analyzing-neural-activity-connectivity-using-intracranial-eeg-data

Analyzing Neural Activity and Connectivity Using Intracranial EEG Data with SPM Software

Measuring neural activity and connectivity associated with cognitive functions at high spatial and temporal resolutions is an important goal in cognitive ...

Shizuoka Institute of Epilepsy and Neurological Disorders

To clarify the clinical significance of ictal high frequency oscillations (HFO) in the medial temporal lobe.

Clinical significance of ictal high frequency oscillations in medial temporal lobe epilepsy.

To clarify the value of versive seizures in lateralizing and localizing the epileptogenic zone in patients with occipital lobe epilepsy, we studied 13 occipital lobe epilepsy patients with at least one versive seizure recorded during preoperative noninvasive video-EEG monitoring, who underwent occipital lobe resection, and were followed postoperatively for more than 2 years with Engel's class I outcome. The videotaped versive seizures were analyzed to compare the direction of version and the side of surgical resection in each patient. Moreover, we examined other motor symptoms (partial somatomotor manifestations such as tonic and/or clonic movements of face and/or limbs, automatisms, and eyelid blinking) associated with version. Forty-nine versive seizures were analyzed. The direction of version was always contralateral to the side of resection except in one patient. Among accompanying motor symptoms, partial somatomotor manifestations were observed in only five patients. In conclusion, versive seizure is a reliable lateralizing sign indicating contralateral epileptogenic zone in occipital lobe epilepsy. Since versive seizures were accompanied by partial somatomotor manifestations in less than half of the patients, it is suggested that the mechanism of version in occipital lobe epilepsy is different from that in frontal lobe epilepsy.

Versive seizures in occipital lobe epilepsy: lateralizing value and pathophysiology.

In seizures with tonic posturing, differentiation of seizures originating in SSMA from seizures originating in cortices other than SSMA and spreading to SSMA has not been previously attempted. Twenty-two patients were studied with intractable focal epilepsy with tonic limb posturing as the most prominent semiology, who underwent resective surgery and obtained favorable postoperative seizure outcomes. These 22 patients were divided into an SSMA group (N = 12) and an extra-SSMA group (N = 10), according to the location of resection. Resection area in the extra-SSMA group was located in the dorsolateral frontal or prefrontal area in four patients, the frontal operculum (insula) in two, the parietal cortex in three, and the temporoparietal cortex in one patient. Video-recorded seizures were carefully reviewed. Tonic posturing characteristics and the presence or absence of accompanying symptoms were compared between groups. Incidence of preservation of consciousness was significantly higher in the SSMA group (p < 0.001). Patients in the SSMA group demonstrated a propensity for having unilateral or bilateral asymmetrical tonic limb posturing. In contrast, patients in the extra-SSMA group had a statistically significantly higher incidence of bilateral symmetrical tonic limb posturing (p < 0.05). These findings may be helpful in identifying seizure origin. 

Seizures with tonic posturing: Semiologic difference between supplementary sensorimotor area (SSMA) origin and extra-SSMA origin.

Focal cortical dysplasia (FCD) is intrinsically epileptogenic, and an MRI-visible lesion typically constitutes the core part of the epileptogenic zone. We aimed to identify ictal EEG patterns that represent the epileptogenic zone by using subdural electrodes placed over the MRI-visible FCD lesion.

Characteristics of EEG Seizure-Onset Patterns Recorded From Subdural Electrodes Over MRI-Visible Frontal Focal Cortical Dysplasia Type IIb Lesions.

Reversible amygdala enlargement: a longitudinal observation of a patient with elderly onset temporal lobe epilepsy.

To verify the long-term efficacy of resective surgery, we created a classification system in which strictly defined patterns of postoperative seizure emergence are incorporated as basic components and the seizure states throughout the entire follow-up period are assessed comprehensively.

A classification system for verifying the long-term efficacy of resective surgery for drug-resistant seizures.

The amygdala and uncus are located close to important neurovascular structures. We describe a safe technique for resection of amygdala and uncus. Under general anesthesia, the patient is positioned supine, with the head rotated approximately 20 degrees to the unoperated side and slightly extended. By using a trans-anterior T subpial approach, the inferior horn of the lateral ventricle is opened, and hippocampectomy is performed. We treat an imaginary plane formed by the inferior circular sulcus of the insula, the endorhinal sulcus, and the inferior choroidal point as the upper border of amygdalar resection. After confirming the position of the inferior choroidal point, the border between the temporal stem and uncus is exposed from anterior to posterior. This border is continuous with the endorhinal sulcus. By exposing the endorhinal sulcus, the anterior choroidal artery and optic tract can be visualized. The amygdala is disconnected through complete exposure of the endorhinal sulcus to the inferior choroidal point. After the lateral side of the uncus is disconnected, the amygdala and uncus are removed en bloc. Since April 2014, we have used the described procedure to remove amygdalar-uncal lesions in 15 patients. The lesion was completely removed in all cases without complications. Histological specimens were obtained in all cases. Our procedure enables safe and complete removal of amygdalar-uncal lesions. Imagining the plane formed by the inferior circular sulcus, inferior choroidal point, and endorhinal sulcus is essential for complete removal of the lesion and for preserving important structures.

Surgical Resection of Amygdala and Uncus.

This study compared temporal lobe epilepsy (TLE) patients with amygdala lesion (AL) without hippocampal sclerosis (HS) (TLE-AL) with patients with TLE and HS without AL (TLE-HS). Both subtypes of TLE arose from the right hemisphere. The TLE-AL group exhibited a lower Working Memory Index (WMI) on the Wechsler Adult Intelligence Scale, third edition (WAIS-III), indicating that the amygdala in the right hemisphere is involved in memory-related function. [18F]fluorodeoxyglucose positron emission topography (FDG-PET) showed glucose hypometabolism limited to the right uncus for the TLE-AL group. The results suggest the importance of considering cognitive functions in the non-dominant hemisphere to prevent impairment after surgery.

Article	Year
Clinical significance of ictal high frequency oscillations in medial temporal lobe epilepsy. Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology\| PubMed ID: 21398175	2011
Versive seizures in occipital lobe epilepsy: lateralizing value and pathophysiology. Epilepsy research\| PubMed ID: 21885252	2011
Seizures with tonic posturing: Semiologic difference between supplementary sensorimotor area (SSMA) origin and extra-SSMA origin. Epilepsia\| PubMed ID: 26660199	2016
Characteristics of EEG Seizure-Onset Patterns Recorded From Subdural Electrodes Over MRI-Visible Frontal Focal Cortical Dysplasia Type IIb Lesions. Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society\| PubMed ID: 28557904	2017
Reversible amygdala enlargement: a longitudinal observation of a patient with elderly onset temporal lobe epilepsy. Journal of neurology\| PubMed ID: 29067519	2017
A classification system for verifying the long-term efficacy of resective surgery for drug-resistant seizures. Epilepsy research\| PubMed ID: 29414384	2018
Surgical Resection of Amygdala and Uncus. Neurologia medico-chirurgica\| PubMed ID: 30089753	2018
Working memory deficit in drug-resistant epilepsy with an amygdala lesion. Epilepsy & behavior case reports\| PubMed ID: 30094180	2018

Akihiko Kondo

Biography

JoVE Journal Publications

Other Publications