Fumitaka Yamane

Comparison of source localization of interictal epileptic spike potentials in patients estimated by the dipole tracing method with the focus directly recorded by the depth electrodes

The purpose of the study was to investigate the accuracy of location of equivalent current dipoles estimated by the dipole tracing method (DT) utilizing a realistic 3-shell (scalp-skull-brain) head model (SSB-DT). Three patients with intractable complex partial seizures, diagnosed as having typical temporal seizures were investigated. We recorded the interictal spike potentials with surface electrodes (International 10/20 system) and with intracerebral depth electrodes simultaneously. We compared the location of dipoles of the spikes estimated by the SSB-DT with the focus of the spikes determined by the recording from the depth electrodes. We found that the location of the dipoles estimated by SSB-DT corresponded to the location of the depth electrodes, which could record the epileptic spikes. This finding proved that SSB-DT is reliable and valid for estimating neural activity in deep locations such as the limbic system.

Effects of Left Amygdala Lesions on Respiration, Skin Conductance, Heart Rate, Anxiety, and Activity of the Right Amygdala During Anticipation of Negative Stimulus:

The present study reports the effects of lesions in the left amygdala on anxiety, respiration, skin conductance, heart rate, and electrical potentials in the right amygdala in two patients. Trait and anticipatory-state anxiety were measured before and after left amygdala resection to control medically intractable epilepsy in the patients. Lesions in the left amygdala resulted in decreases of trait and state anxiety, respiratory rate, and activity in the right amygdala in both patients; one patient also showed notable decreases in skin conductance and heart rate. The study also reports that activities in the right amygdala before the lesion were not observed after the lesion. We suggest that the activity of the right amygdala is dominantly activated in anxiety and anxiety-related physiological responses but needs excitatory inputs from the left amygdala.

Rasmussen Syndrome: Multifocal Spread of Inflammation Suggested from MRI and PET Findings

Summary:  Background: A 6‐year‐old girl with Rasmussen syndrome (RS) showed multiple small high‐signal‐intensity areas independently in the right hemisphere by fluid‐attenuated inversion recovery (FLAIR) imaging on magnetic resonance imaging (MRI) 1 year after the onset of epilepsy.

Subtemporal Amygdalohippocampectomy Prevents Verbal Memory Impairment in the Language-Dominant Hemisphere

Background: In this report, we show the operative and neuropsychological results for 20 patients with medically intractable nonlesional temporal lobe epilepsy treated surgically by subtemporal amygdalohippocampectomy whose mean postoperative follow-up period was more than 6 years. Methods: Pre- and postoperative Wechsler Adult Intelligence Scale-Revised (WAIS/-R) scores, including verbal intelligence quotient (VIQ), performance IQ (PIQ) and full-scale IQ (FIQ) scores, were determined in the 19 adults. The revised Wechsler Intelligent Scale for Children was used in a 9-year-old boy. The verbal paired associates learning test was performed pre- and postoperatively in 15 patients. These data were compared pre- and postoperatively in 10 patients in whom the language-dominant hemisphere side was operated on, and in 5 patients in whom the language-non-dominant side was operated on. Results: Seizure control was achieved in 80% of patients, with improvement into Engel categories I and II without definite permanent complications except for postoperative memory impairment in one patient. VIQ improved after 2 years, and PIQ and FIQ improved after both 2 months and 2 years postoperatively. Conclusion: There was no significant decline in the postoperative verbal memory scores in those patients whose medial temporal structure of the language-dominant side had been removed.

Double-endoscopic approach for management of convexity arachnoid cyst: case report.

BACKGROUND Controversy exists about the best treatment modality for arachnoid cysts. Widely accepted neurosurgical options include craniotomy with open resection of the cyst walls, shunting procedures and stereotactic fenestration of the cyst cavity. Recently, neuroendoscopic approach showed its effectiveness for treatment of these lesions. CASE DESCRIPTION In the presented case the large convexity arachnoid cyst was diagnosed in a 22-year-old woman with head dullness and local bone bulging. No neurologic signs were found. Surgery was performed by double-neuroendoscopic approach with simultaneous use of two flexible ventriculofiberscopes, which permitted wide resection of the inner cyst wall. Complete resolution of symptoms was noted soon after surgery. CONCLUSION Double-endoscopic approach might be useful for complex neuroendoscopic procedures that need different simultaneous surgical actions, particularly for cases of large arachnoid cysts.

