data about efficacy of corpus callosotomy in patients with inadequate response to vagus nerve stimulation.

METHODS

We report seven patients who had complete corpus callosotomy after an inadequate response to vagus nerve stimulation. At the time of surgery, these patients had failed a median of six antiseizure medications, three patients also had failed a trial of ketogenic diet, and all the patients had a vagus nerve stimulation implanted for a mean duration of 2.5 years with maximal tolerated settings.

RESULTS

There was a decrease in total daily seizure frequency of 34.7% (± 94.7; median, 71.4%; interquartile range, 55.3) after corpus callosotomy at a mean follow-up of 2.6 years (± 1.4). One patient achieved complete seizure freedom and five patients had ≥ 50% reduction in seizure frequency. Six patients continued to have partial-onset seizures though the frequency was decreased. Drop attacks and tonic seizures stopped in all the patients.

CONCLUSION

Seizure outcomes after corpus callosotomy in our series are most likely a result of complex dynamic interaction between the natural history of epilepsy, the effect of the surgery, ongoing vagus nerve stimulation modulation, and modification in antiseizure drugs. Our study supports the clinical decision to try corpus callosotomy in patients having nonlateralizing drug-resistant epilepsy with inadequate response to vagus nerve stimulation.

Electrocorticographic language mapping in children by high-gamma synchronization during spontaneous conversation: comparison with conventional electrical cortical stimulation

INTRODUCTION

This study describes development of a novel language mapping approach using high-γ modulation in electrocorticograph (ECoG) during spontaneous conversation, and its comparison with electrical cortical stimulation (ECS) in childhood-onset drug-resistant epilepsy.

METHODS

Patients undergoing invasive pre-surgical monitoring and able to converse with the investigator were eligible. ECoG signals and synchronized audio were acquired during quiet baseline and during natural conversation between investigator and the patient. Using Signal Modeling for Real-time Identification and Event Detection (SIGFRIED) procedure, a statistical model for baseline high-γ (70-116 Hz) power, and a single score for each channel representing the probability that the power features in the experimental signal window belonged to the baseline model, were calculated. Electrodes with significant high-γ responses (HGS) were plotted on the 3D cortical model. Sensitivity, specificity, positive and negative predictive values (PPV, NPV), and classification accuracy were calculated compared to ECS.

RESULTS

Seven patients were included (4 males, mean age 10.28 ± 4.07 years). Significant high-γ responses were observed in classic language areas in the left hemisphere plus in some homologous right hemispheric areas. Compared with clinical standard ECS mapping, the sensitivity and specificity of HGS mapping was 88.89% and 63.64%, respectively, and PPV and NPV were 35.29% and 96.25%, with an overall accuracy of 68.24%. HGS mapping was able to correctly determine all ECS+ sites in 6 of 7 patients and all false-sites (ECS+, HGS- for visual naming, n = 3) were attributable to only 1 patient.

CONCLUSIONS

This study supports the feasibility of language mapping with ECoG HGS during spontaneous conversation, and its accuracy compared to traditional ECS. Given long-standing concerns about ecological validity of ECS mapping of cued language tasks, and difficulties encountered with its use in children, ECoG mapping of spontaneous language may provide a valid alternative for clinical use.

Mapping preictal networks preceding childhood absence seizures using magnetoencephalography

The electrographic hallmark of childhood absence seizures is 3 Hz generalized spike and wave discharges; however, there is likely a focal thalamic or cortical onset that cannot be detected using scalp electroencephalography (EEG). The purpose of this study was to study the earliest preictal changes in children with absence epilepsy. In this report, magnetoencephalography recordings of 44 absence seizures recorded from 12 children with drug-naïve childhood absence seizures were used to perform time frequency analysis and source localization prior to the onset of the seizures. Evidence of preictal magnetoencephalography frequency changes were detected a mean of 694 ms before the initial spike on the EEG. A consistent pattern of focal sources was present in the frontal cortex and thalamus during this preictal period, but source localization occurred synchronously so that independent activity between the 2 structures could not be distinguished.

Low- and high-frequency oscillations reveal distinct absence seizure networks

OBJECTIVE

The aim of this study was to determine the frequency-dependent, spatiotemporal involvement of corticothalamic networks to the generation of absence seizures.

METHODS

Magnetoencephalography recordings were obtained in 12 subjects (44 seizures) with untreated childhood absence seizures. Time-frequency analysis of each seizure was performed to determine bandwidths with significant power at ictal onset. Source localization was then completed to determine brain regions contributing to generalized spike and wave discharges seen on electroencephalogram.

