Injection Of Sodium Amobarbital Research Articles

Transient shivering during Wada test provides insight into human thermoregulation

Some patients with pharmacoresistant epilepsy undergoing the Wada test experience transient shivering. The purpose of this study was to investigate various clinical and radiographic characteristics of these individuals to delineate underlying mechanisms of this phenomenon. A systematic review of prospectively collected information on patients undergoing the Wada test was performed. All demographic, clinical, and radiographic information was obtained and reviewed by the appropriate expert in the field; statistical analysis was performed to determine the predictors of transient shivering. A total of 120 consecutive carotid artery injections in 59 patients were included in the study. Shivering was observed in 46% of the patients, and it was not significantly affected by gender, age, location of epileptogenic zone, brain lesion on magnetic resonance imaging (MRI), side of the first injection, duration of the hemiparesis, or excess slow wave activity on electroencephalography (EEG). However, shivering was more likely to follow sodium amobarbital injection if there was no filling of the posterior circulation on cerebral angiogram. Transient shivering during the Wada test is common. A transient but selective functional lesion of the anterior hypothalamus produced by the effects of sodium amobarbital may result in disinhibition of the posterior hypothalamus and other brainstem thermoregulatory centers, thereby inducing transient shivering.

Functional connectivity in the brain before and during intra-arterial amobarbital injection (Wada test)

We explored the effect of unilateral intracarotid sodium amobarbital injection during the Wada test (intra-arterial amobarbital procedure, IAP) on functional connectivity in the brain assessed by synchronization analysis of the EEG. Patients suffering from pharmaco-resistant epilepsy who were selected for epilepsy surgery and underwent a preoperative IAP to determine language dominance and contralateral memory capacity were eligible. All patients had brain abnormalities (mostly tumors) or mesial temporal sclerosis. Ipsilateral intrahemispheric, contralateral intrahemispheric, and interhemispheric synchronization likelihood (SL) was calculated in seven frequency bands before and during the IAP. Forty-two patients who underwent the IAP (34 left carotid injections, 32 right carotid injections) were included. In the delta and theta bands, SL increased over the hemisphere ipsilateral to injection, while contralateral and interhemispheric SL decreased. The SL increased in the beta band. In the gamma bands, differences between patients with right-sided and left-sided lesions were observed. When a left hemisphere lesion was present, SL increased after injection, while a more unequivocal pattern of change was present in patients with right hemisphere lesions. Our results indicate that amobarbital injection has effects on functional connectivity of both the anaesthetized and non-anaesthetized hemispheres. Synchronization consistently increases in the injected hemisphere. Functional connectivity in the contralateral hemisphere decreases in the lower frequency bands, while it tends to increase in the beta and gamma bands (depending on lesion lateralization). These results indicate that functional connectivity in both the injected as well as in the contralateral hemishere is strongly influenced by the IAP.

WO15 Functional connectivity in the brain before and during unilateral sodium amobarbital injection (Wada test): preliminary results

WO15 Functional connectivity in the brain before and during unilateral sodium amobarbital injection (Wada test): preliminary results

Transcranial Doppler ultrasound: a new method of monitoring hemispheric anesthetization during the intracarotid amobarbital procedure.

