Deep Venous Remodeling in Unilateral Sturge-Weber Syndrome: Robust Hemispheric Differences and Clinical Correlates

BACKGROUND

Enlarged deep medullary veins (EDMVs) in patients with Sturge-Weber syndrome (SWS) may provide compensatory venous drainage for brain regions affected by the leptomeningeal venous malformation (LVM). We evaluated the prevalence, extent, hemispheric differences, and clinical correlates of EDMVs in SWS.

METHODS

Fifty children (median age: 4.5 years) with unilateral SWS underwent brain magnetic resonance imaging prospectively including susceptibility-weighted imaging (SWI); children aged 2.5 years or older also had a formal neurocognitive evaluation. The extent of EDMVs was assessed on SWI by using an EDMV hemispheric score, which was compared between patients with right and left SWS and correlated with clinical variables.

RESULTS

EDMVs were present in 89% (24 of 27) of right and 78% (18 of 23) of left SWS brains. Extensive EDMVs (score >6) were more frequent in right (33%) than in left SWS (9%; P = 0.046) and commonly occurred in young children with right SWS. Patients with EDMV scores >4 had rare (less than monthly) seizures, whereas 35% (11 of 31) of patients with EDMV scores ≤4 had monthly or more frequent seizures (P = 0.003). In patients with right SWS and at least two LVM-affected lobes, higher EDMV scores were associated with higher intelligence quotient (P < 0.05).

CONCLUSIONS

Enlarged deep medullary veins are common in unilateral SWS, but extensive EDMVs appear to develop more commonly and earlier in right hemispheric SWS. Deep venous remodeling may be a compensatory mechanism contributing to better clinical outcomes in some patients with SWS.

Epilepsy Due to Mild TBI in Children: An Experience at a Tertiary Referral Center

Rationale: Posttraumatic epilepsy (PTE) is a common cause of morbidity in children after a traumatic brain injury (TBI), occurring in 10–20% of children following severe TBI. PTE is diagnosed after two or more unprovoked seizures occurring 1-week post TBI. More often, studies have focused on children with epilepsy due to severe TBI. We aim to understand the utility of head computed tomography (HCT), EEG, and the risk of developing drug-resistant epilepsy in children after mild TBI. Method: We retrospectively studied 321 children with TBI at a tertiary pediatric referral center during a 10-year period. Mild TBI was defined as loss of consciousness (LOC) or amnesia < 30 min, moderate TBI as LOC or amnesia between 30 min and 1 day, and severe TBI as LOC or amnesia > 1 day, subdural hemorrhage, or contusion. Multiple clinical variables were reviewed, including past and present antiepileptic drug(s), seizure control, and mode of injury. First and subsequent post-TBI EEGs/prolonged video-EEGs were obtained acutely, subacutely, and/or chronically (range, day 1–3 years, median 1 month). Descriptive analyses were conducted using medians and ranges for continuous data. Categorical data were reported using frequencies and percentages, while comparisons between groups were made using Fisher’s exact test for small sample sizes. Results: Forty-seven children were diagnosed with posttraumatic epilepsy: eight children (17%) due to mild TBI, 39 children (83%) due to severe TBI. For the eight children with mild TBI whom all had an accidental trauma (non-inflicted), the median follow-up time was 25 months (range 1.5 months–84 months). The median age was 10 years (range 4–18 years), and the median age at the time of injury was seven years (range: 23 months–13 years). No relevant previous medical history was present for six patients (80%), and two patients’ (20%) relevant previous medical histories were unknown. Seven patients (88%) had no history of seizures, and patient #6 (12%) had unknown seizure history. Six patients (75%) had normal routine EEG(s). Patient #6 (13%) had an abnormal VEEG 3 months after the initial normal routine EEG, while patient #1 (13%) had an initial prolonged EEG 8 months after TBI. Compared to the 39 patients with severe TBI, 31 (79%) of whom had abnormal EEGs (routine and/or prolonged with video), mild TBI patients were more likely to have normal EEGs, p = 0.005. Head CT scans were obtained acutely for seven patients (90%), all of which were normal. One patient only had brain magnetic resonance imaging (MRI) 8 months after the injury. Compared to the 39 patients with severe TBI, all of whom had abnormal HCTs, mild TBI patients were less likely to have abnormal HCTs, p < 0.0001. In patients with mild TBI, no patient had both abnormal EEG/VEEG and HCT, and no one was on more than one Antiepileptic drug (AED), p < 0.005. Six patients (75%) had MRIs, of which five (63%) were normal. Two patients (#1, 7) did not have MRIs, while one patient’s (#4) MRI was unavailable. Five patients (63%) had a seizure <24 h post TBI, while the rest had seizures after the first week of injury. Conclusion: Children with epilepsy due to mild TBI, loss of consciousness, or amnesia < 30 min are more likely to have normal HCT and EEG and to be on 0–1 AED. Limitations of our study include the small sample size and retrospective design. The current findings add to the paucity of data in children who suffer from epilepsy due to mild TBI.

Hypermetabolism on Pediatric PET Scans of Brain Glucose Metabolism: What Does It Signify?

When one is interpreting clinical ¹⁸F-FDG PET scans of the brain (excluding tumors) in children, the typical abnormality seen is hypometabolism of various brain regions. Focal areas of hypermetabolism are noted occasionally, and the usual interpretation is that the hypermetabolic region represents a seizure focus. In this review, I discuss and illustrate the multiple causes of hypermetabolism on ¹⁸F-FDG PET studies that should not be interpreted as seizure activity, as such an interpretation could potentially be incorrect. Various conditions in which focal hypermetabolism can be encountered on ¹⁸F-FDG PET studies include interictal hypermetabolism, Sturge-Weber syndrome, changes associated with brain plasticity after injury, Rett syndrome, hypoxic-ischemic brain injury, various inborn errors of metabolism, and autoimmune encephalitis. The radiologist or nuclear medicine physician interpreting clinical ¹⁸F-FDG PET studies should be aware of these circumstances to accurately assess the findings.

Consensus Statement for the Management and Treatment of Sturge-Weber Syndrome: Neurology, Neuroimaging, and Ophthalmology Recommendations

BACKGROUND

Sturge-Weber syndrome (SWS) is a sporadic, neurocutaneous syndrome involving the skin, brain, and eyes. Because of the variability of the clinical manifestations and the lack of prospective studies, consensus recommendations for management and treatment of SWS have not been published.

OBJECTIVE

This article consolidates the current literature with expert opinion to make recommendations to guide the neuroimaging evaluation and the management of the neurological and ophthalmologic features of SWS.

METHODS

Thirteen national peer-recognized experts in neurology, radiology, and ophthalmology with experience treating patients with SWS were assembled. Key topics and questions were formulated for each group and included (1) risk stratification, (2) indications for referral, and (3) optimum treatment strategies. An extensive PubMed search was performed of English language articles published in 2008 to 2018, as well as recent studies identified by the expert panel. The panel made clinical practice recommendations.

CONCLUSIONS

Children with a high-risk facial port-wine birthmark (PWB) should be referred to a pediatric neurologist and a pediatric ophthalmologist for baseline evaluation and periodic follow-up. In newborns and infants with a high-risk PWB and no history of seizures or neurological symptoms, routine screening for brain involvement is not recommended, but brain imaging can be performed in select cases. Routine follow-up neuroimaging is not recommended in children with SWS and stable neurocognitive symptoms. The treatment of ophthalmologic complications, such as glaucoma, differs based on the age and clinical presentation of the patient. These recommendations will help facilitate coordinated care for patients with SWS and may improve patient outcomes.

Neuroinflammation in Children With Infantile Spasms: A Prospective Study Before and After Treatment With Acthar Gel (Repository Corticotropin Injection)

The selective effectiveness of adrenocorticotropic hormone (ACTH) in treating infantile spasms suggests an underlying neuroinflammation. Because neuroinflammation is mediated by activated microglia, which express translocator protein (TSPO), we imaged neuroinflammation in children with infantile spasms using positron emission tomography (PET) with ¹¹C-PK11195 (PK), which selectively binds to TSPO. Children were studied prospectively before and following treatment with Acthar Gel (repository corticotropin injection). We hypothesized that PK-PET would show neuroinflammation (increased PET uptake) in cortical and/or subcortical structures before treatment, and that this inflammation will be abolished/reduced following Acthar Gel treatment. Eight children with infantile spasms (5 males; mean age 1.8±1.1, range 0.9-4.1 years) were recruited. After clinical and video electroencephalograph (EEG) evaluation and dynamic PK-PET scan, children underwent treatment with Acthar Gel over 4 weeks, followed by repeat clinical evaluation/video-EEG 2 weeks after initiation of treatment and repeat PK-PET 2 weeks after treatment completion. Visual and quantitative analysis of PK-PET scans were performed. We calculated regional binding potential (measure of receptor-ligand binding) using a reference tissue model. Focal areas of increased PK-binding were found in the pretreatment PK-PET in 5 children. Following treatment, these increases were either reduced or normalized and were associated with cessation (n=4) or significant reduction (n=1) of spasms and complete disappearance of hypsarrhythmia. One child showed increased binding potential in basal ganglia and thalamus, despite normalization of cortical binding potential; however, these increases were likely associated with death-related causes. This study suggests Acthar Gel-responsive neuroinflammatory changes in children with infantile spasms, supporting a potential role of neuroinflammation in the pathogenesis of infantile spasms.

