P1032Efficacy and safety of radiofrequency catheter ablation for atrial fibrillation in patients undergoing hemodaialysis

Introduction

Although radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has become a standard therapy, the ablation outcomes in patients undergoing hemodialysis (HD) has not been fully elucidated. The present study aimed to evaluate the clinical outcomes of RFCA for AF in patients undergoing HD.

Methods

Twenty-three patients undergoing HD (17 men, age 65±8 years, 19 paroxysmal AF) who underwent RFCA for drug-refractory AF in two institutes were enrolled in the study and defined as HD group. The clinical parameters, recurrence free rate and frequency of periprocedural complications were compared to 46 randomly selected age, gender and left atrial diameter matched controls not requiring HD defined as non-HD group (34men, age 67±7 years, 38 paroxysmal AF).

Results

The patients in HD group had a significantly lower body mass index (21±3 vs. 25±3 P<0.01), higher prevalence of coronary artery disease (30% vs. 10% P=0.04), and higher prevalence of congestive heart failure (52% vs. 10% P<0.01) compared to patients in non-HD group. Echocardiography indicated lower left ventricular ejection fraction (57±17% vs. 65±9% P=0.02), higher E/e' (20±8 vs. 12±4 P<0.01), higher tricuspid regurgitation pressure gradient (30mmHg vs. 24mmHg P<0.01) and more impaired left ventricular diastolic function in HD group. All the subjects underwent bilateral pulmonary vein isolation plus additional linear lesion. The number of ablation procedure was similar between the two groups (1.43±0.5 vs. 1.46±0.6 P=0.88). During the follow-up period of 37±25 months after the last procedure, the arrhythmia free rate was similar between the two groups (86% vs. 84% log-rank P=0.82). Vascular access complication occurred in two patients in HD group, and pericardial effusion occurred in one patient in non-HD group, while no life-threatening complications were observed in either group. Cardiogenic cerebral infarction occurred in one patient in non-HD group. Discontinuation of oral anticoagulation after the ablation was more often seen in the HD group compared to non-HD group (91% vs. 60% P<0.01).

Conclusions

Although patients undergoing HD had more impaired left ventricular systolic and diastolic function, RFCA for AF in patients with HD was shown to be as effective and safe as in non-HD patients. RFCA may be an efficient approach to manage AF in patients undergoing HD.

P2848Electrical reconnections after pulmonary vein isolation with or without contact force-guided catheters: a comparison of the proficiency of atrial fibrillation ablation

Background

Atrial fibrillation (AF) ablation is the most commonly performed catheter ablation (CA) procedure today. The 2015 ACC/AHA/HRS Advanced Training Statement reported that the success rate of AF ablation is higher in high-volume centers than in low-volume centers. We tested whether the procedure proficiency of each operator was associated with the outcome of AF ablation, and whether the ablation outcome depended on whether contact force (CF)-guided catheters were used or not, in a high-volume center.

Methods

We conducted a retrospective observational study including all AF patients who underwent radiofrequency CA with or without CF support since 2016 at our hospital. The patients who underwent CA at other hospitals or underwent a balloon or surgical ablation in the first session were excluded. Each ipsilateral pulmonary vein (PV) pair was divided into 8 segments. The reconnection numbers and sites of the PV segment were evaluated in the second session. Operators were divided into the experienced group (≥100 AF cases/year, at least every 3 years) and developing group (other than the experienced group), respectively.

Results

Among 728 patients who underwent an initial AF ablation and were followed for 510±306 days, 131 (90 males, 65±10 years) received a second ablation procedure and were analyzed. A total of 260 and 264 PV isolations (PVI) were performed by the experienced and developing group operators in the initial ablation, respectively. Compared to the experienced group, the developing group had a longer procedure time for the PVI (35±15 vs. 28±10 min, p<0.001), higher frequency of reconnections of the PVs (73% vs. 59%, p=0.01) and higher number of reconnection gaps (2.1±2.0 vs. 1.5±2.0, p=0.02), respectively. There were no significantly differences in the number of gaps between the catheters with and without CF (1.6±2.0 vs. 1.4±2.0, p=0.65) in the experienced group, however, in the developing group a smaller total number of gaps (1.5±1.6 vs. 2.4±2.1, p=0.006) and less frequency reconnection gaps of the posterosuperior segment of the right PV (10% vs. 45%, p=0.005) were seen with catheters with CF than without. There was no significant difference in the procedure time for the PVI between catheters with and without CF.

Conclusions

The operator proficiency may predict the outcome after AF ablation even in high-volume centers. It is preferable to perform PVI with a CF-sensing catheter for operators without adequate proficiency.

Acknowledgement/Funding

JSPS KAKENHI Grant Number JP18K15865

Estimate of Fukushima-derived radiocaesium in the North Pacific Ocean in summer 2012

Distributions of radiocaesium (134Cs and 137Cs) derived from the Tokyo Electric Power Company (TEPCO) Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident in the North Pacific Ocean in the summer of 2012 were investigated. We have estimated the radiocaesium inventory in the surface layer using the optimal interpolation analysis and the subducted amount into the central mode water (CMW) by using vertical profiles of FNPP1-134Cs and mass balance analysis as the first approach. The inventory of the 134Cs in the surface layer in the North Pacific Ocean in August-December 2012 was estimated at 5.1 ± 0.9 PBq on 1 October 2012, which corresponds to 8.6 ± 1.5 PBq when it was decay corrected to the date of the FNPP1 accident, 11 March 2011. It was revealed that 56 ± 10% of the released 134Cs into the North Pacific Ocean, which was estimated at 15.3 ± 2.6 PBq, transported eastward in the surface layer in 2012. The amount of 134Cs subducted in the CMW was estimated to be 2.5 ± 0.9 PBq based on the mass balance among the three domains of the surface layer, subtropical mode water, and CMW.

Pattern of dietary fiber intake among the Japanese general population

OBJECTIVES

To evaluate the dietary fiber (DF) intake pattern among the Japanese general population.

DESIGN

We performed a dietary survey among the general population in northern Japan to evaluate the intake patterns. DF intake was calculated by substituting the DF content of each food in the Dietary Fiber Table for the intake of each food from this dietary survey.

SUBJECTS

Five hundred and seventy-seven subjects participated in the study, 198 men and 379 women.