Electroencephalography (EEG) is traditionally used to assess the duration of hemispheric anesthetization and to monitor return of function in the anesthetized hemisphere during the intracarotid amobarbital procedure (IAP), but EEG changes are not consistently seen. The authors evaluated the role of continuous transcranial Doppler (TCD) monitoring as an alternative to EEG. The authors performed both continuous TCD monitoring and EEG during the IAP in 10 patients with medically intractable partial epilepsy. Mean velocities were monitored continuously in both middle cerebral arteries (MCAs), and changes in MCA velocities on continuous TCD monitoring were time locked with the EEG changes. The average mean MCA velocities were within normal limits bilaterally (50-85 cm/s) in all patients at baseline. Mean MCA velocites increased in all patients to 95-115 cm/s at the start of the test when the patients were asked to raise their hands and start counting. After injection of sodium amobarbital, mean MCA velocities in all patients dropped dramatically on the ipsilateral side to values of 12-39 cm/s and returned to the baseline average value when the hemiparesis recovered. In 8 patients, the duration of delta activity on EEG coincided with the time interval during which the mean MCA velocities were low on TCD monitoring. In 2 patients, despite the presence of hemiparesis clinically and a drop in mean MCA velocities on the ipsilateral side on continuous TCD monitoring, EEG remained normal on the ipsilateral side. Continuous TCD monitoring may be a more sensitive method than EEG in determining the duration of hemispheric anesthetization during IAP. Because the items for assessment of memory are presented during the period of hemispheric anesthetization, TCD may be useful in more precisely defining the time window for memory testing.

Hemispheric asymmetry in categorical versus coordinate visuospatial processing revealed by temporary cortical deactivation.

Kosslyn (1987) proposed that the left hemisphere is better than the right hemisphere at categorical visuospatial processing while the right hemisphere is better than the left hemisphere at coordinate visuospatial processing. In 134 patients, one hemisphere (and then usually the other) was temporarily deactivated by intracarotid injection of sodium amobarbital. After a hemisphere was deactivated, a cognitive test battery was conducted, which included categorical and coordinate visuospatial tasks. Using this technique, the processing capabilities of the intact hemisphere could be determined, thus directly testing Kosslyn's hypothesis regarding hemispheric specialization. Specifically, if the left hemisphere does preferentially process categorical visuospatial relationships, then its deactivation should result in more errors during categorical tasks than right hemisphere deactivation and vise versa for the right hemisphere regarding coordinate tasks. The pattern of results obtained in both categorical and coordinate tasks was consistent with Kosslyn's hypothesis when task difficulty was sufficiently high. However, when task difficulty was low, a left hemispheric processing advantage was found for both types of tasks indicating that: (1) the left hemisphere may be better at "easy" tasks regardless of the type of task and (2) the proposed hemispheric processing asymmetry may only become apparent during sufficiently demanding task conditions. These results may explain why some investigators have failed to find a significant hemispheric processing asymmetry in visuospatial categorical and coordinate tasks.

Intracranial EEG Recording from Intravascular Electrodes in Patients with Temporal Lobe Epilepsy

Purpose: As part of a presurgical extracranial study, we performed intracranial electroencephalographic (EEG) recording by using micro‐guidewires as active intravascular electrodes in two patients with temporal lobe epilepsy in combination with the Wada test. In one case, there was good agreement among information derived from the non‐invasive assessments, such as ictal semiology, interictal and ictal data from long‐term EEG and video monitoring, magnetic resonance imaging (MRI) findings, single photon emission computed tomography (SPECT) findings, and neuropsychological studies, that consistently pointed to one temporal lobe as the epileptogenic region. The other case showed no definite information about the laterality of the epileptogenic region. The interictal scalp EEG for the two cases showed independent, bilateral, anterior to midtemporal spike foci. The ictal EEGs with sphenoidal electrodes showed no apparent changes initially and during simple partial seizures. Methods: After giving informed consent, the patients underwent intracranial EEG recording from intravascular guidewires in combination with the Wada test. With the routine transfemoral catheter technique, two guiding catheters were manipulated into the common carotid arteries via bilateral femoral punctures. These catheters were used not only for the introduction of microcatheters and microguidewires by a “roadmap” technique, but also for the injection of sodium amobarbital for the Wada test. The guidewire tips were advanced 10 mm from the tips of the micro‐catheters, which were placed in the middle meningeal arteries at the level of the foramen spinosum. This distance placed the guidewire tips superficial to the inferior surfaces of the temporal lobes. The proximal end of the steel wire shaft was connected to the recording unit, and the guidewires were used as active intracranial recording electrodes: 10 scalp EEG electrodes were also used to record for ∼1 h, without a sleep tracing. We evaluated the usefulness of this technique by comparison with a simultaneously recorded scalp EEG, and, in addition, with the results of long‐term intracranial EEG recordings. Results: In both cases, intracranial EEG recording from intravascular electrodes revealed frequent spikes and sharp waves from one electrode interictally, but at that time, the scalp EEG revealed no definite paroxysmal discharges except infrequently at the active reference electrode. The laterality of these frequent epileptic discharges was in complete agreement with that of the origin of the ictal discharges recorded from long‐term intracranial EEG electrodes. Conclusions: Currently, the protocol for resections for patients with intractable temporal lobe epilepsy consists of three phases: extracranial studies, long‐term intracranial recording when necessary, and finally surgical resection. Although long‐term intracranial recording is recommended for many patients, the temporal lobectomy may be performed without further invasive EEG studies if there is good agreement among information derived from the noninvasive assessments. For such straightforward cases, if this recording shows interictal discharges on the same side as the noninvasive studies, the outcome of temporal lobectomy may also be improved without further invasive testing and, at least, the reliability of determining the laterality of the epileptogenic focus can be increased. In the cases that have conflicting results from the extracranial studies, it is useful for deciding the side on which the subdural electrodes will be mainly placed. Although the duration of the recording was limited, this technique appears to be very useful because it can be performed easily in the course of angiography without additional invasive steps.

