Language assessment in Wada test: Comparison of methohexital and amobarbital

AbstractIntroductionMethohexital has replaced amobarbital during Wada testing at many centers. The objective of our study was to compare the use of methohexital and amobarbital during Wada testing regarding language and memory lateralization quotients as well as speech arrest times.MethodsA chart review of 582 consecutive patients undergoing 1041 Wada-procedures was performed (left=60, right=63, bilateral=459). Language lateralization was calculated based on duration of speech arrest using a laterality index, defined as (L−R)/(L+R). Memory lateralization was expressed as percentage of retained objects and laterality quotient.ResultsLanguage and memory lateralization revealed a similar distribution with amobarbital and methohexital. Speech arrest after left and right-sided injection was significantly longer in the amobarbital group as compared to the methohexital group. Language lateralization did not differ in the two groups. Percentage of retained memory items was higher in the methohexital group and there were fewer presented test items in the methohexital group.DiscussionLanguage and memory testing during the Wada test can successfully be performed with methohexital instead of amobarbital. The shorter half-life of methohexital allows repeated injections and shorter interhemispheric testing intervals, but also shortens the testing window

Usefulness of Unilateral Interictal Sharp Waves of Temporal Lobe Origin in Prolonged Video‐EEG Monitoring Studies

The value of EEG interictal epileptiform activity in predicting location of the seizure focus remains controversial. In 64 patients, scalp video‐EEG monitoring studies showed one or two ipsilateral interictal foci in the temporal lobe. The site of these interictal foci correlated with location of the seizure focus recorded during prolonged video‐electrocorticography (ECoG) with use of subdural grids placed under the mesiobasal temporal region and over the lateral temporal convexity. Our findings suggest that unilateral anterotemporal interictal foci can accurately predict location of seizure onset. This is also true in patients with two ipsilateral temporal interictal foci, provided that the dominant focus is localized in anterotemporal regions. We believe that in such patients invasive recordings are not warranted, but we caution against sole use of interictal epileptiform criteria for localization of the seizure focus. Correlation with clinical information, ictal EEG, neuropsychometric, and neu‐roimaging studies is required before performance of epilepsy surgery

Can Sharp Waves Localized at the Sphenoidal Electrode Accurately Identify a Mesio‐temporal Epileptogenic Focus?

In our patient population that had undergone antero‐temporal lobectomy, we found 20 patients with a unilateral sphenoidal/antero‐temporal interictal focus. All patients had normal computed tomography (CT) scans. Invasive recordings with subdural electrode arrays placed over and under the temporal lobe were used in every patient. We found that the scalp interictal focus predicted for all patients that both the interictal sharp waves and ictal onset would be mesiobasal/anterotemporal in location on the subdural arrays. Seventy‐five percent of these patients had an excellent outcome with temporal lobectomy. RÉSUMÉ Parmi leur population de patients opérés par lobectomie temporale antérieure, les auteurs ont retenu 20 observations chez lesquelles ils avaient mis en évidence un foyer intercritique temporal unilatéral antérieur ou sphénoïdal. Tous ces patients avaient une tomodensitométrie normale. Les enregistrements invasifs au moyen d'électrodes sous‐durales placées sur et sous le lobe temporal ont été pratiqués chez chacun de ces patients. Les auteurs ont trouvé que le foyer intercritique superficiel permettait de prédire chez tous les patients que les éléments paroxystiques intercritiques et que le début des crises auraient une localisation temporale médio‐basale ou antérieure lors de l'enregistrement sous‐dural. 75% de ces patients ont évolué très favorablement après lobectomie temporale. RESUMEN En nuestra población de pacientes que habían sido sometidos a una lobectomía temporal anterior, encontramos 20 casos que tenían un foco interictal temporal esfenoidal/anterior, unilateral. Todos los pacientes tenían CT's normales. En cada paciente se utilizaron registros invasivos con series de electrodos subdurales implantados por encima y por debajo del lóbulo temporal. Encontramos que el foco interictal, registrado desde el cuero cabelludo, predijo en todos los casos que, tanto las ondas agudas interictales como su comienzo ictal, serían de localización mesial‐basal/anterior temporal en las series de electrodos subdurales. El 75% de estos pacientes tuvieron resultados excelentes tras una lobectomía temporal. ZUSAMMENFASSUNG Unter unseren Patienten mit anteriorer Temporolobektomie fanden wir 20 Patienten mit einem einseitigen interiktalen Fokus sphenoidal‐temporal‐vorne. Alle Patienten boten ein normales CT. Jeder Patient wurde mit subduralen Elektrodenanordnungen im Bereich des Temporallappens untersucht. Es stellte sich heraus, daß der interiktale Skalp‐Fokus bei alien Pantienten zu einer richtigen Voraussage geführt hatte, sowohl bezüglich interiktaler sharp‐waves, als auch iktalem Beginn entsprechend der mesio‐basalen/temporo‐anterioren Lokalisation der subduralen Elektrodenplaziemng