Biomedical subjects

Yoko Ohtsuka

Publications and source records attributed to Yoko Ohtsuka.

At least 37 records · Page 2Linked to original sources

PubMed2005

Characteristics of slow waves on EEG associated with epileptic spasms.

PURPOSE: The high-voltage slow waves (HVSs) on EEG associated with epileptic spasms were investigated to clarify their characteristics and their relation to the pathophysiology of spasms in West syndrome and related disorders. METHODS: In 14 patients, digitally recorded EEG segments showing the ictal HVSs were extracted and their traces were overlaid by using an average reference. The ictal HVSs were also averaged to build maps for investigation of the pattern of potential distribution over the scalp. RESULTS: In a total of 685 recorded spasms, 346 (50.5%) with minimal artifacts were selected to demonstrate that the ictal HVSs had a largely consistent waveform and distribution in each patient. The ictal HVSs were symmetrical in 10 patients and asymmetrical in the other four, and were relatively negative over the posterior region and positive over the frontal or temporal regions in 11 patients. Two symptomatic patients showed a marked deviation of the distribution of HVSs to the pathologically more involved hemisphere. An infant with Aicardi syndrome had two different types of spasms, each type showing a consistent pattern of HVSs with a lateralized distribution. CONCLUSIONS: The patterns of distribution of the ictal HVS may be related to the abnormal activation of the brain in the generation of spasms.

Brain↗

PubMed2005

[Clinical application of the modified wisconsin card sorting test to children with attention deficit/hyperactivity disorder].

The cases with attention deficit/hyperactivity disorder (AD/HD) are known to have difficulties in performing various neuropsychological tests related to the executive function. Among them, the Wisconsin Card Sorting Test (WCST) is already applied to many children with AD/HD. There are, however, differences in the measurement of WCST, and also in the background conditions of the patients, such as the status of medication and the level of Intelligence Quotient (IQ), and presumably as a result, the outcome of WCST shows a diversity. The Keio version WCST (KWCST) is a modified WCST by reducing the number of cards and presenting subjects in two steps separated by a short pause, during which a brief instruction is given. This study was undertaken to compare the performances of children with AD/HD to normal controls using KWCST according to full-scale IQ (FIQ) and also the subtypes of AD/HD. Subjects in this study were 21 unmedicated children with AD/HD, ranging from 5 to 15 years of age, and 21 normal controls who were matched on sex and age. Children with AD/HD whose FIQ was above 80 showed significant low scores in such indices as categories achieved (CA), total errors (TE) , and nonperseverative errors of Nelson (NPEN) in the second step. As to the analysis according to the subtypes, the predominantly inattentive type showed significant low scores in CA, TE and NPEN of the second step, while the combined and predominantly hyperactive-impulsive types showed no significant differences compared with the normal controls. These results suggest that patients with AD/HD have difficulties in effectively utilizing their experiences in the first step as well as instructions which are given before the second step, and also indicate the importance of the second step from a view of the clinical applications.

Adolescent↗

PubMed2004

CYP2C polymorphisms, phenytoin metabolism and gingival overgrowth in epileptic subjects.

Previous studies suggested that the onset of phenytoin-induced gingival overgrowth depended on serum phenytoin concentration. Cytochrome P450 2C (CYP2C) plays an important role in phenytoin metabolism. Recently, single nucleotide polymorphisms in the coding region of CYP 2C influencing phenytoin metabolism were identified. The purpose of the present study was to see if CYP 2C polymorphisms might relate to the onset and severity of phenytoin-induced gingival overgrowth. Twenty-eight epileptic patients taking phenytoin aged 15 to 75 (mean age: 42.2 years old, 20 males and 8 females) and 56 unrelated healthy subjects aged 30 to 48 (mean age: 36.8 years old, 48 males and 8 females) were examined for CYP 2C polymorphisms. All epileptic subjects were examined for the degree of gingival overgrowth, daily phenytoin dose and serum phenytoin concentration. The results indicated about 7% of the subjects including epileptic and healthy subjects examined were positive for CYP 2C9*3. However, the degree of gingival overgrowth did not directly correlate with CYP 2C polymorphisms. Nevertheless, the subjects with severer gingival overgrowth exhibited significantly higher serum phenytoin concentration, indicating that phenytoin metabolism is an important determinant for the severity of the disease. Additionally, CYP 2C9*3 carriers exhibited significantly higher serum drug concentration to drug dose. Therefore, we concluded although the gene analysis is not directly related to diagnose the disease itself, it can be utilized in estimating serum phenytoin concentration from drug dose, which in turn serves to predict the future development and clinical course of the disease.

