Intracarotid Amobarbital Test Research Articles

32 Prediction of Seizure Outcome with Presurgical IAT, MRI, and PET in Patients with Temporal Lobe Epilepsy Undergoing Surgery

Objective:Anterior temporal lobectomy is a common surgical approach for medication-resistant temporal lobe epilepsy (TLE). Prior studies have shown inconsistent findings regarding the utility of presurgical intracarotid sodium amobarbital testing (IAT; also known as Wada test) and neuroimaging in predicting postoperative seizure control. In the present study, we evaluated the predictive utility of IAT, as well as structural magnetic resonance imaging (MRI) and positron emission tomography (PET), on long-term (3-years) seizure outcome following surgery for TLE.Participants and Methods:Patients consisted of 107 adults (mean age=38.6, SD=12.2; mean education=13.3 years, SD=2.0; female=47.7%; White=100%) with TLE (mean epilepsy duration =23.0 years, SD=15.7; left TLE surgery=50.5%). We examined whether demographic, clinical (side of resection, resection type [selective vs. non-selective], hemisphere of language dominance, epilepsy duration), and presurgical studies (normal vs. abnormal MRI, normal vs. abnormal PET, correctly lateralizing vs. incorrectly lateralizing IAT) were associated with absolute (cross-sectional) seizure outcome (i.e., freedom vs. recurrence) with a series of chi-squared and t-tests. Additionally, we determined whether presurgical evaluations predicted time to seizure recurrence (longitudinal outcome) over a three-year period with univariate Cox regression models, and we compared survival curves with Mantel-Cox (log rank) tests.Results:Demographic and clinical variables (including type [selective vs. whole lobectomy] and side of resection) were not associated with seizure outcome. No associations were found among the presurgical variables. Presurgical MRI was not associated with cross-sectional (OR=1.5, p=.557, 95% CI=0.4-5.7) or longitudinal (HR=1.2, p=.641, 95% CI=0.4-3.9) seizure outcome. Normal PET scan (OR= 4.8, p=.045, 95% CI=1.0-24.3) and IAT incorrectly lateralizing to seizure focus (OR=3.9, p=.018, 95% CI=1.2-12.9) were associated with higher odds of seizure recurrence. Furthermore, normal PET scan (HR=3.6, p=.028, 95% CI =1.0-13.5) and incorrectly lateralized IAT (HR= 2.8, p=.012, 95% CI=1.2-7.0) were presurgical predictors of earlier seizure recurrence within three years of TLE surgery. Log rank tests indicated that survival functions were significantly different between patients with normal vs. abnormal PET and incorrectly vs. correctly lateralizing IAT such that these had seizure relapse five and seven months earlier on average (respectively).Conclusions:Presurgical normal PET scan and incorrectly lateralizing IAT were associated with increased risk of post-surgical seizure recurrence and shorter time-to-seizure relapse.

Seizure in Patient with Neurofibromatosis and Amygdala Low-Grade Glioma

A 31-year-old male with history of bipolar disorder, suicidal attempts requiring inpatient hospitalization, and seizures on antiepileptic medications presented with increasing seizure frequency. He was neurologically intact yet had multiple facial, axillary, and inguinal flat pigmented macules (cafe au lait spots) and ophthalmologic examination with iris hamartomas (Lisch nodules) consistent with neurofibromatosis type1. Electroencephalogram was notable for multiple right temporal lobe seizures with anterior temporal interictal epileptiform discharges. Magnetic resonance imaging revealed a T2 hyperintense mass centered in the right amygdala, contiguous with the cystic area. Preoperative intracarotid sodium amobarbital testing showed left-sided language and memory dominance. The patient was operated on for right amygdalohippocampectomy, and initial pathology was consistent with a low-grade neuroepithelial neoplastic process. Further pathologic examination found hypercellular proliferation of predominantly bland, spindled cells with scattered, embedded neurocytic elements with dysplastic appearance, consistent with low-grade glioma. The patient was clinically diagnosed with neurofibromatosis type1.

Presurgical Functional Cortical Mapping Using Electromagnetic Source Imaging.