Evolution of Surgical Management for Intractable Epileptic Spasms

The understanding and management of epileptic spasms has considerably evolved since the mid 19th century. The realization that epileptic spasms can be generated from a focal brain lesion played a pivotal role in the development of neurosurgical management for intractable forms of this epilepsy. During pre-surgical planning, the addition of functional FDG PET imaging has further refined the electroencephalographic localization of epileptogenic lesions. In some cases, neurosurgical resection of a focus that is co-localized by the FDG PET scan and electroencephalography can lead to partial or complete reversal of developmental delay along with reduced seizure frequency or seizure freedom. In cases where near-complete hemispheric cortex is implicated in spasm generation, subtotal hemispherectomy has shown encouraging results. Moreover, palliative resection of the major perpetrating focus in carefully chosen patients with bilateral multifocal spasms has also led to favorable outcomes. However, in patients with tuberous sclerosis with high tuber burden, the localizing value of FDG PET imaging may be limited. In such cases, employment of AMT PET technology has become a valuable tool for localization of actively epileptogenic tubers. This article highlights the historic steps in the successful advancements of neurosurgical interventions for the treatment of intractable epileptic spasms.

Positron Emission Tomography in Pediatric Neurodegenerative Disorders

Application of molecular neuroimaging using positron emission tomographic techniques to assess pediatric neurodegenerative disorders has been limited, unlike in adults where positron emission tomography has contributed to clinical diagnosis, monitoring of neurodegenerative disease progression, and assessment of novel therapeutic approaches. Yet, there is a huge unexplored potential of molecular imaging to improve our understanding of the pathophysiology of neurodegenerative disorders in children and provide radiological biomarkers that can be applied clinically. The obstacles in performing PET scans on children include sedation, radiation exposure, and access but, as will be illustrated, these barriers can be easily overcome. This review summarizes findings from PET studies that have been performed over the past three decades on children with various neurodegenerative disorders, including the neuronal ceroid lipofuscinoses, juvenile Huntington disease, Wilson disease, Niemann-Pick disease type C, Dravet syndrome, dystonia, mitochondrial disorders, inborn errors of metabolism, lysosomal storage diseases, dysmyelinating disorders, Rett syndrome, neurotransmitter disorders, glucose transporter Glut 1 deficiency, and Lesch-Nyhan disease. Because positron emission tomographic scans have often been clinically useful and have contributed to the management of these disorders, we suggest that the time has come for glucose metabolism positron emission tomographic scans to be reimbursed by insurance carriers for children with neurodegenerative disorders, and not restricted only to epilepsy surgery evaluation.

TLR7 activation in epilepsy of tuberous sclerosis complex

BACKGROUND

Neuroinflammation and toll-like receptors (TLR) of the innate immune system have been implicated in epilepsy. We previously reported high levels of microRNAs miR-142-3p and miR-223-3p in epileptogenic brain tissue resected for the treatment of intractable epilepsy in children with tuberous sclerosis complex (TSC). As miR-142-3p has recently been reported to be a ligand and activator of TLR7, a detector of exogenous and endogenous single-stranded RNA, we evaluated TLR7 expression and downstream IL23A activation in surgically resected TSC brain tissue.

METHODS

Gene expression analysis was performed on cortical tissue obtained from surgery of TSC children with pharmacoresistent epilepsy. Expression of TLRs 2, 4 and 7 was measured using NanoString nCounter assays. Real-time quantitative PCR was used to confirm TLR7 expression and compare TLR7 activation, indicated by IL-23A levels, to levels of miR-142-3p. Protein markers characteristic for TLR7 activation were assessed using data from our existing quantitative proteomics dataset of TSC tissue. Capillary electrophoresis Western blots were used to confirm TLR7 protein expression in a subset of samples.

RESULTS

TLR7 transcript expression was present in all TSC specimens. The signaling competent form of TLR7 protein was detected in the membrane fraction of each sample tested. Downstream activation of TLR7 was found in epileptogenic lesions having elevated neuroinflammation indicated by clinical neuroimaging. TLR7 activity was significantly associated with tissue levels of miR-142-3p.

CONCLUSION

TLR7 activation by microRNAs may contribute to the neuroinflammatory cascade in epilepsy in TSC. Further characterization of this mechanism may enable the combined of use of neuroimaging and TLR7 inhibitors in a personalized approach towards the treatment of intractable epilepsy.

Neurological Complications of Sturge-Weber Syndrome: Current Status and Unmet Needs

OBJECTIVE

We aimed to identify the current status and major unmet needs in the management of neurological complications in Sturge-Weber syndrome.

METHODS

An expert panel consisting of neurologists convened during the Sturge-Weber Foundation Clinical Care Network conference in September 2018. Literature regarding current treatment strategies for neurological complications was reviewed.

RESULTS

Although strong evidence-based standards are lacking, the implementation of consensus-based standards of care and outcome measures to be shared across all Sturge-Weber Foundation Clinical Care Network Centers are needed. Each patient with Sturge-Weber syndrome should have an individualized seizure action plan. There is a need to determine the appropriate abortive and preventive treatment of migraine headaches in Sturge-Weber syndrome. Likewise, a better understanding and better diagnostic modalities and treatments are needed for stroke-like episodes. As behavioral problems are common, the appropriate screening tools for mental illnesses and the timing for screening should be established. Brain magnetic resonance imaging (MRI) preferably done after age one year is the primary imaging modality of choice to establish the diagnosis, although advances in MRI techniques can improve presymptomatic diagnosis to identify patients eligible for preventive drug trials.

CONCLUSION

We identified the unmet needs in the management of neurological complications in Sturge-Weber syndrome. We define a minimum standard brain MRI protocol to be used by Sturge-Weber syndrome centers. Future multicenter clinical trials on specific treatments of Sturge-Weber syndrome-associated neurological complications are needed. An improved national clinical database is critically needed to understand its natural course, and for retrospective and prospective measures of treatment efficacy.

Linking spherical mean diffusion weighted signal with intra-axonal volume fraction

Diffusion MRI has been widely used to assess brain tissue microstructure. However, the conventional diffusion tensor imaging (DTI) is inadequate for characterizing fiber direction or fiber density in voxels with crossing fibers in brain white matter. The constrained spherical deconvolution (CSD) technique has been proposed to measure the complex fiber orientation distribution (FOD) using a single high b-value (b ≥ 3000 s/mm²) to derive the intra-axonal volume fraction (V_in) from the calculated FOD. Recently, the spherical mean technique (SMT) was developed to fit V_in directly from a multi-compartment model with multi-shell b-values. Although different numbers of b-values are needed in the two techniques, both methods have been suggested to be related to the spherical mean diffusion weighted signal (S¯). The current study compared the two techniques on the same high-quality Human Connectome Project diffusion data and investigated the relation between S¯ and V_in systematically. At high b-values (b ≥ 3000 s/mm²), S¯ is linearly related to V_in, and S¯ provides similar contrast with V_in in white matter. At low b-values (b ~ 1000 s/mm²), the linear relation between S¯ and V_in is sensitive to the variations of intrinsic diffusivity. These results demonstrate that S¯ measured with the typical b-value of 1000 s/mm² is not an indicator of V_in, and previous DTI studies acquired with b = 1000 s/mm² cannot be re-analyzed to provide V_in-weighted contrast.

Evolution of Brain Glucose Metabolic Abnormalities in Children With Epilepsy and SCN1A Gene Variants

Three children with drug-refractory epilepsy, normal magnetic resonance image (MRI), and a heterozygous SCN1A variant underwent 2-deoxy-2-[¹⁸F]fluoro-d-glucose positron emission tomography (FDG-PET) scanning between age 6 months and 1 year and then at age 3 years 6 months to 5 years 5 months. Regional FDG uptake values were compared to those measured in age- and gender-matched pseudo-controls. At baseline, the brain glucose metabolic pattern in the SCN1A group was similar to that of the pseudo-controls. At follow-up, robust decreases of normalized FDG uptake was found in bilateral frontal, parietal and temporal cortex, with milder decreases in occipital cortex. Children with epilepsy and an SCN1A variant have a normal pattern of cerebral glucose metabolism at around 1 year of age but develop bilateral cortical glucose hypometabolism by age 4 years, with maximal decreases in frontal, parietal, and temporal cortex. This metabolic pattern may be characteristic of epilepsy associated with SCN1A variants and may serve as a biomarker to monitor disease progression and response to treatments.