RESULTS

Significant power in the time-frequency analysis was seen within 1 to 20Hz, 20 to 70Hz, and 70 to 150Hz bandwidths. Source localization revealed that sources localized to the frontal cortex similarly for the low- and gamma-frequency bandwidths, whereas at the low-frequency bandwidth (3-20Hz) significantly more sources localized to the parietal cortex (odds ratio [OR] = 16.7). Cortical sources within the high-frequency oscillation (HFO) bandwidth (70-150Hz) localized primarily to the frontal region compared to the parietal (OR = 7.32) or temporal (OR = 2.78) areas.

INTERPRETATION

Neuromagnetic activity within frontal and parietal cortical regions provides further confirmation of hemodynamic changes reported using functional magnetic resonance imaging that have been associated with absence seizures. The frequency-dependent nature of these networks has not previously been reported, and the presence of HFOs during absence seizures is a novel finding. Co-occurring frontal and parietal corticothalamic networks may interact to produce a pathological state that contributes to the generation of spike and wave discharges. The clinical and pathophysiological implications of HFOs within the frontal cortical region are unclear and should be further investigated.

The surgical management of pediatric brain tumors causing epilepsy: consideration of the epileptogenic zone

OBJECTIVE

Children suffering from epilepsy with suspected low-grade tumors may benefit from a surgical approach that considers the epileptogenic zone, which can be more extensive than the tumor region. This study aimed to determine the prevalence of epilepsy in children undergoing supratentorial tumor resection and the factors predictive of postoperative seizure freedom in children with low-grade tumors.

METHODS

Subjects 3 months to 21 years undergoing supratentorial brain tumor resection between 2007 and 2011 were included in this retrospective study. Children with supratentorial, cortically based tumors and a preoperative diagnosis of epilepsy were considered epilepsy surgery candidates. Pre- and postoperative MRI were reviewed and scored for extent of resection, adjacent dysplasia, and remaining abnormal cortex postoperatively.

RESULTS

The prevalence of seizures in all cases of supratentorial tumors was 46/87 (53 %). Eighteen were epilepsy surgery candidates. Eight of 18 (44 %) were seizure-free postoperatively with a mean follow-up of 39 months. Children who were seizure free postoperatively had tried fewer anticonvulsants than those with continued seizures (1.7 v. 2.9, p = 0.01). Presurgical evaluation was nonstandardized, and a more extensive workup and resection were performed in children who continued to have seizures postoperatively.

CONCLUSIONS

All epilepsy surgery candidates had low-grade tumors on histological evaluation, indicating that a surgical approach that takes into consideration the epileptogenic zone is reasonable in this population. Gross total resection should be the goal, with additional attention to resection of the epileptogenic zone when located in the noneloquent cortex.

Acute postoperative seizures and long-term outcome following pediatric epilepsy surgery

PURPOSE

Acute post-operative seizures (APOS) after epilepsy surgery, previously believed to be benign, are increasingly associated with poor long-term prognosis. Prior literature has focused primarily on adult temporal lobe epilepsy. This retrospective study aimed to identify the prevalence, prognostic significance and risk factors for APOS in pediatric epilepsy surgery at a single center.

METHOD

Retrospective chart review of all children aged 0-21 years undergoing resective surgery for epilepsy between 2009 and 2012 at a single center. APOS were defined as seizures within 30 days of resection. Surgical outcome was determined, using a minimum of 12 months postoperative follow-up for inclusion.

RESULTS

APOS, defined as a seizure within 30 days of resection, were identified in 50/112 (44%) of patients. APOS were a significant predictor of poor postoperative seizure outcome (ILAE 4-6); only 26% of those with APOS had a good outcome (ILAE 1-3), compared to 76% without APOS. Timing of postoperative seizure was not correlated with outcome. Most (54%) with APOS and good outcome had continued seizures between 14-30 days postoperatively. Patients with APOS after temporal (p=0.05) and extratemporal (p<0.001) resections had a significantly worse prognosis. APOS after hemispherectomy were not associated with a worse prognosis (p=0.22). Key risk factors for APOS include lack of ictal EEG lateralization to operated hemisphere/side of MRI abnormality.

CONCLUSION

This study shows an association between APOS and poor outcome in both temporal and extratemporal pediatric epilepsy surgery. Findings support the expansion of APOS duration to 30 days.

The patellofemoral joint: do age and gender affect skeletal maturation of the osseous morphology in children?

BACKGROUND

The osseous morphology of the patellofemoral joint is an independent factor that affects the biomechanics of patellofemoral instability.

OBJECTIVE

The purpose of this study is to determine age- and gender-related differences in the osseous morphology of the patellofemoral joint in children during skeletal maturation.