Preoperative localization of functionally eloquent cortex (functional cortical mapping) is common clinical practice in order to avoid or reduce postoperative morbidity. This review aims at providing a general overview of magnetoencephalography (MEG) and high-density electroencephalography (hdEEG) based methods and their clinical role as compared to common alternatives for functional cortical mapping of (1) verbal language function, (2) sensorimotor cortex, (3) memory, (4) visual, and (5) auditory cortex. We highlight strengths, weaknesses and limitations of these functional cortical mapping modalities based on findings in the recent literature. We also compare their performance relative to other non-invasive functional cortical mapping methods, such as functional Magnetic Resonance Imaging (fMRI), Transcranial Magnetic Stimulation (TMS), and to invasive methods like the intracarotid Amobarbital Test (WADA-Test) or intracranial investigations.

Presurgical electromagnetic functional brain mapping in refractory focal epilepsy

BackgroundElectroencephalography (EEG) and magnetoencephalography (MEG) are neurophysiological methods used to investigate noninvasively the spatial, temporal, and spectral dynamics of human brain functions.ObjectivesThis article reviews data on the use of EEG and MEG for presurgical functional brain mapping in patients with refractory focal epilepsy. The focus is on the localization of the primary sensorimotor (SM1) cortex as well as the verbal language and episodic memory functions.Material and methodsThe English literature was reviewed based on a PubMed search. Relevant references in the selected papers were also included.ResultsPresurgical MEG functional localization of the SM1 cortex generally overlaps with intracranial mapping. MEG allows for determination of hemispheric verbal (receptive and expressive) language dominance in neurosurgical patients with a high degree of concordance with the intracarotid amobarbital test. MEG represents an interesting technique for assessing postoperative memory outcome in patients with mesial temporal lobe epilepsy. Very few studies have evaluated the yield of EEG in these three clinical indications. High-density EEG might be a promising technique that needs further validation.ConclusionMEG is a validated and robust technique for noninvasive functional mapping of the SM1 cortex and verbal language hemispheric dominance in patients with refractory focal epilepsy. Current data also suggest that MEG is a promising technique for assessing the hemispheric dominance of memory function. Further studies are needed to assess the clinical added value of high-density EEG in these clinical indications.

Preoperative evaluation for epilepsy surgery: Process improvement.

Epilepsy surgery (ES) can improve seizure outcome. A prolonged duration of presurgical evaluation contributes to epilepsy-related morbidity and mortality. We introduced process changes to decrease evaluation time (ET) and increase ES numbers (excluding vagus nerve stimulation). The University of Colorado Hospital patient database was searched for ESs between January 2009 and May 2016. Measures to reduce ET included (1) increasing patient care conference (PCC) frequency; (2) faster intracarotid amobarbital test (IAT) scheduling; (3) dedicated ES clinic; and (4) adding a nurse navigator. ET from noninvasive video-EEG monitoring (P1) to IAT, PCC, and ES, and ES volume were determined and compared for a baseline group (P1 January 2009-March 2013) and a group exposed to process changes (P1 after March 2013), the postchanges group, to assess the effect of these measures. ES number was 61 for the baseline group and 77 for the postchanges group, increasing the annual rate at 3 years after changes from 14.4 to 36.8 (p = 0.0008; 37% yearly increase postchanges). Interventions lowered average ET by 96 days (p ≤ 0.0001), P1 to IAT by 39 days (p = 0.0011), and P1 to PCC by 58 days (p = 0.0002). Simple process changes, including more frequent patient care conferences, faster scheduling, a dedicated ES clinic, and a nurse navigator significantly decreased evaluation times and increased ES numbers. Centers could utilize similar strategies to improve process and surgical volume and thereby increase patient seizure control and safety.

Can Neuropsychological Rehabilitation Determine the Candidacy for Epilepsy Surgery? Implications for Cognitive Reserve Theorizing

Objective: The purpose of this study was to explore the effectiveness of a neuro-optimization intervention to determine the suitability for surgery in a patient suffering from left medial temporal lobe epilepsy (MTLE) and hippocampal sclerosis (HS). The rehabilitation program was aimed at amplifying cognitive resources and improving memory functioning, particularly in the non-dominant healthy hemisphere. Method: A preoperative neuro-optimization program, inspired by the functional reserve model and the right hemisphere’s verbal processing potential, was adopted. This neuro-optimization program targeted global cognitive and metacognitive enhancement with an emphasis on memory functions of the right temporal lobe, i.e., the functional upgrade of the healthy right hippocampus and related structures to assist memory after surgery. Results: After a 32 weeks neuro-optimization program, the patient once again underwent intracarotid amobarbital test (IAT). This time his right hemisphere memory functioning yielded a borderline score, allowing us to consider surgery. Immediately after surgery, the patient was seizure free and did not show any clinically significant memory impairment. At six months post-surgery he had largely preserved memory optimization gains. Conclusion: Preoperative optimization interventions aiming at enhancing cognition, in general and memory of the healthy hemisphere, in particular, may contribute to a positive memory outcome after left selective amygdalohippocampectomy.