Adolescent↗

PubMed2004

Ictal MEG in two children with partial seizures.

UNLABELLED: We report on the successful identification of epileptic foci in two children with partial epilepsy using ictal magnetoencephalography (MEG). Case 1 is a 12-year-old male suffering with simple partial seizures with leftwards nystagmus. Ictal SPECT revealed a hyperperfusion area in the right lateral occipital area, and MRI revealed cortical dysplasia in the same area. Interictal EEG dipoles were concentrated in the right mesial occipital lobe. Both interictal and ictal MEG dipoles were concentrated in the right mesial occipital lobe, which corresponded well with neuroimaging data and his clinical features. Case 2 is a 5-year-old female suffering with simple partial seizures with left-side facial twitching. Interictal EEG dipoles were located in her left motor area, the pre-sylvian fissure, close to the location of the interictal MEG-estimated dipoles. Ictal EEGs showed no remarkable changes associated with her clinical manifestations. However, ictal MEG showed high-voltage slow waves over her left hemisphere, and ictal MEG iso-contour maps revealed a clear dipolar pattern, which suggested that the MEG dipole was located in the area of the sylvian fissure. Ictal SPECT revealed hyperperfusion areas around the left sylvian fissure. CONCLUSION: Ictal MEG is useful for determining the precise location of epileptic focus in patients with motionless seizures, including children.

Cerebral Cortex↗

PubMed2004

Kinesigenic attacks with ictal electroencephalographic abnormalities.

We report on a 14-year 5-month-old male who had attacks similar to those of paroxysmal kinesigenic choreoathetosis. The attacks were elicited exclusively by sudden movements. On several occasions, these attacks were immediately followed by loss of consciousness or a seizure. Ictal electroencephalograms of his attacks without loss of consciousness or a seizure indicated 1.5-3.0 Hz activity in the left hemisphere. A small dosage of carbamazepine was remarkably effective in stopping the attacks. This case demonstrates that a thorough ictal electroencephalographic examination is indispensable for clarifying the pathophysiology of kinesigenic attacks. The relationship between paroxysmal kinesigenic choreoathetosis and supplementary motor area seizures is also discussed.

Adolescent↗

PubMed2004

Prognosis after withdrawal of antiepileptic drugs in childhood-onset cryptogenic localization-related epilepsies.

The purpose of this study was to clarify the risk factors of relapse following discontinuation of AEDs in patients with childhood-onset cryptogenic localization-related epilepsies. The subjects were 82 patients who fulfilled the following criteria: (1) age at first visit of less than 15 years, (2) follow-up period of more than 5 years, (3) suffering from cryptogenic localization-related epilepsies, and (4) the patient underwent AED withdrawal during the follow-up period. As a basic principle, we decided to start withdrawing AEDs when both of the following two conditions were met: (1) the patient had a seizure-free period of 3 years or more, and (2) there were no epileptic discharges on EEGs just prior to the start of withdrawal. Seizures recurred in eight of the 82 patients (9.8%). Univariate analysis revealed that the following factors were correlated with higher rates of seizure relapse: 6 years of age or higher at onset of epilepsy; 15 years of age or higher at the start of AED withdrawal; 5 years or more from the start of AED treatment to seizure control; five or more seizures before seizure control; and two or more AEDs administered before seizure control. Among these risk factors, 6 years of age or higher at onset and 5 years or more from the start of AED treatment to seizure control were determined by multivariate analysis to be independent risk factors for relapse. Thus, we conclude that the physician should be more careful in discontinuing AEDs in these higher-risk patients groups, and more generous in discontinuing AEDs in lower-risk groups.

Adolescent↗

PubMed2004

Clinical and electroencephalographic characteristics of children with febrile seizures plus.

OBJECTIVES: Febrile seizures plus (FS+) are attracting attention for their corresponding genetic abnormalities, and are defined as febrile seizures (FS) continuing beyond 6 years of age (late FS) or those associated with afebrile seizures. We tried to elucidate their clinical and EEG characteristics as compared with those of children having only FS. SUBJECTS AND METHODS: We reviewed clinical records in a pediatric neurology clinic to identify 31 patients with FS+ (group FS+) and 51 with only FS (group FS). Their family history of seizures, clinical features and EEG findings were compared. RESULTS: A family history of seizures was noted in 14 patients (45.2%) of group FS+ and in 24 (47.1%) of group FS. In group FS+, 19 patients had late FS, 11 had afebrile seizures, and the remaining one had both types of seizures. Two patients had seizures induced by TV/video-game as well, and another suffered from absences. Epileptic EEG abnormalities, which included diffuse spike-waves and focal spikes, were noted in 13 patients (41.9%) of group FS+ and 12 (23.5%) of group FS. CONCLUSIONS: The clinical and EEG characteristics of the children having FS+ were diverse, without significant differences from those with FS except for the seizures types.