Preoperative mapping for patients with supplementary motor area epilepsy: Multimodality brain mapping

Abstract  Surgical management and strategies for the supplementary motor area (SMA) epilepsy are described. The following is our preoperative evaluations. The steps include functional magnetic resonance imaging (fMRI), interictal dipole tracing (DT), subdural electrodes mapping, measurements of movement‐related cortical potential (MRCP), and the use of the intraoperative open MRI under conscious craniotomy. Six patients with SMA epilepsy underwent surgery after the mapping procedures and are now seizure‐free. Combinations of preoperative (fMRI, subdural electrodes mapping) and intraoperative mapping allow exact localization and identification of the critical functional areas. Early postoperative deficits in motor and speech function were profound but patients recovered rapidly. It is concluded that the step of mapping procedures plays an important role in the management of SMA epilepsy surgery.

Agraphia caused by left thalamic hemorrhage.

A 71-year-old right-handed man was admitted to our hospital with right hemiparesis and sensory impairment associated with mild aphasia. Although aphasia gradually resolved within 2 weeks after stroke onset, his writing ability remained disturbed. A computed tomography (CT) scan at stroke onset revealed a hematoma in the left thalamus, but no cortical lesions were observed. Further, a single-photon emission CT (SPECT) scan showed decreased blood flow in the left thalamus, in the cortical region extending from the left superior temporal gyrus to the parietal lobe, and in the frontal lobe. It is possible that agraphia may have directly resulted from the thalamic lesion, but SPECT findings strongly suggested that a general decrease in left cortical function concomitant with a disruption of the thalamocortical and cortico-thalamocortical projection fibers produced these cognitive deficits.

Dysphagia following Acute Thalamic Haemorrhage: Clinical Correlates and Outcomes

Objective: A high incidence of dysphagia is seen during the acute phase of cerebral haemorrhage; however, there have been only rare reports of dysphagia caused by thalamic haemorrhage. We studied cases of thalamic haemorrhage during the acute period after hospitalization and examined the relationships between the frequency of dysphagia, stroke focus and haematoma volume. Methods: There were 113 subjects in this study, selected from 247 patients with thalamic haemorrhage who visited our rehabilitation centre. Patients were excluded if they had a history of dementia, stroke, confusion, epileptic seizure, surgical treatment or tracheotomy. We conducted a bedside swallowing assessment (BSA) by using the repetitive saliva swallowing test and modified water swallowing test. The relationships between oral intake condition at the time of hospital discharge, discharge destination (e.g. home), type of haematoma and haematoma volume were examined. Results: Abnormal BSA was found in 55% of the subjects (n = 62) with thalamic haemorrhage. Existence of a swallowing disorder was related to haematoma type and haematoma volume. A regular diet was possible in 41% of the subjects (n = 46). Age, haematoma volume, initial BSA evaluation and cognitive function had the greatest influence on a subjects ability to eat a general diet at the time of hospital discharge. Of those subjects in whom the initial BSA evaluation was normal, 70% were able to eat a regular diet at discharge. However, of those in whom the BSA evaluation was abnormal, >70% were discharged with enteral feeding. Furthermore, the rates of discharge to home were 95% in patients who could eat a regular diet and 30% in patients who needed enteral feeding. Conclusions: In the acute phase of thalamic haemorrhage, dysphagia was found in a high percentage of subjects. Dysphagia is associated with a poor prognosis for early hospital discharge.

Microanatomy of Medial Temporal Area and Subtemporal Amygdalohippocampectomy

For seizure control in temporal lobe epilepsy, the head of the hippocampus to the choroidal point, parahippocampal gyrus, entorhinal area, uncus, and at least the basolateral nucleus of the amygdala should be completely removed. The subtemporal approach should be selected for removal of these structures, and it does not interrupt the temporal stem and optic radiation. Pre- and postoperative neuropsychological examinations revealed that there is no significant decline of scores of various examinations including WAIS, WMS, Randt memory, and verbal associates learning tests, even if the resection were performed on the language dominant side. Seizure control for the 20 non-lesional patients operated with this approach is 60% (Class I and II), without definite permanent complications.

Brain temperature measurements during speech in patients with brain tumors: New methods for identification of the speech area in intraoperative brain mappings

Abstract In the present study, the usefulness of a functional thermography (fTG) for determining critical speech area was assessed in three patients with brain tumors in language areas. The results of the fTG were also compared with functional MRI (fMRI), subdural electrodes and intraoperative cortical stimulations. Measurements of the regional brain temperature were done using the thermography. The temperature increased after 8–10 s later from the speech and decreased with a few seconds delay after interruption of the task. The areas of increased temperature were coincident with the bridging veins and functional areas identified using fMRI and direct cortical stimulations. The use of fTG increases the sensitivity and specificity for the detection of essential motor language area.