Absence of simple partial seizure in temporal lobe epilepsy: its diagnostic and prognostic significance.

The diagnostic and prognostic significance of the absence of simple partial seizures (SPS) immediately preceding complex partial seizures (CPS) was examined in patients with temporal lobe epilepsy. The status of self-reported SPS in 193 patients with temporal lobe epilepsy who had surgical therapy more than 2 years ago was reviewed. Before surgery, 37 patients never experienced SPS before CPS (Group A), 156 patients either always or occasionally had SPS before CPS (Group B). The frequency of mesial temporal sclerosis (MTS) was lower and the age at onset of epilepsy was higher in Group A. The seizure focus was in the language-dominant temporal lobe in 73% of the cases in Group A, compared with 40% in Group B. The surgical outcome did not differ between the two groups. The findings suggest that temporal lobe seizures without preceding SPS tend to originate in the language-dominant temporal lobe that contains a pathologic etiology other than MTS, especially in the lateral temporal lobe. The surgical outcome in patients without SPS is similar to that in patients with SPS.

[Neuroimaging and electrophysiological study in epilepsy].

There exist various morphological and biochemical changes closely associated with electrophysiological phenomena which cause epileptic seizures in the brains of epilepsy patients. Recent developments in investigation methods, not only electrophysiological(EEG and MEG), but also neuroimaging involving morphological imaging(CT and conventional MRI) and functional imaging(SPECT, PET, functional MRI and MRS) is able to demonstrate these changes. SPECT and PET can particularly clarify the changes of cerebral blood flow and glucose metabolism between interictal and ictal periods. In our experience of 423 patients who underwent epilepsy surgery for intractable seizures, these interventions provide important information to identify the epileptogenic foci. However, in practice, discordance in the results of these presurgical evaluations is recognized, and invasive intracranial recordings are needed in such cases. These problems in diagnosis were shown especially in patients with mesial temporal sclerosis and focal cortical dysplasia. To detect an epileptogenic focus more clearly, a combination of morphological and functional findings, new functional imaging such as neurotransmitter receptor imaging, EEG-triggered or neuropharmacological functional MRI, as well as, statistical parametric analysis may be needed.

[Focal cortical dysplasia and epilepsy surgery].

We conducted corticectomy in twenty-five patients with intractable partial epilepsy due to focal cortical dysplasia (FCD). MRI could not detect FCDs in three patients, interictal SPECT, however, revealed hypoperfusion corresponding to FCDs in two of these patients, while the FCD in one remaining patient was histologically identified in a resected specimen. The location of FCDs was as follows: the frontal lobe in sixteen patients, the temporal in five, the occipital in two, fronto-parietal in one, and the temporo-parietal in one. Prior to the surgery, twenty-one patients underwent invasive long-term intracranial EEG/CCTV monitoring. Of the fourteen patients who were tracked for longer than 2 years following surgery, eleven belonged to Class I according to Engel's criteria, two to Class II, and one to Class III. We compared intracranial EEG findings (interictal and ictal) between these twenty-one patients and eight patients with frontal lobe epilepsy resulting from different lesions. The results of this comparison, together with the seizure outcome following surgery, indicated that FCD is intrinsically epileptogenic. The invasive long-term monitoring should, as a rule, be performed in all patients with FCDs prior to the corticectomy.

Acute psychosis during intracranial EEG monitoring: close relationship between psychotic symptoms and discharges in amygdala.

PURPOSE: This report examined the underlying mechanism of psychosis associated with epilepsy. METHODS: An adult patient with epilepsy manifesting acute psychosis during long-term EEG monitoring is presented, together with a literature review on this subject. RESULTS: A 25-year-old woman with intractable temporal lobe epilepsy developed acute psychosis while she underwent long-term intracranial EEG monitoring. After a clustering of seizures, she manifested psychotic symptoms including hallucination, stupor, and repeated fear. The transition of psychotic symptoms corresponded to the changes in frequency and morphology of seizure discharges restricted to the left amygdala. Improvement of psychosis coincided with disappearance of seizure discharges. CONCLUSIONS: This case confirmed a close relationship between psychotic symptoms and seizure discharges in the left amygdala. It is suggested that paroxysmal bombardment of the medial temporal lobe structure may be a pathogenetic factor of acute psychosis associated with epilepsy.

New type of starch-binding domain: the direct repeat motif in the C-terminal region of Bacillus sp. no. 195 alpha-amylase contributes to starch binding and raw starch degrading.

