Memory Functions of Temporal Lobe Epileptic Patients in the Intracarotid Amobarbital Procedure:I. Lateralizing Value

BACKGROUNDS: To examine the effects of seizure laterality and stimulus type on Wada memory performance in patients with temporal lobe epilepsy(TLE). METHODS: The subjects were 43 patients with medically intractable TLE (left TLE 26, Right TLE 17) who had no or rare seizures after surgery. The memory stimuli were concrete figures for some subjects and abstract figures for the other subjects. RESULTS: A clinical criterion of at least 2-points difference between left and right injections correctly classified 31(72%) patients into left and right TLE groups, with 4(9%) patients falsely classified. A discriminant function analysis(DFA) based on left and right injection scores allowed for a correct classification of 37(86%) patients into left and right TLE groups. When the memory stimuli were concrete figures, the correct classification rate was greater for right than left TLE patients. In contrast, with abstract figures, the correct classification rate was greater for left than right TLE patients. CONCLUSIONS: The Wada memory test is a valuable diagnostic aid in lateralizing temporal epileptogenic foci. Stimulus type as well as seizure lateralization is a major determinant of Wada memory asymmetries.

Interictal scalp EEG in intractable temporal lobe epilepsy

BACKGROUNDS: The localization validity of interictal scalp EEG abnormalities in the patients with temporal lobe epilepsy(TLE) has been a subject of much debate. This study was an attempt to assess the general characteristics and the lateralization value of interictal scalp EEG abnormalities of TLE. We also examined the possible etiologic factors of bitemporal independent epileptiform discharges(BIED). METHODS: We investigated the interictal scalp EEGs of 59 patients. All patients have been seizure free but might have had persistent auras (Engel's classification, class I) after anterior temporal lobectomy(ATL) with minimum follow-up of 1 year. Long term scalp EEG monitoring records were evaluated for interictal EEG abnormalities in all patients. RESULTS: Scalp EEGs from 59 patients exhibited clear epileptiform discharges. Strictly unitemporal epileptiform discharge(UED) was present in 23 patients (39%). It was concordant with the side of seizure origin in 22 patients (95%), and discordant in 1 patient (5%). Thirty six patients (61%) had BIED. Twenty two patients with BIED showed lateralized preponderance which was defined as at least 80% laterality. It was concordant with the side of seizure origin in 21 patients (95%), and discordant in 1 patient (5%), and 14 patients were not lateralized. Bilateral synchronous epileptiform discharges were present in 4 patients (7%), and extratemporal spike in only 1 patient (2%). Localized temporal slow waves were shown in 33 patients (56%). It was concordant with the side of seizure origin in 28 patients, discordant in 1 patient. Four of 33 patients had bilateral temporal slow waves. There was no statistically significant difference in age at seizure onset, duration of epilepsy between the groups with UED and with BIED. Febrile seizures occurred similarly in both groups. CONCLUSIONS: It seems obvious that patients with UED or lateralized interictal temporal spike or sharp waves have a strong likelihood of ictal onset from the ipsilateral temporal region.

Overexpression of Mutant p53 in Human Anaplastic Astrocytoma and Glioblastoma Multiforme

A total of 30 cases of cerebral gliomas, including 6 cases of low grade astrocytomas, 6 anaplasticastrocytoomas and l8 glioblastomas multiforme, was examined immunohistochemically to demonstrate the overexpression of mutant forms of p53 protein and to evaluate their relationships with histological subtypes. A p53 monoclonal antibody was applied to the routine formalin fixed, paraffin-embedded tissues for this study using microwave-assisted avidin-biotin method. Overexpression of p53 protein was identified in 4 out of 6 anaplastic astrocytomas (66.7%) and in l3 out of l8 glioblastomas multiforme (72.2%). No immunohistochemical positivity of p53 was found in adjacent normal brain tissue, gliosis and 6 cases of astrocytoma. These results suggest that overexpression of mutant p53 may be an important step in the development and progression of malignant astrocytoma, especially of the aggressive subtypes of glioma, including glioblastoma multiforme.