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1.
We previously reported the results of a magnetoencephalographic study in patients with Panayiotopoulos syndrome manifesting occipital epileptic discharges, in which the equivalent current dipoles of spike discharges were clustered alongside the major cortical sulci, such as parieto-occipital and calcarine. This report is the result of a magnetoencephalographic study of three patients with Panayiotopoulos syndrome exhibiting equivalent current dipoles clustering in the frontal area. Patient 1, a 13-year-old male, exhibited clustering equivalent current dipoles alongside right inferior frontal sulcus, but the orientations were irregular. Patient 2 is an 11-year-old younger brother of Patient 1, whose magnetoencephalograph revealed equivalent current dipoles clustering alongside right prefrontal sulcus and regular orientations. Patient 3 is a 10-year-old female who had equivalent current dipoles clustering alongside right superior frontal sulcus and extremely regular orientations. The locations of clustering equivalent current dipoles of frontal spike discharges were not restricted to one specific frontal sulcus but were present in various locations over the convexity of the prefrontal area. In conclusion, these findings suggest that it is inappropriate to classify Panayiotopoulos syndrome as occipital epilepsy. In addition, the result of this study, that frontal spike discharges seem to occur in relatively older patients, may suggest a correlation between brain maturation and spike occurrence.  相似文献   

2.
OBJECTIVE: To evaluate whether the orientation of interictal spikes, localized in major sulci by magnetoencephalography (MEG), predicts the epileptogenic side of the sulcal wall. METHODS: Sixteen epilepsy patients were analyzed in whom equivalent current dipoles (ECDs) of MEG spikes were localized on the central (four patients), interhemispheric (4), or sylvian fissure (8); and the epileptogenic side across the sulci had been confirmed by seizure semiology, structural lesions, or intracranial electroencephalography (EEG). ECD was classified as epileptogenic side or normal side oriented and correlated to the scalp EEG map. RESULTS: All central (n=50) and interhemispheric (n=83) spike ECDs were oriented toward the epileptogenic side at peak latency. In scalp EEG, 91% of the spikes showed radial pattern of broad negativity above the sulcus whereas 9% showed tangential pattern with positive maximum above the epileptogenic side. Sylvian spikes were only found in patients with temporal lobe epilepsy (TLE). In sylvian spikes (n=220), 73% of ECDs were oriented toward the epileptogenic side, whereas 27% were oriented toward the normal side. CONCLUSIONS: In central and interhemispheric spikes, epileptogenic side cortex may be gross surface negative through the sulcal wall to the adjacent gyrus. Inconsistent orientation of the sylvian spikes suggests a complex pattern of spike propagation in TLE. SIGNIFICANCE: ECD orientation of central and interhemispheric spikes in MEG may predict the epileptogenic side.  相似文献   

3.
OBJECTIVE: To report the ictal magnetoencephalography (MEG) in a patient with ring chromosome 20 mosaicism, a rare chromosomal anomaly associated with intractable epilepsy. METHODS: MEG and simultaneous EEG were recorded with a 204 channel whole head MEG system. Ten habitual seizures occurred during the acquisition, which was done twice. The equivalent current dipoles (ECDs) for ictal discharges on MEG were calculated using a single dipole model. The ECDs were superimposed on a magnetic resonance image. RESULTS: During the seizures, EEG showed prolonged bursts of 5-6 Hz high voltage slow waves with spike components, dominantly in the bilateral frontal region. MEG showed epileptiform discharges corresponding to the ictal EEG. Ictal discharges on MEG were dominant in the frontal area in the initial portion, and then spread in the bilateral temporal area in the middle of the seizure. ECDs obtained from the spikes of the initial portion were clustered in the medial frontal lobe. CONCLUSIONS: The source of the ictal MEG was localised in the medial frontal lobe. The findings suggest that the mechanism underlying epilepsy in this case might be similar to medial frontal lobe epilepsy. Ictal MEG is a valuable tool for detecting the site of seizure onset.  相似文献   

4.
To assess the clinical value of magnetoencephalography (MEG) in investigating the origin of secondary bilateral synchrony (SBS) in patients with partial epilepsy. MEG and simultaneous electroencephalography (EEG) were recorded with a 204-channel whole-head MEG system in 2 patients. The equivalent current dipoles (ECDs) for epileptic discharges on MEG were calculated according to a single dipole model. In patient 1, the ictal EEG showed bursts of bilateral synchronous 3-Hz spike-and-slow-wave complexes. ECDs obtained from the ictal MEG localized to the right medial frontal lobe. On the second patient's MEG recordings, epileptic discharges corresponding to prolonged EEG bursts of bilateral synchronous spike-and-slow-wave complexes were obtained. ECDs calculated from the prolonged bursts were clustered in the left medial frontal lobe. MEG detected the sources of SBS in the medial frontal lobe. MEG is extremely useful for the identification of the source of SBS.  相似文献   

