Praxis‐induced reflex seizures in two Japanese cases with ring chromosome 20 syndrome

Ring chromosome 20 syndrome is an epileptic and neurodevelopmental encephalopathy that occurs in children, characterised by a triad of refractory frontal lobe seizures, recurrent non‐convulsive status epilepticus and frontal lobe‐dominant paroxysmal discharges. However, details of other clinical features associated with ring chromosome 20 syndrome remain unknown. Here, we report two patients with ring chromosome 20 syndrome who had praxis‐induced reflex seizures. Case 1 was an 11‐year‐old girl who presented with seizures triggered by specific activities such as mental and written calculations, writing, decision‐making, recall, sudden changes in routine or ambient temperature and bathing. During calculations, left frontal lobe‐dominant, 3‐Hz slow‐wave bursts were observed on EEG. Lacosamide effectively suppressed her tonic seizures. Case 2 was a six‐year‐old boy who presented with seizures triggered by specific activities such as calculations, recall and bathing. During calculations, frontal lobe‐dominant, 3‐Hz spike and slow‐wave bursts were observed on EEG. Although his epilepsy was refractory, gabapentin reduced the frequency of focal seizures. In both cases, the hyperexcitability in the frontal lobe may have spread to the motor cortex and precipitated praxis‐induced seizures. Therefore, in addition to the known characteristic triad, praxis‐induced reflex seizures may also be a feature of ring chromosome 20 syndrome.     

Ring chromosome 20: a distinctive syndrome identifiable by electroclinical diagnosis

The ring chromosome 20 syndrome is characterized by treatment resistant non-convulsive status epilepticus, and slow waves intercalated by spikes/spike waves predominantly in the front-temporal regions. Here, we describe the case of an 18 year old patient, whose seizures began at the age of 10, these being resistant to treatment. Neurologic examination and cranial MRI were normal. Interictal EEG showed normal background activity with burst of 2-20 seconds with bilateral spike wave. Ictal EEG showed continuous paroxysmal activity with generalized spike waves discharges and slow delta waves, coinciding with nonconvulsive status epilepticus. After 1 mg of intravenous clonazepam, both clinical semiology and EEG abnormalities disappeared. A cytogenetic study showed ring chromosome 20 in 35 % of metaphases. The epilepsy associated with ring chromosome 20 constitutes a syndrome with its distinctive electroclinical characteristics.     

Gelastic seizures in ring chromosome 20 syndrome: a case report with video illustration

Although increasingly recognised, ring chromosome 20 (r[20]) syndrome is still diagnosed with delay, sometimes leading to inappropriate presurgical evaluation. The focal, presumed frontal, character of the seizures manifesting with fear and hypermotor behaviour and episodes of non-convulsive status epilepticus (NCSE) are most typical, as well as cognitive impairment with behavioural problems and, sometimes, dysmorphic signs. We present a girl diagnosed at the age of 13 years who suffered from an atypical clinical presentation, with minimal cognitive problems, absence of dysmorphic symptoms, and hypermotor/gelastic seizures. [Published with video sequences].     

Complex partial status epilepticus is an unrecognised feature in SESA syndrome: new insights into its pathophysiology.

We report a patient diagnosed as having subacute encephalopathy with frequent seizures in alcoholics (SESA syndrome), in which recurrent, non-convulsive seizures of frontal origin contributed significantly to the alteration of the mental state. Our case suggests that the occurrence of episodes of complex partial status epilepticus (CPSE) may contribute greatly to the origin and pathophysiology of the confusional state in this rare, epileptic entity.     

Ictal magnetoencephalographic study in a patient with ring 20 syndrome

OBJECTIVE: To report the ictal magnetoencephalography (MEG) in a patient with ring chromosome 20 mosaicism, a rare chromosomal anomaly associated with intractable epilepsy. METHODS: MEG and simultaneous EEG were recorded with a 204 channel whole head MEG system. Ten habitual seizures occurred during the acquisition, which was done twice. The equivalent current dipoles (ECDs) for ictal discharges on MEG were calculated using a single dipole model. The ECDs were superimposed on a magnetic resonance image. RESULTS: During the seizures, EEG showed prolonged bursts of 5-6 Hz high voltage slow waves with spike components, dominantly in the bilateral frontal region. MEG showed epileptiform discharges corresponding to the ictal EEG. Ictal discharges on MEG were dominant in the frontal area in the initial portion, and then spread in the bilateral temporal area in the middle of the seizure. ECDs obtained from the spikes of the initial portion were clustered in the medial frontal lobe. CONCLUSIONS: The source of the ictal MEG was localised in the medial frontal lobe. The findings suggest that the mechanism underlying epilepsy in this case might be similar to medial frontal lobe epilepsy. Ictal MEG is a valuable tool for detecting the site of seizure onset.     

