Language and social functioning in children and adolescents with epilepsy.

Individuals with epilepsy have difficulties with social function that are not adequately accounted for by seizure severity or frequency. This study examined the relationship between language ability and social functioning in 193 children with epilepsy over a period of 36months following their first recognized seizure. The findings show that children with persistent seizures have poorer language function, even at the onset of their seizures, than do their healthy siblings, children with no recurrent seizures, and children with recurrent but not persistent seizures. They continue to demonstrate poorer language function 36months later. This poor language function is associated with declining social competence. Intervention aimed at improving social competence should include consideration of potential language deficits that accompany epilepsy and social difficulty.

Establishing a Core Outcome Set for Creatine Transporter Deficiency and Guanidinoacetate Methyltransferase Deficiency.

Creatine transporter (CTD) and guanidinoacetate methyltransferase (GAMT) deficiencies are rare inborn errors of creatine metabolism, resulting in cerebral creatine deficiency. Patients commonly exhibit intellectual and developmental disabilities, often accompanied by behavior problems, delayed speech, seizures, and motor impairments. There is currently no efficacious treatment for CTD, while the current management for GAMT requires lifelong treatment with a protein restricted diet and intake of high amounts of oral supplements. Efforts to develop effective, sustainable treatments for these disorders are limited by the lack of clinical and patient-derived meaningful outcomes. A core outcome set (COS) can facilitate consensus about outcomes for inclusion in studies. Unfortunately, patient and caregiver perspectives have historically been overlooked in the COS development process, thus limiting their input into the outcome selection. We partnered with caregivers and health professionals to establish the first COS for CTD and GAMT. The COS developed includes seven outcomes ("Adaptive Functioning", "Cognitive Functioning", "Emotional Dysregulation", "MRS Brain Creatine", "Seizure/Convulsions", "Expressive Communication", and "Fine Motor Functions") for both CTD and GAMT, and an additional outcome for GAMT ("Serum/Plasma Guanidinoacetate") that are important to stakeholders and consequently should be considered for measurement in every clinical trial. Caregivers were valued partners throughout the COS development process, which increased community engagement and facilitated caregiver empowerment. We expect this COS will ensure a patient-centered approach for accelerating drug development for CTD and GAMT, make clinical trial results comparable, minimize bias in clinical trial outcome selection, and promote efficient use of resources. 1-sentence take home message: A core outcome set for creatine transporter (CTD) and guanidinoacetate methyltransferase (GAMT) deficiencies was created through a multiphase process in partnership with caregivers and health professionals.

Self-esteem and symptoms of depression in children with seizures: relationships with neuropsychological functioning and family variables over time.

PURPOSE: To test over time the relationships of neuropsychological functioning to mental health in children following a first recognized seizure and, of primary importance, to determine if the strength of these relationships differs based on risk and protective factors. METHODS: In a larger prospective study, 135 children with a first seizure (ages 8-14 years) and 73 healthy sibling controls completed neuropsychological testing at baseline and 36 months. Structured telephone interviews were used to obtain data from children on mental health and family environment; major caregiving parents provided data on demographic and family variables. Data analyses included correlation coefficients and linear regression models. RESULTS: Children with seizures showed an overall trend for improvement in mental health. More children with seizures than siblings had declines in processing speed. Declines in neuropsychological functioning were correlated with worse mental health. With regard to risk and protective factors, higher parent education protected against decline in self-esteem related to decline in processing speed. Better family functioning and greater parental support protected against decline in self-esteem related to decrease in verbal memory and learning. Older child age protected against increase in depressive symptoms related to decline in processing speed. DISCUSSION: Seizure onset had a negative impact on mental health in children with declines in cognitive functioning except for older children and those with more family resources. Children should be assessed for declines in processing speed and, if found, those subgroups of children with less educated or more anxious parents and those in less supportive families should be targeted for interventions.

The effect of temperament and neuropsychological functioning on behavior problems in children with new-onset seizures.