Adolescent↗

PubMed2004

EEG in childhood absence epilepsy.

UNLABELLED: We performed a longitudinal clinico-electroencephalographic study of 23 children who were diagnosed as having absence epilepsy on their initial visits to our facility and we analysed those factors which lead to an unfavourable prognosis. SUBJECTS AND METHODS: We divided the 23 patients into three groups according to their clinical courses: Group A: eight patients who responded well to the therapy and became seizure free without relapse of epileptic discharges on EEGs; Group B: thirteen patients who suffered from relapse of epileptic discharges on EEGs despite clinical seizure cessation; Group C: two patients who continued to suffer from seizures. RESULTS: (1) Fifty-six percent of all patients had focal epileptic discharges, including a surprising 63% of patients in Group A. (2) "Lead in" in the ictal EEGs and automatisms during seizures were most commonly observed in patients in Group B, although there were no significant differences between the three groups. (3) The epilepsy of one patient in Group C evolved into complex partial seizures or absence status during her clinical course. She seemed to suffer from so-called "frontal absence", despite the fact that her initial EEG did not show any focal abnormalities. (4) Patients in Group B were treated with lower AED dosages than those in Group A. In addition, one patient in Group C was treated irregularly. CONCLUSION: We conclude that it is not uncommon for patients with absence epilepsy to show focal abnormalities on EEGs and clinical ictal automatisms. Thus, the existence of clinical ictal automatisms and focal signs in electroencephalographic features are not sufficient indicators of the final outcome. Furthermore, it appears that regular and adequate drug therapy is important for a favourable prognosis.

Anticonvulsants↗

PubMed2004

Very fast rhythmic activity on scalp EEG associated with epileptic spasms.

PURPOSE: Very fast activity was investigated on the ictal EEGs of epileptic spasms to elucidate the pathophysiology of West syndrome (WS) and related disorders from a novel point of view. METHODS: The traces of scalp ictal EEG of spasms temporally were expanded in 11 patients whose clinical diagnosis was symptomatic WS in six, cryptogenic WS in two, Aicardi syndrome in one, and symptomatic generalized epilepsy after WS in the remaining two. Time evolution of averaged power spectra of the ictal fast activity also was analyzed in each patient. RESULTS: Rhythmic gamma activity with frequency ranging from 50 to 100 Hz was detected in a total of 345 of 537 spasms. Fast activity was seen bilaterally in nine patients, was lateralized to one hemisphere in another, and appeared independently on each hemisphere in the remaining infant with Aicardi syndrome. Power spectra showed a clear peak corresponding to spasm-associated gamma rhythm, with frequency centering approximately 65 Hz and ranging from 51 to 98 Hz. The morphology and spectral characteristics of ictal gamma rhythm were completely different from those of muscle activity or alternating current (AC) artifacts. CONCLUSIONS: Spasm-associated gamma activity was clearly detected on the scalp. This observation may provide a clue to the pathophysiology of spasms.

Cerebral Cortex↗

PubMed2004

Utility of scalp-recorded ictal electroencephalograms in childhood epilepsy with complex partial seizures.

BACKGROUND: The authors evaluated the usefulness of scalp-recorded ictal electroencephalograms (EEG) in diagnosing the epileptogenic area in epilepsy with complex partial seizures. METHODS: The authors analyzed the ictal EEG of 395 seizures in 43 patients with complex partial seizures. Based on EEG findings the patients were classified according to the degree of localization of their onset areas. The results were then compared with neuroimaging findings. RESULTS: Only 10 patients fell into the category 'discrete', meaning that all the onset areas (as measured by ictal EEG) were localized in the same lobe of the same hemisphere. Seven patients were categorized as 'lateralized', meaning that all the onset areas were clearly lateralized in the same hemisphere but without consistent localization. Eleven patients were classified as 'localized', meaning that the onset area were localized simultaneously in bilateral same lobes, or changed consistently from one lobe in one hemisphere to the same lobe in the opposite hemisphere. The onset area could not be defined in 15 patients and these were categorized as 'not defined'. No patient who underwent seven or more ictal recordings was categorized as discrete. However, when confined only to those patients in whom over 75% of the ictal recordings showed the same onset area, there was a high correlation between the epileptogenic lesions detected by ictal EEG and those detected by neuroimaging techniques. CONCLUSIONS: The findings of the present study indicate that ictal EEG recordings are useful for determining the epileptogenic area in epilepsy with complex partial seizures, provided that more than 75% of the ictal recordings show the same ictal onset area.