Use of the intracarotid amobarbital procedure in the evaluation of memory.

The intracarotid amobarbital procedure (IAP) involves the temporary inactivation of one cerebral hemisphere by the injection of sodium amobarbital, which allows independent testing of the contralateral hemisphere. Initially used for lateralization of language, IAP later found a role in the evaluation of memory function in patients with intractable temporal lobe epilepsy being considered for resective surgery. IAP technique varies widely across centers, but, in general, memory is assessed by presenting the patient with a number of items during the period of hemispheric inactivation and testing recall or recognition of these items after the effect of the drug has worn off. Because the medial temporal lobe is not directly perfused by the internal carotid artery, concerns have been raised about the ability of the IAP to test hippocampal memory function. Consequently, a variety of selective procedures have been devised. Findings on both intracranial EEG recordings and pathologic and neuroimaging studies support the association of IAP memory results with hippocampal function. The IAP memory test was originally designed to predict the risk for development of global amnesia following unilateral temporal lobectomy. More recently, it also has been used as an adjunct in lateralizing the seizure focus and for predicting postoperative selective memory deficits and seizure outcome.

Reading Errors following Right Hemisphere Injection of Sodium Amobarbital

The role of the nondominant hemisphere in reading is controversial. We characterized the reading errors made by 64 right-handed adults with complex partial seizures (half with seizure foci on the right and half on the left), after right hemisphere injection of sodium amobarbital. Subjects were presented with 20 six-word sentences and all were found to have speech associated with the left hemisphere only. A variety of reading errors occurred, most of which fell under the syndrome of “neglect dyslexia” including deletions and substitutions of whole words on the left side of a line of text as well as within-word neglect errors. The nature of these errors indicated that they may have been caused by an interaction between a peripheral processing deficit and more centrally located conceptual knowledge of linguistic structure. Other errors could be attributed to a general decrease in attentional mechanisms. Neglect errors at the level of the sentence occurred in the absence of neglect errors at the level of the word although the converse was not true. This suggests that the latter may represent a more severe deficit in the mechanism that causes the former. A double dissociation existed between single word neglect dyslexia errors and “visual” errors, indicating separate processing mechanisms.

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.

