Intracarotid Sodium Amobarbital Procedure Research Articles

Utilization of MEG Among the US Epilepsy Centers: A Survey-Based Appraisal.

The purported underutilization of magnetoencephalography (MEG) among the USA epilepsy centers has never been studied, and any evidence-based understanding of its magnitude is lacking. Two hundred twenty-five National Association of Epilepsy Centers centers (2016) were invited to participate anonymously in a 13-question web-based survey of clinical practice focused on MEG use. On average, centers (N = 70; 61 of which were level 4) reported <6 epileptologists, >7 dedicated epilepsy monitoring unit beds, 206 phase 1 studies, 15 phase 2 studies, 10 direct resections, and 9 indirect resections; 27% owned MEG. On average, 11.2 MEGs per year were ordered for epilepsy localization and 7.6 for any presurgical mapping modalities. Wada test aka the intracarotid sodium amobarbital procedure (ISAP) (43%) and functional MRI (29%) were preferred over MEG (4%) for language mapping. The number of epileptologists and the number of epilepsy monitoring unit beds correlated positively with the most clinical volumes. The centers who own a MEG had surgical volumes significantly higher than those without. The number and complexity of patients as well as the proximity of a MEG were perceived as significant contributors/obstacles to increased MEG use. Only the centers with larger surgical volumes incorporate MEG regularly in presurgical evaluation of patients with drug-resistant epilepsy. A reversal of the pervasive underutilization of epilepsy surgery can benefit from MEG, but this requires a sustained concerted promotion by the epilepsy and MEG communities.

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The intracarotid sodium amobarbital procedure (IAP) is currently regarded as the best method for the determination of hemispheric specialization for speech, and it is universally relied on as a prognostic test for patients with medically refractory epilepsy who are candidates for neurosurgical intervention. Since its initial development, the IAP also has been adapted for assesssing lateralized mesiotemporal contributions to memory functioning in this patient population, and it is now in wide use for both basic and applied research in behavioral neuroscience on language, memory, visuospatial functions, emotion, attention, and consciousness. Despite the IAP's wide range of applications, little has been said about its history and development. This essay recounts and discusses this history.

Pathology type does not predict language lateralization in children with medically intractable epilepsy

We examined potential differences in the effects of pathology type on language lateralization in pediatric epilepsy. We examined findings from intracarotid sodium amobarbital procedure (IAP/Wada) in a large consecutive sample of children with refractory epilepsy. Subjects were assigned to one of three pathology groups: developmental (n = 28), acquired (n = 26), and tumor (n = 20); groups were compared for language lateralization. Rates of atypical language lateralization did not differ across groups. Greater than half of the subjects with left hemisphere insults and seizure onset before 6 years of age had atypical language lateralization, independent of pathology type. Atypical language lateralization may occur in the context of developmental, acquired, and/or tumor pathology.

Asymmetries in the effect of side of seizure onset on recognition memory following intracarotid amobarbital injection.

To assess interhemispheric differences in recognition memory for objects during the intracarotid amobarbital sodium procedure (IAP). The recognition memory for real objects of patients with either right (RTLE; n = 28) or left (LTLE; n = 22) temporal lobe epilepsy was assessed at baseline, and after left and right intracarotid amobarbital sodium injection. There were no differences between groups on baseline performance. Performance following injection ipsilateral to the side of seizure focus was relatively lower for the LTLE as compared with the RTLE group, but this difference did not reach statistical significance. However, performance following injection contralateral to the side of seizure focus was significantly lower for the RTLE as compared with the LTLE group. Within-group differences in performance after ipsilateral as compared with contralateral injection were significant for the RTLE but not the LTLE group. The difference in interhemispheric asymmetry in IAP memory performance between RTLE and LTLE groups was reflected in decreased ability to classify LTLE patients as compared with RTLE patients about side of seizure onset, using a clinically applicable decision rule. Recognition memory during the IAP for real objects, simultaneously named and presented visually during encoding, is mediated effectively by both the left and right hemisphere when there is no seizure focus present. However, memory appears to be more vulnerable to the presence of a seizure focus in the right as compared with the left hemisphere.

Level of Consciousness and Memory during the Intracarotid Sodium Amobarbital Procedure

Controversy exists regarding differential effects on consciousness of left/right cerebral inactivation via intracarotid amobarbital. Further, the effects of level of consciousness (LOC) on memory during the intracarotid sodium amobarbital procedure (IAP) are unclear. A modified version of the Glasgow Coma Scale altered to avoid the confounding effects of aphasia was employed to assess LOC in 97 patients during the IAP. A greater impairment in LOC occurred with left cerebral inactivation. Memory was more impaired following left hemisphere injections as well as from injections contralateral to seizure focus. Memory was correlated with LOC, and this effect was more prominent for right hemisphere injections and for injections ipsilateral to seizure focus. These findings support differential cerebral roles in consciousness and demonstrate that IAP memory performance may be affected by the patient's LOC.