Imaging Brain Metabolism in the Newborn

In this review, we discuss molecular brain imaging studies using positron emission tomography (PET) with 2-deoxy-2(¹⁸F)fluoro-d-glucose (FDG) in human newborns and infants, and illustrate how this technology can be applied to probe the neuropathophysiology of neonatal neurologic disorders. PET studies have been difficult to perform in sick babies because of patient transportation issues and suboptimal spatial resolution. With approval from the FDA and the institutional review board, we modified and installed the Focus 220 animal microPET scanner (Concorde Microsystems, Knoxville, TN) directly in our neonatal intensive care unit in Children's Hospital of Michigan and verified the high spatial resolution (<2 mm full-width-at-half-maximum) of this microPET. The neonatal pattern of glucose metabolism is very consistent, with the highest degree of activity in primary sensory and motor cortex, medial temporal region, thalamus, brain stem, and cerebellar vermis. Prior studies have shown that increases of glucose utilization are seen by 2 to 3 months in the parietal, temporal, cingulate, and primary visual cortex; basal ganglia; and cerebellar hemispheres. Between 6 and 8 months, lateral and inferior frontal cortex becomes more functionally active and, eventually, between 8 and 12 months, the dorsal and medial frontal regions also show a maturational increase. These findings are consistent with the physical, behavioral, and cognitive maturation of the infant. At birth, metabolic rates of glucose utilization in cortex are about 30% lower than in adults but rapidly rise such that, by 3 years, the cerebral cortical rates exceed adult rates by more than 2-fold. At around puberty, the rates for cerebral cortex begin to decline and gradually reach adult values by 16-18 years. These nonlinear changes of glucose utilization indirectly reflect programed periods of synaptic proliferation and pruning in the brain. Positron emission tomographic (PET) imaging of GABA_A receptors (using ¹¹C-flumazenil) in newborns also show a pattern very different from adults, with high binding in amygdala-hippocampus, sensory-motor cortex, thalamus, brain stem, and basal ganglia, in that order. We speculate that the early development of amygdala/hippocampus prepares the baby for bonding, attachment, and memory, and the deprivation of such experiences during a sensitive period results in malfunction of these networks and psychopathology, as has been shown in studies on severely socioemotionally deprived children. Recently developed hybrid PET/magnetic resonance (MR) scanners allow the simultaneous acquisition of PET and MR data sets with advanced applications. These devices are particularly advantageous for scanning babies and infants because of the high spatial resolution, automated coregistration of anatomical and functional images and, in the case of need for sedation, maximal data acquired in 1 session.

Minimal number of gradient directions for robust measurement of spherical mean diffusion weighted signal

PURPOSE

Determination of the minimum number of gradient directions (N_min) for robust measurement of spherical mean diffusion weighted signal (S¯).

METHODS

Computer simulations were employed to characterize the relative standard deviation (RSD) of the measured spherical mean signal as a function of the number of gradient directions (N). The effects of diffusion weighting b-value and signal-to-noise ratio (SNR) were investigated. Multi-shell high angular resolution Human Connectome Project diffusion data were analyzed to support the simulation results.

RESULTS

RSD decreases with increasing N, and the minimum number of N needed for RSD ≤ 5% is referred to as N_min. At high SNRs, N_min increases with increasing b-value to achieve sufficient sampling. Simulations showed that N_min is linearly dependent on the b-value. At low SNRs, N_min increases with increasing b-value to reduce the noise. RSD can be estimated as σS¯N, where σ = 1/SNR is the noise level. The experimental results were in good agreement with the simulation results. The spherical mean signal can be measured accurately with a subset of gradient directions.

CONCLUSION

As N_min is affected by b-value and SNR, we recommend using 10 × b / b₁ (b₁ = 1 ms/μm²) uniformly distributed gradient directions for typical human diffusion studies with SNR ~ 20 for robust spherical mean signal measurement.

Objective PET study of glucose metabolism asymmetries in children with epilepsy: Implications for normal brain development

Clinical interpretation of cerebral positron emission tomography with 2-deoxy-2[F-18]fluoro-d-glucose (FDG-PET) images often relies on evaluation of regional asymmetries. This study was designed to establish age-related variations in regional cortical glucose metabolism asymmetries in the developing human brain. FDG-PET scans of 58 children (age: 1-18 years) were selected from a large single-center pediatric PET database. All children had a history of epilepsy, normal MRI, and normal pattern of glucose metabolism on visual evaluation. PET images were analyzed objectively by statistical parametric mapping with the use of age-specific FDG-PET templates. Regional FDG uptake was measured in 35 cortical regions in both hemispheres using an automated anatomical labeling atlas, and left/right ratios were correlated with age, gender, and epilepsy variables. Cortical glucose metabolism was mostly symmetric in young children and became increasingly asymmetric in older subjects. Specifically, several frontal cortical regions showed an age-related increase of left > right asymmetries (mean: up to 10%), while right > left asymmetries emerged in posterior cortex (including portions of the occipital, parietal, and temporal lobe) in older children (up to 9%). Similar trends were seen in a subgroup of 39 children with known right-handedness. Age-related correlations of regional metabolic asymmetries showed no robust gender differences and were not affected by epilepsy variables. These data demonstrate a region-specific emergence of cortical metabolic asymmetries between age 1-18 years, with left > right asymmetry in frontal and right > left asymmetry in posterior regions. The findings can facilitate correct interpretation of cortical regional asymmetries on pediatric FDG-PET images across a wide age range.

A Multidisciplinary Consensus for Clinical Care and Research Needs for Sturge-Weber Syndrome

BACKGROUND

Sturge-Weber syndrome is a neurocutaneous disorder associated with port-wine birthmark, leptomeningeal capillary malformations, and glaucoma. It is associated with an unpredictable clinical course. Because of its rarity and complexity, many physicians are unaware of the disease and its complications. A major focus moving ahead will be to turn knowledge gaps and unmet needs into new research directions.

METHODS

On October 1-3, 2017, the Sturge-Weber Foundation assembled clinicians from the Clinical Care Network with patients from the Patient Engagement Network of the Sturge-Weber Foundation to identify our current state of knowledge, knowledge gaps, and unmet needs.

RESULTS

One clear unmet need is a need for consensus guidelines on care and surveillance. It was strongly recommended that patients be followed by multidisciplinary clinical teams with life-long follow-up for children and adults to monitor disease progression in the skin, eye, and brain. Standardized neuroimaging modalities at specified time points are needed together with a stronger clinicopathologic understanding. Uniform tissue banking and clinical data acquisition strategies are needed with cross-center, longitudinal studies that will set the stage for new clinical trials. A better understanding of the pathogenic roles of cerebral calcifications and stroke-like symptoms is a clear unmet need with potentially devastating consequences.

CONCLUSIONS

Biomarkers capable of predicting disease progression will be needed to advance new therapeutic strategies. Importantly, how to deal with the emotional and psychological effects of Sturge-Weber syndrome and its impact on quality of life is a clear unmet need.

Evolution of lobar abnormalities of cerebral glucose metabolism in 41 children with drug-resistant epilepsy

OBJECTIVE

We analyzed long-term changes of lobar glucose metabolic abnormalities in relation to clinical seizure variables and development in a large group of children with medically refractory epilepsy.

METHODS

Forty-one children (25 males) with drug-resistant epilepsy had a baseline positron emission tomography (PET) scan at a median age of 4.7 years; the scans were repeated after a median of 4.3 years. Children with progressive neurological disorders or space-occupying lesion-related epilepsy and those who had undergone epilepsy surgery were excluded. The number of affected lobes on 2-deoxy-2(18 F)-fluoro-D-glucose-PET at baseline and follow-up was correlated with epilepsy variables and developmental outcome.

RESULTS

On the initial PET scan, 24 children had unilateral and 13 had bilateral glucose hypometabolism, whereas 4 children had normal scans. On the follow-up scan, 63% of the children showed an interval expansion of the hypometabolic region, and this progression was associated with persistent seizures. In contrast, 27% showed less extensive glucose hypometabolism at follow-up; most of these subjects manifested a major interval decrease in seizure frequency. Delayed development was observed in 21 children (51%) at baseline and 28 (68%) at follow-up. The extent of glucose hypometabolism at baseline correlated with developmental levels at the time of both baseline (r = .31, P = .05) and follow-up scans (r = .27, P = .09).

SIGNIFICANCE

In this PET study of unoperated children with focal epilepsy, the lobar pattern of glucose hypometabolism changed over time in 90% of the cases. The results support the notion of an expansion of metabolic dysfunction in children with persistent frequent seizures and its association with developmental delay, and support that optimized medical treatment to control seizures may contribute to better neurocognitive outcome if no surgery can be offered.