Ictal Speech Manifestations in Temporal Lobe Epilepsy: A Video‐EEG Study

To evaluate ictal speech manifestations in complex partial seizures (C PS), we reviewed videotapes of 68 consecutive patients who underwent anterior temporal lobectomy (ATL) for treatment of intractable epilepsy in Taiwan. In all, 261 CPS were collected from their video-EEG (VEEG) recordings. Cerebral speech dominance was determined by intracarotid injection of sodium amobarbital (Wada test) in all cases. Ictal speech manifestations, classified as verbalization or vocalization, occurred in 32 patients (47.1%) with 96 seizures (36.8%). Ictal verbalization occurred in 10 patients (14.7%). Ictal vocalization was observed in 28 patients (41.2%); including 6 patients who also had ictal verbalization. Thirty-six patients (52.9%) had no seizure with ictal speech manifestations. Ictal verbalization had significant lateralization value: 90% of patients with this manifestation had seizure focus in the nondominant temporal lobe (p = 0.049). Seizures of patients with ictal vocalization were not more likely to arise from either temporal lobe. We also observed bilingual patients who exclusively spoke in their mother tongue (Taiwanese) rather than the acquired language (Mandarin) in 72.2% of seizures with verbalization. This finding is significant and contrary to a commonly held notion that the acquired language is used in seizures associated with speech behaviors.

Preliminary results of an incremental intracarotid amobarbital procedure: Evaluation of language and memory without sedation

To evaluate the effects of performing the intracarotid amobarbital procedure (IAP) using an incremental injection, the results obtained using this technique in seven patients were compared to the findings in a second group of seven patients who received a bolus injection of amobarbital, which was typically 100 mg. Videotapes of each IAP were rated by two observers for level of sedation using a modified version of the Reaction Level Scale. The bolus procedure used a higher dosage and produced significantly greater sedation as compared to the incremental IAP. The incremental IAP also revealed linguistic errors and/or speech arrest, which identified the hemisphere specialized for language. Memory for material introduced during the drug phase was significantly impaired in the epileptogenic hemisphere as compared to the intact hemisphere in the group receiving an incremental injection of sodium amobarbital. Pending replication of this preliminary study, these preliminary findings provide support for the efficacy of using incremental IAP to mitigate sedation.

Ocular complications of the Wada test

The injection of sodium amobarbital into the internal carotid artery (Wada test) is used preoperatively to identify the dominant hemisphere and to evaluate the possible effects of temporal lobectomy on speech, language, and memory. Although transient ocular side effects of the Wada test have been described, we present two cases of permanent ocular complications, consistent with a toxic reaction to sodium amobarbital.

Hemispheric specialization for emotional expression: A reexamination of results from intracarotid administration of sodium amobarbital

Emotional and behavioral responses to sodium amobarbital injection were examined in 44 epilepsy surgery candidates. Thirty-three emotional reactions occurred in 26 patients, 44% of the reactions following right hemisphere injection and 32% after injection of the left hemisphere. Among all patients examined, laughter/elated mood was statistically more frequent following right hemisphere injection while crying was statistically associated with left hemisphere injections. These observed effects were not related to amobarbital dose, sex, bilateral hemispheric inactivation (angiographic crossflow), general cognitive status, or side of seizure onset. These results support differing specialization of emotional expression in the right and left cerebral hemispheres and their subcortical connections.

薬物により誘発される眼球運動に関する研究 アモバルビタール

Eight healthy adults were examined electro-nystagmographically to evaluate the influence of sodium amobarbital on the human vestibular system. Seven of them showed direction-changing positional nystagmus with the direction toward the lower ear in six, and toward the upper ear in one. There was no difference of mean slow phase velocity between right and left positional nystagmus. Downbeat nystagmus, horizontal and vertical gaze nystagmus, and saccadic pursuit were also observed in the supine position. We concluded that direction-changing positional nystagmus after a I.V. injection of sodium amobarbital is due mainly to its action on the central vestibular system.