RESULTS

In subjects with higher DF intakes the origins of the DF that were from all food groups, but with the notable exception of rice. The contribution of the seaweed group was of particular interest. From multiple regression analysis, as for food group, seaweeds showed the highest positive correlation with DF intake in both genders, followed by vegetables, pulses, fruits. On the other hand, rice showed the negative correlation with DF intake in both genders. As for life factor, body mass index showed the negative correlation with DF intake in women.

CONCLUSION

Seaweed, a typical Japanese food, was most related to the increase in DF intake for the Japanese general population, whereas rice, the Japanese staple, had a small influence on decreased DF intake.

Longitudinal study of auditory brainstem response in leigh syndrome

To assess the utility of auditory brainstem response (ABR) in diagnosing brainstem changes in patients with Leigh syndrome (LS), we performed a longitudinal study of five patients with LS using both ABR and neuroimaging techniques (CT and MRI). The brainstem components of the initial ABRs we performed on the patients were abnormal in all five patients. In four of the patients, these abnormal findings preceded any clinical signs of brainstem impairment. Improvements in clinical findings were reflected in improvements in ABR findings in three patients. In one of these three patients, improvements in clinical findings were also reflected in improvements in MRI findings. In the other two patients, MRI findings showed no improvements, despite the improvements in clinical findings. In two of our patients, ABR clearly revealed functional improvements in the brainstem which were not revealed by MRI. Therefore, we conclude that ABR is an essential diagnostic technique for patients with LS.

Age-related clinical and neurophysiologic characteristics of intractable epilepsy associated with cortical malformation

PURPOSE

To elucidate the relationship between the characteristics of cortical malformation (CM) and those of associated epilepsy, and also to investigate the prognostic value of the clinical and magnetic resonance imaging (MRI) findings for the seizure and mental outcome.

METHODS

We studied 41 patients with CM and epilepsy, and the patients were divided according to the age at onset of epilepsy into two groups: one group of 15 patients with very early onset before age 3 months, and the other group of 26 patients with onset at 3 months or later. Statistical relationship was examined between the types of dysplastic lesions demonstrated by MRI and the age at onset of epilepsy. The effects of the onset age and the features of CM on the outcome of seizures and mental or developmental state also were analyzed.

RESULTS

The very early-onset epilepsy was related to the dysplastic patterns of reduced sulci and blurred cortical-subcortical junction, which suggested focal CM, whereas the later-onset epilepsy was related to polymicrogyria. The age at onset of epilepsy was related to the poor seizure outcome, and both the onset age and wide distribution of CM were related to severe retardation.

CONCLUSIONS

The type of CM influences the expression of associated epilepsy, especially its age-related features. The age at onset of epilepsy plays an important role in the seizure and mental outcome.

The relationship between paroxysmal kinesigenic choreoathetosis and epilepsy

PURPOSE

To clarify the relationship between paroxysmal kinesigenic choreoathetosis (PKC) and epilepsy, we investigated the clinical and electroencephalographic (EEG) findings of patients with familial PKC and epilepsy, as well as sporadic cases with both PKC and epilepsy.

PATIENTS AND METHODS

Patients consisted of 12 familial cases from seven families and three sporadic cases. The period of follow-up ranged from 17 months to 33 years, 7 months (average: 16 years, 8 months). During the follow-up, a total of 163 EEGs (11 EEGs per subject) were studied, including interictal and ictal EEGs.

RESULTS

Transient epileptic discharges were found in ten of the 15 patients (66.7 %) during the clinical course. As for focus, centro-midtemporal and frontal spikes were most often observed. The ictal EEG of an afebrile convulsion in one patient showed a partial seizure with secondary generalization which originated from the frontal area.

CONCLUSIONS

It appears that patients who suffer from both PKC and epilepsy have a functional abnormality of the cerebral cortex, particularly in the perirolandic and frontal regions.

Spasms in clusters in epilepsies other than typical West syndrome

Although spasms in clusters are one of the major characteristics of West syndrome (WS), there are a significant number of patients who show spasms in clusters but do not fit the standard pattern of WS. It is possible to divide these atypical cases into the following three groups. Group 1: refractory epilepsies beginning in early infancy, associated with atypical electroencephalographic (EEG) features; Group 2: generalized epilepsies with spasms in clusters at ages of 2-3 years or above; and Group 3: localization-related epilepsies with spasms in clusters. Ictal clinical and EEG findings of spasms in clusters in these atypical patients and also those in WS are similar. Patients in Group 1 often suffer from Aicardi syndrome, cortical malformations, early myoclonic encephalopathy and Ohtahara syndrome. Most patients in Group 2 suffer from Lennox-Gastaut syndrome and other generalized epilepsies such as severe epilepsy with multiple independent spike foci. A significant number of them had a history of WS. Small number of patients in Group 2 can be diagnosed as having late-onset WS or long-lasting WS. In Groups 1 and 3 patients, cortical mechanisms play a critical role in their pathophysiology. The presence of older patients with spasms in clusters might indicate not only developing process of the brain but also some selective dysfunction of the brain plays an important role in the occurrence of spasms in clusters. Investigations on these atypical patients can help the understanding of pathophysiological mechanisms of WS and its related epileptic syndromes.

A population-based neuroepidemiological survey of West syndrome in Okayama Prefecture, Japan

It is important for the fields of child neurology and child public health to clarify the prevalence and incidence rates of West syndrome because this syndrome is a major cause of developmental disorders.However, there have been few reports in Japan on the prevalence rate of West syndrome in the general population. We carried out a population-based survey in Okayama Prefecture, in western Japan in 1994. The population under 2 years of age in Okayama Prefecture in 1994 was 37,085. Six cases of West syndrome were identified. The prevalence rate was 0.16 per 1000.