Cognitive and motor outcomes in children with unilateral Sturge-Weber syndrome: Effect of age at seizure onset and side of brain involvement

PURPOSE

Most children with Sturge-Weber syndrome (SWS) develop seizures that may contribute to neurocognitive status. In this study, we tested the hypothesis that very early seizure onset has a particularly detrimental effect on the cognitive and/or motor outcomes of children with unilateral SWS. We also tested whether side of SWS brain involvement modulates the effect of seizure variables on the pattern of cognitive abnormalities.

METHODS

Thirty-four children (22 girls; mean age 6.1years) with unilateral SWS and history of epilepsy in a longitudinal cohort underwent neurological and cognitive evaluations. Global intelligent quotient (GIQ), verbal intelligent quotient (VIQ), nonverbal intelligent quotient (IQ), and motor function were correlated with epilepsy variables, side and extent of brain involvement on magnetic resonance imaging (MRI).

RESULTS

Mean age at seizure onset was 1.3years (0.1-6years) and mean IQ at follow-up was 86 (45-118). Age at seizure onset showed a logarithmic association with IQ, with maximum impact of seizures starting before age 1year, both in uni- and multivariate regression analyses. In the left SWS group (N=20), age at seizure onset was a strong predictor of nonverbal IQ (p=0.001); while early seizure onset in the right-hemispheric group had a more global effect on cognitive functions (p=0.02). High seizure frequency and long epilepsy duration also contributed to poor outcome IQ independently in multivariate correlations. Children with motor involvement started to have seizures at/before 7months of age, while frontal lobe involvement was the strongest predictor of motor deficit in a multivariate analysis (p=0.017).

CONCLUSION

These findings suggest that seizure onset prior to age 1year has a profound effect on severity of cognitive and motor dysfunction in children with SWS; however, the effect of seizures on the type of cognitive deficit is influenced by laterality of brain involvement.

Postoperative axonal changes in the contralateral hemisphere in children with medically refractory epilepsy: A longitudinal diffusion tensor imaging connectome analysis

To determine brain plasticity changes due to resective epilepsy surgery in children, we performed a longitudinal connectome analysis on the pattern of axonal connectivity in the contralateral hemisphere. Pre- and postoperative diffusion tensor imaging (DTI) data were acquired from 35 children with intractable focal epilepsy. A total of 54 brain regions of interest (ROIs) were generated in the hemisphere contralateral to the resection. Within a 54 × 54 connectivity matrix, a pairwise connectivity score was calculated for each connection between two ROIs, based on the DTI fiber streamline number in each connection. A permuted Spearman's ρ-rank analysis was used to identify specific inter-regional connections showing a significant association between the postoperative change of connectivity score and clinical variables. Nineteen connections in the contralateral hemisphere showed postoperative increases in the strength of connectivity. Postoperative increase in connectivity between insular-inferior frontal operculum regions as well as that between superior frontal orbital and mid frontal orbital regions were both significantly associated with a larger surgical resection volume (ρ > +0.40) and a younger patient age (ρ > -0.34). These increases were more robust in patients with frontal resection and in those achieving seizure freedom. Neuropsychological evaluation on subsets of patients revealed that such increases in connectivity were associated with preserved or improved cognitive functions such as visual memory and planning. Resective epilepsy surgery may lead to increased contralateral axonal connectivity in children with focal epilepsy. Our data lead to a hypothesis that such increased connectivity may be an imaging marker of postoperative brain plasticity to compensate for cognitive function. Hum Brain Mapp 37:3946-3956, 2016. © 2016 Wiley Periodicals, Inc.

Metabolic correlates of cognitive function in children with unilateral Sturge-Weber syndrome: Evidence for regional functional reorganization and crowding

To evaluate metabolic changes in the ipsi- and contralateral hemisphere in children showing a cognitive profile consistent with early reorganization of cognitive function, we evaluated the regional glucose uptake, interhemispheric metabolic connectivity, and cognitive function in children with unilateral SWS. Interictal 2-deoxy-2[¹⁸ F]fluoro-D-glucose (FDG)-PET scans of 27 children with unilateral SWS and mild epilepsy and 27 age-matched control (non-SWS children with epilepsy and normal FDG-PET) were compared using statistical parametric mapping (SPM). Regional FDG-PET abnormalities calculated as SPM(t) scores in the SWS group were correlated with cognitive function (IQ) in left- and right-hemispheric subgroups. Interhemispheric metabolic connectivity between homotopic cortical regions was also calculated. Verbal IQ was substantially (≥10 points difference) higher than non-verbal IQ in 61% of the right- and 71% of the left-hemispheric SWS group. FDG SPM(t) scores in the affected hemisphere showed strong positive correlations with IQ in the left-hemispheric, but not in right-hemispheric SWS group in several frontal, parietal, and temporal cortical regions. Significant positive interhemispheric metabolic connectivity, present in controls, was diminished in the SWS group. In addition, the left-hemispheric SWS group showed inverse metabolic interhemispheric correlations in specific parietal, temporal, and occipital regions. FDG SPM(t) scores in the same regions of the right (unaffected) hemisphere showed inverse correlations with IQ. These findings suggest that left-hemispheric lesions in SWS often result in early reorganization of verbal functions while interfering with ("crowding") their non-verbal cognitive abilities. These cognitive changes are associated with specific metabolic abnormalities in the contralateral hemisphere not directly affected by SWS.

A distinct microRNA expression profile is associated with α[11C]-methyl-L-tryptophan (AMT) PET uptake in epileptogenic cortical tubers resected from patients with tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is characterized by hamartomatous lesions in various organs and arises due to mutations in the TSC1 or TSC2 genes. TSC mutations lead to a range of neurological manifestations including epilepsy, cognitive impairment, autism spectrum disorders (ASD), and brain lesions that include cortical tubers. There is evidence that seizures arise at or near cortical tubers, but it is unknown why some tubers are epileptogenic while others are not. We have previously reported increased tryptophan metabolism measured with α[¹¹C]-methyl-l-tryptophan (AMT) positron emission tomography (PET) in epileptogenic tubers in approximately two-thirds of patients with tuberous sclerosis and intractable epilepsy. However, the underlying mechanisms leading to seizure onset in TSC remain poorly characterized. MicroRNAs are enriched in the brain and play important roles in neurodevelopment and brain function. Recent reports have shown aberrant microRNA expression in epilepsy and TSC. In this study, we performed microRNA expression profiling in brain specimens obtained from TSC patients undergoing epilepsy surgery for intractable epilepsy. Typically, in these resections several non-seizure onset tubers are resected together with the seizure-onset tubers because of their proximity. We directly compared seizure onset tubers, with and without increased tryptophan metabolism measured with PET, and non-onset tubers to assess the role of microRNAs in epileptogenesis associated with these lesions. Whether a particular tuber was epileptogenic or non-epileptogenic was determined with intracranial electrocorticography, and tryptophan metabolism was measured with AMT PET. We identified a set of five microRNAs (miR-142-3p, 142-5p, 223-3p, 200b-3p and 32-5p) that collectively distinguish among the three primary groups of tubers: non-onset/AMT-cold (NC), onset/AMT-cold (OC), and onset/AMT-hot (OH). These microRNAs were significantly upregulated in OH tubers compared to the other two groups, and microRNA expression was most significantly associated with AMT-PET uptake. The microRNAs target a group of genes enriched for synaptic signaling and epilepsy risk, including SLC12A5, SYT1, GRIN2A, GRIN2B, KCNB1, SCN2A, TSC1, and MEF2C. We confirmed the interaction between miR-32-5p and SLC12A5 using a luciferase reporter assay. Our findings provide a new avenue for subsequent mechanistic studies of tuber epileptogenesis in TSC.

GNAQ Mutation in the Venous Vascular Malformation and Underlying Brain Tissue in Sturge-Weber Syndrome

The recent identification of the somatic GNAQ mutation (c.548G > A) provides insight into the pathogenesis of Sturge–Weber syndrome (SWS). Although the primary SWS brain pathology is the leptomeningeal angiomatosis (LMA), cerebral cortical and white matter abnormalities play a prominent role in the disease manifestations. In some cases, SWS brain involvement is present even without detectable LMA on magnetic resonance imaging (MRI). To expand our understanding of the etiology of SWS brain pathology, surgical SWS brain specimens from nine children (age: 0.8–7.5 years) were carefully separated into LMA and (non-LMA) brain tissue; the latter did not contain any vascular malformation. A custom Competitive Allele-Specific TaqMan PCR (castPCR) assay to detect the mutation in GNAQ was performed in these separated specimens. The mutation was present in all nine LMA and seven of the nine non-LMA brain tissues. LMA tissues were significantly enriched by the mutation, as compared with non-LMA brain (mean: 7.2 ± 2.1% and 1.2 ± 0.4%, respectively; p = 0.008). These results demonstrate that the somatic GNAQ mutation in SWS is not confined to the venous vascular malformation but can directly (although less severely) affect underlying brain parenchyma, not directly affected by LMA, and possibly contribute to SWS brain pathology. Future studies should identify the specific cell type(s) affected by the mutation in the SWS-affected brain parenchyma.