Taking Sides: Physician's Perceptions on the Use of the Wada Test in Epilepsy Surgery-Q-PULSE Survey Commentary.

The recent Q-PULSE Survey compiled by Chad Carlson asked members to place the Wada test (bilateral intracarotid amobarbital test) in the context of the current practice of epilepsy surgery. Historically, the Wada test has three purposes: to lateralize language, to assess the risk of memory loss after epilepsy surgery, and to help provide predictive data in localization of the epileptic focus.

Grammar tests increase the ability to lateralize language function in the Wada test

Grammar is a core component of the language system, yet it is rarely assessed during the Wada (intracarotid amobarbital) test. It is hypothesized that adding grammar tests to the recovery phase of the Wada test will increase our ability to lateralize language function. Sixteen individuals (nine females, fifteen right-handed, mean age 38.4 years, SD=10.7) with medically refractory temporal lobe epilepsy participated in the study. On EEG ten patients had seizures originating in the left hemisphere (LH), five in the right hemisphere (RH), and one was insufficiently lateralized. We included only patients who were LH-dominant on the standard test in the encoding phase of the Wada test. In the recovery phase of Wada testing the participants underwent evaluation with a standard language and a new test of grammar, the CYCLE-N. Ten patients underwent bilateral injections, six unilateral (one RH, five LH). As expected, injection in the LH decreased language performance to a greater extent than injection to the RH on both tests. However, the CYCLE-N produced more profound language deficits in the injected LH compared to the RH (p=0.01), whereas the standard tests did not cause such pronounced differences (p=0.2). The results suggest that the standard tests did not significantly differentiate the effects of the injections and the CYCLE-N, for the most part, did. Our results are of particular relevance to patients who are too obtunded to speak in the encoding phase. In sum, the CYCLE-N may be helpful in assessing hemispheric dominance for language.

Differential influence of hippocampal subfields to memory formation: insights from patients with temporal lobe epilepsy.

To clarify the anatomical organization of human memory remains a major challenge in clinical neuroscience. Experimental data suggest dentate gyrus granule cells play a major role in memory acquisition, i.e. pattern separation and rapid pattern completion, whereas hippocampal CA1 neurons are implicated in place memory and autobiographical memory retrieval. Patients with temporal lobe epilepsy present with a broad spectrum of memory impairment, which can be assessed during clinical examination. Although long seizure histories may contribute to a pathophysiological reorganization of functional connectivity, surgical resection of the epileptic hippocampus offers a unique possibility to anatomically study the differential contribution of hippocampal subfields to compromised learning and memory in humans. Herein, we tested the hypothesis of hippocampal subfield specialization in a series of 100 consecutive patients with temporal lobe epilepsy submitted to epilepsy surgery. Memory profiles were obtained from intracarotid amobarbital testing and non-invasive verbal memory assessment before surgery, and correlated with histopathologically quantified cell loss pattern in hippocampal subfields obtained from the same patients using the new international consensus classification for hippocampal sclerosis proposed by the International League against Epilepsy (HS ILAE). Interestingly, patients with CA1 predominant cell loss (HS ILAE Type 2; n = 13) did not show declarative memory impairment and were indistinguishable from patients without any hippocampal cell loss (n = 19). In contrast, 63 patients with neuronal loss affecting all hippocampal subfields including CA1, CA4 and dentate gyrus (HS ILAE Type 1), or predominant cell loss in CA4 and partially affecting also CA3 and dentate gyrus (HS ILAE Type 3, n = 5) showed significantly reduced declarative memory capacities (intracarotid amobarbital testing: P < 0.001; verbal memory: P < 0.05). Our results suggested an alternative model of how memory processing can be organized amongst hippocampal subfields, and that CA1 pyramidal cells are less critically involved in declarative human memory acquisition compared to dentate gyrus granule cells or CA4/CA3 pyramidal cells.