Clinical spectrum of epileptic spasms associated with cortical malformation

The spectrum of clinico-electrical characteristics of epileptic spasms associated with cortical malformation was studied in detail. The subjects were 15 patients suffering from spasms and cortical malformation demonstrated by MRI. The types of cortical malformation causing spasms were various, including hemimegalencephaly, diffuse pachygyria, focal cortical dysplasia, and polymicrogyria. Ohtahara syndrome was diagnosed in 3 patients, and West syndrome in 8. Symptomatic localization-related epilepsy preceded West syndrome in 4 patients, and a transition from Ohtahara syndrome to West syndrome was observed in one. West syndrome was followed by symptomatic generalized epilepsy including Lennox-Gastaut syndrome in 4 patients. Nine patients showed a condition which was labeled "epilepsy with partial seizures and spasms" (EPS) and characterized by the coexistence of partial seizures and spasms, and multifocal epileptic discharges on EEG. Spasms occurred only as EPS in 5 patients. EPS appeared following Ohtahara syndrome or West syndrome in 4 patients, and showed a transition to symptomatic localization-related epilepsy in 4. However, EPS did not evolve into generalized epilepsy, and persisted until the time of last follow-up in 5 patients. Therefore, the clinico-electrical pictures of patients with spasms and cortical malformation were diverse and not always limited within those of typical generalized epilepsy.

Incidence of epileptic discharge in various epileptic syndromes

Three hundred eight patients with childhood and adolescent epilepsy were examined to clarify the incidence of epileptic discharges on initial and follow-up electroencephalograms. Epileptic discharges were found in 75.6% patients on the initial electroencephalogram, which is higher than figures previously reported for adults. The cumulative incidence of epileptic discharges was 92.3% by the third electroencephalogram recording. However, in 17.1% patients with nonspecific idiopathic generalized epilepsy, no epileptic discharges were found even after three electroencephalogram recordings. The incidence of epileptic discharges in patients with generalized epilepsy (84.3%) was significantly higher than in patients with localization-related epilepsy (71.6%). The incidence of epileptic discharges in patients with partial seizures was lower than those in patients with generalized seizures. The incidence of epileptic discharges was low in the 0- to 3-year-old and 15- to 20-year-old groups, and high in the 3- to 12-year-old groups. In the positive epileptic discharge patients, 38.8% of electroencephalograms were abnormal only during the waking or sleeping portion of the recordings. Knowing the incidence of epileptic discharges for each type of epilepsy will be useful in planning further electroencephalogram research and performing electroencephalograms in the clinical setting.

Utility of the scalp-recorded ictal EEG in childhood epilepsy

PURPOSE

To evaluate the usefulness of the scalp-recorded ictal EEGs in diagnosing childhood epilepsy.

METHODS

We analyzed the ictal EEGs of 259 seizures in 183 patients who visited the department of child neurology, Okayama University Medical School, during the past 6 years.

RESULTS

We divided all seizures into the following four categories, according to the diagnostic usefulness of ictal EEGs in determining the seizure type: 1. (a) Ictal EEGs confirmed the diagnosis of the seizure type based on seizure symptoms (101 seizures); (b) Ictal EEGs aided in the classification of the seizure type based on the seizure symptoms (101 seizures); (c) Ictal EEGs corrected errors in the classification (37 seizures); and (d) Ictal EEGs revealed previously unreported/undocumented seizure type (20 seizures). 2. Of the 37 misdiagnosed seizures (group C), 11 were nonepileptic seizures misdiagnosed as epileptic seizures, eight were complex partial seizures (CPS) misdiagnosed as the other seizure types, and 10 were other seizure types misdiagnosed as CPSs. 3. Of the 20 previously unreported/undocumented seizures (group D), nine were myoclonic seizures, five were absence seizures, five were CPS, and one was tonic spasms. 4. Seventy-two patients had CPS. Among them, 11 patients showed no epileptic spikes in their interictal EEG recordings. Therefore, ictal recordings confirmed the diagnosis of epilepsy.

CONCLUSIONS

Ictal EEG recording is a very useful diagnostic tool not only for determining seizure types, but also for uncovering the existence of the unsuspected seizure types. It supplies the physician with useful information for the classification and the treatment of epilepsy. In particular, ictal EEGs are useful in diagnosing patients with CPS.

Electroencephalographic changes and their regional differences during pediatric cardiovascular surgery with hypothermia

Monitoring brain function by EEG is an important means of preventing cerebral insults in pediatric cardiovascular surgery. We studied intraoperative EEG changes and their regional differences associated with hypothermia and brain ischemia. The subjects of this study consisted of 13 children ranging in age from 4 months to 4 years and 6 months. Multi-channel EEGs were recorded using a portable digital EEG system, and the EEG changes were examined by visual inspection and computerized analyses. The results were as follows. (1) During cooling, a discontinuous EEG pattern was transiently observed in four patients, and this phenomenon indicated rapid suppression of cerebral function and subsequent adaptation. (2) Regarding the patterns of change in equivalent potentials induced by hypothermia, there were two different patterns depending on the degree of hypothermia, and the borderline rectal temperature was found to be around 32 degrees C. (3) During cooling, regional differences in the changes in equivalent potentials were observed in nine patients. A decrease in slow waves was marked in the occipital head area, and a decrease in fast waves was prominent in the anterior head area. (4) Arterial hypotension caused transient EEG abnormalities. Of them, bilaterally synchronous rhythmic high voltage slow waves were remarkable and exhibited bifrontal or bicentral dominance. (5) The EEG changes induced by hypothermia were influenced not only by the rectal temperature itself, but also by the rate of change in rectal temperature, and we speculated that this phenomenon was a result of adaptation. In intraoperative EEG monitoring, these findings constitute the basis for early detection of a cerebral hypoxic-ischemic state during pediatric cardiovascular surgery.

Combined use of sphenoidal electrodes and the dipole localization method for the identification of the mesial temporal focus

We attempted to sub-classify four cases who show temporal spikes on standard scalp electroencephalogram (EEG), using sphenoidal electrodes and the dipole localization

METHOD

In a case with mesial temporal epilepsy, spikes showed phase reversal in a sphenoidal electrode, and the spike dipoles were estimated to be in the mesial temporal lobe. In a case with lateral temporal epilepsy, spikes showed no phase reversal in a sphenoidal electrode, and the spike dipoles were estimated to be in the lateral temporal lobe. In two cases out of four, spikes showed phase reversal in sphenoidal electrodes, whilst the dipoles were estimated to be in the frontal lobe. Clinical features also suggested a diagnosis of frontal lobe epilepsy. In one of the two cases in which frontal lobe epilepsy was suspected, ictal dipoles as well as interictal spike dipoles indicated participation of the frontal lobe in the genesis of seizures. Nevertheless, only mesial temporal lobectomy was performed based on results obtained by invasive subdural electrodes. As a result, seizures were not controlled. Although sphenoidal electrodes were useful for differentiating between mesial and lateral temporal lobe foci, it is advisable to use them in combination with the dipole localization method to identify frontal lobe foci.