Clinical and metabolic correlates of cerebral calcifications in Sturge-Weber syndrome

AIM

To evaluate clinical and metabolic correlates of cerebral calcifications in children with Sturge-Weber syndrome (SWS).

METHOD

Fifteen children (11 females, four males; age range 7mo-9y, mean 4y 1mo) with unilateral SWS underwent baseline and follow-up magnetic resonance imaging (MRI) with susceptibility weighted imaging (SWI), glucose metabolism positron emission tomography (PET), and neurocognitive assessment (mean follow-up 1y 8mo). Calcified brain volumes measured on SWI were correlated with areas of abnormal glucose metabolism, seizure variables, and cognitive function (IQ).

RESULTS

Ten children had brain calcification at baseline and 11 at follow-up. Mean calcified brain volume increased from 1.69 to 2.47cm³ (p=0.003) in these children; the rate of interval calcified volume increase was associated with early onset of epilepsy (Spearman's rho [r_s ]=-0.63, p=0.036). Calcified brain regions showed a variable degree of glucose hypometabolism with the metabolic abnormalities often extending to non-calcified cerebral lobes. Larger calcified brain volumes at baseline were associated with longer duration of epilepsy (r_s =0.69, p=0.004) and lower outcome IQ (r_s =-0.53, p=0.042).

INTERPRETATION

Brain calcifications are common and progress faster in children with SWS with early epilepsy onset, and are associated with a variable degree of hypometabolism, which is typically more extensive than the calcified area. Higher calcified brain volumes may indicate a risk for poorer neurocognitive outcome.

Corpus Callosotomy for Intractable Epilepsy Revisited: The Children's Hospital of Michigan Series

Corpus callosotomy is a palliative procedure performed to reduce the severity of drug-resistant epilepsy. The authors assessed its efficacy on different seizure types in 20 subjects (age range 5-19 years); 8 with active vagus nerve stimulator. Fifteen had complete callosotomy, 3 had anterior 2/3, and 2 had anterior 2/3 followed later by complete callosotomy. Ten had endoscopic approach. In all, 65% had ≥ 50% reduction of generalized seizures leading to falls (atonic, tonic, myoclonic); 35% became seizure-free (follow-up period: 6 months to 9 years; mean 3 years). Seizure outcome distribution was better for generalized than for partial seizures ( P = .003). Endoscopic approach was as effective as transcranial approach. Seven subjects who failed vagus nerve stimulator therapy responded with ≥50% seizure reduction. Corpus callosotomy is an effective treatment for intractable generalized epilepsy leading to falls with significant seizure reduction or even elimination of seizures, in the majority of children.

Objective 3D surface evaluation of intracranial electrophysiologic correlates of cerebral glucose metabolic abnormalities in children with focal epilepsy

To determine the spatial relationship between 2-deoxy-2[¹⁸ F]fluoro-D-glucose (FDG) metabolic and intracranial electrophysiological abnormalities in children undergoing two-stage epilepsy surgery, statistical parametric mapping (SPM) was used to correlate hypo- and hypermetabolic cortical regions with ictal and interictal electrocorticography (ECoG) changes mapped onto the brain surface. Preoperative FDG-PET scans of 37 children with intractable epilepsy (31 with non-localizing MRI) were compared with age-matched pseudo-normal pediatric control PET data. Hypo-/hypermetabolic maps were transformed to 3D-MRI brain surface to compare the locations of metabolic changes with electrode coordinates of the ECoG-defined seizure onset zone (SOZ) and interictal spiking. While hypometabolic clusters showed a good agreement with the SOZ on the lobar level (sensitivity/specificity = 0.74/0.64), detailed surface-distance analysis demonstrated that large portions of ECoG-defined SOZ and interictal spiking area were located at least 3 cm beyond hypometabolic regions with the same statistical threshold (sensitivity/specificity = 0.18-0.25/0.94-0.90 for overlap 3-cm distance); for a lower threshold, sensitivity for SOZ at 3 cm increased to 0.39 with a modest compromise of specificity. Performance of FDG-PET SPM was slightly better in children with smaller as compared with widespread SOZ. The results demonstrate that SPM utilizing age-matched pseudocontrols can reliably detect the lobe of seizure onset. However, the spatial mismatch between metabolic and EEG epileptiform abnormalities indicates that a more complete SOZ detection could be achieved by extending intracranial electrode coverage at least 3 cm beyond the metabolic abnormality. Considering that the extent of feasible electrode coverage is limited, localization information from other modalities is particularly important to optimize grid coverage in cases of large hypometabolic cortex. Hum Brain Mapp 38:3098-3112, 2017. © 2017 Wiley Periodicals, Inc.

The Role of Radionuclide Imaging in Epilepsy, Part 1: Sporadic Temporal and Extratemporal Lobe Epilepsy

Epilepsy is one of the most common yet diverse neurologic disorders, affecting almost 1%-2% of the population. Presently, radionuclide imaging such as PET and SPECT is not used in the primary diagnosis or evaluation of recent-onset epilepsy. However, it can play a unique and important role in certain specific situations, such as in noninvasive presurgical localization of epileptogenic brain regions in intractable-seizure patients being considered for epilepsy surgery. Radionuclide imaging can be particularly useful if MR imaging is either negative for lesions or shows several lesions of which only 1 or 2 are suspected to be epileptogenic and if electroencephalogram changes are equivocal or discordant with the structural imaging. Similarly, PET and SPECT can also be useful for evaluating the functional integrity of the rest of the brain and may provide useful information on the possible pathogenesis of the neurocognitive and behavioral abnormalities frequently observed in these patients.

Agenesis of the Corpus Callosum and Aicardi Syndrome: A Neuroimaging and Clinical Comparison

BACKGROUND

Agenesis of the corpus callosum can occur in individuals with epilepsy, either in isolation or as part of various neurological conditions, such as Aicardi syndrome. In this study, we evaluated the clinical and neuroradiological differences between children with nonsyndromic agenesis of the corpus callosum and those with Aicardi syndrome.

METHODS

We evaluated 31 children with epilepsy and agenesis of the corpus callosum (11 males, 20 females), 14 of whom had Aicardi syndrome (all females). We compared their clinical evaluations, radiological and electrophysiological findings, treatments, and their outcome.

RESULTS

Median age at seizure onset was lower in the Aicardi syndrome group compared with nonsyndromic agenesis of the corpus callosum (two versus five months, P = 0.006). The developmental impairment in terms of verbalization and ambulation was significantly worse in patients with Aicardi syndrome. The severity of magnetic resonance imaging (MRI) and glucose metabolism positron emission tomography (PET) involvement was more extensive in children with Aicardi syndrome than in nonsyndromic agenesis of the corpus callosum. In both groups, the PET scan showed a much more extensive area of involvement than suggested by the MRI scan. Four children underwent epilepsy surgery with significant improvement, but were not seizure free. Outcome was worse in those with PET showing abnormalities in the nonsurgical hemisphere despite normal appearance on MRI. All children who did not undergo surgery also continued to have seizures at last follow-up.

CONCLUSIONS

Children with Aicardi syndrome have earlier seizure onset, worse developmental outcome, and larger areas of brain abnormalities on neuroimaging compared with nonsyndromic agenesis of the corpus callosum patients. PET reveals larger area of abnormalities, compared with MRI. Although epilepsy surgery in agenesis of the corpus callosum may offer some palliative benefit in seizure frequency, none of our patients became seizure free.

Predictors of Cognitive Functions in Children With Sturge-Weber Syndrome: A Longitudinal Study

BACKGROUND

Sturge-Weber syndrome is often accompanied by seizures and neurocognitive deterioration, although previous studies have suggested that early functional brain reorganization may diminish the cognitive sequelae in some children with unilateral Sturge-Weber syndrome. The "rules" governing these plasticity mechanisms are poorly understood. In this study, we evaluated longitudinal changes of cognitive functioning (intelligence quotient [IQ]) and assessed the performance of clinical, electroencephalography (EEG), and magnetic resonance imaging (MRI) variables for predicting IQ in children with Sturge-Weber syndrome.

METHODS

Thirty-three young children (mean age: 3.3 years at baseline) with unilateral Sturge-Weber syndrome underwent MRI, scalp EEG, and neuropsychology evaluation twice, with a median follow-up of 2 years. None of the children had epilepsy surgery. Longitudinal IQ changes were calculated. Seizure variables, interictal EEG abnormalities, and extent and location of MRI brain involvement were correlated with IQ assessed at follow-up.

RESULTS

Global IQ showed a highly variable course with both increases and decreases over time. Lower IQ at baseline was associated with interval IQ increase. In univariate analyses, lower outcome IQ was associated with baseline EEG abnormalities (P < 0.001), young age at seizure onset (P = 0.001), high seizure frequency (P = 0.02), and early frontal-lobe involvement on MRI (P = 0.01). In multivariate analysis, EEG abnormalities at baseline remained a robust, independent predictor of outcome IQ.