Reliability of the sodium amobarbital test for memory

Two studies were conducted on epileptic patients to examine the reliability of Milner's protocol for testing memory after the unilateral injection of sodium amobarbital into the carotid artery. The first study examined alternate-form reliability in 10 patients who underwent 18 repeat injections of the same hemisphere. Major changes in memory performance from pass to fail or vice versa occurred in 8 of 18 repeat injections. Seven of the eight changes were associated with identifiable variation in external factors (e.g., technically unsatisfactory first injections or reported deterioration in functioning over time). Of the eight injections that were technically satisfactory but were repeated to re-examine the initial memory score, seven outcomes remained stable across both injections, despite variability between test-retest conditions. In the second study, data from 70 patients given bilateral injections were analyzed, and no evidence for a practice effect was found when comparing memory scores from the first to the second injection. Whether the left or right side was injected first did not affect memory scores, nor did other variables such as sex, hand preference, or hemisphere injected. As expected, memory functions were more impaired for the injection contralateral than ipsilateral to the major temporal lobe seizure focus. We concluded that reliable results can be obtained from a sodium amobarbital memory protocol, adapted from Milner, which employs a pass/fail criterion based on chance performance.

薬物により誘発される眼球運動に関する研究 塩酸ケタミンとジアゼパム

Eight healthy adults were examined electro-nystagmographically to evaluate the influence of sodium amobarbital on the human vestibular system. Seven of them showed direction-changing positional nystagmus with the direction toward the lower ear in six, and toward the upper ear in one. There was no difference of mean slow phase velocity between right and left positional nystagmus. Downbeat nystagmus, horizontal and vertical gaze nystagmus, and saccadic pursuit were also observed in the supine position. We concluded that direction-changing positional nystagmus after a I.V. injection of sodium amobarbital is due mainly to its action on the central vestibular system.

Resumption of behavior following intracarotid sodium amobarbital injection.

Recovery rates of selected behaviors following intracarotid sodium amobarbital injection were examined in 17 patients with unilateral focal temporal lobe epilepsy. Left hemisphere injections resulted in more prolonged disruption of naming (p less than 0.00001), reading (p less than 0.0001), matching-to-sample behaviors (p less than 0.05), and short-term recognition memory for pictures (p less than 0.0001) and words (p less than 0.0003) than did right hemisphere injections. In addition, recovery of behaviors was prolonged if the injection was administered to the hemisphere contralateral to that with the primary seizure focus (p less than 0.005). A trend toward a similar pattern was seen in the postinjection electroencephalogram with the maximum slowing found in the injected hemisphere prolonged if the epileptic focus was in the contralateral hemisphere (p = 0.06). These findings suggest a negative effect of an epileptic lesion on the contralateral hemisphere.

アモバルビタールソーダ頸動脈注射によるてんかん焦点局在診断に関する研究

アモバルビタールソーダ頸動脈注射によるてんかん焦点局在診断に関する研究

アモバルビタールソーダ頸動脈注射によるてんかん焦点局在診断に関する研究

アモバルビタールソーダ頸動脈注射によるてんかん焦点局在診断に関する研究

アモバルビタールソーダ頸動脈注射によるてんかん焦点局在診断に関する研究

An attempt was made to analyze the changes of EEG secondary to the intracarotid injection of 50 to 100 mg of sodium amobarbital: 33 trials on 20 patients.1) There appeared to be a marked change in all cases; limited or dominant ipsilaterally to the side of administration.2) The latter was found in 22 out of 33 trials, and noted at the records of the frontal leads.3) The change was composed of high amplitude and low frequency or of low amplitude and high frequency or of the mixed of both, occurring at 3 to 6 seconds after the onset of the injection and gradually disappearing to regain the normal state within 30 minutes.4) These changes, especially the high amplitude and slow waves immediately after the injection at the same side were markedly noticed when the injection was in large dosage and in high speed.5) There was no difference in such changes given arise by either side of administration in the same patient.6) It is to be noted that there were no hazardous complications at the intracarotid injection of 10% sodium amobarbital under sufficient attention.