Neuroimaging of drug resistance in epilepsy

Drug resistance is an important clinical problem: it is associated with higher rates of somatic and psychiatric comorbidities and cognitive/memory decline, with seizures being just the 'tip of the iceberg'. This review summarizes recent developments in imaging research, focusing specifically on the functional consequence of chronic epilepsies and mechanisms of drug resistance, restricted to work published in 2013. Functional imaging approaches reliably identify underlying specific networks in patients with different epileptic syndromes, show specific responses to certain antiepileptic drugs and differentiate between responder and nonresponder. Functional MRI (fMRI) and the intracarotid amobarbital test (IAT) are generally congruent, but fMRI may be more sensitive than IAT to right hemisphere language processing. In addition, memory fMRI supports the functional adequacy of ipsilateral structures rather than functional reserve of the contralateral hemisphere. There is further evidence from group analysis of fMRI data for a node within the ipsilateral piriform cortex to be important for seizure modulation in focal refractory epilepsies of different cortical origin. Molecular imaging with verapamil-PET identifies P-glycprotein overexpression as a mechanism contributing to drug resistance in individual patients. Neuroimaging in epilepsy has progressed from correlations with demographic, semiologic, neuropsychological and other observational data primarily in patients undergoing presurgical investigations to imaging network connectivity changes in epilepsy syndromes, and testing specific mechanisms underlying drug-resistant epilepsy.

Naming outcome after left or right temporal lobectomy in patients with bilateral language representation by Wada testing

ObjectiveThis study aimed to examine language outcome after left or right anterior temporal lobectomy (ATL) in patients with epilepsy with bilateral language representation on intracarotid sodium amobarbital (Wada) testing. MethodsTwenty-two patients with epilepsy with bilateral language (Wada laterality index between −50 and 50) underwent right ATL (RATL, n=10) or left ATL (LATL, n=12). All the patients were administered the Boston Naming Test preoperatively and six months postoperatively. ResultsLeft anterior temporal lobectomy patients showed greater postoperative naming decline than RATL patients. Group differences were also observed on subtests of the Wada test. Performance on the Wada naming and comprehension subtests was better in the nonsurgical hemisphere than in the surgical hemisphere in the RATL group, but there was no difference between the nonsurgical and the surgical hemisphere naming and comprehension performance in the LATL group. ConclusionsLeft anterior temporal lobectomy patients with bilateral language are at greater risk for naming decline than RATL patients with bilateral language. This difference may be due to relatively better naming and comprehension abilities in the nonsurgical hemisphere in the RATL group.

Simulating memory outcome before right selective amygdalohippocampectomy

In this paper we present the case of a left-sided speech dominant patient with right medial temporal sclerosis (RMTS) and pharmacoresistant epilepsy who showed improved verbal memory during intracarotid amobarbital test (IAT) at his right hemisphere as compared with his own performance before the drug injection (baseline), as well as after right selective amygdalohippocampectomy. We suggest that the defective verbal memory shown by this patient is due to abnormal activity of his right hippocampus that interfered with the function of his left hippocampus. This hypothesis was demonstrated by the fact that disconnection of the two hippocampi, either by anesthetisation or by resection of the right hippocampus, disengaged the left hippocampus and, consequently improved its function. This paper main objective is twofold: first to contribute to the field of neuropsychology of epilepsy surgery by emphasising on postoperative memory outcomes in right medial temporal lobe epilepsy (RMTLE) patients, particularly those undergoing amygdalohippocampectomy, as the pattern of memory changes after resection of the right temporal lobe is less clear; second, by focusing on memory performance asymmetries during IAT, and comparatively considering them with neuropsychological memory performance, because of their possible prognostic-simulating value.

Determination of Hemispheric Language Dominance in the Surgical Epilepsy Patient

Presurgical evaluation for refractory epilepsy typically includes assessment of cognitive and language functions. The reference standard for determination of hemispheric language dominance has been the intracarotid amobarbital test (IAT) but functional magnetic resonance imaging (fMRI) is increasingly used. To critically assess current evidence regarding the diagnostic properties of fMRI in comparison with the IAT for determination of hemispheric language dominance. The objective was addressed through the development of a structured critically appraised topic. This included a clinical scenario, structured question, literature search strategy, critical appraisal, results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and content experts in the fields of epilepsy and neurosurgery. A systematic review and meta-analysis that compared the sensitivity and specificity of fMRI to IAT-determined language lateralization was selected for critical appraisal. The review included data from 23 articles (n=442); study methodology varied widely. fMRI was 83.5% sensitive and 88.1% specific for detection of hemispheric language dominance. There are insufficient data to support routine use of fMRI for the purpose of determining hemispheric language dominance in patients with intractable epilepsy. Larger, well-designed studies of fMRI for language and other cognitive outcomes as part of the presurgical and postsurgical evaluation of epilepsy patients are necessary.