5.
PURPOSE: To determine the electromagnetic sources of localized epileptic activities using magnetoencephalography (MEG) in three adult patients with epilepsy suggestive of Lennox-Gastaut syndrome (LGS).METHODS: MEG and simultaneous electroencephalography (EEG) were recorded from three adult patients using a 204-channel, whole-head MEG system. Equivalent current dipoles (ECDs) were calculated for epileptic spikes on MEG according to the single dipole model.RESULTS: In two patients, MEG showed epileptiform discharges restricted to the unilateral temporal area, corresponding to the EEG spikes. The ECDs calculated from these MEG spikes were clustered in the unilateral temporal lobe. In our third patient, MEG spikes appeared in the right centroparietal area; ECDs were located to the right parietal lobe.CONCLUSIONS: The sources of epileptiform discharges that were detected in a restricted area were localized to specific parts of the brain cortex. Despite certain limitations (small number of patients; atypical late-onset epilepsy in one) our study suggests that MEG may prove to be a useful tool for investigating electromagnetic features of localized epileptic discharges in patients with LGS. Based on these preliminary results, further studies performed in patients with typical LGS features are justified.  相似文献   

6.
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.  相似文献   

7.
OBJECTIVE: Early onset benign occipital lobe epilepsy (Panayiotopoulos syndrome [PS]) is a common and easily recognizable epilepsy. Interictal EEG spike activity is often multifocal but most frequently localized in the occipital lobes. The origin and clinical significance of the extra-occipital spikes remain poorly understood. METHODS: Three patients with the PS and interictal EEG spikes with frontal lobe topography were studied using high-resolution EEG. Independent component analysis (ICA) was used to decompose the spikes in components with distinct temporal dynamics. The components were mapped in the scalp with a spline-laplacian algorithm. RESULTS: The change in scalp potential topography from spike onset to peak, suggests the contribution of several intracranial generators, with different kinetics of activation and significant overlap. ICA was able to separate the major contributors to frontal spikes and consistently revealed an early activating group of components over the occipital areas in all the patients. The local origin of these early potentials was established by the spline-laplacian montage. CONCLUSIONS: Frontal spikes in PS are consistently associated with early and unilateral occipital lobe activation, suggesting a postero-anterior spike propagation. SIGNIFICANCE: Frontal spikes in the PS represent a secondary activation triggered by occipital interictal discharges and do not represent an independent focus.  相似文献   

8.
BACKGROUND: A child whose left temporal lobe contained mesial, anterior and basal structures but lacked superio-lateral cortex had intractable epilepsy secondary to a porencephalic cyst. Magnetoencephalography (MEG) shows equivalent current dipoles (ECDs) as dipole modeling for temporal lobe epilepsy rather than in an exact location. AIM: We hypothesized that the magnetic fields generated by the epileptic discharges in mesio-basal temporal areas could be detected by MEG without interference from the superio-lateral temporal cortices. METHODS: We analyzed MEG spikes using single dipole analysis and synthetic aperture magnetometry (SAM), and compared with EEG spike topography. RESULTS: Two MEG ECDs corresponding to T3 spikes localized to the anterior mesio-basal temporal region with vertical orientation. Sixteen MEG ECDs corresponding to T5 spikes localized to the middle to posterior mesio-basal temporal region with vertical orientation. SAM revealed maximum current density at hippocampus and anterior fusiform gyrus for T3 spikes, and at posterior hippocampus and fusiform gyrus for T5 spikes. CONCLUSION: Vertically oriented ECDs were obtained without superio-lateral temporal cortices because of temporo-parieto-occipital porencephalic cyst. The absence of superio-lateral temporal cortices, prominent temporal EEG spikes, less prominent MEG spikes, and mesio-basal SAM spikes indicated that the vertically oriented ECDs were projected directly from the mesio-basal temporal region.  相似文献   

9.
Focal spike activities in Panayiotopoulos syndrome involve all brain regions in electroencephalography, and commonly reveal multiple foci, often through occipital predominance. To investigate correlations between developmental brain maturation and spike origin in Panayiotopoulos syndrome, we evaluated age-related or duration-related magnetoencephalographic spike localization in 25 patients with Panayiotopoulos syndrome. Regarding age at examination, patients with frontal spikes were significantly older than patients with spikes on rolandic, parieto-occipital, or calcarine sulci. Occipital spikes were classified into two subgroups, located at the calcarine sulcus and parieto-occipital sulcus. Both calcarine and parieto-occipital localizations were seen in patients around the same age. Follow-up magnetoencephalography was performed on three patients, and demonstrated shifting localization or disappearance of magnetoencephalographic spikes. These results suggest that the location of spike discharges is not directly related to seizure symptoms, but instead indicates maturation-related cortical hyperexcitability in patients with Panayiotopoulos syndrome.  相似文献   

10.
PURPOSE: Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy that is frequently associated with abundant multifocal spikes other than main occipital spikes on the EEG. In this study, we investigated the characteristic features of dipoles in PS. METHODS: We performed dipole analysis of the interictal occipital spike discharges seen in 10 children with PS (group A) and in 10 children with other types of symptomatic localization-related epilepsy (group B). We analyzed the dipoles of the averaged spike in each patient. RESULTS: In group A, the averaged occipital spikes in each patient showed dense dipole locations in the mesial occipital area; in group B, widely scattered dipole locations were observed. In Group A, the geometric centers of the dipoles at each time point (such as at the main negative peak and before or after the main peak) were estimated in the neighboring locations. In contrast, they tended to be scattered in group B. CONCLUSIONS: Our study reveals that PS has high dipole stability, similar to that of rolandic epilepsy. From the electroencephalographic view, this seems to indicate a close link between these two syndromes.  相似文献   

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