The present study is part of a larger project that seeks to identify factors that predict children's behavioral, social, and cognitive adaptation to epilepsy. Children with seizures are more likely to have internalizing and externalizing behavior problems than either healthy children or children with other chronic illnesses. The present research examines risk factors for behavior problems. Early temperament and neuropsychological functioning, specifically executive function and language abilities, are evaluated as unique and moderating predictors of adverse behavioral outcomes in 229 children with a first recognized seizure. Parents assessed temperament, children were administered neuropsychological tests, and teachers evaluated behavior 36 months after seizure onset. Results revealed that early temperament and neuropsychological functioning, specifically executive function, predicted behavioral outcomes 3 years after seizure onset.

Seizure recurrence risk following a first seizure in neurologically normal children.

PURPOSE: To define seizure recurrence rates in normal children who had had a single seizure and to define electroencephalography (EEG) or magnetic resonance imaging (MRI) utility in predicting seizure recurrence. METHODS: We studied 150 children (6 to 14 years) with a first afebrile, unprovoked seizure. Inclusion criteria were: Normal physical and neurological examination, undergone EEG and MRI studies of the brain, and followed for at least 27 months. These children participated in an ongoing prospective study of new onset seizures in childhood. RESULTS: The seizure recurrence rate was 66.4%. An abnormal EEG had no association with seizure recurrence at 9, 18, or 27 months (p = 0.1806, p = 0.2792, and p = 0.2379, respectively). A "significant" MRI abnormality, which occurred in 16.0% of patients, was associated with an increased seizure recurrence risk at 9 months (p = 0.0389) but not at 18 or 27 months. DISCUSSION: EEG findings poorly predict recurrence after a single seizure. The high rate of MRI abnormalities suggests that MRI may need consideration as a routine test to evaluate epilepsy in normal children.

The relationship between sleep problems and neuropsychological functioning in children with first recognized seizures.

Epilepsy is associated with sleep disturbance, but little is known about how early this relationship develops and how it affects neuropsychological functioning. This study documented the frequency and types of sleep problems and examined how sleep problems are associated with seizures and neuropsychological functioning in 332 children following their first recognized seizure (ages 6-14) and in 225 sibling controls. Formal neuropsychological batteries were administered to all subjects. Sleep was measured using the Sleep Behavior Questionnaire and the Child Behavior Checklist. Sleep problems were more frequent in the seizure sample relative to siblings and previously published norms; bedtime difficulties, daytime somnolence, and parasomnias were the most frequently occurring sleep problems. In the seizure group, sleep problems were related to seizure parameters and to neuropsychological functioning. Seizure patients with significant sleep problems had worse neuropsychological functioning on all measures. Findings demonstrate the significant impact of sleep disturbance on children with newly recognized seizures.

Magnetic resonance imaging findings in children with a first recognized seizure.

This study characterized structural abnormalities associated with onset of seizures in children, using magnetic resonance imaging and a standardized classification system in a large prospective cohort. Two hundred eighty-one children aged 6-14 years completed magnetic resonance imaging within 6 months of their first recognized seizure. Most examinations were performed with a standardized, dedicated seizure protocol; all were scored using a standard scoring system. At least one magnetic resonance imaging abnormality was identified in 87 of 281 (31%) children with a first recognized seizure. Two or more abnormalities were identified in 34 (12%). The commonest abnormalities were ventricular enlargement (51%), leukomalacia/gliosis (23%), gray-matter lesions such as heterotopias and cortical dysplasia (12%), volume loss (12%), other white-matter lesions (9%), and encephalomalacia (6%). Abnormalities defined as significant, or potentially related to seizures, occurred in 40 (14%). Temporal lobe and hippocampal abnormalities were detected at a higher frequency than in previous studies (13/87). Magnetic resonance imaging and a standardized, reliable, valid scoring system demonstrated a higher rate of abnormal findings than previously reported, including findings formerly considered incidental. Practice parameters may need revision, to expand the definition of significant abnormalities and support wider use of magnetic resonance imaging in children with newly diagnosed seizures.

Functional characterization of missense variants in the creatine transporter gene (SLC6A8): improved diagnostic application.