Predictors and underlying causes of medically intractable localization-related epilepsy in childhood

The goal of this study is to clarify the prognostic factors in childhood localization-related epilepsy in a tertiary medical center. Children (n = 113) with symptomatic and cryptogenic localization-related epilepsy were divided into groups of intractable patients (average seizure frequency: one or more per month during the 6 months before the last follow-up; n = 40) and well-controlled patients (no seizures for at least 1 year before the last follow-up; n = 73). Clinical and electroencephalogram (EEG) factors were examined to elucidate prognostic factors. The subtypes of epilepsies and causes were also investigated. Univariate analyses indicated that the following factors were correlated with seizure outcome: (1) seizure type at the first visit; (2) seizure frequency; (3) underlying cause; (4) age at onset of epilepsy; (5) status epilepticus occurring as the first seizure and before the first visit; and (6) diffuse epileptic discharges on first visit interictal EEGs. Multivariate analyses revealed that seizure type at the first visit, seizure frequency, status epilepticus before the first visit, and underlying causes were significant independent predictive factors. The rate of intractable patients was highest in multilobar epilepsy, followed by frontal-lobe epilepsy. Regarding etiologies, the intractable group contained nine patients with encephalitis of unknown origin and three each with localized cortical malformation and mesial temporal sclerosis.

Myoclonic seizures combined with partial seizures and probable pathophysiology of secondary bilateral synchrony

OBJECTIVE

We report on a patient who showed an unusual transition from complex partial seizures to a combination of myoclonic seizures and partial seizures, and then to isolated myoclonic seizures. The pathophysiological mechanism of the myoclonic seizures in this uncommon condition was studied.

METHODS

The interhemispheric small time differences were estimated in the ictal EEG discharges of myoclonic seizures for differentiation between primary and secondary bilateral synchrony. The estimation was performed by coherence and phase analysis based on the two-dimensional autoregressive model.

RESULTS

The estimated interhemispheric time differences were at most 27.4 ms. The ictal activity of the myoclonic seizures was suggested to originate from a cortical focus in the right hemisphere, which was also the origin of the partial seizures.

CONCLUSION

The patient was considered to have an unusual type of myoclonic seizures with a probable pathophysiological mechanism of secondary bilateral synchrony.

Long-term follow-up of vitamin B(6)-responsive West syndrome

We performed a clinical and electroencephalographic follow-up study on 25 patients with West syndrome that was responsive to vitamin B(6) (eight cryptogenic patients and 17 symptomatic patients) who were older than 3 years at the last follow-up. All cryptogenic patients and 13 symptomatic patients were seizure free at the last follow-up. All cryptogenic patients and seven symptomatic patients had intelligent quotient or developmental quotient scores of 75 or higher. The recurrence of clinical seizures was always associated with increases in epileptic discharges. We could successfully discontinue pyridoxal phosphate administration in four cryptogenic and four symptomatic patients who were 1 year, 8 months to 24 years old.

[A case with congenital hydrocephaly and west syndrome who recovered from hypsarrhythmia after the resolution of shunt trouble]

Hydrocephalus occasionally causes West syndrome, but the mechanism is unknown. We experienced a case with West syndrome and congenital hydrocephaly, in which the EEG findings improved after the resolution of shunt complications. The course of this case implied the pathogenesis of West syndrome associated with congenital hydrocephaly, as well as the origin of the seizures and that of the EEG findings in West syndrome. A 7-month-old girl had congenital hydrocephaly. A prenatal diagnosis was made by ultrasonography, and ventricle-peritoneal shunting was performed 7 days after birth. During the following 7 months several shunt replacements were done because of recurrent shunt complications. Her first series of infantile spasms began at the age of 6 months, and treatment was started under the diagnosis of West syndrome. One month later, her seizures were controlled by pyridoxal phosphate, while the EEG still showed hypsarrythmia. Her shunt was then removed again, because of bacterial meningitis due to shunt infection. The recovery from shunt complication resulted in marked improvement of the hypsarrhythmia. Our experience and previous literature suggest the involvement of cerebral cortex in the occurrence of West syndrome associated with congenital hydrocephaly.

[Nation-wide survey on hemimegalencephaly in Japan]

We report here 38 Japanese patients with hemimegalencephaly collected by a national survey study. All the patients were sporadic. There was no familial occurrence or sex difference. Some patients had basic diseases: hypomelanosis of Ito in 3 cases and organic nevus syndromes in 8. Most patients had hemiparesis, and 11 were bed-ridden. All except for 3 patients had mental retardation, being profound in half of them. There was no correlation between the side of hemimegalencephaly and clinical symptoms. All patients had epileptic seizures, which first appeared within 24 hours after birth in 4 cases, within 7 days in 7, within a month in 2, within 6 months in 10, and within a year in 4. Antiepileptic drugs were not very effective for controlling seizures. In 7 patients, however, functional hemispherectomy resulted in seizure control and improved development. The patients whose epileptic symptom occurred earlier tended to be more severe in clinical symptoms.

Suppression-burst patterns in intractable epilepsy with focal cortical dysplasia

We report on a patient with early-onset spasms in series and partial seizures associated with focal cortical dysplasia whose EEGs showed suppression-burst patterns during early infancy. These electroclinical characteristics suggested a diagnosis of Ohtahara syndrome, but the EEG findings were atypical because of the lack of suppression-burst patterns during wakefulness. In addition, the patient did not have severe psychomotor retardation. With high-dose pyridoxal phosphate therapy, seizures were suppressed and suppression-burst patterns disappeared at 2 months of age. Focal motor seizures recurred later and they often evolved into epilepsia partialis continua. Patients with early-onset intractable seizures associated with suppression-burst patterns on EEGs have several different etiologies, and these patients should be categorized according to their etiology in addition to their syndromic diagnosis.

