Cortico-muscular and cortico-cortical coherence changes resulting from Perampanel treatment in patients with cortical myoclonus.

OBJECTIVE: To investigate the mechanisms by which Perampanel (PER) reduces the severity of action myoclonus, we studied on MEG signals the changes occurring in cortico-muscular coherence (CMC) and cortico-cortical connectivity in patients with progressive myoclonus epilepsies. METHODS: The subjects performed an isometric extension of the hand; CMC and cortico-cortical connectivity were assessed using autoregressive models and generalized partial-directed coherence. The contralateral (Co) sensors showing average CMC values >0.7 of the maximum (set to 1) were grouped as central (C) regions of interest (ROI), while adjacent sensors showing CMC values >0.3 were grouped as Surrounding (Sr) ROIs. RESULTS: Under PER treatment, CMC decreased on Co C and Sr ROIs, but also on homologous ipsilateral (Ip) ROIs; out-degrees and betweenness centrality increased in Co ROIs and decreased in Ip ROIs. The flow from Ip to Co ROIs and from activated muscles to Ip C ROI decreased. CONCLUSION: The improvement of myoclonus corresponded to decreased CMC and recovered leadership of the cortical regions directly involved in the motor task, with a reduced interference of ipsilateral areas. SIGNIFICANCE: Our study highlights on mechanisms suitable to treating myoclonus and suggests the role of a reduced local synchronization together a better control of distant synaptic effects.

Electroclinical findings and long-term outcomes in epileptic patients with inv dup (15).

OBJECTIVE: To define the electroclinical phenotype and long-term outcomes in a cohort of patients with inv dup (15) syndrome. MATERIAL AND METHODS: The electroclinical data of 45 patients (25 males) affected by inv dup (15) and seizures were retrospectively analysed, and long-term follow-up of epilepsy was evaluated. RESULTS: Epilepsy onset was marked by generalized seizures in 53% of patients, epileptic spasms in 51%, focal seizures in 26%, atypical absences in 11% and epileptic falls in 9%. The epileptic syndromes defined were: generalized epilepsy (26.7%), focal epilepsy (22.3%), epileptic encephalopathy with epileptic spasms as the only seizure type (17.7%) and Lennox-Gastaut syndrome (33.3%). Drug-resistant epilepsy was detected in 55.5% of patients. There was a significant higher prevalence of seizure-free patients in those with seizure onset after the age of 5 years and with focal epilepsy, with respect to those with earlier epilepsy onset because most of these later developed an epileptic encephalopathy (69.2% vs 34.4%; P = .03), usually Lennox-Gastaut Syndrome in type. In fact, among patients with early-onset epilepsy, those presenting with epileptic spasms as the only seizure type associated with classical hypsarrhythmia achieved seizure freedom (P < .001) compared to patients with spasms and other seizure types associated with modified hypsarrhythmia. CONCLUSIONS: Epilepsy in inv dup (15) leads to a more severe burden of disease. Frequently, these patients show drug resistance, in particular when epilepsy onset is before the age of five and features epileptic encephalopathy.

Outcome of childhood-onset epilepsy from adolescence to adulthood: Transition issues.

This is the second of three papers that summarize the second symposium on Transition in Epilepsies held in Paris in June 2016. This paper addresses the outcome for some particularly challenging childhood-onset epileptic disorders with the goal of recommending the best approach to transition. We have grouped these disorders in five categories with a few examples for each. The first group includes disorders presenting in childhood that may have late- or adult-onset epilepsy (metabolic and mitochondrial disorders). The second group includes disorders with changing problems in adulthood (tuberous sclerosis complex, Rett syndrome, Dravet syndrome, and autism). A third group includes epilepsies that change with age (Childhood Absence Epilepsy, Juvenile Myoclonic Epilepsy, West Syndrome, and Lennox-Gastaut syndrome). A fourth group consists of epilepsies that vary in symptoms and severity depending on the age of onset (autoimmune encephalitis, Rasmussen's syndrome). A fifth group has epilepsy from structural causes that are less likely to evolve in adulthood. Finally we have included a discussion about the risk of later adulthood cerebrovascular disease and dementia following childhood-onset epilepsy. A detailed knowledge of each of these disorders should assist the process of transition to be certain that attention is paid to the most important age-related symptoms and concerns.