Functional magnetic resonance imaging for language mapping in temporal lobe epilepsy.

Functional magnetic resonance imaging (fMRI) is a noninvasive technique that is increasingly used to understand the cerebral cortical networks and organizations. In this paper, we describe the role of fMRI for mapping language networks in the presurgical workup of patients with medically intractable temporal lobe epilepsy (TLE). Studies comparing fMRI with the intracarotid sodium amobarbital (Wada) test and fMRI with intraoperative cortical stimulation mapping for language lateralization and/or localization in medically intractable TLE are discussed.

Effectiveness of four different clinical fMRI paradigms for preoperative regional determination of language lateralization in patients with brain tumors

Blood oxygen level-dependent functional magnetic resonance imaging (fMRI) has demonstrated its capability to provide comparable results to gold standard intracarotid sodium amobarbital (Wada) testing for preoperative determination of language hemispheric dominance. However, thus far, no consensus has been established regarding which fMRI paradigms are the most effective for the determination of hemispheric language lateralization in specific categories of patients and specific regions of interest (ROIs). Forty-one brain tumor patients who performed four different language tasks-rhyming (R), silent word generation (SWG) sentence completion, and sentence listening comprehension (LC)-for presurgical language mapping by fMRI were included in this study. A statistical threshold-independent lateralization index (LI) was calculated and compared among the paradigms in four different ROIs for language activation: functional Broca's (BA) and Wernicke's areas (WA) as well as larger anatomically defined expressive (EA) and receptive (RA) areas. The two expressive paradigms evaluated in this study are very good lateralizing tasks in expressive language areas; specifically, a significantly higher mean LI value was noted for SWG (0.36 ± 0.25) compared to LC (0.16 ± 0.24, p = 0.009) and for R (0.40 ± 0.22) compared to LC (0.16 ± 0.24, p = 0.001) in BA. SWG LI (0.28 ± 0.19) was higher than LC LI (0.12 ± 0.16, p = 0.01) also in EA. No significant differences in LI were found among these paradigms in WA or RA. SWG and R are sufficient for the determination of lateralization in expressive language areas, whereas new semantic or receptive paradigms need to be designed for an improved assessment of lateralization in receptive language areas.

Role of Functional MRI in Presurgical Evaluation of Memory Function in Temporal Lobe Epilepsy

Many diagnostic tools have been employed to predict the likelihood of a postoperative memory decline after a standard temporal lobectomy, including the intracarotid amobarbital testing (IAT) or Wada, regarded as the gold standard test for over the past half a century. Functional MRI (fMRI) is also a promising tool in that regard. Its routine use to predict the postoperative memory decline has been limited because of the varied study paradigms, discrepancies in analysis, and interpretation of the results. Based on the existing literatures, fMRI cannot replace IAT for the routine presurgical evaluation of the patients with temporal lobe epilepsy (TLE) yet. Large multicentre studies with a panel of memory test are required to determine the full potential of fMRI and use it reliably to replace IAT in the routine clinical practice. In this paper, we review various aspects of memory fMRI, including the experimental designs, data analysis, and findings.

Cambios en la memoria verbal y no verbal asociados a la implantación de electrodos hipocampales bilaterales en cirugía de la epilepsia

An appropriate localization of ictal onset zone in refractory temporal lobe epilepsy favors an adequate outcome associated with surgical treatment. When video-electroencephalogram (video-EEG) and magnetic resonance imaging do not provide accurate data to locate ictal onset zone, the use of subdural or deep intracranial electrodes is indicated. Hippocampal electrode placement could generate functional changes in an unaffected hippocampus. To describe mnesic changes in patients admitted for epilepsy surgery, with previous bilateral hippocampal implantation using depth electrodes. We identified eight patients undergoing video-EEG using bilateral hippocampal electrodes. Verbal and nonverbal mnesic performance was evaluated before/after the procedure. The following aspects were considered for the analysis: memory lateralization according to intracarotid amobarbital test (Wada test), invasive ictal onset zone, side of resection and pattern of electrocorticographic dissemination. In patients with memory dominance, contralateral to the ictal onset zone, there was an improvement in verbal and nonverbal memory, suggesting that invasive recordings did not impair mnesic skills of the unaffected hippocampus. In patients with bilateral representation of memory, ipsilateral mnesic impairment was associated with the resection. Contralateral improvement in memory was seen when the right side was resected, as opposed to no changes with resections made on the left side, indicating that electrode implantation of unaffected hippocampus did not generate a functional decline. Based on the preservation of verbal and nonverbal memory after depth electrode placement, invasive recordings of the hippocampus seem to be safe.