Brain↗

PubMed2004

Memory function decline over 18 months after selective amygdalohippocampectomy.

We report on a 22 year-old woman with left temporal lobe epilepsy who had suffered complex partial seizures since childhood. At 19 years 10 months of age she underwent selective amygdalohippocampectomy, which resulted in a complete cessation of seizures. Preoperatively, the Logical Memory II section of the WMS-R revealed poor logical memory function. Postoperatively, the patient's scores on several neuropsychological tests had deteriorated, namely, the Miyake Paired-Associate Word Learning Test (related and unrelated pairs), several sections of the WMS-R (Figural Memory, Logical memory I, Visual Reproduction II, Visual Paired Associates I, and Verbal Paired Associates I and II), and the BVRT-R. In particular, her scores on the Visual Paired Associates I, Verbal Paired Associates I and II sections of the WMS-R, and the BVRT-R not only declined at one and three months post-surgery, but also showed progressive deterioration at 16 and 18 months post-surgery. It should be kept in mind that selective amygdalohippocampectomy can result in progressive postoperative, deterioration in some aspects of memory function.

Adult↗

PubMed2003

Paroxysmal movement disorders in severe myoclonic epilepsy in infancy.

We report on the electroclinical findings and the results of a molecular genetic study of a patient with typical severe myoclonic epilepsy in infancy (TSME) and three with borderline SME (BSME) who showed paroxysmal movement disorders, such as choreoathetosis, dystonia and ballismus, during their clinical course. BSME was defined as a clinical entity that shares common characteristics with TSME but lacks myoclonic seizures associated with ictal EEG changes. When the paroxysmal movement disorders were first observed, all the patients in this study were being treated with polytherapy including phenytoin (PHT), and these abnormal movements disappeared when PHT was discontinued or reduced. However, on other occasions, two of our cases also showed the same abnormal movements even when not being treated with PHT. One patient with TSME and two of the three patients with BSME had SCN1A gene mutations that lead to truncation of the associated protein. We conclude that paroxysmal movement disorders seen in SME patients were closely related to their AED therapy, especially the use of PHT. It is thought that patients with both TSME and BSME have some predisposition toward paroxysmal movement disorders, and that this predisposition is partly related to sodium channel dysfunction, although some other factors might influence the occurrence of this phenomenon.

Adolescent↗

PubMed2003

Is phenotype difference in severe myoclonic epilepsy in infancy related to SCN1A mutations?

We classified 28 patients with severe myoclonic epilepsy in infancy (SME) according to the presence or absence of myoclonic seizures and/or atypical absences. Eleven of the patients had myoclonic seizures and/or atypical absences, and we refer to this condition as 'typical SME (TSME)'. Seventeen of the patients had only segmental myoclonias, and we refer to this condition as 'borderline SME (BSME)'. We then analyzed the electroclinical and genetic characteristics of these two groups. Ten of the 11 TSME patients had a photoparoxysmal response at some time during their clinical course, while none of the BSME patients showed this response. TSME and BSME showed a significant difference in regard to gender ratio: female dominance in TSME and male dominance in BSME (P=0.008). The detection rate of the voltage-gated sodium channel alpha1-subunit (SCN1A) gene mutations was 72.7 and 88.2% in TSME and BSME, respectively. There was no difference in the type or rate of mutation between TSME and BSME. We conclude that TSME and BSME show distinct differences in photoparoxysmal response and gender, which might be caused by some genetic mechanism(s) other than the SCN1A gene mutation.

Adolescent↗

PubMed2003

A simulation study of the error in dipole source localization for EEG spikes with a realistic head model.

OBJECTIVE: We tried to determine the error range of dipole modeling for EEG spikes originating from various clinically important sources by a simulation study employing a realistic head model. The computed error range was also compared with the degree of disturbance of dipole modeling caused by adding background activity to the spike. METHODS: The scalp fields generated by temporal, frontal and rolandic epileptic sources with spatial extent were simulated, and the corresponding 3-dimensional maps of residual variance (RV) were built by computing the RV for a single dipole at each point on a fine imaginary grid in the brain. Single dipole modeling was also performed for the simulated scalp fields after adding real background activity. RESULTS: The brain volume corresponding to a small RV was compact for the frontal sources and the lateral and baso-mesial temporal sources, and large for the anterior and baso-lateral temporal sources. The distribution of dipoles estimated for spikes contaminated with background corresponded to that of the volume of small RV and to spike-amplitude. Estimates were improved by employing inferior temporal electrodes. CONCLUSIONS: When evaluating dipole models of epileptic spikes, error ranges can be estimated and they vary considerably from region to region. SIGNIFICANCE: This study illustrates the variability of the error in dipole modeling of epileptic spikes. This variability is important when considering the clinical interpretation of modeling results.