Early add-on immunoglobulin administration in Rasmussen encephalitis: the hypothesis of neuroimmunomodulation.

Rasmussen encephalitis (RE) is a chronic inflammatory disease leading to unilateral hemispheric atrophy, associated with progressive neurological dysfunction and intractable seizures. The best approach to RE is hemispherectomy. However long-term immunotherapy seems to prevent or slow down hemispheric tissue loss and the associated functional decline. We describe a girl with epilepsia partialis continua (EPC) and progressive neurological dysfunction compatible with RE. The brain MRI showed a lesion that was initially interpreted as focal cortical dysplasia. Combined antiepileptic and immunomodulation were administered for two years with initial beneficial effects. The follow-up MRI, 4 year later showed. atrophic change in right parietal region. The association of antiepileptic and immunomodulation therapies may inhibit pathogenetic mechanisms responsible for neuronal loss in RE, slowing down the progression of the disease.

Transporters in drug-refractory epilepsy: clinical significance.

Drug resistance remains an unmet challenge in a variety of neurological disorders, but epilepsy is probably the refractory disease that has received most experimental, preclinical, and therapeutic attention. Although resective surgery continues to improve our ability to provide seizure relief, new discoveries have potential as alternative therapeutic approaches to multiple drug resistance. As discussed here, the field is replete with controversies and false starts, in particular as it concerns the existence of genetic predisposition to inadequate pharmacological seizure control.

Joubert syndrome with bilateral polymicrogyria: clinical and neuropathological findings in two brothers.

Joubert syndrome (JS) is characterized by hypotonia, ataxia, developmental delay, and a typical neuroimaging finding, the so-called "molar tooth sign" (MTS). The association of MTS and polymicrogyria (PMG) has been reported as a distinct JS-related disorder (JSRD). So far, five patients have been reported with this phenotype, only two of them being siblings. We report on one additional family, describing a living child with JS and PMG, and the corresponding neuropathological picture in the aborted brother. No mutations were detected in the AHI1 gene, the only so far associated with the JS + PMG phenotype. Moreover, linkage analysis allowed excluding all known gene loci, suggesting further genetic heterogeneity.

An open-label trial of levetiracetam in severe myoclonic epilepsy of infancy.

OBJECTIVE: To conduct an open-label, add-on trial on safety and efficacy of levetiracetam in severe myoclonic epilepsy of infancy (SMEI). PATIENTS AND METHODS: SMEI patients were recruited from different centers according to the following criteria: age > or =3 years; at least four tonic-clonic seizures/month during the last 8 weeks; previous use of at least two drugs. Levetiracetam was orally administrated at starting dose of approximately 10 mg/kg/day up to 50 to 60 mg/kg/day in two doses. Treatment period included a 5- to 6-week up-titration phase and a 12-week evaluation phase. Efficacy variables were responder rate by seizure type and reduction of the mean number per week of each seizure type. Analysis was performed using Fisher exact and Wilcoxon tests. RESULTS: Twenty-eight patients (mean age: 9.4 +/- 5.6 years) entered the study. Sixteen (57.1%) showed SCN1A mutations. Mean number of concomitant drugs was 2.5. Mean levetiracetam dose achieved was 2,016 mg/day. Twenty-three (82.1%) completed the trial. Responders were 64.2% for tonic-clonic, 60% for myoclonic, 60% for focal, and 44.4% for absence seizures. Number per week of tonic-clonic (median: 3 vs 1; p = 0.0001), myoclonic (median: 21 vs 3; p = 0.002), and focal seizures (median: 7.5 vs 3; p = 0.031) was significantly decreased compared to baseline. Levetiracetam effect was not related to age at onset and duration of epilepsy, genetic status, and concomitant therapy. Levetiracetam was well tolerated by subjects who completed the study. To date, follow-up ranges 6 to 36 months (mean, 16.2 +/- 13.4). CONCLUSION: Levetiracetam add-on is effective and well tolerated in severe myoclonic epilepsy of infancy. Placebo-controlled studies should confirm these findings.