The alpha-amylase from Bacillus sp. no. 195 (BAA) consists of two domains: one is the catalytic domain similar to alpha-amylases from animals and Streptomyces in the N-terminal region; the other is the functionally unknown domain composed of an approx. 90-residue direct repeat in the C-terminal region. The gene coding for BAA was expressed in Streptomyces lividans TK24. Three active forms of the gene products were found. The pH and thermal profiles of BAAs, and their catalytic activities for p-nitrophenyl maltopentaoside and soluble starch, showed almost the same behaviours. The largest, 69 kDa, form (BAA-alpha) was of the same molecular mass as that of the mature protein estimated from the nucleotide sequence, and had raw-starch-binding and -degrading abilities. The second largest, 60 kDa, form (BAA-beta), whose molecular mass was the same as that of the natural enzyme from Bacillus sp. no. 195, was generated by proteolytic processing between the two repeat sequences in the C-terminal region, and had lower activities for raw starch binding and degrading than those of BAA-alpha. The smallest, 50 kDa, form (BAA-gamma) contained only the N-terminal catalytic domain as a result of removal of the C-terminal repeat sequence, which led to loss of binding and degradation of insoluble starches. Thus the starch adsorption capacity and raw-starch-degrading activity of BAAs depends on the existence of the repeat sequence in the C-terminal region. BAA-alpha was specifically adsorbed on starch or dextran (alpha-1,4 or alpha-1,6 glucan), and specifically desorbed with maltose or beta-cyclodextrin. These observations indicated that the repeat sequence of the enzyme was functional in the starch-binding domain (SBD). We propose the designation of the homologues to the SBD of glucoamylase from Aspergillus niger as family I SBDs, the homologues to that of glucoamylase from Rhizopus oryzae as family II, and the homologues of this repeat sequence of BAA as family III.

Electrical stimulation of the contralateral mesial temporal structure induces an ipsilateral seizure pattern in mesial temporal lobe epilepsy.

PURPOSE: We examined the mode of seizure development induced by electrical stimulation in patients with mesial temporal lobe epilepsy. METHODS: Of 25 patients undergoing intracranial EEG evaluation and electrical stimulation ipsilateral to the presumed site of habitual seizure origin, 17 patients had additional stimulation studies on the contralateral temporal lobe. RESULTS: Fourteen of the 25 patients had seizures induced with ipsilateral stimulation, and two of the 17 patients had seizures with contralateral stimulation. Seizures induced by ipsilateral stimulation started in the ipsilateral temporal lobe, whereas those induced by contralateral stimulation originated from the ipsilateral temporal lobe structure and were identical to the habitual seizures. CONCLUSIONS: Electrical stimulation of the temporal lobe structure opposite the site of habitual seizure origin is said to induce a seizure rarely. However, according to our preliminary results, if contralateral stimulation elicits a habitual seizure in the ipsilateral temporal lobe, it might be considered additional confirmatory evidence of seizure lateralization.

Surgical treatment of epilepsy in the comprehensive care program: advantages and considerations.

To properly establish the surgical treatment of epilepsy in the comprehensive care program, we planned a surgical strategy mainly for a temporal lobe epilepsy and have performed 60 temporal lobectomies. The surgical candidates were selected from 142 patients who met the initial criteria, and passed the initial evaluation for surgical intervention. Forty-five patients had long-term intracranial EEG recording, and circumscribed organic lesions were disclosed in 27 patients by neuroimaging techniques. The outcome of 23 patients who were followed for 2 years postoperatively was complete freedom from complex partial seizures in 17 patients (74%) and an increase in full employment from 2 to 10 patients. Despite the possible surgical complications, including detrimental effects on the higher cerebral functions, it is essential that the surgical treatment of epilepsy should be established as a part of the comprehensive care program. Our experiences and analyses of the state of the art in surgical intervention also suggest that surgical indications for more intractable patients whose social adjustment is less hopeful should be established and the surgical care system for these patients should also be planned. Furthermore, some patients may be free from recurrent seizures postoperatively, but still have difficulties in social rehabilitation. The problems for such patients remain unsolved.

Subtypes of temporal lobe epilepsies: a clinical point of view.

We studied 40 patients with temporal lobe epilepsies who had long-term intracranial EEG recordings and temporal lobectomies. They were divided into 3 groups on the basis of the anatomical site of seizure origin. An electrode implantation technique combined intracerebral depth electrodes with subdural strip electrodes. The seizures were of amygdalo-hippocampal origin in 18 patients, lateral temporal in 13 patients, and temporo-basal in 9 patients. The clinical and EEG features were reviewed retrospectively with regard to 3 factors in each patient: localization of interictal spikes in the scalp-recorded EEG, signal symptoms (auras), and presumed etiologies. Epilepsy with amygdalo-hippocampal and lateral temporal seizures was found to be distinguishable by the electroclinical features. It seems practical to classify these 2 subtypes of temporal lobe epilepsies as in the 1989 Classification of Epilepsies and Epileptic Syndromes. Temporal lobe epilepsies thus defined can be regarded as epileptic syndromes rather than a cluster of seizure manifestations.