Dipole analysis in a case with tumor-related epilepsy

In order to evaluate the effectiveness of presurgical dipole analysis of interictal spikes as a non-invasive technique for the determination of epileptogenic area, we compared the results of this method with those of electrocorticography (ECoG) localization in the diagnosis of a patient with tumor-related epilepsy. A preoperative MRI revealed a temporal lobe tumor on the right side. The individual dipoles estimated from the interictal spikes were located mainly in the anterolateral region of the right temporal lobe, although some were located in the mesial side. The ECoG recorded frequent spikes in the anterolateral region of the right temporal lobe consistent with the location estimated by dipole analysis. After surgery, the patient suffered from residual seizures. Therefore, the residual epileptogenic area was examined by dipole analysis using a four-layered head model instead of the previous three-layered head model. As a result, the dipole analysis was able to pinpoint the epileptic focus in the area directly adjacent to the resected area, and in the mesial temporal lobe. In conclusion, EEG dipole analysis appears to hold promise as a non-invasive presurgical evaluation technique for locating epileptogenic areas as well as for postsurgical evaluation of residual epileptic focus.

Nonconvulsive status epilepticus in childhood localization-related epilepsy

PURPOSE

To report on three children with localization-related epilepsy who exhibited minor seizures (atypical absences, brief atonic, and myoclonic) and nonconvulsive status epilepticus (NCSE) consisting of these minor seizures, and to elucidate their significance.

METHODS

We studied the electroclinical characteristics of these children. Ictal electroencephalograms (EEGs) of NCSE were evaluated by using simultaneous video-EEG-electromyogram (EMG) polygraphic recordings.

RESULTS

All patients began to have partial seizures between the ages of 6 months and 2 years 7 months, with minor seizures appearing later, between the ages of 1 year 11 months and 6 years 6 months. These minor seizures evolved into NCSE. Complex partial seizures remained after suppression of the minor seizures. Interictal EEGs taken when the minor seizures appeared showed excessive diffuse epileptic discharges in addition to multifocal spike-waves. Before and after suppression of the minor seizures, focal epileptic discharges predominated on the EEGs. On ictal EEGs of brief atonic and myoclonic seizures, diffuse spike-wave and polyspike-wave bursts were detected. Ictal EEGs of the atypical absences revealed diffuse spike-wave bursts mixed with irregular high-voltage slow waves, often interspersed with brief atonic and myoclonic seizures. When atypical absences lasted for a long time, patients manifested NCSE. Polytherapy might be related to the occurrence of minor seizures and NCSE, because all patients were treated with polytherapy at their appearance, and simplification of antiepileptic drug (AED) therapy seemed to be effective.

CONCLUSIONS

We concluded that this NCSE is a type of atypical absence status which is an age-dependent, transient, electroclinical condition. The mechanism of occurrence of these minor seizures might be related to secondary bilateral synchrony.

Electroclinical characteristics of hemimegalencephaly

Presented here are two long-term follow-up patients with hemimegalencephaly. Patient 1 had Ohtahara's syndrome, which evolved into West's syndrome. Patient 2 had localization-related epilepsy, which demonstrated epilepsia partialis continua throughout the clinical course. The patients' interictal electroencephalograms revealed asymmetric suppression-burst patterns sometime during the clinical course: only during early infancy in patient 1 and until the last follow-up (at 30 years of age) in patient 2. Both patients had moderate mental and motor disturbances with persistence of seizures. Hemiplegia was progressive during early childhood. Aggravation of hemiplegia might be related to frequent seizures and persistent electroencephalographic abnormalities during early childhood. Although asymmetric suppression-burst patterns are considered characteristic electroencephalographic findings in these cases, the duration of their appearance did not have definite prognostic significance.

Long-term follow-up of an individual with vitamin B6-dependent seizures

We report on a 31-year-old female with vitamin B6-dependent seizures whose seizure onset was in the neonatal period. Her elder brother had the same disorder and died in infancy. Administration of vitamin B6 was initiated in the postnatal period. At the age of 12 years 1 month, 2 months after withdrawal of vitamin B6, visual seizures began to occur frequently. Myoclonic seizures and occasional generalized convulsive seizures were also observed. At the same time, photoparoxysmal response and spontaneous diffuse spike-wave bursts were seen on her EEG. Myoclonic seizures were provoked by intermittent photic stimulation during the EEG. It is distinctive that visual seizures were one of the main seizure types in this patient, that her clinical course was relatively benign, and that she has normal intellectual outcome.

Analysis of ictal EEGs of epilepsy associated with tuberous sclerosis

PURPOSE

To investigate the significance of cortical pathology of tonic spasms in patients with tuberous sclerosis.

METHODS

The subjects were 38 patients with epilepsy associated with tuberous sclerosis. We analyzed ictal EEGs of tonic spasms and partial seizures by means of video-EEG monitoring for a total of 763 tonic spasms in 20 patients and 107 partial seizures in 15 patients. We also investigated the relation between partial seizures and magnetic resonance imaging (MRI) findings of these patients.

RESULTS

Ictal EEG patterns of tonic spasms were divided into generalized and focal patterns. Thirteen patients had only generalized patterns, whereas seven had both patterns. In five patients who had focal ictal patterns of tonic spasms and partial seizures, the location of focal patterns corresponded with the location of onset of partial seizures. Focal discharges were seen immediately before, after, and in the middle of tonic spasms in series in 13 patients. The location of focal discharges also corresponded with the location of the onset of partial seizures in 10 of the 13 patients. Regarding partial seizures, four patients had multiple active epileptogenic foci during the same period, and two others had shifting epileptogenic foci with increasing age.

CONCLUSIONS

These findings indicate that cortical pathology plays an important role in the occurrence not only of partial seizures but also of tonic spasms in patients with tuberous sclerosis.

Photosensitive fits elicited by TV animation: an electroencephalographic study

BACKGROUND

We carried out a clinical and electroencephalographic (EEG) study to reveal the pathophysiology of acute symptoms elicited by a TV animation program.

METHODS

Clinical data and EEG were obtained from 20 patients ranging in age from 6 to 30 years. A pattern presentation and an intermittent photic stimulation were performed.

RESULTS

Of 20 patients, 13 had a convulsion and seven had other symptoms, mainly nausea and/or vomiting. A photoparoxysmal response (PPR) was confirmed in 12 of 13 patients (92.3%) who had a convulsion. Only one of seven patients (14.3%) without a convulsion showed a PPR. The incidence of PPR was significantly higher in patients with convulsion than those without convulsion. There were no significant differences in the family history of convulsion, gender, parameters associated with TV watching and basic EEG between the two groups. All patients with PPR had a convulsion or consciousness disturbance.

CONCLUSION

Acute symptoms, such as convulsion and impairment of consciousness, are supposed to be based on photosensitivity.