Revelation of a novel CLN5 mutation in early juvenile neuronal ceroid lipofuscinosis.

Neuronal ceroid lipofuscinoses (NCLs) are relatively common storage diseases of childhood and early adolescence. Ultrastructural shape of storage cytosomes, type of disease gene, and age of onset serve to classify the different NCLs, some of which appear to cluster in Scandinavian countries. The CLN5 form usually presents as a classical epileptiform encephalopathy of late infancy but a more aggressive cognitive impairment has been described in a single family. We report two sibs harbouring a novel mutation (p.Tyr258Asp) in the CLN5 gene and displaying behaviour disturbances and mental deterioration, rather than epilepsy, as the dominant disease manifestation at onset.

Pathogenesis, diagnosis and treatment of Rasmussen encephalitis: a European consensus statement.

Rasmussen encephalitis (RE) is a rare but severe immune-mediated brain disorder leading to unilateral hemispheric atrophy, associated progressive neurological dysfunction and intractable seizures. Recent data on the pathogenesis of the disease, its clinical and paraclinical presentation, and therapeutic approaches are summarized. Based on these data, we propose formal diagnostic criteria and a therapeutic pathway for the management of RE patients.

Subcortical nodular heterotopia: a functional MRI and somatosensory evoked potentials study.

Subcortical nodular heterotopia (SNH) associated with refractory epilepsy may be surgically treated, and a positive outcome can be expected following the complete excision of the malformed tissue. Recent functional neuroimaging studies have suggested the possible functional relevance of cerebral malformations, and may make it possible to improve presurgical planning, thus allowing extended resections and minimising post-operative deficits. We here report the case of a 19-year-old man with epilepsy and a giant SNH associated with diffused abnormal gyrations of the right temporal-parietal regions. Cortical functional organisation was investigated by means of functional magnetic resonance imaging (MRI) during sensory and motor tasks, and somatosensory evoked potentials. The results revealed enlarged and displaced motor and sensory cortical areas with heterotopic tissue functional activation. The relevance of these findings is discussed in the light of the possible surgical treatment of drug-refractory epilepsy associated with cerebral malformations: surgical treatment based on conventional MRI studies alone, without taking the functional nature of dysplastic tissues into account, may lead to considerable side effects.

Experience with immunomodulatory treatments in Rasmussen's encephalitis.

The authors investigated immunomodulatory treatments in 15 patients with Rasmussen encephalitis (RE) (14 with childhood and one with adolescent onset RE). Positive time-limited responses were obtained in 11 patients using variable combinations of corticosteroids, apheresis, and high-dose IV immunoglobulins. Although surgical exclusion of the affected hemisphere is the only treatment that halts disease progression, immunomodulation can be considered when early surgery is not feasible, in late-onset patients with slower disease progression, and in the few cases of bilateral disease.

Rasmussen's syndrome.

Rasmussen's encephalitis (RE) is characterized by focal seizures, often associated with epilepsia partialis continua, progressive neurological deterioration, hemispheric atrophy, and inflammatory histopathology. Surgical exclusion of the affected hemisphere is the only treatment that halts progression of the disease. The possible role played by serum antibodies against the glutamate receptor GluR3 in the animal model and in a number of affected patients supports a disimmune component in the pathogenesis of the disease and provides a rational basis for considering the use of immunomodulatory treatments in selected cases. The use of intravenous immunoglobulins has produced encouraging results in adult-onset RE but further studies are needed to assess the effect, dosage, and schedules in childhood-onset RE.

Spectrum of SCN1A mutations in severe myoclonic epilepsy of infancy.