Effects of Hemisphere Speech Dominance and Seizure Focus on Patterns of Behavioral Response Errors for Three Types of Stimuli

We used a protocol consisting of a continuous presentation of stimuli with associated response requests during an intracarotid sodium amobarbital procedure (IAP) to study the effects of hemisphere injected (speech dominant vs. nondominant) and seizure focus (left temporal lobe vs. right temporal lobe) on the pattern of behavioral response errors for three types of visual stimuli (pictures of common objects, words, and abstract forms). Injection of the left speech dominant hemisphere compared to the right nondominant hemisphere increased overall errors and affected the pattern of behavioral errors. The presence of a seizure focus in the contralateral hemisphere increased overall errors, particularly for the right temporal lobe seizure patients, but did not affect the pattern of behavioral errors. Left hemisphere injections disrupted both naming and reading responses at a rate similar to that of matching-to-sample performance. Also, a short-term memory deficit was observed with all three stimuli. Long-term memory testing following the left hemisphere injection indicated that only for pictures of common objects were there fewer errors during the early postinjection period than for the later long-term memory testing. Therefore, despite the inability to respond to picture stimuli, picture items, but not words or forms, could be sufficiently encoded for later recall. In contrast, right hemisphere injections resulted in few errors, with a pattern suggesting a mild general cognitive decrease. A selective weakness in learning unfamiliar forms was found. Our findings indicate that different patterns of behavioral deficits occur following the left vs. right hemisphere injections, with selective patterns specific to stimulus type.

The Intracarotid Amobarbital Procedure: An Historical Perspective

The intracarotid sodium amobarbital procedure (IAP) is currently regarded as the best method for the determination of hemispheric specialization for speech, and it is universally relied on as a prognostic test for patients with medically refractory epilepsy who are candidates for neurosurgical intervention. Since its initial development, the IAP also has been adapted for assesssing lateralized mesiotemporal contributions to memory functioning in this patient population, and it is now in wide use for both basic and applied research in behavioral neuroscience on language, memory, visuospatial functions, emotion, attention, and consciousness. Despite the IAP's wide range of applications, little has been said about its history and development. This essay recounts and discusses this history.

Assessment of the Functional Effect of the Intracarotid Sodium Amobarbital Procedure Using Co-registered MRI/HMPAO-SPECT and SEEG

We studied the functional effect of injection of sodium amobarbital (SA) in 10 patients with intractable epilepsy. During the intracarotid amobarbital procedure, we measured delta activity in EEG recordings from implanted electrodes and regional cerebral blood flow (rCBF) using HMPAO-SPECT co-registered with MRI. SA injection resulted in an increase in delta activity and a decrease in rCBF in all areas examined. Direct functional changes were observed in structures perfused by the carotid artery injected. In addition, we observed indirect effects, probably owing to deafferentation of neuronal pathways connecting these structures to ipsilateral and contralateral regions, including middle and posterior hippocampus.

Lateralization of memory for music: Evidence from the intracarotid sodium amobarbital procedure

The present study was conducted to determine whether material-specific memory for unfamiliar tonal patterns could be demonstrated for the right temporal lobe during the intracarotid sodium amytal procedure (IAP). Thirty-one patients with intractable complex partial seizures associated with either left temporal lobe epilepsy (LTLE) or right temporal lobe epilepsy (RTLE) underwent assessment of memory for tonal patterns during a baseline phase and right and left cerebral hemisphere anaesthesia during the IAP. Patients were presented unfamiliar tonal patterns which were later selected from a set of distracter patterns. Findings indicated that there was no difference between the LTLE and RTLE patients during injection of the right cerebral hemisphere suggesting no specific involvement of left mesial temporal structures. However, a significant effect was noted during left injection with the LTLE group performing significantly better than the RTLE group. This latter finding supports a specific role of right mesial temporal lobe structures in mediating memory for music. Copyright © 1996 Elsevier Science Ltd

The Association of Multiple Personality and Temporolimbic Epilepsy

What is the relationship of "multiple personality disorder" in patients with temporolimbic epilepsy to certain types of hemispheric interaction? Case series. Tertiary care referral center. Two patients with temporolimbic epilepsy considered to be surgical candidates referred for the intracarotid amobarbital sodium procedure (IAP). Each individual had presented with different "personalities" in a characteristic temporal relationship to their seizures. Intracarotid amobarbital sodium procedure, Wada test, and electroencephalogram. Behavioral observations made during the performance of the IAP. During the IAP, each patient's peri-ictal "personality" changes were precisely replicated. No seizure activity was noted during the IAPs. These observations suggest that the association of multiple personality and temporolimbic epilepsy is not dependent on seizure discharges per se, but rather may be related to certain types of hemispheric interaction.

Memory following intracarotid amobarbital injection contralateral to hippocampal damage.

We examined the relationship between memory performance and hippocampal damage in temporal lobe epileptics undergoing the intracarotid amobarbital sodium procedure (IAP). Overall memory performance in the course of IAP was correlated with seizure lateralization. The hemisphere of seizure focus had impaired IAP memory in 63% (19/30) of the patients. The IAP memory performance following perfusion of the hemisphere contralateral to severe hippocampal lesions was impaired in five of six patients. These patients also exhibited hypometabolism of the impaired temporal lobe as determined independently by positron emission tomography. The single patient with a severely damaged hippocampus who did not demonstrate IAP memory impairment with contralateral hemisphere injection did not exhibit perfusion of the ipsilateral posterior cerebral artery with amobarbital. Memory performance following intracarotid amobarbital injection contralateral to a less severely damaged hippocampus was impaired in 14 of 24 patients and was not related to extent of hippocampal damage, temporal lobe hypometabolism of labeled glucose, perfusion of the ipsilateral posterior cerebral artery, hemispheric language dominance, or order of injection. These results indicate that impaired memory performance during IAP may reflect severe hippocampal damage and/or epileptogenic abnormality.