Long-term follow-up of childhood epilepsy associated with tuberous sclerosis

PURPOSE

To study the clinical and electroencephalographic (EEG) characteristics of patients whose epilepsy is associated with tuberous sclerosis, with special reference to their clinical course.

METHODS

We investigated the electroclinical and radiologic features of 38 patients with epilepsy associated with tuberous sclerosis.

RESULTS

Eleven patients showed only generalized epilepsy, and 10 showed only localization-related epilepsy throughout their clinical course. Among the other 17 cases, the nature of the epilepsy changed between generalized and localization-related epilepsies during the clinical course. A shift from generalized to localization-related epilepsies was more common than the reverse. Seventeen had West syndrome (WS), three had Lennox-Gastaut syndrome (LGS), and eight had epilepsies that evolved from WS to LGS. Tonic spasms, mostly in series, were seen in all 28 patients with generalized epilepsy. Eleven of the 28 patients had partial seizures and tonic spasms in the same period. Six of them showed "simultaneous seizures," consisting of tonic spasms in series and a partial seizure. Partial seizures were the main seizure type in 27 patients with localization-related epilepsy, but three of them also showed tonic spasms that included "simultaneous seizures." Ictal EEGs revealed multiple active foci in the same period that could shift during the clinical course. Neither the location nor number of tubers was related to the clinical course. As for seizure outcome, 12 (32%) of 38 patients were free from seizures at follow-up.

CONCLUSIONS

In epilepsies associated with tuberous sclerosis, there may be an interrelation between generalized and localization-related epilepsies, as well as one between generalized and partial seizures.

Steady-state serum concentrations of carbamazepine and valproic acid in obese and lean patients with epilepsy

Steady-state serum concentrations of carbamazepine (CBZ) and valproic acid (VPA) were investigated in normal weight (body mass index; BMI 20 to 25), lean (smaller than 20 BMI) and moderately obese subjects (greater than 25 BMI) who received either 400 mg/day of CBZ or 800 mg/day of VPA. The CBZ serum concentration in lean subjects was significantly higher than that in normal weight subjects. However, no significant differences in VPA serum concentration were found between the three groups. The CBZ serum concentration decreased with increases in total body weight, and the VPA serum concentration decreased with increases in ideal body weight. However, both serum concentrations were not correlated with BMI. These results suggest that VPA doses should be calculated using ideal body weight and that degree of obesity may affect CBZ serum concentration rather than VPA serum concentration.

Epileptic encephalopathies in early infancy

Of the epileptic syndromes beginning in early infancy, we described the clinical and electrical characteristics of early myoclonic encephalopathy (EME) and Ohtahara syndrome (OS), and the differential diagnosis between the two syndromes, reviewing previous articles and our own study of 6 cases with EME and 15 cases with OS. With regard to the clinical seizure types, the main seizure type was tonic spasms in OS while myoclonias, especially erratic myoclonias, and frequent partial seizures were predominant in EME. The suppression-burst (S-B) pattern was a common feature of both syndromes, although their form, time of appearance, and duration of appearance differed considerably. The S-B pattern in OS was characterized by periodic and consistent appearances during both waking and sleeping states, whereas in EME, the S-B pattern was enhanced by sleep and often not manifested in the awake states. OS showed a specific pattern of evolution as age-dependent epileptic encephalopathy with concomitant EEG change while EME had no specific evolution with age. In OS, obvious brain lesions such as brain malformations were often seen. In contrast, frequent occurrence of familial cases suggested some kind of congenital metabolic disorder as the etiological factor in EME.

Mental deterioration in childhood epilepsy

Mental retardation is detected in 20-30% of children with epilepsy at hospitals specializing in treatment of childhood epilepsy. However, the incidence of mental deterioration in childhood epilepsy is not high. In this study, mental deterioration was found in 52 (1.8%) of the 2,880 children with epilepsy at Okayama University Hospital. The patients showing mental deterioration mostly suffered from specific epileptic syndromes, such as West syndrome, Lennox-Gastaut syndrome, severe myoclonic epilepsy in infancy and epilepsy with continuous spike-waves during slow wave sleep. These types of epilepsy show generalized electroencephalographic (EEG) abnormalities. It is presumed that mental deterioration is caused by the total effects of prolonged diffuse EEG abnormalities and the age of the patients. Antiepileptic drugs exert a relatively minor effect on mental deterioration.

Cerebral blood flow velocity in handicapped children

Using a transcranial Doppler blood flowmeter, the blood flow velocity (BFV) ratio of the middle cerebral artery (MCA) to the basilar artery (BA) was investigated in 12 patients with severe motor and intellectual disability syndrome. The BFV of the MCA was also investigated in 58 handicapped children, classified according to the severity of their motor and intellectual disability. The ratio of the MCA to the BA was lower by 2 SD from the mean of our previously reported standard value in 8 out of the 12 cases with severe motor and intellectual disability syndrome, suggesting a more profound decrease in the level of brain activity in the MCA area than that of the BA area. The BFV of the MCA mainly decreased in cases belonging to the category of the most severe motor disability (bed-ridden). Hence, it is suggested that motor disability is the main factor related to the decrease in the BFV of the MCA.

Electroclinical study of localization-related epilepsies in early infancy

To clarify the characteristics of localization-related epilepsies in early infancy, we performed an electroclinical study of 28 epileptic patients whose first seizures occurred before 6 months of age. The patients were retrospectively divided into two groups: the seizure-controlled group (8 patients) and the refractory group (20 patients). The seizure-controlled group included the patients whose seizures were suppressed within 1 year after onset; the refractory group included all other patients. The characteristics of the refractory group were as follows: (1) most patients had serious underlying pathologies; (2) the seizure type in most cases was simple partial seizure or complex partial seizure without secondary generalization; (3) the interictal EEG showed focal abnormalities and severe dysrhythmia on the basic pattern associated with multifocal spikes in most cases; and (4) in some patients, West syndrome developed after localization-related epilepsies and generalized seizures appeared later in some cases.

Partial seizures in West syndrome

PURPOSE

To study the occurrence of partial seizures (PS) and elucidate the characteristics of patients with West syndrome (WS) with PS.

METHODS

We investigated the electroclinical and radiologic features in 92 children with WS who were older than 3 years at follow-up.