OBJECTIVES: SCN1A mutations were recently reported in several patients with severe myoclonic epilepsy in infancy (SMEI). The authors analyzed SCN1A mutations in 93 patients with SMEI and made genotype-phenotype correlation to clarify the role of this gene in the etiology of SMEI. METHODS: All patients fulfilled the criteria for SMEI. The authors analyzed all patients for SCN1A mutations using denaturing high performance liquid chromatography. If a patient's chromatogram was abnormal, the authors sequenced the gene in the patient and both parents. RESULTS: SCN1A mutations were identified in 33 patients (35%). Most mutations were de novo, but were inherited in three patients. Parents carrying the inherited mutations had either no symptoms or a milder form of epilepsy. A greater frequency of unilateral motor seizures was the only clinical difference between patients with SCN1A mutations and those without. Truncating mutations were more frequently associated with such seizures than were missense mutations. The percentage of cases with family history of epilepsy was significantly higher in patients with SCN1A mutations. CONCLUSIONS: Unilateral motor seizures may be a specific clinical characteristic of SMEI caused by SCN1A mutations. Ten percent of SCN1A mutations are inherited from an asymptomatic or mildly affected parent, suggesting that SMEI is genetically heterogeneous. The increased frequency of familial epilepsy indicates that other genetic factors may contribute to this disorder.

Diagnostic imaging in 13 cases of Rasmussen's encephalitis: can early MRI suggest the diagnosis?

Rasmussen's encephalitis (RE) is a rare, progressive, chronic encephalitis characterised by drug-resistant epilepsy, progressive hemiparesis and mental impairment. It typically involves only one cerebral hemisphere, which becomes atrophic. We present neuroradiological findings in 13 children with RE. MRI was performed in all patients, fluorodeoxyglucose positron-emission tomography (PET) in three, Tc-99m hexamethylpropylenamine oxime single-photon emission computed tomography (SPECT) in two and proton MR spectroscopy ((1)HMRS) in two. MRI showed progression of the hemisphere atrophy, always prevalent in the region primarily involved (13 patients), spread of the abnormal signal in white matter (11) and cortex (10) and progression of atrophy of the head of the caudate nucleus (nine). Associated secondary changes were: atrophy of the contralateral cerebellar hemisphere (in four patients), the ipsilateral hippocampus (in five) and the brain stem (in five). The earliest CT and MRI abnormalities, seen between 1 day and 4 months after the first seizure (in 12 patients examined, nine of whom had MRI) in one cerebral hemisphere included: high signal on T2-weighted images in the cortex (seven patients) and white matter (nine), cortical atrophy usually involving the frontoinsular region, with mild or severe enlargement of the lateral ventricle (eight) and moderate atrophy of the head of the caudate nucleus (seven). Cortical swelling in the early stage of the disease was recognisable only in two patients. PET revealed hypometabolism, SPECT decreased perfusion, and (1)HMRS reduction of N-acetylaspartate in the affected hemisphere. PET and SPECT were usually performed in the late stages and did not provide specific findings. MRI thus demonstrates the progression of RE and may suggest the diagnosis in the early stages, often before the appearance of neurological deficits. Early diagnosis of RE may be crucial for selecting patients for aggressive medical therapy or major surgical interventions such as hemispherectomy.

Rasmussen's encephalitis: early characteristics allow diagnosis.

OBJECTIVE: To identify early manifestations of Rasmussen encephalitis (RE) that can prompt early and reasonably secure diagnosis, allowing medical or surgical therapies at an early stage when they may be more effective in slowing the disease. METHODS: The authors studied 12 patients with clinical and neuropathologic diagnosis of RE, followed from disease onset, assessing clinical history, imaging, and EEG and focusing on early characteristics. Anti-GluR3 antibody assays were also considered in 11 patients. RESULTS: By 4 months from first symptoms, all cases had 1) refractory focal seizures with a predominant motor component, 2) slow focal activity on EEG contralateral to the motor manifestations, and 3) focal contralateral white matter hyperintensity with insular cortical atrophy on neuroimaging. Less constant or later findings were epilepsia partialis continua, oligoclonal bands, and serum anti-GluR3 antibodies. CONCLUSIONS: The association of partial seizures with focal EEG and neuroimaging changes allows a tentative diagnosis of RE 4 to 6 months after first symptoms.

Similar binding to glutamate receptors by Rasmussen and partial epilepsy patients' sera.