Ring chromosome 20 epilepsy syndrome in children: electroclinical features

Ring chromosome 20 mosaicism is associated with dysmorphic features, mental retardation, and intractable seizures, including recurrent episodes of nonconvulsive status epilepticus. The authors' findings in four children, all without dysmorphic features, indicate that mental deterioration and frequent subtle nocturnal frontal lobe seizures, associated with a characteristic EEG pattern, represent prominent additional clinical features not previously described in this syndrome. This emphasizes the importance of full-night video-EEG in children with frontal lobe seizures and cognitive deterioration.     

Ring 17 syndrome: first clinical report without intellectual disability

Ring chromosomes are rare abnormalities caused by the fusion of the telomeric regions. Three‐ring chromosome syndromes (Cr 20, Cr 17 and Cr 14) cause epilepsy with variable phenotypes. In ring 17 patients with mild phenotype, some authors have shown an epilepsy syndrome similar to that of ring 20. We report the first case of a girl with ring chromosome 17 and a normal neurological and general cognitive profile. She had had, from 9 years old, focal pharmacoresistant epilepsy associated with episodes of non‐convulsive status epilepticus with mainly autonomic features. Cytogenetic analysis revealed an abnormal karyotype characterised by the presence of de novo ring chromosome 17 in 19% of metaphases. The array CGH (100 KB) did not show any genetic deletion. The clinical and epilepsy phenotype was, to a certain degree, similar to that of ring 20 syndrome.     

Surgery for intractable epilepsy after severe encephalopathy with reversible splenial lesion and new onset hippocampal lesion associated with parechovirus

We describe a case of severe encephalopathy with reversible splenial lesion associated with parechovirus, followed by intractable temporal lobe epilepsy (TLE), which was improved by epilepsy surgery. A 3-year-old girl was admitted because of fever, consciousness disturbance and generalized tonic clonic seizure. Her seizure lasted for four hours. Fluid-attenuated inversion recovery (FLAIR) showed a hyperintensity in the splenium of the corpus callosum. Electroencephalogram (EEG) demonstarated continuous diffuse epileptic activity represented by synchronous and rhythmic high-amplitude spikes and waves, which led to the diagnosis of status epilepticus. Her consciousness was improved with fosphenytoin, midazolam and methylprednisolone pulse after 3 days. Seven days later, FLAIR hyperintensity in the splenium of the corpus callosum was disappeared; however, a hyperintensity in the right hippocampus was detected. Since the stool examination was positive for parechovirus, her final diagnosis was reversible splenial lesion syndrome (RESLES) associated with parechovirus. At age 8, she experienced epigastric sensation and consciousness disturbance once a week. Based on the scalp EEG and radiological findings, she was diagnosed with intractable right TLE. We performed a right selective amygdalohippocampectomy and anterior temporal disconnection at 10 years of age. One year and 3 months after surgery, she was seizure free. To our knowledge, this is the first report of severe febrile epilepticus status.with RESLES associated with parechovirus, followed by intractable TLE, which was resolved by epilepsy surgery.     

Electroencephalographic findings in functional psychoses: State or trait indicators?

The clinical significance of electroencephalographic (EEG) changes in patients with functional psychoses is not yet clearly defined, particularly whether these changes are state indicators or trait indicators. In the present review, the EEG abnormalities in schizophrenia are discussed. In early EEG studies of schizophrenics, the various specific EEG patterns were suggested to be trait indicators, but those findings were not confirmed. The EEG patterns of some patients with catatonic schizophrenia, especially periodic catatonia, were thought to be episode or state indicators, and some of the patients diagnosed as having atypical psychoses in Japan were suggested to show state indicator EEG findings. As the computerized and spectral analyses of EEG have advanced, the contradictory findings of EEG in schizophrenia have been reported, interpreted as `hyperstable' or `hypernormal' EEG findings and `hypofrontal' EEG findings (slow waves in the frontal region). However, no conclusion can be made as to whether these EEG findings are state or trait indicators. On the borderland of functional psychoses, the behavioral changes in temporal lobe epilepsy were described as a trait indicator, and the psychotic states in non-convulsive generalized status epilepticus and acute confusional states were suggested to be state indicators. Further studies of EEG abnormalities in schizophrenia are necessary from multi-dimensional perspectives, including in comparison with the symptomatic psychoses.     