CONCLUSIONS

The early trajectory of cognitive changes in children with unilateral Sturge-Weber syndrome is highly variable; children with improving IQ likely undergo effective unimpeded functional reorganization. Early onset, frequent seizures, and interictal epileptiform abnormalities on EEG likely interfere with this process resulting in poor cognitive functions. Future studies assessing interventions should target this high-risk subgroup to optimize cognitive outcome in Sturge-Weber syndrome.

Autism Spectrum Disorders in Africa: Current Challenges in Identification, Assessment, and Treatment: A Report on the International Child Neurology Association Meeting on ASD in Africa, Ghana, April 3-5, 2014

Prevalence of autism spectrum disorders has increased over recent years, however, little is known about the identification and management of autism spectrum disorder in Africa. This report summarizes a workshop on autism spectrum disorder in Africa under the auspices of the International Child Neurology Association and the African Child Neurology Association through guided presentations and working group reports, focusing on identification, diagnosis, management, and community support. A total of 47 delegates participated from 14 African countries. Although there was a huge variability in services across the countries represented, numbers of specialists assessing and managing autism spectrum disorder was small relative to populations served. Strategies were proposed to improve identification, diagnosis, management and support delivery for individuals with autism spectrum disorder across Africa in these culturally diverse, low-resource settings. Emphasis on raising public awareness through community engagement and improving access to information and training in autism spectrum disorder. Special considerations for the cultural, linguistic, and socioeconomic factors within Africa are discussed.

Review : Metabolic Imaging: A Window on Brain Development and Plasticity

Various biochemical and physiological processes that undergo maturational changes during human brain development can be now studied in vivo using PET. The distribution of local cerebral glucose utilization shows regional alterations in the first year of life in agreement with behavioral, neurophysiological, and anatomical changes known to occur during development of the infant. Measurement of the absolute rates of glucose utilization with PET reveals that during the major portion of the first decade, the human brain has a higher energy (glucose) demand compared with both the newborn and adult brains. With adolescence, glucose utilization rates decline to reach adult values by age 16-18 years. This nonlinear course of cerebral glucose 'metabolic' maturation is also seen in a number of animal models and coincides with the develop mental course of transient synaptic exuberance associated with enhanced brain plasticity and efficient learn ing. Evidence of brain reorganization detected with PET is discussed in children with unilateral brain injury and early sensory deprivation. NEUROSCIENTIST 5:29-40, 1999

Cortical thickness asymmetries and surgical outcome in neocortical epilepsy

PURPOSE

We evaluated if cortical thickness measures were associated with surgical outcome in patients with non-lesional neocortical epilepsy.

METHODS

Twenty-one young patients (age: 2.4-19.7years) with epilepsy of neocortical origin and normal MRI underwent two-stage epilepsy surgery with subdural EEG monitoring. Cortical thickness was measured on presurgical volumetric MRI using the FreeSurfer software. The prognostic value of hemispheric and lobar/regional cortical thickness measures for 1-year and 2-year post-surgical seizure outcome has been analyzed.

RESULTS

At one-year follow-up, 14 patients (67%) were seizure-free. Hemispheric and frontal lobe cortical thickness showed no/minimal asymmetry in seizure-free patients but thinner cortex ipsilateral to the seizure focus in those with recurrent seizures (p=0.02). More robust differences were found in patients≥6years of age (p=0.006 for frontal asymmetries), whose cortical thickness asymmetries remained prognostic for 2-year post-surgical outcome (p=0.007). By using an optimal cutoff threshold based on a receiver operating characteristic analysis, mean hemispheric asymmetry predicted one-year seizure freedom with 93% sensitivity and 71% specificity in the whole group, and with 100% sensitivity and 92% specificity in patients≥6years of age.

CONCLUSION

In patients with neocortical epilepsy and normal MRI, neocortical thinning in the epileptic hemisphere, particularly in frontal cortex, is associated with poor surgical outcome. Although these results require validation in a larger cohort prospectively, these data suggest that presurgical evaluation of cortical thickness may assist in identification of patients at high risk for surgical failure.

Relationship between genotype and arcuate fasciculus morphology in six young children with global developmental delay: Preliminary DTI stuy

PURPOSE

To investigate whether different genetic mutations observed in children with global developmental delay (GD) are associated with unique patterns of the arcuate fasciculus dysmorphology.

MATERIALS AND METHODS

Six children with GD (age: 36.8 ± 14.1 months, 5 boys) having mutations in MID1, CDK4, SFRP1, EN2, RXRG-GLRB, or MECP2, and five children with typical development (TD, age: 38.5 ± 20.5 months, 4 boys) underwent a 3 Tesla MRI including diffusion weighted imaging (DWI). Five language pathway segments in the left hemisphere, "C₁ : Broca's to Wernicke's area," "C₂ : Broca's to premotor area," "C₃ : premotor to Wernicke's area," "C₄ : Wernicke's to inferior parietal area," and "C₅ : premotor to inferior parietal area" were objectively identified using the DWI "maximum a posteriori probability" classifier.

RESULTS

Affinity propagation clustering analysis found that three arcuate pathway segments, C_1,2,4 , of MID1, CDK4, EN2, and MECP2 had a similar pattern of volume ratio while those of SFRP1 and RXRG-GLRB had a heterogeneous pattern of volume ratio (net similarity = -0.01). Using receiver operating characteristic curve analysis, the fiber ratios of C_1,2,4 showed a high probability to discriminate between GD and TD, yielding an accuracy of 0.91, 0.91, 1.00, respectively. The fiber volumes of C₁ and C₄ showed a strong correlation with expressive language (R²  = 0.6019; P-value = 0.033) and receptive language (R²  = 0.6379; P-value = 0.028), respectively.

CONCLUSION

The findings of the present study provide preliminary evidence to suggest that different segments of the arcuate fasciculus are formed under the regulation of different genes which, when mutated, may result in developmental delay. J. Magn. Reson. Imaging 2016;44:1504-1512.

Efficacy of Low-Dose Buspirone for Restricted and Repetitive Behavior in Young Children with Autism Spectrum Disorder: A Randomized Trial

OBJECTIVES

To determine safety and efficacy of the 5HT1A serotonin partial agonist buspirone on core autism and associated features in children with autism spectrum disorder (ASD).

STUDY DESIGN

Children 2-6 years of age with ASD (N = 166) were randomized to receive placebo or 2.5 or 5.0 mg of buspirone twice daily. The primary objective was to evaluate the effects of 24 weeks of buspirone on the Autism Diagnostic Observation Schedule (ADOS) Composite Total Score. Secondary objectives included evaluating the effects of buspirone on social competence, repetitive behaviors, language, sensory dysfunction, and anxiety and to assess side effects. Positron emission tomography measures of tryptophan metabolism and blood serotonin concentrations were assessed as predictors of buspirone efficacy.

RESULTS

There was no difference in the ADOS Composite Total Score between baseline and 24 weeks among the 3 treatment groups (P = .400); however, the ADOS Restricted and Repetitive Behavior score showed a time-by-treatment effect (P = .006); the 2.5-mg buspirone group showed significant improvement (P = .003), whereas placebo and 5.0-mg buspirone groups showed no change. Children in the 2.5-mg buspirone group were more likely to improve if they had fewer foci of increased brain tryptophan metabolism on positron emission tomography (P = .018) or if they showed normal levels of blood serotonin (P = .044). Adverse events did not differ significantly among treatment groups.

CONCLUSIONS

Treatment with 2.5 mg of buspirone in young children with ASD might be a useful adjunct therapy to target restrictive and repetitive behaviors in conjunction with behavioral interventions.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00873509.

Imaging increased glutamate in children with Sturge-Weber syndrome: Association with epilepsy severity

BACKGROUND

Sturge-Weber syndrome (SWS) is strongly associated with epilepsy. Brain tissue studies have suggested that epileptic activity in SWS is driven by glutamatergic synaptic activity. Here, we used proton magnetic resonance spectroscopic imaging (MRSI) to test if glutamate (GLU) concentrations are increased in the affected hemisphere and if such increases are associated with severity of epilepsy in children with SWS. We also studied the metabolic correlates of MRSI abnormalities, using glucose positron emission tomography (PET) imaging.

METHODS

3T MRI and glucose PET were performed in 10 children (age: 7-78 months) with unilateral SWS and a history of epilepsy. MRSI data were acquired from the affected (ipsilateral) and non-affected (contralateral) hemispheres. GLU, N-acetyl-aspartate (NAA) and creatine (Cr) were quantified in multiple voxels; GLU/Cr and NAA/Cr ratios were calculated and compared to seizure frequency as well as glucose PET findings.

