Biomedical subjects

Mutsuo Sasagawa

Publications and source records attributed to Mutsuo Sasagawa.

4 recordsLinked to original sources

PubMed2006

Single and multiple clusters of magnetoencephalographic dipoles in neocortical epilepsy: significance in characterizing the epileptogenic zone.

PURPOSE: To characterize the epileptogenic zone in neocortical epilepsy (NE) by using magnetoencephalography (MEG). METHODS: We defined and compared locations of single and multiple clusters of equivalent current dipoles (ECDs) for interictal spikes with MRI findings, ictal-onset zones (IOZs) from subdural electroencephalography (SDEEG), resected areas, and postsurgical outcomes of 20 patients who underwent cortical resection for medically intractable NE. RESULTS: Fourteen patients had single clusters; six had multiple clusters. Overlap of clusters and IOZs defined group A (nine patients), in which a single cluster coincided with the IOZ; group B1 (four patients), in which a single cluster was within or partially overlapped the IOZ; group B2 (five patients), in which multiple-cluster sections overlapped IOZs; group C (two patients; one single; one multiple), in which no overlap was seen. More single clusters (nine of 14) than multiple clusters (none of six) coincided with the IOZ (p = 0.014). More patients with single clusters (10 of 14) than patients with multiple clusters (one of six) had seizure-free outcomes (p = 0.049). Eight of nine patients in group A, versus three of 11 in groups B1, B2, and C, achieved seizure-free outcomes (p = 0.0098). Correlations between MRI findings and postsurgical outcomes were not statistically significant; eight of 13 patients with single lesions, one of four with no lesions, and two of three with multifocal lesions had seizure-free outcomes. CONCLUSIONS: In neocortical epilepsy, MEG ECD clusters correlated with SDEEG IOZs. Single clusters indicated discrete epileptogenic zones that required complete resection for seizure-free outcome. Multiple clusters necessitated that the multiple or extensive epileptogenic zones be completely identified and delineated by SDEEG.

Adolescent↗

PubMed2006

Magnetoencephalography in patients with tuberous sclerosis and localization-related epilepsy.

PURPOSE: To clarify the usefulness of magnetoencephalography (MEG) for diagnosis of the spatial relations between spike foci and suspicious epileptogenic tubers on MRI in patients with tuberous sclerosis (TS) and to compare MEG spike foci with single-photon emission computed tomography (SPECT) findings. METHODS: We analyzed magnetic fields of epileptic spike discharges in 15 patients with TS and localization-related epilepsy (LRE) by using MEG (a whole-head 204-channel magnetometer system). We investigated the spatial relation between the equivalent current dipoles (ECDs) of interictal spike discharges and visible cortical tubers on MRI. We also compared results of MEG and MRI with SPECT findings. RESULTS: MEG detected a cluster of ECDs around one cortical tuber in six of 15 patients and clusters of ECDs around two cortical tubers in five patients. Interictal SPECT was disappointing in detection of epileptic foci in TS. However, MEG spike foci showed spatial consistency with ictal hyperperfusion areas in two patients. Three patients with single ECD clusters underwent surgical treatment: two have been seizure free, and one has obtained seizure reduction of >90%. CONCLUSIONS: ECDs were located around visible tuber nodules. MEG enabled precise localization of the epileptic foci and provided crucial information for surgical treatment in patients with TS and partial epilepsy. TS patients showing a single ECD cluster on MEG may be appropriate candidates for surgical treatment.

Adolescent↗

PubMed2006

False lateralization of mesial temporal lobe epilepsy by noninvasive neurophysiological examinations.

Mesial temporal lobe epilepsy (mTLE) is the most common form of symptomatic localization-related epilepsy and is surgically remediable. Lateralization of the seizure onset is particularly important to determine from a surgical perspective. A 39-year-old woman with intractable mTLE first exhibited seizure at the age of 3 years. She experienced epigastric sensation and placed her right hand on her abdomen before falling backward. Although interictal scalp electroencephalography (EEG), sphenoidal scalp ictal EEG, and magnetoencephalography showed right temporal side focus, computed tomography and magnetic resonance imaging showed atrophy of the left cerebral hemisphere. Single photon emission computed tomography with technetium-99m ethyl cysteinate dimmer and I-123 iomazenil showed obscure focus on the left side. As a discrepancy existed between the results of neurophysiological examinations and imaging, we performed subdural electrode implantation on the bilateral temporal lobe. Although a bemegride-induced seizure arose from the right side during the subdural recording, the onset of 5 habitual seizures was observed in the left hippocampus. On the basis of these results, the seizure was diagnosed as left mTLE, and left anterior temporal lobectomy and amygdalohippocampectomy were performed. The patient has been free from the seizures for more than 1.5 years of follow up. Bilateral subdural electrode measurement of habitual seizures is indispensable for clarifying the actual focus when a discrepancy exists between neuroimaging and noninvasive neurophysiological examinations.

Adult↗

PubMed2005

Multi-institutional study on the correlation between chromosomal abnormalities and epilepsy.

While there is an abundance of literature describing the association of chromosome aberrations with epilepsy, only a few refer to the detailed features of epilepsy. It is important to investigate the associations between specific chromosome abnormalities and features of epilepsy to identify genes involved in epilepsy and treat them more effectively. We investigated the correlation between specific chromosome aberrations and epilepsy by sending questionnaires to the members of Kyoto Multi-institutional Study Group of Pediatric Neurology. Seventy-six patients were collected from 10 institutions. Chromosome abnormalities included: Down syndrome (n = 19); Angelman syndrome (n = 8); Prader-Willi syndrome (n = 4); 4p- syndrome (n = 3); 1q- syndrome (n = 2); 5p- syndrome (n = 2); Miller-Dieker syndrome (n = 2); 18q- syndrome; (n = 2); Klinefelter syndrome; (n = 2); and 32 other individual chromosomal aberrations. Overall, the severity of mental retardation correlated with the severity of epilepsy. We could abstract characteristic features of epilepsy in some syndromes. In Angelman and Prader-Willi syndromes, febrile seizures occurred frequently, the onset of epilepsy was in early childhood and seizure phenotype was multiple. Paroxysmal discharge of the occipital region and diffuse high voltage slow wave on electroencephalography were characteristic in Angelman syndrome. In Down syndrome, West syndrome and focal epilepsy were common and the prognosis of epilepsy in West syndrome with Down syndrome was good. In 4p- syndrome, febrile seizures were often seen, and unilateral or generalized clonic or tonic-clonic status epilepticus were characteristic. For the other chromosomal aberrations investigated here, the patient numbers were too small to abstract common features of epilepsy.

Adolescent↗