the effect of age on rate of functional recovery after intracarotid Amobarbital injection

Summary:  Purpose: The duration of the drug effect during the intracarotid Amobarbital procedure (IAP) is an important factor when considering the prioritization of behavioral testing during the IAP. Previous studies of thiopental, a barbiturate similar to sodium Amobarbital, found that age and gender significantly affect the dose required to induce anesthesia, such that younger patients require higher dosage.

Methods: A total of 55 patients who underwent the IAP procedure at Johns Hopkins Hospital were included in the study (110 hemispheric injections). The patient group included 30 female and 25 male patients, ranging in age from 11 to 50 years. To determine if a higher dose of sodium Amobarbital was needed for younger patients during the IAP, we analyzed the time to return to preinjection EEG baseline status and time to return to 5/5 strength as a function of patient age and gender.

Results: We found that younger patients (11–20 years old) returned to preinjection baseline EEG status and full (5/5) strength faster than older patients. No gender difference was found.

Conclusions: The sodium Amobarbital effect during IAP dissipates faster in young patients. Consideration of this difference in rate of recovery in 11-to 20-year-old patients has important clinical implications in terms of prioritizing behavioral testing.

tailored cognitive testing with provocative Amobarbital injection preceding avm embolization

BACKGROUND AND PURPOSE: Transarterial embolization of cerebral arteriovenous malformations (AVMs) has been associated with postprocedural neurologic complications in 7-39% of patients. We sought to determine whether a method of targeted neurologic and cognitive testing during AVM embolization reduces the incidence of focal cognitive and other neurologic deficits associated with the procedure. METHODS: A cognitive neurologist extensively examined 12 patients prior to AVM embolization. In each patient, a battery of tests tailored to their specific abilities was developed by using stimuli selected from standard and experimental cognitive tests to probe specific brain regions related to the location of the AVM. In each feeder vessel to be embolized, a 50-mg bolus of sodium Amobarbital was superselectively administered through a microcatheter; this was followed immediately by neurologic and cognitive testing with the tailored battery. After testing, the position of the microcatheter tip was checked with fluoroscopy. If the provocative test results were negative, the evaluated feeder was embolized with N-butyl cyanoacrylate glue. RESULTS: Although results with 27 of 29 provocative Amobarbital injections were negative, results with two injections in two different individuals revealed cognitive deficits during tailored provocative testing. In both, the evoked deficits resolved with dissipation of the Amobarbital effect; the feeder vessels were not embolized. Neurologic and cognitive evaluation after each of 27 embolizations revealed no major or minor deficits. CONCLUSION: In our experience, provocative Amobarbital testing prior to AVM embolization was helpful in identifying vascular territories where embolization may lead to neurologic and cognitive deficits.

anatomic correlates of memory from intracarotid Amobarbital injections with technetium tc 99m hexamethylpropyleneamine oxime spect

• Objective. —To better identify regions of the brain affected by intracarotid Amobarbital injections and to more precisely predict whether resections of specific brain regions will cause postoperative memory deficits. Design. —We modified the standard intracarotid Amobarbital procedure by adding a radioactive tracer to the Amobarbital injection, thereby providing better correlation between behavior and deactivated brain region. Setting. —Tertiary-care hospital center with a dedicated program for medical and surgical treatment of epilepsy. Patients. —We studied 39 patients with medically intractable epilepsy drawn from a regional referral base. Intervention. —Intracarotid injection of 125 mg of sodium Amobarbital with 37 MBq of technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO), followed by language and memory testing. Main Outcome Measures. —The distribution of Amobarbital as measured by single photon emission computed tomographic imaging of HMPAO and patient performance on memory tasks. Results. —Medial temporal regions were irrigated by the Amobarbital in only 28% of the injections. Overall, findings suggest that medial temporal and lateral neotemporal cortex play a role in memory. Conclusions. —The regions involved in memory function vary by individual, as does the distribution of Amobarbital. Thus, the most accurate method of determining correlation of brain region with memory function during intracarotid Amobarbital injection involves the use of a tracer such as HMPAO.

satscom selective Amobarbital test intraarterial spect coregistered to mri description of a method assessing selective perfusion

Abstract For evaluation of potential functional deficits, an intraarterial Amobarbital test is performed prior to neurosurgical or neuroradiological interventions. To visualize individual Amobarbital perfusion patterns, simultaneous injection of 99mTc-HMPAO was performed previously. The present study describes for the first time a method of coregistration of intraarterial SPECT during selective Amobarbital test to MRI. Three patients undergoing selective Amobarbital test of the posterior cerebral artery were included. SATSCOM (Selective Amobarbital test intraarterial SPECT coregistered to MRI) was performed by skull extraction in SPECT and MRI followed by surface matching. In all three patients, SATSCOM revealed accurate matching results. With this functional–anatomical mapping, suppression of higher cortical functions can be correlated to anatomical regions. Furthermore, a more precise mapping of Amobarbital effect improves planning invasive interventions, particularly those close to eloquent areas.