Metabolic evidence for episodic memory plasticity in the nonepileptic temporal lobe of patients with mesial temporal epilepsy

Metabolic changes have been described in the nonepileptic temporal lobe of patients with unilateral mesiotemporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS). To better understand the functional correlate of this metabolic finding, we have sought to characterize brain regions in patients with MTLE that show correlation between unilateral episodic memory performances, as assessed by intracarotid amobarbital test (IAT), and interictal regional cerebral metabolism measured by [(18) F]-fluorodeoxyglucose positron emission tomography (FDG-PET). Resting FDG-PET was performed interictally in 26 patients with unilateral MTLE caused by HS (16 female, mean age: 36 years; 16 left HS). Using statistical parametric mapping (SPM8), we performed a group comparison analysis comparing brain metabolism in the patients and in 54 adult controls (27 female, mean age: 32 years), with FDG-PET data of right HS patients being flipped. IAT scores of nonepileptic hemisphere functions (amobarbital injection ipsilateral to HS) were used as covariates of interest in a correlation analysis with regional brain metabolism. The group comparison analysis revealed significant hypometabolic areas in a widespread temporofrontal network ipsilateral to HS. In addition, a significant increase in metabolism was found in mesial and lateral temporal regions contralateral to HS. Significant positive correlations were found between IAT scores of nonepileptic hemisphere functions and mesial temporal metabolism in this hemisphere. This study demonstrates the existence of significant increase in relative regional cerebral glucose metabolism in mesial and lateral temporal regions contralateral to the epileptic focus in patients with unilateral MTLE associated with HS. The positive correlation in these brain regions between IAT scores and metabolism supports the role of disease-induced plasticity mechanisms contralateral to HS in the preservation of episodic memory processes.

The contribution of functional near-infrared spectroscopy (fNIRS) to the presurgical assessment of language function in children

Before performing neurosurgery, an exhaustive presurgical assessment is required, usually including an investigation of language cerebral lateralization. Among the available procedures, the intracarotid amobarbital test (IAT) was formerly the most widely used. However, this procedure has many limitations: it is invasive and potentially traumatic, especially for children. To overcome these limitations, neuroimaging techniques such as functional magnetic resonance imaging (fMRI) have been used. Again, these methods are difficult to use with children, who must remain motionless during data acquisition. Functional near-infrared spectroscopy (fNIRS) is a noninvasive functional imaging technique that is easily applied to pediatric and cognitively limited patients. It has been used recently in epileptic children for presurgical assessment of expressive and receptive language brain lateralization. The aim of this review is to present the contribution of fNIRS to the presurgical assessment of language function in children with neurological diseases.

Wada test using secobarbital sodium (Ional) to determine language dominance

The intracarotid sodium amobarbital (Amytal) test, the Wada test, remains an efficient test for evaluation of language and memory function. However, due to a world shortage of amobarbital, it has become necessary to investigate the use of alternatives. We report the efficacy of the Wada test using secobarbital sodium (Ional) in determining language dominance. An accurate determination of language dominance was required in 43 patients preoperatively at our institution. Patients underwent the Wada test using secobarbital sodium, effectiveness and safety were assessed. Patients were monitored for vital signs (blood pressure, respiratory rates, heart rates and saturation of oxygen). Ten patients were further monitored for continuous intra-arterial blood pressure and monitored with scalp electroencephalography (EEG). Language dominance was determined by the Wada test with secobarbital sodium in all patients. Total volume of secobarbital sodium injected was 10–25 mg (mean 16.5 ± 3.2 mg). Changes in vital signs were minimal and any induced neurological deficits completely disappeared within 8 min. On EEG records, induced theta waves immediately appeared on the ipsilateral side of the intra-arterial injection and disappeared within 6 min. One patient described a scintillating scotoma (sensation of shimmering light in his eyes) at the moment of injection; another experienced an epileptic episode during the test and recovered after 6 min. No adverse events were observed in the remaining 41 cases. We propose secobarbital sodium as a safe and reliable alternative to sodium amobarbital used in the Wada test to determine language dominance.