Focal CT abnormality and epileptogenic focus.

In 31 patients with temporal lobe epilepsy, the precise site of epileptogenic focus was determined by means of a depth EEG recording as one of the presurgical evaluations. In 13 patients, a CT scan revealed focal lesions; 7 in the left temporal lobe and 6 in the right temporal lobe. In 5 of the 7 patients and in 5 of the 6 patients the epileptogenic foci were determined in the temporal lobe on the side of a CT lesion. However, in 2 of the patients with a CT lesion in the left temporal lobe, independent epileptogenic foci were found in both the temporal lobes, and in the other patient with a CT lesion in the right temporal lobe, they were found in the right frontal and left temporal lobes. Thus, the CT lesions agreed in lateralization and focality with the epileptogenic foci in 10 of the 13 patients (77%), but they disagreed in 3 (23%). A CT lesion disclosed in the temporal lobe does not necessarily indicate the side and/or site where the epileptogenic focus may be localized. Although exceptions may be made, spatial disagreement was exemplified between the CT lesion and epileptogenic focus. Therefore, extreme caution has to be taken on the side and/or site of the epileptogenic focus when functional surgical indication is to be made.

MRI lesion and epileptogenic focus in temporal lobe epilepsy.

The spatial relationship between a circumscribed lesion in the temporal lobe detected by MRI and an epileptogenic focus identified by ictal depth EEG along with a correlation of the MRI lesion with neuropathological findings were investigated in patients with medically intractable temporal lobe epilepsy but without any focal lesion on CT. Four parameters (an areal ratio of the temporal lobe against the hemisphere, area and calculated T1, T2 values of the hippocampus) were used to determine the abnormal MRI side. An agreement was reached in 67-72% of 18 patients between the abnormal values of the hippocampal area and of calculated T1, T2 and the side of the epileptogenic focus. In 14 of 17 patients, typical hippocampal sclerosis was demonstrated in resected tissue in accordance with the MRI lesions (atrophy and/or prolonged T2 of hippocampus). These results imply: 1) MRI abnormality thus defined may, if not all, indicate the side of the epileptogenic focus, and 2) also the presence of hippocampal sclerosis. It was emphasized that the MRI lesion would be a usable instrument to explore the causal relationship of hippocampal sclerosis to a generation of epileptogenic lesions as well as for presurgical evaluation.

A correlative study between hippocampal atrophy quantified by tomo-pneumoencephalography and epileptogenic focus in temporal lobe epilepsy.

It appeared certain that we can quantify the rate of hippocampal atrophy by utilizing the sagittal cuts in tomo-pneumoencephalography. This is a reliable method to infer the side of the epileptogenic focus in temporal lobe epilepsy since a close correlation was disclosed between the side with more atrophic features of the hippocampus and that of the epileptogenic focus explored by depth EEG, in particular, in the mesial temporal focus group. On the other hand, it seems to be plausible that the hippocampal atrophy could be secondarily induced by epileptic discharges in the lateral temporal group. Namely, controversies dealing with the casual relationship of hippocampal atrophy should be discussed based on the epileptogenic focus localization in temporal lobe epilepsy.

Conditions for omitting invasive long-term monitoring before surgical resection in patients with temporal lobe epilepsy.

The omission of invasive long-term monitoring before surgical resection in patients with epilepsy should be permitted only for those in whom the epileptogenic focus is presumed to localize unilaterally in the mesial aspect of the temporal lobe. The localization may well be confirmed through noninvasive measures. Retrospective analyses of data obtained from noninvasive investigations (scalp-recorded and sphenoidal EEGs, neuroimages, and electroclinical seizure manifestations) were carried out in 58 patients. The localization of their epileptogenic focus was subsequently confirmed by the implantation of both intracerebral and subdural electrodes; the focus had an amygdalohippocampal origin in 41 patients and a lateral temporal origin in 17 patients. From the comparison of noninvasive findings between these two groups, we propose the following indispensable conditions for omitting an invasive evaluation: 1. Appearance of focal epileptic discharges unilaterally in the sphenoidal lead observed during the simple phase of partial seizures, or unilateral discharges with predominancy in the sphenoidal lead during the early phase of complex partial seizures. 2. Interictal spikes on scalp-recorded EEGs localizing unilaterally in the anterior region of the temporal lobe, and if bilaterally independent, presenting with unilateral predominancy in a ratio of greater than 4:1. 3. Presence of autonomic signs in the initial phase of signal symptoms. 4. Neuroimaging findings in the mesial temporal region: elongated T2 on MRI and hippocampal atrophy, or a tumorous lesion. The lateralization conforms to interictal and ictal paroxysmal EEG findings. There were 8 patients with seizure of amygdalohippocampal origin who satisfied all the indispensable condition, but not a single patient with seizures of lateral temporal origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuropsychological evaluation before and after surgical treatment of temporal lobe epilepsy.