Immunoreactivity of sera from patients with Rasmussen encephalitis (RE) and patients with partial epilepsy (PE) was analyzed by immunohistoblot on rat brain sections and the staining pattern compared with that obtained with antibodies to a-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and NMDA receptors. Staining for anti-glutamate receptor 3 (GluR3) was found in 82% of patients with RE and 64% of patients with PE. Histoblot analysis showed a positive staining in GluR3- and NMDA-specific regions of rat brain, providing a comprehensive CNS immunolocalization.

Labeling of rat neurons by anti-GluR3 IgG from patients with Rasmussen encephalitis.

The authors report the immunocytochemical localization in rat brain of affinity-purified anti-GluR3 (glutamate receptor) antibodies from two patients with Rasmussen encephalitis (RE) and from immunized rabbits. The distribution of immunolabeling was similar using antibodies from rabbits and patients with RE. No electrophysiologic responses were elicited from acutely dissociated kainate-responsive neurons isolated from rat brain when these antibodies were applied. These findings show that anti-GluR3 antibodies purified from patients with RE bind to specific regions of the CNS but do not act through an excitotoxic mechanism.

Single-dose pharmacokinetics of lamotrigine in children: influence of age and antiepileptic comedication.

To evaluate the influence of pediatric age and antiepileptic comedication on the single-dose pharmacokinetics of lamotrigine, 19 patients with epilepsy (10 comedicated with enzyme inducers and 9 comedicated with valproic acid) aged 8 months to 30 years received a single oral dose of lamotrigine (0.6 to 2.2 mg/kg) after an overnight fast. Blood samples were collected for at least 36 hours and plasma lamotrigine concentrations were determined by high-performance liquid chromatography. Pharmacokinetic parameters were calculated by noncompartmental analysis. Lamotrigine half-life (T1/2) and oral clearance (Cl/F) values were significantly lower and significantly higher, respectively, in patients comedicated with enzyme inducers than in those receiving valproic acid (T1/2 = 8.1 vs. 41.7 hours respectively, P < 0.001; Cl/F = 0.11 vs. 0.04 L/h per kg respectively, P < 0.005, geometric means), whereas Cmax and Tmax values were comparable in the two groups. The differences in pharmacokinetic parameters persisted when comparisons were made within subgroups stratified according to age. Within groups of patients homogeneous for type of comedication, Cmax and AUC values tended to be lower in children aged less than 12 years than in older patients. There was no significant relationship between half-life values and age. The authors conclude that both age and type of comedication influence lamotrigine pharmacokinetics. The reduction in lamotrigine concentrations caused by enzyme inducers and the elevation caused by valproic acid can be explained by stimulation and inhibition, respectively, of lamotrigine glucuronidation. On the other hand, the lower plasma lamotrigine levels in children than in adolescents and older patients may not be explainable solely by differences in metabolic rate.

Epileptic phenotypes associated with mitochondrial disorders.

OBJECTIVE: To define the clinical and EEG features of the epileptic syndromes occurring in adult and infantile mitochondrial encephalopathies (ME). METHODS: Thirty-one patients with recurrent and apparently unprovoked seizures associated with primary ME were included in the study. Diagnosis of ME was based on the recognition of a morphologic, biochemical, or molecular defect. RESULTS: Epileptic seizures were the first recognized symptom in 53% of the patients. Many adults (43%) and most infants (70%) had nontypical ME phenotypes. Partial seizures, mainly with elementary motor symptoms, and focal or multifocal EEG epileptiform activities characterized the epileptic presentation in 71% of the patients. Generalized myoclonic seizures were an early and consistent symptom only in the five patients with an A8344G mitochondrial DNA point mutation with classic myoclonus epilepsy with ragged red fibers (MERRF) syndrome or "overlapping" characteristics. Photoparoxysmal EEG responses were observed not only in patients with typical MERRF, but also in adult patients with ME with lactic acidosis and strokelike episodes (MELAS), or overlapping phenotypes, and in one child with Leigh syndrome. CONCLUSIONS: Epilepsy is an important sign in the early presentation of ME and may be the most apparent neurologic sign of nontypical ME, often leading to the diagnostic workup. Except for those with an A8344G mitochondrial DNA point mutation, most of our patients had partial seizures or EEG signs indicating a focal origin.