Amobarbital effects on the posterior hippocampus during the intracarotid Amobarbital test

Objective: To relate functional effects on the hippocampus during the intracarotid Amobarbital test (IAT) to its direct perfusion with Amobarbital. Methods: In 17 patients with intractable temporal lobe epilepsy, 28 hemispheres were perfused with 2.3 mL of 10% solution of 200 mg Amobarbital and 37 MBq 99m Tc-hexamethylpropylene amine oxime (HMPAO). For evaluation of Amobarbital effects, data were combined from stereo-EEG (S-EEG) recordings from intrahippocampal depth electrodes and high-resolution SPECT after intracarotid injection of HMPAO. Results: Perfusion of the entire hippocampus was observed only in hemispheres with a fetal origin of the posterior cerebral artery (PCA). In 10 hemispheres, S-EEG recordings could not unequivocally be assigned to either the anterior or the posterior part of the hippocampus. In the remaining 18 hemispheres, only the two with a fetal type of PCA showed perfusion of the entire hippocampus. In both, hippocampal electrical activity changed under the influence of Amobarbital but did not differ in anterior and posterior contacts. In 15 of 16 hemispheres in which SPECT demonstrated perfusion of the anterior hippocampus only, Amobarbital injection resulted in significant S-EEG activity change in both the anterior and the posterior parts of the hippocampus. Conclusion: S-EEG effects on the posterior hippocampus during the IAT can occur without direct perfusion of those brain areas.

Linguistic perseveration in dominant-side intracarotid Amobarbital tests.

Abstract 148 patients with medically intractable complex-partial seizures received bilateral intracarotid Amobarbital tests. In 21 patients (14,2%), there were inappropriate responses (intrusions: N = 10; perseverations: N = 11) to a series repetition task (counting backwards) given immediately before Amobarbital injection. Five cases from the perseveration subgroup are discussed in detail. In these patients, linguistic perseveration occurred with left-sided Amobarbital injection, although they were all found to have left hemispheric speech dominance according to language testing during the Amobarbital procedure. It is argued that these perseverations are best explained as a right hemispheric continuation of a speech motor program previously initiated by the left hemisphere.

anatomic correlates of memory from intracarotid Amobarbital injections with technetium tc 99m hexamethylpropyleneamine oxime spect

• Objective. —To better identify regions of the brain affected by intracarotid Amobarbital injections and to more precisely predict whether resections of specific brain regions will cause postoperative memory deficits. Design. —We modified the standard intracarotid Amobarbital procedure by adding a radioactive tracer to the Amobarbital injection, thereby providing better correlation between behavior and deactivated brain region. Setting. —Tertiary-care hospital center with a dedicated program for medical and surgical treatment of epilepsy. Patients. —We studied 39 patients with medically intractable epilepsy drawn from a regional referral base. Intervention. —Intracarotid injection of 125 mg of sodium Amobarbital with 37 MBq of technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO), followed by language and memory testing. Main Outcome Measures. —The distribution of Amobarbital as measured by single photon emission computed tomographic imaging of HMPAO and patient performance on memory tasks. Results. —Medial temporal regions were irrigated by the Amobarbital in only 28% of the injections. Overall, findings suggest that medial temporal and lateral neotemporal cortex play a role in memory. Conclusions. —The regions involved in memory function vary by individual, as does the distribution of Amobarbital. Thus, the most accurate method of determining correlation of brain region with memory function during intracarotid Amobarbital injection involves the use of a tracer such as HMPAO.

mapping the distribution of Amobarbital sodium in the intracarotid wada test by use of tc 99m hmpao with spect

The intracarotid Amobarbital sodium, or Wada, test has been used to localize speech and memory function prior to surgical treatment of temporal lobe seizures. The authors mixed technetium-99m hexamethyl-propyleneamine oxime (HMPAO) with Amobarbital sodium and injected the mixture in 25 patients with epilepsy. Single photon emission computed tomography (SPECT) of the brain was then performed to determine intracerebral distribution of the Amobarbital sodium. Results of SPECT were compared with those of conventional and digital subtraction angiography (DSA). The distribution of Tc-99m HMPAO and, presumably, Amobarbital sodium varied from patient to patient. SPECT revealed a statistically different distribution from that predicted with conventional angiography. The distribution also often differed from that of DSA, although the difference was not significant. SPECT revealed infrequent delivery to mesial temporal lobe structures. This emphasizes the need for caution in the use of the intracarotid Amobarbital s…

dominant side intracarotid Amobarbital spares comprehension of word meaning

• Abolition of speech production after intracarotid Amobarbital injection is generally considered evidence for language laterality. However, complex auditory comprehension may be preserved after injection of the dominant (left) side. The possibility that this sparing may be due to the intracarotid Amobarbital injection not adequately deactivating some of the areas responsible for speech comprehension in the posterior part of the hemisphere was tested with a task known to be critically dependent on the left posterotemporal-in-feroparietal region, one assessing visuoverbal semantic relatedness. Even when the intracarotid injection of the left side produced marked deficits of speech production, comprehension of semantic relations was still intact in eight of 15 patients. Ten of these 15 patients also received right carotid injections, none of which affected comprehension of semantic relatedness. These data indicate that the intracarotid Amobarbital injection cannot always specify the laterality of all language functions, an important concern when considering surgical procedures in the dominant posterotemporal-inferoparietal region.