RESULTS

The highest GLU/Cr ratios were found in the affected hemisphere in all children except one with severe atrophy. The maximum ipsilateral/contralateral GLU/Cr ratios ranged between 1.0 and 2.5 (mean: 1.6). Mean ipsilateral/contralateral GLU/Cr ratios were highest in the youngest children and showed a strong positive correlation with clinical seizure frequency scores assessed at the time of the scan (r=0.88, p=0.001) and also at follow-up (up to 1 year, r=0.80, p=0.009). GLU increases in the affected hemisphere coincided with areas showing current or previous increases of glucose metabolism on PET in 5 children. NAA/Cr ratios showed no association with clinical seizure frequency.

CONCLUSIONS

Increased glutamate concentrations in the affected hemisphere, measured by MRSI, are common in young children with unilateral SWS and are associated with frequent seizures. The findings lend support to the role of excess glutamate in SWS-associated epilepsy.

Frontal Aslant Tract Abnormality on Diffusion Tensor Imaging in an Aphasic Patient With 49, XXXXY Syndrome

BACKGROUND

The karyotype 49, XXXXY is one of the most severe forms of chromosome aneuploidy and is characterized clinically by developmental delay and profound language impairment, particularly involving expressive language functions. We describe the neurocognitive profile and structural anatomy of language pathway in a 2-year-old boy with 49, XXXXY syndrome with expressive aphasia.

METHODS

Retrospective chart review of the patient was performed. We characterized the language deficits using neuropsychologic testing. We further studied the language pathways using diffusion tensor imaging analytical technique.

RESULTS

The neurocognitive profile of the patient showed relative weakness of expressive language skills compared with other domains. Diffusion tensor imaging analysis demonstrated a poorly developed frontal aslant tract, a weak indirect segment of arcuate fasciculus, and normally developed direct segment of arcuate fasciculus. The frontal aslant tract is a novel pathway that connects the Broca's area with the anterior cingulate and presupplementary motor area and plays a role in the "motor stream" of language.

CONCLUSION

A poorly developed frontal aslant tract may underlie the expressive language deficits and provide some insight into the role of X chromosome in modulating the development of language tracts.

Differentiation of Speech Delay and Global Developmental Delay in Children Using DTI Tractography-Based Connectome

BACKGROUND AND PURPOSE

Pure speech delay is a common developmental disorder which, according to some estimates, affects 5%-8% of the population. Speech delay may not only be an isolated condition but also can be part of a broader condition such as global developmental delay. The present study investigated whether diffusion tensor imaging tractography-based connectome can differentiate global developmental delay from speech delay in young children.

MATERIALS AND METHODS

Twelve children with pure speech delay (39.1 ± 20.9 months of age, 9 boys), 14 children with global developmental delay (39.3 ± 18.2 months of age, 12 boys), and 10 children with typical development (38.5 ± 20.5 months of age, 7 boys) underwent 3T DTI. For each subject, whole-brain connectome analysis was performed by using 116 cortical ROIs. The following network metrics were measured at individual regions: strength (number of the shortest paths), efficiency (measures of global and local integration), cluster coefficient (a measure of local aggregation), and betweeness (a measure of centrality).

RESULTS

Compared with typical development, global and local efficiency were significantly reduced in both global developmental delay and speech delay (P < .0001). The nodal strength of the cognitive network is reduced in global developmental delay, whereas the nodal strength of the language network is reduced in speech delay. This finding resulted in a high accuracy of >83% ± 4% to discriminate global developmental delay from speech delay.

CONCLUSIONS

The network abnormalities identified in the present study may underlie the neurocognitive and behavioral consequences commonly identified in children with global developmental delay and speech delay. Further validation studies in larger samples are required.

Surgical treatment for refractory epileptic spasms: The Detroit series

OBJECTIVE

We reviewed our experience of surgery for epileptic spasms (ES) with or without history of infantile spasms.

METHODS

Data were reviewed from 65 (33 male) patients with ES who underwent surgery between 1993 and 2014; palliative cases were excluded.

RESULTS

Mean age at surgery was 5.1 (range 0.2-19) years, with mean postsurgical follow-up of 45.3 (6-120) months. Mean number of anticonvulsants used preoperatively was 4.2 (2-8), which decreased to 1.2 (0-4) postoperatively (p < 0.0001). Total hemispherectomy was the most commonly performed surgery (n = 20), followed by subtotal hemispherectomy (n = 17), multilobar resection (n = 13), lobectomy (n = 7), tuberectomy (n = 6), and lobectomy + tuberectomy (n = 2), with International League Against Epilepsy (ILAE) class I outcome in 20, 10, 7, 6, 3, and 0 patients, respectively (total 46/65 (71%); 22 off medication). Shorter duration of epilepsy (p = 0.022) and presence of magnetic resonance imaging (MRI) lesion (p = 0.026) were independently associated with class I outcome. Of 34 patients operated <3 years after seizure onset, 30 (88%) achieved class I outcome. Thirty-seven (79%) of 47 patients with lesional MRI had class-I outcome, whereas 9 (50%) of 18 with normal MRI had class I outcome. Positron emission tomography (PET) scan was abnormal in almost all patients [61 (97%) of 63 with lateralizing/localizing findings in 56 (92%) of 61 patients, thus helping in surgical decision making and guiding subdural grid placements, particularly in patients with nonlesional MRI. Fifteen patients had postoperative complications, mostly minor.

SIGNIFICANCE

Curative epilepsy surgery in ES patients, with or without history of infantile spasms, is best accomplished at an early age and in those patients with lesional abnormalities on MRI with electroencephalography (EEG) concordance. Good outcomes can be achieved even when there is no MRI lesion but positive PET localization.

Alternating Hemiplegia of Childhood: Retrospective Genetic Study and Genotype-Phenotype Correlations in 187 Subjects from the US AHCF Registry

Mutations in ATP1A3 cause Alternating Hemiplegia of Childhood (AHC) by disrupting function of the neuronal Na+/K+ ATPase. Published studies to date indicate 2 recurrent mutations, D801N and E815K, and a more severe phenotype in the E815K cohort. We performed mutation analysis and retrospective genotype-phenotype correlations in all eligible patients with AHC enrolled in the US AHC Foundation registry from 1997-2012. Clinical data were abstracted from standardized caregivers’ questionnaires and medical records and confirmed by expert clinicians. We identified ATP1A3 mutations by Sanger and whole genome sequencing, and compared phenotypes within and between 4 groups of subjects, those with D801N, E815K, other ATP1A3 or no ATP1A3 mutations. We identified heterozygous ATP1A3 mutations in 154 of 187 (82%) AHC patients. Of 34 unique mutations, 31 (91%) are missense, and 16 (47%) had not been previously reported. Concordant with prior studies, more than 2/3 of all mutations are clustered in exons 17 and 18. Of 143 simplex occurrences, 58 had D801N (40%), 38 had E815K (26%) and 11 had G937R (8%) mutations. Patients with an E815K mutation demonstrate an earlier age of onset, more severe motor impairment and a higher prevalence of status epilepticus. This study further expands the number and spectrum of ATP1A3 mutations associated with AHC and confirms a more deleterious effect of the E815K mutation on selected neurologic outcomes. However, the complexity of the disorder and the extensive phenotypic variability among subgroups merits caution and emphasizes the need for further studies.

Detection of hand and leg motor tract injury using novel diffusion tensor MRI tractography in children with central motor dysfunction

PURPOSE

To examine whether an objective segmenation of corticospinal tract (CST) associated with hand and leg movements can be used to detect central motor weakness in the corresponding extremities in a pediatric population.

MATERIAL AND METHODS

This retrospective study included diffusion tensor imaging (DTI) of 25 children with central paresis affecting at least one limb (age: 9.0±4.2years, 15 boys, 5/13/7 children with left/right/both hemispheric lesions including ischemia, cyst, and gliosis), as well as 42 pediatric control subjects with no motor dysfunction (age: 9.0±5.5years, 21 boys, 31 healthy/11 non-lesional epilepsy children). Leg- and hand-related CST pathways were segmented using DTI-maximum a posteriori (DTI-MAP) classification. The resulting CST volumes were then divided by total supratentorial white matter volume, resulting in a marker called "normalized streamline volume ratio (NSVR)" to quantify the degree of axonal loss in separate CST pathways associated with leg and hand motor functions. A receiver operating characteristic curve was applied to measure the accuracy of this marker to identify extremities with motor weakness.

RESULTS

NSVR values of hand/leg CST selectively achieved the following values of accuracy/sensitivity/specificity: 0.84/0.84/0.57, 0.82/0.81/0.55, 0.78/0.75/0.55, 0.79/0.81/0.54 at a cut-off of 0.03/0.03/0.03/0.02 for right hand CST, left hand CST, right leg CST, and left leg CST, respectively. Motor weakness of hand and leg was most likely present at the cut-off values of hand and leg NSVR (i.e., 0.029/0.028/0.025/0.020 for left-hand/right-hand/left-leg/right-leg). The control group showed a moderate age-related increase in absolute CST volumes and a biphasic age-related variation of the normalized CST volumes, which were lacking in the paretic children.