Creatine transporter deficiency is an X-linked mental retardation disorder caused by mutations in the creatine transporter gene (SLC6A8). So far, 20 mutations in the SLC6A8 gene have been described. We have developed a diagnostic assay to test creatine uptake in fibroblasts. Additionally, we expanded the assay to characterize novel SLC6A8 missense variants. A total of 13 variants were introduced in the SLC6A8 cDNA by site-directed mutagenesis. All variants were transiently transfected in SLC6A8-deficient fibroblasts and tested for restoration of creatine uptake in deficient primary fibroblasts. Thus, we proved that nine variants (p.Gly87Arg, p.Phe107del, p.Tyr317X, p.Asn336del, p.Cys337Trp, p.Ile347del, p.Pro390Leu, p.Arg391Trp, and p.Pro554Leu) are pathogenic mutations and four variants (p.Lys4Arg, p.Gly26Arg, p.Met560Val, and p.Val629Ile) are nonpathogenic. The present study provides an improved diagnostic tool to classify sequence variants of unknown significance.

Comprehensive mutation analysis of GLDC, AMT, and GCSH in nonketotic hyperglycinemia.

Nonketotic hyperglycinemia (NKH) is an inborn error of metabolism characterized by accumulation of glycine in body fluids and various neurological symptoms. NKH is caused by deficiency of the glycine cleavage multi-enzyme system with three specific components encoded by GLDC, AMT, and GCSH. We undertook the first comprehensive screening for GLDC, AMT, and GCSH mutations in 69 families (56, six, and seven families with neonatal, infantile, and late-onset type NKH, respectively). GLDC or AMT mutations were identified in 75% of neonatal and 83% of infantile families, but not in late-onset type NKH. No GCSH mutation was identified in this study. GLDC mutations were identified in 36 families, and AMT mutations were detected in 11 families. In 16 of the 36 families with GLDC mutations, mutations were identified in only one allele despite sequencing of the entire coding regions. The GLDC gene consists of 25 exons. Seven of the 32 GLDC missense mutations were clustered in exon 19, which encodes the cofactor-binding site Lys754. A large deletion involving exon 1 of the GLDC gene was found in Caucasian, Oriental, and black families. Multiple origins of the exon 1 deletion were suggested by haplotype analysis with four GLDC polymorphisms. This study provides a comprehensive picture of the genetic background of NKH as it is known to date.

Overexpression of wild-type creatine transporter (SLC6A8) restores creatine uptake in primary SLC6A8-deficient fibroblasts.

In the study reported, we prove that mutations in the SLC6A8 gene are responsible for SLC6A8 deficiency, a cerebral creatine deficiency syndrome (CCDS), since overexpression of the wild-type SLC6A8 open reading frame (ORF) restores the creatine uptake profile in SLC6A8-deficient fibroblasts.

Magnetic resonance imaging (MRI) and electroencephalographic (EEG) findings in a cohort of normal children with newly diagnosed seizures.

In the initial assessment of children with new-onset seizures, the suggestion that electroencephalography (EEG) should be standard and that magnetic resonance imaging (MRI) should be optional has been questioned. The purposes of this study were to (1) describe the frequency of EEG and MRI abnormalities and (2) explore relationships between MRI and EEG findings to determine their relevance in the assessment of children with new-onset seizures who are otherwise developing normally. As part of an ongoing, prospective study of children with new-onset seizures, we studied 181 children (90 girls and 91 boys). Children were entered into the study within 3 months of their first-recognized seizure. The association between EEG and MRI abnormalities was explored using a chi-square test. Abnormal MRI findings were found in 32.6% (n = 59) of the sample. The EEG and MRI results agreed with respect to classification into normal or abnormal in 37% (n = 67). Of the 50 children with a normal EEG, however, 21 (42%) were found to have an abnormal MRI. We found an unexpectedly high frequency of imaging abnormalities in our sample of otherwise normal children, although the significance of these findings is not clear. Follow-up of these patients will help us interpret the importance of the abnormalities. Despite our relatively small sample, however, our findings indicate that a normal EEG does not reliably predict a normal MRI in children with first seizures.