Brain Mapping↗

PubMed2003

[A child with ictal fear as the primary epileptic manifestation].

We report a 4-year-old boy with ictal fear as his primary epileptic manifestation. Following an arrest of motion, the boy started to scream and struggle with an expression of horror on his face. Oral automatisms appeared around the end of the seizure. Complex visual and gustatory hallucinations and pain in the left leg were also observed. Ictal and interictal scalp EEGs revealed epileptic discharges in bilateral frontal regions. Ictal SPECT (99 mTc-HMPAO) showed hyperperfusion in right medial temporal area. These findings suggest that ictal fear associated with other ictal manifestations such as various hallucinations and oral automatisms resulted from rapid spread of epileptic discharges from frontal lobes to the right anterior temporal region.

Brain↗

PubMed2002

Significant correlation of the SCN1A mutations and severe myoclonic epilepsy in infancy.

To investigate the possible correlation between genotype and phenotype of epilepsy, we analyzed the voltage-gated sodium channel alpha1-subunit (SCN1A) gene, beta1-subunit (SCN1B) gene, and gamma-aminobutyric acid(A) receptor gamma2-subunit (GABRG2) gene in DNAs from peripheral blood cells of 29 patients with severe myoclonic epilepsy in infancy (SME) and 11 patients with other types of epilepsy. Mutations of the SCN1A gene were detected in 24 of the 29 patients (82.7%) with SME, although none with other types of epilepsy. The mutations included deletion, insertion, missense, and nonsense mutations. We could not find any mutations of the SCN1B and GABRG2 genes in all patients. Our data suggested that the SCN1A mutations were significantly correlated with SME (p<.0001). As we could not find SCN1A mutations in their parents, one of critical causes of SME may be de novo mutation of the SCN1A gene occurred in the course of meiosis in the parents.

Amino Acid Sequence↗

PubMed2002

Childhood-onset epilepsy associated with polymicrogyria.

To study the electroclinical characteristics of patients with childhood-onset epilepsy who showed polymicrogyria (PMG) on MRI, we classified 15 patients according to the location of PMG on MRI. The composition of the subjects was as follows: four patients with PMG in both hemispheres; three with localized PMG in one hemisphere associated with other lesions such as porencephaly; and eight with only localized PMG in one hemisphere. We investigated the electroclinical characteristics of the epileptic syndromes associated with these different types of PMG. Four patients suffered from infantile spasms during their clinical course. Five patients suffered from epilepsy with electrical status epilepticus during slow sleep (ESES) and ESES-related epilepsy. The other six patients had only localization-related epilepsy throughout their clinical course. Patients with PMG in both hemispheres, and localized PMG in one hemisphere associated with other lesions tended to have early-onset intractable seizures, especially infantile spasms. On the other hand, patients with only localized PMG in one hemisphere had ESES and ESES-related epilepsy or localization-related epilepsy, and their seizure prognosis was relatively favorable. These findings are useful in predicting the outcome of patients with PMG.

Adolescent↗

PubMed2002

Benefit of simultaneous recording of EEG and MEG in dipole localization.

PURPOSE: In this study, we tried to show that EEG and magnetoencephalography (MEG) are clinically complementary to each other and that a combination of both technologies is useful for the precise diagnosis of epileptic focus. METHODS: We recorded EEGs and MEGs simultaneously and analyzed dipoles in seven patients with intractable localization-related epilepsy. MEG dipoles were analyzed by using a BTI Magnes 148-channel magnetometer. EEG dipoles were analyzed by using a realistically shaped four-layered head model (scalp-skull-fluid-brain) built from 2.0-mm slice magnetic resonance imaging (MRI) images. RESULTS: (a) In two of seven patients, MEG could not detect any epileptiform discharges, whereas EEG showed clear spikes. However, dipoles estimated from the MEG data corresponding to the early phase of EEG spikes clustered at a location close to that of the EEG-detected dipole. (b) In two of seven patients, EEG showed only intermittent high-voltage slow waves (HVSs) without definite spikes. However, MEG showed clear epileptiform discharges preceding these EEG-detected HVSs. Dipoles estimated for these EEG-detected HVSs were located at a location close to that of the MEG-detected dipoles. (c) Based on the agreement of the results of these two techniques, surgical resection was performed in one patient with good results. CONCLUSIONS: Dipole modeling of epileptiform activity by MEG and EEG sometimes provides information not obtainable with either modality used alone.

Adolescent↗