Prolonged Electrocerebral Silent Barbiturate Coma in Intractable Seizure Disorders

Barbiturate coma (BC) is a known modality for terminating resistant convulsive status epilepticus. It is usually applied until seizure activity ends. We recently adopted a modified protocol of prolonged, electrocerebral silent BC to treat patients with chronic seizure activity resistant to multiple regimens of antiepileptic drugs. Four patients, aged 4 months to 10 years, with long-standing intractable generalized seizures were treated. Seizure frequency ranged from one to two to numerous times per day. Following BC, one patient has been seizure free during 8 months of follow-up, and another has had only two seizures in 18 months. A 4-month-old infant was seizure-free for 2 weeks after BC and then died from underlying CNS disease. A 10-year-old girl died during BC from shock and hyperpyrexia. The results obtained in our patients indicate that prolonged electrocerebral silent BC may exert a beneficial long-term effect in treatment of intractable seizure disorders. This procedure might also be beneficial in other forms of epilepsy.     

Ring chromosome 17 epilepsy may resemble that of ring chromosome 20 syndrome.

A four-year-old boy with ring chromosome 17 presenting with early-onset, pharmacoresistant epilepsy underwent repeated 24-hour video-EEG monitoring and cytogenetic analyses, including fluorescent in situ hybridization with telomeric and locus-specific probes of chromosome 17. Epilepsy was characterized by nocturnal motor seizures and by prolonged diurnal electrical status epilepticus. The 46, XY, r (17) karyotype was observed in the majority of cell lines. Fluorescent in situ hybridization revealed a deletion at the 17p telomere on the ring chromosome, whereas the 17q telomere and the Miller-Dieker lissencephaly locus were undeleted. The epileptic syndrome observed in this case of ring chromosome 17 resembles the one described in the ring chromosome 20 syndrome, raising the question of the specificity and the pathogenesis of ring chromosome epileptic syndromes. [Published with videosequences].     

Factors underlying scalp-EEG interictal epileptiform discharges in intractable frontal lobe epilepsy.

AIMS: Scalp-EEG interictal epileptiform discharges (IEDs) may be less predictive of the outcome of frontal lobe epilepsy surgery than of temporal lobe epilepsy surgery. We identified factors associated with the location of scalp-EEG IEDs in intractable frontal lobe epilepsy. METHODS: Ten factors were assessed in a retrospective review of 53 patients with either concordant (frontal lobe seizure focus) or discordant (generalized or outside frontal seizure focus) IED or both, who had excellent surgical outcomes. The Fisher exact test and the Wilcoxon rank sum test determined statistically significant associations. RESULTS: Thirty-six patients (68%) had concordant IED, 24 (45%) discordant IED, and 17 (32%) both. Younger age at onset was significantly associated with discordant IED (mean, 7.5 years versus 17 years for patients without discordant IED; P < 0.01), whereas duration of epilepsy was not. Seizure foci at the frontal convexity were associated with concordant IED. About 72% of patients with a convexity seizure focus had concordant IED, compared with only 33% of patients with mesial frontal foci having concordant IED (P = 0.06). CONCLUSIONS: Early seizure onset in intractable frontal lobe epilepsy is associated with IEDs discordant with seizure focus. Frontal convexity seizure foci are more likely than mesial frontal seizure foci to be associated with concordant discharges.     

Absence status epilepticus in monozygotic twins with Jeavons syndrome

As a generalized form of nonconvulsive status epilepticus (NCSE), absence status epilepticus is the most common form. It manifests as prolonged, confusional states of varying severity, and continuous or repetitive generalized discharges of spikes, multiple spikes, and slow waves on EEG. Jeavons syndrome (JS) is a new type of epilepsy syndrome. Hitherto, only four sets of monozygotic twin with JS have been reported. Absence status epilepticus occurring in monozygotic twins with JS have not been reported. Here we report on monozygotic male twins of Chinese origin with JS. Both of them presented with status epilepticus with eyelid myoclonia and absences. [Published with video sequences].     

额叶癫痫的长程视频脑电特征及其在额叶癫痫诊断和外科定位中的应用

目的探讨长程视频脑电（VEEG）在额叶癫痫诊断及手术定位中应用的意义。方法回顾性分析47例诊断为额叶性癫痫并进行手术治疗患者的长程视频脑电特征及临床资料。结果癫痫临床发作有以下特点：①持续时间短;②睡眠中较多见;③继发难治全身性发作多见;④强直性或运动性姿势症状突出;⑤常伴发声。癫痫发作间期VEEG存在以下形式：①脑电无异常;②一侧额部或一侧前头部异常波形波幅优势;③额部或前头部异常波形波幅优势且双侧对称;发作期VEEG存在以下形式：①多见去同步化低电压;②一侧或双侧额叶低幅快活动;③一侧或双侧额叶的高幅优势放电;④全导联同步对称异常放电。38例患者的癫痫灶术前被精确定位,9例患者癫痫灶术前不能确定侧别。结论应用长程视频脑电监测能够较全面了解额叶癫痫临床发作表现及脑电图特点,有助于准确诊断及术前定位。     

Intractable epilepsy with ring chromosome 20 syndrome treated with vagal nerve stimulation: case report and review of the literature

We report a case of a 6-year old girl with ring chromosome 20 syndrome whose medically intractable seizures were successfully treated with vagal nerve stimulation therapy. Medically intractable seizures are an expected part of this rare syndrome, and the dramatic improvement in seizure control with vagal nerve stimulation is emphasized. Earlier use of vagal nerve stimulation in similar cases should be considered.     