CONCLUSIONS

This study demonstrates that DTI-MAP classification may provide a new imaging tool to quantify axonal loss in children with central motor dysfunction. Using this technique, we found that early-life brain lesions affect the maturational trajectory of the primary motor pathway which may be used as an effective marker to facilitate evidence-based treatment of paretic children.

Evaluation of basal ganglia and thalamic inflammation in children with pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection and tourette syndrome: a positron emission tomographic (PET) study using 11C-[R]-PK11195

We applied PET scanning with (11)C-[R]-PK11195 (PK) to evaluate neuroinflammatory changes in basal ganglia and thalamus in children with clinically diagnosed pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) and Tourette syndrome. Seventeen children with PANDAS (mean age: 11.4 ± 2.6 years; 13 males), 12 with Tourette syndrome (mean age: 11.0 ± 3.0 years; 10 males), and 15 normal adults (mean age: 28.7 ± 7.9 years; 8 males) underwent dynamic PK PET imaging and binding potential, a measure of ligand-TSPO receptor (expressed by activated microglia) binding, was calculated for basal ganglia and thalamus. Binding potential values, suggesting underlying activated microglia-mediated neuroinflammation, were found to be increased in bilateral caudate and bilateral lentiform nucleus in the PANDAS group and in bilateral caudate nuclei only in the Tourette syndrome group, compared to control group. These differences in the pattern and extent of neuroinflammation also signify a possible difference in pathophysiological etiology between PANDAS and Tourette syndrome patients.

Novel diffusion tensor imaging technique reveals developmental streamline volume changes in the corticospinal tract associated with leg motor control

BACKGROUND

Diffusion tensor imaging (DTI) has expanded our knowledge of corticospinal tract (CST) anatomy and development. However, previous developmental DTI studies assessed the CST as a whole, overlooking potential differences in development of its components related to control of the upper and lower extremities. The present cross-sectional study investigated age-related changes, side and gender differences in streamline volume of the leg- and hand-related segments of the CST in children.

SUBJECTS AND METHODS

DTI data of 31 children (1-14 years; mean age: 6±4 years; 17 girls) with normal conventional MRI were analyzed. Leg- and hand-related CST streamline volumes were quantified separately, using a recently validated novel tractography approach. CST streamline volumes on both sides were compared between genders and correlated with age.

RESULTS

Higher absolute streamline volumes were found in the left leg-related CST compared to the right (p=0.001) without a gender effect (p=0.4), whereas no differences were found in the absolute hand-related CST volumes (p>0.4). CST leg-related streamline volumes, normalized to hemispheric white matter volumes, declined with age in the right hemisphere only (R=-.51; p=0.004). Absolute leg-related CST streamline volumes showed similar, but slightly weaker correlations. Hand-related absolute or normalized CST streamline volumes showed no age-related variations on either side.

CONCLUSION

These results suggest differential development of CST segments controlling hand vs. leg movements. Asymmetric volume changes in the lower limb motor pathway may be secondary to gradually strengthening left hemispheric dominance and is consistent with previous data suggesting that footedness is a better predictor of hemispheric lateralization than handedness.

Localization of specific language pathways using diffusion-weighted imaging tractography for presurgical planning of children with intractable epilepsy

OBJECTIVE

To examine whether diffusion-weighted imaging (DWI) tractography can detect multiple white matter pathways connected to language cortices, we employed a maximum a posteriori probability (MAP) classification method, which has been recently validated for the corticospinal tract.

METHODS

DWI was performed in 12 normally developing children and 17 children with intractable focal epilepsy who underwent subsequent two-stage epilepsy surgery with intracranial functional mapping. First, whole-brain DWI tractography was performed to identify unique pathways originating from Broca's area, premotor area, and Wernicke's area on functional magnetic resonance imaging (fMRI) of normal children and intracranial electrical stimulation mapping (ESM) of children with epilepsy. Group averaging of these pathways based on fMRI was performed to construct the probability maps of language areas in standard MRI space. These maps were finally used to design a DWI-MAP classifier, which can automatically sort individual fibers originating from fMRI language areas as well as ESM language areas.

RESULTS

In normally developing children, the DWI-MAP classifier predicted language-activation areas on fMRI with up to 77% accuracy. In children with focal epilepsy, the DWI-MAP classifier also showed high accuracy (up to 82%) for the fibers terminating in proximity to essential language areas determined by ESM. Decreased volumes in DWI-MAP-defined pathways after epilepsy surgery were associated with postoperative language deficits.

SIGNIFICANCE

This study encourages further investigations to determine if DWI-MAP analysis can serve as a noninvasive diagnostic tool during pediatric presurgical planning by estimating not only the location of essential language cortices, but also the underlying fibers connecting these cortical areas.

Cortical Tubers: Windows into Dysregulation of Epilepsy Risk and Synaptic Signaling Genes by MicroRNAs

Tuberous sclerosis complex (TSC) is a multisystem genetic disorder caused by mutations in the TSC1 and TSC2 genes. Over 80% of TSC patients are affected by epilepsy, but the molecular events contributing to seizures in TSC are not well understood. Recent reports have demonstrated that the brain is enriched with microRNA activity, and they are critical in neural development and function. However, little is known about the role of microRNAs in TSC. Here, we report the characterization of aberrant microRNA activity in cortical tubers resected from 5 TSC patients surgically treated for medically intractable epilepsy. By comparing epileptogenic tubers with adjacent nontuber tissue, we identified a set of 4 coordinately overexpressed microRNAs (miRs 23a, 34a, 34b*, 532-5p). We used quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic profiling to investigate the combined effect of the 4 microRNAs on target proteins. The proportion of repressed proteins among the predicted targets was significantly greater than in the overall proteome and was highly enriched for proteins involved in synaptic signal transmission. Among the combinatorial targets were TSC1, coding for the protein hamartin, and several epilepsy risk genes. We found decreased levels of hamartin in epileptogenic tubers and confirmed targeting of the TSC1 3' UTR by miRs-23a and 34a.

"Subtotal" hemispherectomy in children with intractable focal epilepsy

OBJECTIVE

Cortical resections in epilepsy surgery tend to be larger in children, compared to adults, partly due to underlying pathology. Some children show unilateral multifocal seizure onsets involving much of the hemisphere. If there were a significant hemiparesis present, hemispherectomy would be the procedure of choice. Otherwise, it is preferable to spare the primary sensorimotor cortex. We report the results of "subtotal" hemispherectomy in 23 children.

METHODS

All children (ages 1 year and 4 months to 14 years and 2 months) were operated on between 2001 and 2013 at Children's Hospital of Michigan (Detroit). Patients were evaluated with scalp video-electroencephalography (EEG), magnetic resonance imaging (MRI), (18) F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scans, and neuropsychological assessments when applicable. Subsequently, each case was discussed in a multidisciplinary epilepsy surgery conference, and a consensus was reached pertaining to candidacy for surgery and optimum surgical approach. The actual extent of resection was based on the results from subdural electrocorticography (ECoG) monitoring. The surgical outcome is based on International League Against Epilepsy (ILAE) classification (class 1-6).

RESULTS

Among the 23 patients, 11 had epileptic spasms as their major seizure type; these were associated with focal seizures in 3 children. MRI showed focal abnormalities in 12 children. FDG-PET was abnormal in all but one subject. All except two children underwent chronic subdural ECoG. Multiple subpial transections were performed over the sensorimotor cortex in three subjects. On histopathology, various malformations were seen in 9 subjects; the remainder showed gliosis alone (n = 12), porencephaly (n = 1), and gliosis with microglial activation (n = 1). Follow-up ranged from 13 to 157 months (mean = 65 months). Outcomes consisted of class 1 (n = 17, 74%), class 2 (n = 2), class 3 (n = 1), class 4 (n = 1), and class 5 (n = 2).

SIGNIFICANCE

Extensive unilateral resections sparing only sensorimotor cortex can be performed with excellent results in seizure control. Even with the presence of widespread unilateral epileptogenicity or anatomic/functional imaging abnormalities, complete hemispherectomy can often be avoided, particularly when there is little hemiparesis.

Radiosynthesis of (11)C-Levetiracetam: A Potential Marker for PET Imaging of SV2A Expression

The multistep preparation of (11)C-levetiracetam ((11)C-LEV) was carried out by a one-pot radiosynthesis with 8.3 ± 1.6% (n = 8) radiochemical yield in 50 ± 5.0 min. Briefly, the propionaldehyde was converted to propan-1-imine in situ as labeling precursor by incubation with ammonia. Without further separation, the imine was reacted with (11)C-HCN to form (11)C-aminonitrile. This crude was then reacted with 4-chlorobutyryl chloride and followed by hydrolysis to yield (11)C-LEV after purification by chiral high-performance liquid chromatography (HPLC). Both the radiochemical and enantiomeric purities of (11)C-LEV were >98%.