MATERIALS AND METHODS

This study was approved by the institutional review board and was HIPAA-compliant. We included 97 children and young adults (age range 5-22 years; 51 girls and 46 boys, mean ages 14.3 years and 13.7 years, respectively). We studied 1.5-T knee MR exams, measuring the osseous morphology of the patellofemoral joint (lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, patellar height ratio, tibial tubercle-trochlear groove distance, and lateral patellofemoral angle) for each MR exam. We compared measurements to published values for patellofemoral instability. Physeal patency (open or closing/closed) was determined on MR. We assessed the associations between MR osseous measurements and gender, age and physeal patency using Wilcoxon rank sum test and least square means regression models.

RESULTS

The osseous patellofemoral joint morphology measurements were all within a normal range. There were no significant correlations between MR osseous measurements and age, gender or physeal patency.

CONCLUSION

During skeletal maturation, age and gender do not affect the osseous morphology or congruency of the patellofemoral joint.

Cerebrospinal fluid neuropeptide Y in combat veterans with and without posttraumatic stress disorder

Accruing evidence indicates that neuropeptide Y (NPY), a peptide neurotransmitter, is a resilience-to-stress factor in humans. We previously reported reduced cerebrospinal fluid (CSF) NPY concentrations in combat-related posttraumatic stress disorder (PTSD) subjects as compared with healthy, non-combat-exposed volunteers. Here we report CSF NPY in combat-exposed veterans with and without PTSD. We quantified NPY concentrations in morning CSF from 11 male subjects with PTSD from combat in Iraq and/or Afghanistan and from 14 combat-exposed subjects without PTSD. NPY-like immunoreactivity (NPY-LI) was measured by EIA. The relationship between CSF NPY and clinical symptoms, as measured by the Clinician-Administered PTSD Scale (CAPS) and Beck Depression Inventory (BDI), was assessed, as was the relationship between combat exposure scale (CES) scores and CSF NPY. As compared with the combat-exposed comparison subjects without PTSD, individuals with PTSD had significantly lower concentrations of CSF NPY [mean CSF NPY was 258. 6 ± 21.64 pg/mL in the combat trauma-no PTSD group but only 180.5 ± 12.62 pg/mL in PTSD patients (p=0.008)]. After adjusting for CES and BDI scores the two groups were still significantly different with respect to NPY. Importantly, CSF NPY was negatively correlated with composite CAPS score and intrusive (re-experiencing) subscale scores, but did not significantly correlate with CES or BDI scores. Our current findings further suggest that NPY may regulate the manifestation of PTSD symptomatology, and extend previous observations of low CSF NPY concentrations in the disorder. Central nervous system NPY may be a clinically important pharmacotherapeutic target, and/or diagnostic measure, for PTSD.

Objective measurement of minimal fat in normal skeletal muscles of healthy children using T2 relaxation time mapping (T2 maps) and MR spectroscopy

BACKGROUND

Various skeletal muscle diseases result in fatty infiltration, making it important to develop noninvasive biomarkers to objectively measure muscular fat.

OBJECTIVE

We compared T2 relaxation time mapping (T2 maps) and magnetic resonance spectroscopy (MRS) with physical characteristics previously correlated with intramuscular fat to validate T2 maps and MRS as objective measures of skeletal muscle fat.

MATERIALS AND METHODS

We evaluated gluteus maximus muscles in 30 healthy boys (ages 5-19 years) at 3 T with T1-weighted images, T2-W images with fat saturation, T2 maps with and without fat saturation, and MR spectroscopy. We calculated body surface area (BSA), body mass index (BMI) and BMI percentile (BMI %). We performed fat and inflammation grading on T1-W imaging and fat-saturated T2-W imaging, respectively. Mean T2 values from T2 maps with fat saturation were subtracted from T2 maps without fat saturation to determine T2 fat values. We obtained lipid-to-water ratios by MR spectroscopy. Pearson correlation was used to assess relationships between BSA, BMI, BMI %, T2 fat values, and lipid-to-water ratios for each boy.

RESULTS

Twenty-four boys completed all exams; 21 showed minimal and 3 showed no fatty infiltration. None showed muscle inflammation. There was correlation between BSA, BMI, and BMI %, and T2 fat values (P < 0.05), and between BMI and BMI %, and lipid-to-water ratios (P < 0.05). There was strong correlation between T2 fat values and lipid-to-water ratios (P < 0.0001, r = 0.83).

CONCLUSION

T2 maps and MR spectroscopy correlate with physical characteristics associated with fatty infiltration of skeletal muscles, even in microscopic amounts, and validate each other. Both techniques might enable detection of minimal pathological fatty infiltration in children with skeletal muscle disorders.