RESULTS

Thirty-six (39.1%) children had PS at some time during the course of the disease. They had a significantly high incidence of asymmetric spasms, hemiparesis, and asymmetric hypsarrhythmia. Their seizure prognosis was significantly less favorable. PS appeared only before spasms (group A, six children), concomitant with spasms (group B, 18 children), and only after spasms ceased (group C, 12 children). Five children in group B had PS after spasms stopped. PS in group A and during the period of active spasms in group B showed high seizure frequency and variability of both seizures and EEG manifestations. The PS and EEG epileptiform discharges were mainly in parietal-posterior temporal-occipital, and central regions. Late PSs in group B and PSs in group C were characterized by stereotyped manifestations and relatively low seizure frequency. These PSs originated mostly from frontal regions.

CONCLUSIONS

In some children with WS, cortical lesions can induce both PS and spasms in series, whereas in others, both types of seizures occur with abnormally increased excitability throughout the cortex rather than as the result of a single cortical lesion. These findings suggest caution in interpreting focal discharges, which may fluctuate and are not necessarily indicative of a surgically accessible lesion. When the discharges are stable and correlate with an equally stable clinical pattern, the likelihood of an underlying cortical lesion is greater.

Effects of high-dose antiepileptic drugs on event-related potentials in epileptic children

N200 and P300 of event-related potentials (ERPs) were recorded from 22 epileptic children receiving high-dose antiepileptic drugs. The patients were undergoing monotherapy with supratherapeutic serum level and were not mentally retarded. P300 latency was prolonged in 5 of 8 patients (62.5%) of the carbamazepine (CBZ) group and in 4 of 7 patients (57.1%) of the phenytoin (PHT) group. Only one child of the PHT group showed abnormality in brain-stem auditory evoked potentials (BAEPs). Abnormality of P300 was more frequent than that of BAEP. In patients of the PHT group who underwent examinations consecutively before and after changing the dose, P300 latency was prolonged rapidly when the PHT level exceeded 30 micrograms/ml. This suggested that the prolongation was dose dependent. In all patients of the valproic acid (VPA) group, P300 latency was normal. Only 2 patients of the PHT group had P300 prolongation simultaneously with clinical signs of intoxication. Others demonstrated changes in P300 without symptoms of side effects.

Investigation of bilateral synchronous spike-wave discharge by EEG topography

To investigate the generator mechanism of the generalized discharge in childhood epilepsy, we studied its voltage field distribution using linked ear reference (L + R), common averaged reference (CA), and source derivation methods (SD). Two cases of epilepsy with clinical lapse of consciousness, and diffuse EEG spike-wave burst were divided into primary bilateral synchrony (PBS) and secondary bilateral synchrony (SBS), using coherence-phase analysis. Spike topograph images were shown by three different references. The difference in spike voltage between CA and SD was also investigated (CA-SD). By all three different references, PBS spike topography showed a broad symmetrical voltage gradient. In SBS, a left frontal focal negativity was shown with a steep voltage gradient in the topographic images of spikes by L + R, CA and SD. This asymmetry disappeared gradually at the end of the spike-wave burst. Both patients showed almost identical broad symmetrical voltage gradients on CA-SD topogram. EEG topography using various references suggested that the potential fields produced by deep generators were identical for PBS and SBS, although those generated by surface generators were different. These findings support the hypothesis that SBS may be projected from the subcortical system, and activated by cortical firing.

Mesial temporal lobe epilepsy in childhood

To clarify the clinical picture of mesial temporal lobe epilepsy (MTLE) in childhood, we carried out a clinical, electroencephalographic, and neuroradiologic study of 19 patients. MTLE was noted in 19 (0.82%) of 2,319 epileptic patients with childhood onset. Three types of initial seizure were recognized: febrile convulsion, afebrile generalized convulsion, and complex partial seizure (CPS). As presumed causes, various prolonged convulsions (persisting for > 30 min) were found in 12 (63.2%) cases. Regardless of the presence of preceding convulsions (febrile or afebrile), the clinical course was not uniform, with CPS in the early period temporarily controlled in some cases and intractable from the early period in others. Unilateral hippocampal abnormalities were confirmed on magnetic resonance imaging (MRI) before the age of 5 years in two cases, suggesting that mesial temporal sclerosis (MTS) is formed within a relatively short period in some cases. Seizures were controlled for > 6 months in only two (10.5%) cases and persisted in 17. In four (21.1%) cases, surgical treatment was considered to be available.

Spike dipole analysis using SEP dipole as a marker

In dipole localization analysis many problems remain which affect the accuracy of localization. We performed dipole estimation of spikes and SEP components in identical patients. The subjects are 8 cases of benign childhood epilepsy with centrotemporal spikes (BCECS), and two cases of temporal lobe epilepsy (TLE). In 8 of 10 cases, we also investigated dipoles using a 3-layer model in addition to a single layer (homogenous) model.

RESULTS

1) In 8 cases of BCECS, the spike dipoles were concentrated at the central line near the SEP dipoles, at a slightly fronto-lateral-downward position to the latter. The spike dipoles seemed to be situated at the bottom of the sensory cortex. 2) In two cases of TLE, the spike dipoles were located at the same coronal plane with the SEP dipoles, and more deeply seated mesially. The spike dipoles seemed to be at the bottom of the mesial temporal area. 3) Using 3-layer models, both the spike dipoles and the SEP dipoles located more superficially, while conserving the positional relationship with each other.

CONCLUSION

It is possible to more accurately define spike dipoles by using the SEP dipole as a marker.

Neuroepidemiological study of childhood epilepsy by application of international classification of epilepsies and epileptic syndromes (ILAE, 1989)

A population-based survey of childhood epilepsy was made in 1975 on the total population of children aged < 10 years living in Okayama Prefecture (n = 2,378 patients). Using the data obtained, we attempted to reclassify the various types of epilepsy according to the international classification (ILAE, 1989). Reclassification was possible in 1,872 (78.7%) of the 2,378 cases. The 1,872 cases consisted of 1,045 (55.8%) with localization-related epilepsies, 824 (44.0%) with generalized epilepsies, and 3 (0.2%) with epilepsies undetermined whether focal or generalized. Classification of the epilepsies in a population-based survey using the international classification involves difficulties, because both clinical and EEG findings are essential. However, if an appropriate area is selected, classification of epilepsies and epileptic syndromes in a population-based survey is possible by referring to all medical records stored at every hospital and practitioner's clinic that administers treatment to patients with epilepsy in the area.