Muscle coenzyme Q: a potential test for mitochondrial activity and redox status.

The aim of this study is to determine whether coenzyme Q (CoQ) muscle concentrations and redox state are associated with pathologic changes in muscle biopsy specimens. Skeletal muscle biopsies were collected (January 2002-February 2004) and underwent pathologic evaluation. Quadriceps specimens (n = 47) were stratified accordingly: Group 1, controls without evidence of pathologic abnormalities; Group 2, type I myofiber predominance; Group 3, type II myofiber atrophy; Group 4, lower motor unit disease; and Group 5, muscular dystrophy. Ubiquinol-10, ubiquinone-10, total coenzyme Q10 (CoQ10), coenzyme Q9 (CoQ9), total CoQ (CoQ9+CoQ10) concentrations were analyzed in biopsy muscle by high-performance liquid chromatography. Ubiquinone-10, total CoQ10, and total CoQ concentrations were significantly decreased in Group 5. Significant positive correlations (r congruent with 0.40) were found between muscle ubiquinone-10, total CoQ10, and total CoQ concentrations vs the percentage of myofibers having subsarcolemmal mitochondrial aggregates. CoQ redox ratio and the fraction CoQ9/total CoQ were negatively correlated with subsarcolemmal mitochondrial aggregates. A significant correlation (r = 0.328) also occurred between ubiquinol-10 concentration and citrate synthase activity. This study suggests that total CoQ concentration provides a new method for estimating mitochondrial activity in biopsy muscle; and that the muscle CoQ test is feasible and potentially useful for diagnosing CoQ deficiency states.

Incidence of brain creatine transporter deficiency in males with developmental delay referred for brain magnetic resonance imaging.

Several case reports describe children with global developmental delay who have brain creatine deficiency, where the deficiency was due to a lack of creatine transport into the brain or altered creatine synthesis. The purpose of this study was to determine what percentage of males with developmental delay referred for brain magnetic resonance imaging (MRI) at the authors' institution in a 12-month period was found to have brain creatine deficiency due to a defect in the creatine transporter gene. In the authors' facility, single voxel proton magnetic resonance spectroscopy (MRS) is routinely performed on any male child age 2 to 18 years with a history of language and/or developmental delay referred for a brain MRI. Charts for the 12-month time period were retrospectively reviewed. Fourteen subjects met inclusion criteria for global developmental delay. Two of the 14 patients had brain creatine deficiency on MRS. In the remaining 12, other structural and white matter abnormalities were identified. This study suggests that brain creatine deficiency is an important consideration in the differential diagnosis of males with global developmental delay referred for brain MRI; brain MRS should be considered in such cases.

Correlation of lamotrigine concentrations between serum and saliva.

STUDY OBJECTIVE: To compare the relationship between serum and salivary concentrations of lamotrigine in pediatric and adult epilepsy populations. DESIGN: Paired-sample pharmacokinetic study. SETTING: University neurology clinic. PATIENTS: Thirty-seven patients with epilepsy, aged 2-60 years, who were taking lamotrigine and whose physicians had ordered a lamotrigine serum concentration. MEASUREMENTS AND MAIN RESULTS: Patients spit a minimum of 0.25 ml into a cup to provide saliva samples. Blood samples were obtained by phlebotomy. Serum and salivary lamotrigine concentrations were determined by high-performance liquid chromatography. Linear regression analysis was used to evaluate correlations. Six patients' results were omitted due to the lack of a serum or saliva specimen or clearly erroneous results, leaving 31 patients for analysis. There was a strong correlation between the serum results reported by two reference laboratories (coefficient of correlation [r] = 0.988). The correlations between salivary and serum lamotrigine concentrations were similar for reference laboratory A (r = 0.81) and reference laboratory B (r = 0.84). Saliva:serum concentration ratios ranged from 0.41-1.26 (mean +/- SD 0.62 +/- 0.19) for reference laboratory A and from 0.40-1.19 ((mean +/- SD 0.64 +/- 0.18) for reference laboratory B. CONCLUSION: There is a good correlation between salivary and serum concentrations for lamotrigine. However, there is wide interpatient variability in the saliva:serum ratio. The data suggest that salivary monitoring may play a role in the monitoring of lamotrigine for adult and pediatric patients.