Atypical language representation in children with intractable temporal lobe epilepsy

This study evaluated language organization in children with intractable epilepsy caused by temporal lobe focal cortical dysplasia (FCD) alone or dual pathology (temporal lobe FCD and hippocampal sclerosis, HS). We analyzed clinical, neurological, fMRI, neuropsychological, and histopathologic data in 46 pediatric patients with temporal lobe lesions who underwent excisional epilepsy surgery. The frequency of atypical language representation was similar in both groups, but children with dual pathology were more likely to be left-handed. Atypical receptive language cortex correlated with lower intellectual capacity, verbal abstract conceptualization, receptive language abilities, verbal working memory, and a history of status epilepticus but did not correlate with higher seizure frequency or early seizure onset. Histopathologic substrate had only a minor influence on neuropsychological status. Greater verbal comprehension deficits were noted in children with atypical receptive language representation, a risk factor for cognitive morbidity.     

Non-convulsive status epilepticus with marked neuropsychiatric manifestations and MRI changes after treatment of hypercalcaemia

We describe a 77-year-old woman who developed a confusional state, cognitive impairment, behavioural abnormalities and dysphasia after treatment of hypercalcaemia. Repeated EEG recording revealed rhythmic sharp-wave activity over the right parietal-occipital lobe. Magnetic resonance imaging (MRI) showed marked hyperintense signal changes bilaterally. The diagnosis of a non-convulsive status epilepticus (NCSE) was made. With antiepileptic treatment the patient improved and MRI as well as EEG changes were almost all reversible. NCSE is an important differential diagnosis of patients with neuropsychiatric symptoms and can develop after rapid lowering of serum calcium levels in hypercalcaemia.     

Intractable epilepsy and disturbed visuomotor performance

The factors relevant to intractability, types of epilepsy and impairment of dexterity in patients with intractable epilepsy were studied independently in different groups of patients. The factors relevant to intractable epilepsy that were disclosed in 202 patients, who required hospitalization more than twice, were as follows: strong seizure propensity, neuropsychiatric disorders including mental deterioration of various degrees, ataxia, personality changes and psychotic episodes, intolerance to antiepileptic drugs due to acute or chronic side effects, idiosyncrasy and internal disorders, self-induced seizure, misdiagnosis and mistreatment, and breakdown of family care of patients. The types of epilepsy in 224 patients with intractable epilepsy whose seizures were not adequately controlled and recurred on a monthly basis in spite of hospitalization were classified as follows: 101 patients with localization-related epilepsies or syndromes, 106 with generalized epilepsies or syndromes, 16 with undetermined epilepsies or syndromes and one with specific syndrome. In regard to partial epilepsies, frontal lobe epilepsy and partial epilepsy with multiple foci were at least partially intractable as temporal lobe epilepsy. With respect to intractable generalized epilepsies, miscellaneous symptomatic generalized epilepsies like intractable grand mal epilepsy with progressive mental retardation in childhood were as important as Lennox-Gastaut or West syndrome though it defies classification into any established syndromes. The proposed International Classification of Epileptic Syndromes and Epilepsies was found adequate for analysis of intractable epilepsy. The disturbance of fine motor performance found in 84 patients who participated in occupational therapy was investigated by test programs comprising nine subbatteries.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prolonged confusion following convulsions due to generalized nonconvulsive status epilepticus

Among patients with a prolonged confusional state after convulsive seizure, we diagnosed 8 cases as generalized nonconvulsive status epilepticus. Six had a history of seizures, and 2 had new onset. The convulsive seizures were generalized in 6 and focal in two. The postictal confusion lasted up to 36 hours in the most prolonged case, and a delayed response to anticonvulsant medications occurred in all cases. The clinical symptoms ranged from mild confusion to coma. Psychiatric manifestations or automatisms were rare. The presumed etiology was due to diverse causes, but a withdrawal state was the most common. EEG demonstrated continuous or nearly continuous generalized ictal discharges of variable morphology. These cases call attention to the fact that some prolonged confusional states following convulsive seizures are in fact due to persistent seizure activity that can be diagnosed by EEG.