We present the results of pre- and postoperative neuropsychological evaluations of 58 patients with temporal lobe epilepsy who underwent a chronic intracranial EEG monitoring and a subsequent standard anterior temporal lobectomy. Wada's test provided valuable information on the speech dominant side and on the focus localization. Some warning signs as well as verbal automatisms indicated the effect for focus localization and lateralization. The results of interictal neuropsychological tests suggested that each subgroup of TLE performed differently. A postoperative neuropsychological performance has improved in many tests that may be explained by the diminished epileptic bombardment resulting from the resection.

Neuroradiologic findings in focal cortical dysplasia: histologic correlation with surgically resected specimens.

PURPOSE: We investigated the neuroradiologic characteristics of focal findings of surgically resected specimens obtained from 47 patients with focal cortical dysplasia (FCD). METHODS: Forty cases were detected by magnetic resonance imaging (MRI), and two cases were detected only by single-photon emission computed tomography (SPECT), but five cases could not be detected before operation. RESULTS: MRI revealed abnormal gyri and sulci in 34 patients (pachygyric in 18, polymicrogyric in 10, both in six), and blurring of the gray matter-white matter junction in 29 (72%) patients. Signal abnormalities were found in 36 (90%) patients, in the gray matter in 32, with white matter in 30, and at the gray matter-white matter junction in 13. Moreover, peculiar patterns of abnormal signals in the white matter were recognized, including remarkably abnormal subcortical signals of T2 hyperintensity and T1 hypointensity adjacent to the dysplastic cortex in 15 cases, high radiated T2 signals extending from the ependymal surface of the lateral ventricle to the overlying cortex in 11 cases, and widespread abnormal signals in the white matter with gray matter involvement in four cases. Histologically, these abnormal signals corresponded to various degrees of dyslamination and morphologic abnormalities of neurons and glial cells in the gray matter, and to dysmyelination, ectopic clustering of dysplastic neurons, glial proliferation, and necrotic change in the white matter. Regional cerebral blood flow SPECT showed interictal hypoperfusion in 29 (62%) of the 47 patients, interictal hyperperfusion in two, and ictal hyperperfusion in 28 of the 34 patients associated with FCD. [123I]iomazenil SPECT demonstrating the distribution of central benzodiazepine receptors showed low accumulations localized spatially corresponding to the epileptogenic foci associated with FCD in seven of eight patients. CONCLUSIONS: These results demonstrate that neuroimaging reflects various structural and functional changes closely related to epileptogenesis in FCD.

Improvement of quality-of-life following resective surgery for temporal lobe epilepsy: results of patient and family assessments.

In order to evaluate the quality-of-life (QOL) of epilepsy surgery patients, we surveyed patients' degree of life satisfaction and their families' degree of satisfaction with patient's status in a range of domains both pre- and post-operatively. Of 100 patient-family sets of surveys that were mailed out, 93 were completed and returned from patients and 91 from their families. All patients surveyed had temporal lobe epilepsy and had been followed for longer than 2 years after resective surgery. Patients and their families rated overall QOL as having markedly improved following surgery. However, they rated social domains of QOL, including role activities, financial status, and social and family relationships as having improved relatively little. Despite freedom from seizures, a few patients' families were dissatisfied with the patients' post-operative status, primarily for psychosocial reasons. Patients operated on at a later age reported little gains in life satisfaction following surgery. This study supports the conclusion that surgical intervention should occur before patients are subjected to the psychological conflicts and social handicaps associated with chronic intractable epilepsy.

Feasibility of subclassification of temporal lobe epilepsy (1989): an etiological overview.

Temporal lobe epilepsy with amygdalohippocampal seizures may have episodes of severe convulsions in childhood more frequently and the onset age is significantly lower compared to epilepsy with lateral temporal seizures. To the contrary, tumorous lesions are found more frequently in epilepsy with lateral temporal seizures. In view of the presumed known etiologies in relation to the localization of epileptogenic foci, the Classification of Epileptic Syndrome (1989), subdividing temporal lobe epilepsies into 2 groups, was found to be useful.