Topiramate concentration in saliva: an alternative to serum monitoring.

This study examines the relationship between serum and saliva topiramate concentrations, and attempts to determine if saliva may be a useful alternative to serum for therapeutic monitoring. Saliva and blood specimens were collected from 31 epilepsy patients (mean age 10.5 +/- 6.0 years; range 2.5 years to 24.8 years), and topiramate concentrations were determined by fluorescence polarization immunoassay. One patient's results were omitted because the saliva concentration was below the limit of quantitation of the assay. A strong correlation exists between serum and saliva topiramate concentrations (adjusted r(2) = 0.97, n = 30, P < 0.0001). The mean fraction of saliva to serum concentration is 89.8% +/- 12.1% (range 62.9% to 112.7%). The results of this study support the use of saliva as a viable alternative to serum for monitoring topiramate therapy. Topiramate concentration in saliva: an alternative to serum monitoring.

Enzyme inducing antiepileptic drugs are associated with mitochondrial proliferation and increased cytochrome c oxidase activity in muscle of children with epilepsy.

PURPOSE: To evaluate the effects of epilepsy-related factors associated with mitochondrial pathology and function in skeletal muscle of children with suspected mitochondrial disorders. METHODS: This case-control study evaluated patients and age-matched controls with muscle biopsies at Cincinnati Children's Hospital Medical Center obtained between January, 2000 and December, 2008. RESULTS: A total of 65 epilepsy patients and 65 age-matched controls met the inclusion criteria. No significant clinical, pathological, or biochemical differences were found between the epilepsy and control groups. Treatment resistance was associated with decreased electron transport chain (ETC) complex II+III activity compared to treatment-responsive patients. Only patients receiving enzyme inducer antiepileptic drugs (AEDs) had ETC complex activities equivalent to or greater than other study groups. Robust regression modeling found a significant effect between percentage of myofibers with subsarcolemmal mitochondrial aggregates (SSMA) and ETC complex IV activity for the enzyme inducer AED group. Least squares regression showed that only complex IV/citrate synthase ratio was strongly correlated with SSMA percentage for the enzyme inducer AED group. As far as we can determine this is the first study to show an association between enzyme inducer AED treatment and enhanced ETC complex IV activity. CONCLUSIONS: In skeletal muscle mitochondrial density, assessed by SSMA percentage, and ETC complex IV activity are positively correlated in patients receiving enzyme inducer AED treatment.

Importance of muscle light microscopic mitochondrial subsarcolemmal aggregates in the diagnosis of respiratory chain deficiency.

The purpose of this study was to evaluate relationships between subsarcolemmal mitochondrial aggregates and electron transport chain deficiencies in skeletal muscle with the objective of establishing an association between mitochondrial accumulation and electron transport chain complex deficiency. We conducted a large-scale, retrospective study to evaluate factors associated with subsarcolemmal mitochondrial aggregates (percent) in pediatric patients who received muscle biopsies for suspected respiratory chain disorders. Patients were included if they had histochemical stains for assessment of mitochondrial pathology and had biochemical testing for muscle electron transport chain complex activities. Significant positive bivariate correlations (n = 337) were found between subsarcolemmal mitochondrial aggregate percentage and electron transport chain complexes II, IV, I + III, and II + III activities. Evaluation showed that a cutoff value of > 2% subsarcolemmal mitochondrial aggregates had poor overall diagnostic accuracy (mean, 32%), compared with a < 5% cutoff (mean, 60%). To better evaluate the effects of subsarcolemmal mitochondrial aggregates percentages, patients were stratified according to lower one-third (group 1, n = 120 plus ties) and upper one-third (group 2, n = 115 plus ties) of subsarcolemmal mitochondrial aggregates values. Although only minor clinical and pathologic differences were observed, group 1 participants had significantly lower electron transport chain complex activities than group 2 for all enzymes except complex III. Logistic regression showed over 2-fold greater odds of deficiency for electron transport chain complexes I + III (P = .01) and II + III (P = .03) for group 1 participants compared with group 2. We conclude that, contrary to the previous > 2.0% subsarcolemmal mitochondrial aggregates cutoff for respiratory chain disorder, patients with a low subsarcolemmal mitochondrial aggregates percentage (≤4%) are significantly more likely to have electron transport chain complex deficiency than patients with increased subsarcolemmal mitochondrial aggregates percentage (≥10%). This morphological approach for assessment of mitochondrial proliferation may assist clinicians to select further testing to rule out an electron transport chain complex deficiency in children by other methods, including direct biochemical testing of electron transport chain complex activities, measurement of muscle coenzyme Q10 content, or evaluation for a mitochondrial DNA depletion syndrome.

