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.

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.

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.

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.

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.

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

UNLABELLED: 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.

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.

Evaluation of the severity of chronic heart failure by the reactivity of peripheral vessels.

We developed a method to evaluate the severity of chronic cardiac failure by Doppler image analysis. Doppler images of the whole arterial lumen were consecutively recorded on video tape and the power spectrum (sum of intensity multiplied by frequency) of each frame was considered as an index of the blood flow volume (VI). The right brachial artery was occluded for 15-60 seconds by a occluding cuff, and was released quickly. The VI was determined until the VI returned to the level at rest and total VI was calculated as an O2 repayment. The O2 repayment rate (R-Rate) was calculated as a ratio of the O2 repayment divided by total VI during interruption. The cardiac function was evaluated by sub-maximal exercise using bicycle ergometer and was compared with the R-Rate. The subjects were 22 patients (18 males and 4 females) with chronic cardiac failure of NYHA class I (9), class II (6), class III (4), class IV (3) and 12 healthy controls. R-Rate was almost unchanged by the duration of occlusion and showed positive correlation with exercise capacity. R-Rate decreased as the class of NYHA advanced. In conclusion, determination of reactive hyperemia can be used for objectively evaluating the severity of cardiac failure. Doppler sonography; cardiac failure; reactive hyperemia; peripheral circulation

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.

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.

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.

[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.