Epilepsy with electrical status epilepticus during slow sleep and secondary bilateral synchrony

In 3 children with "epilepsy with electrical status epilepticus during slow sleep" (ESES), we estimated interhemispheric small time differences (TDs) during spike-wave activity in EEG by coherence and phase analysis by the two-dimensional autoregressive model to differentiate their continuous diffuse spike-waves during slow-wave sleep (CSWS) between primary bilateral synchrony and secondary bilateral synchrony (SBS). Maximal TDs at onset of apparently bilateral synchronous spike-wave bursts (BSSWs) during slow-wave sleep were 12.0-26.5 ms (mean 20.3 ms) with consistent leading hemispheres in eight bursts of the 3 patients, indicating SBS as pathophysiology of their CSWS. This suggestion was supported by their clinico-EEG findings, including the effect of a single oral dose of clobazam (CLB) on EEG. Three ictal BSSWs of atypical absence seizures in 2 patients were also analyzed to obtain maximal TDs of 17.9-41.7 ms (mean 26.3 ms) at onset, with the same leading sides as in sleep, also indicating SBS. Examination of intraburst TD variations showed no consistent disappearance of TDs during the latter part of the bursts, in either sleep or the ictal EEGs of atypical absences, and a role of the corpus callosum was suggested in the generation of SBS in ESES.

The effects of age on the N200 component of the auditory event-related potentials

This study was undertaken to determine the effects of development and aging on N200 of event-related potentials from childhood to adulthood. Event-related potentials were recorded from 164 normal subjects ranging in age from 4 to 77 years. A total of 127 of the 164 subjects demonstrated N200 peaks. N200 showed marked developmental changes. During childhood, the N200 latency decreased rapidly with age to the minimum (217 +/- 17.3 ms) at 16 years of age, while it was prolonged gradually with age during adulthood. The latency/age slope in the subjects from 5 to 15 years of age was -9.03 ms/year, while +0.97 ms/year in those from 16 to 77. The N200-P300 interpeak latency remained constant in all age groups and showed no age-related changes. The N200 amplitude decreased as age increased. Nineteen young cases showed N200 peaks to the frequent stimuli. Their ages ranged from 5 to 17 years. Our study suggests that N200 is valuable in evaluating the developmental and aging processes in the central nervous system. The results of this study could be used as normative data in clinical practices.

Myoclonus epilepsy with ragged-red fibers: a clinical and electrophysiologic follow-up study on two sibling cases

We performed a 5-year clinical and electrophysiologic follow-up study on two sibling cases with myoclonus epilepsy with ragged-red fibers. Both had myoclonus, intention tremor, slight muscle weakness, slight mental disturbance, hearing impairment, and optic atrophy. Neither had epileptic attacks or truncal or gait ataxia. Biochemical activity of cytochrome c oxidase was at the lower limit of the normal range of values, and an adenine to guanine transition mutation at nucleotide 8344 in the transfer RNA specific for lysine of mitochondrial DNA was detected in both cases. The electroencephalograms showed slowing of basic patterns, diffuse spike-and-wave complexes, occipital dominant wave-and-spike phantoms, 6- and 14-Hz positive spikes, and photosensitivity. No definite deterioration of basic patterns was seen, and diffuse spike-and-wave complexes and photosensitivity gradually disappeared during the slowly progressive clinical course. P2 latencies of pattern-reversal visual evoked potentials throughout the clinical course and III through V interpeak latencies of auditory brainstem responses at follow-up were prolonged without giant sensory evoked potentials in both cases.

Aicardi syndrome: a longitudinal clinical and electroencephalographic study

We report clinical and EEG follow-up of 6 children with Aicardi syndrome. Age at seizure onset was < 3 months in 5 patients and 4 months in 1 patient. All patients had spasms, and these continued at time of follow-up in 5 patients. Five patients had seizures other than spasms which disappeared during early infancy. Bilateral independent bursts (BIBs) characteristic of Aicardi syndrome were noted in 4 patients. In 1, BIBs showed suppression-burst patterns. BIBs converted to hypsarrhythmia or multifocal spikes with a tendency to BIBs during sleep. BIBs disappeared completely during both waking and sleeping states between the ages of 3 years 1 month and 4 years 9 months. After BIB disappearance, the EEG of 1 patient showed diffuse slow spike-and-wave complexes most of which appeared asynchronously. At onset, 1 patient had early-infantile epileptic encephalopathy with suppression-burst which evolved initially into West syndrome (WS) and then Lennox-Gastaut syndrome (LGS). The other 3 children also had WS.

Prenatal etiologies of West syndrome

We investigated the etiology of West syndrome (WS) with special reference to prenatal factors in 180 cases. Prenatal cause was the most frequent diagnosis (77 cases, 42.8%), followed by perinatal (25 cases, 13.9%) and postnatal factors (12 cases, 6.7%); 48 cases (26.7%) were of uncertain etiology; eighteen cases (10.0%) were idiopathic. Of the three forms of age-dependent epileptic encephalopathy, prenatal cause was present in 12 of 15 cases (80.0%) of early-infantile epileptic encephalopathy with suppression-burst, 77 of 180 cases (42.8%) of WS, and 31 of 123 cases (25.2%) of Lennox-Gastaut syndrome (LGS). Prenatal factors of WS included tuberous sclerosis (23), chromosome abnormalities (10), cerebral dysgenesis (10), porencephaly (7), hydrocephalus (5), Aicardi syndrome (3), Aicardi syndrome associated with chromosome abnormality (1), and other causes (18). Chromosome abnormalities with WS consisted of 6 cases with 21 trisomy and one case each with 18q duplication, t(1;y) translocation, 7q duplication, and partial 2p trisomy. One patient with Aicardi syndrome also had a t(12;21) translocation. No significant difference was observed in the age of onset of WS among the five etiologic groups. The evolution from WS to LGS was not influenced by etiology, except for the idiopathic group. In patients followed for over 3 years, seizure remission occurred in 46.8% (22 of 47 cases) of the prenatal group. This was lower than the other four groups. Intellectual prognosis was also relatively poor in those with prenatal onset. Pyridoxal phosphate (PAL-P) treatment was effective in 9 of 70 (12.9%) prenatal cases and 5 of 18 (27.8%) idiopathic cases.(ABSTRACT TRUNCATED AT 250 WORDS)