Cyclocreatine treatment improves cognition in mice with creatine transporter deficiency.

The second-largest cause of X-linked mental retardation is a deficiency in creatine transporter (CRT; encoded by SLC6A8), which leads to speech and language disorders with severe cognitive impairment. This syndrome, caused by the absence of creatine in the brain, is currently untreatable because CRT is required for creatine entry into brain cells. Here, we developed a brain-specific Slc6a8 knockout mouse (Slc6a8-/y) as an animal model of human CRT deficiency in order to explore potential therapies for this syndrome. The phenotype of the Slc6a8-/y mouse was comparable to that of human patients. We successfully treated the Slc6a8-/y mice with the creatine analog cyclocreatine. Brain cyclocreatine and cyclocreatine phosphate were detected after 9 weeks of cyclocreatine treatment in Slc6a8-/y mice, in contrast to the same mice treated with creatine or placebo. Cyclocreatine-treated Slc6a8-/y mice also exhibited a profound improvement in cognitive abilities, as seen with novel object recognition as well as spatial learning and memory tests. Thus, cyclocreatine appears promising as a potential therapy for CRT deficiency.

Design and implementation of the first randomized controlled trial of coenzyme CoQ10 in children with primary mitochondrial diseases.

We report the design and implementation of the first phase 3 trial of CoenzymeQ10 (CoQ10) in children with genetic mitochondrial diseases. A novel, rigorous set of eligibility criteria was established. The trial, which remains open to recruitment, continues to address multiple challenges to the recruitment of patients, including widely condoned empiric use of CoQ10 by individuals with proven or suspected mitochondrial disease and skepticism among professional and lay mitochondrial disease communities about participating in placebo-controlled trials. These attitudes represent significant barriers to the ethical and scientific evaluation--and ultimate approval--of nutritional and pharmacological therapies for patients with life-threatening inborn errors of energy metabolism.

Creatine transporter (CrT; Slc6a8) knockout mice as a model of human CrT deficiency.

Mutations in the creatine (Cr) transporter (CrT; Slc6a8) gene lead to absence of brain Cr and intellectual disabilities, loss of speech, and behavioral abnormalities. To date, no mouse model of CrT deficiency exists in which to understand and develop treatments for this condition. The purpose of this study was to generate a mouse model of human CrT deficiency. We created mice with exons 2-4 of Slc6a8 flanked by loxP sites and crossed these to Cre:CMV mice to create a line of ubiquitous CrT knockout expressing mice. Mice were tested for learning and memory deficits and assayed for Cr and neurotransmitter levels. Male CrT(⁻/y) (affected) mice lack Cr in the brain and muscle with significant reductions of Cr in other tissues including heart and testes. CrT(⁻/y) mice showed increased path length during acquisition and reversal learning in the Morris water maze. During probe trials, CrT(⁻/y) mice showed increased average distance from the platform site. CrT(⁻/y) mice showed reduced novel object recognition and conditioned fear memory compared to CrT(+/y). CrT(⁻/y) mice had increased serotonin and 5-hydroxyindole acetic acid in the hippocampus and prefrontal cortex. Ubiquitous CrT knockout mice have learning and memory deficits resembling human CrT deficiency and this model should be useful in understanding this disorder.