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Determination of language dominance with near-infrared spectroscopy: comparison with the intracarotid amobarbital procedure.

PURPOSE: To determine the efficacy of near-infrared spectroscopy (NIRS) in identifying the hemisphere associated with language by measuring changes in bilateral lateral inferior frontal blood flow during a word generation task in epilepsy surgery patients and healthy volunteers. METHODS: Sixteen patients who underwent the intracarotid amobarbital procedure (IAP) and eight healthy right-handed/right-footed individuals were tested with NIRS during a word generation paradigm. RESULTS: Increases in lateral inferior frontal total hemoglobin concentrations agreed with the IAP in 11 of 16 patients, including 2 of 3 with right hemisphere (atypical) speech dominance (P = 0.13). NIRS revealed increases in lateral inferior frontal total hemoglobin concentrations congruent with language dominance predicted by handedness/footedness in 18 of 24 subjects, including 100% of healthy right-handed subjects (P = 0.02). CONCLUSION: NIRS is a simple, non-invasive, safe modality for measuring cerebral blood flow. Further research and development of testing procedures and instrumentation are needed before routine implementation in pre-surgical testing.

Adult↗

Transient global amnesia triggered by the intracarotid amobarbital procedure.

The emergence of a sudden, global, and fully reversible amnestic state during an intracarotid amobarbital procedure (IAP) performed in a patient with a right temporal tumor is described. Forms of amnesia during the IAP are discussed, and it is argued that because of its appearance, the associated behavioral abnormalities, and EEG findings, this state was a transient global amnesia (TGA). In addition to other origins such as bitemporal lesions, increased barbiturate levels, seizures, and epileptic amnesia, TGA may triggered by stress or angiography during the IAP.

Adult↗

Memory performance during the intracarotid amobarbital procedure and neuropsychological assessment in medial temporal lobe epilepsy: the limits of material specificity.

We investigated the relationship between material-specific memory performance elicited during the Wada test, or intracarotid amobarbital procedure (IAP), and classic neuropsychological assessment in 89 surgical candidates with refractory medial temporal lobe epilepsy (MTLE). The neuropsychological battery included measures of simple and complex verbal and visual memory, whereas the IAP material consisted of verbal and dually encodable stimuli. Neuropsychological testing revealed that reduced verbal memory performance was associated with left-sided MTLE, whereas visual memory tasks revealed no differences between patients with left-sided and right-sided MTLE. During IAP, memory performance was worse with the ipsilesional hemisphere, regardless of lesion side. Most importantly, performance on verbal memory tests was significantly, but moderately, correlated with left hemispheric IAP performance, indicating that memory tasks using verbal material are a valid marker of left hemispheric integrity in left language-dominant MTLE patients and significantly predict left hemispheric memory performance during IAP. In contrast, performance on classic visual memory tests is unrelated to right hemispheric IAP performance, suggesting that the currently used visual memory stimuli do not reflect right hemispheric sensitivity.

Adult↗

Comparing the Fused Dichotic Words Test and the Intracarotid Amobarbital Procedure in children with epilepsy.

The validity of the Fused Dichotic Words Test (FDWT) in predicting the nature of speech representation, as determined by the Intracarotid Amobarbital Procedure (IAP), was examined in a sample of 28 children with epilepsy. Various methods of analysis (difference score, lambda, and lambda(*)), for the FDWT data were calculated and compared. Results showed the validity of the FDWT did not change depending on the method of analysis. The difference scores showed that 18 of the 19 patients with left hemisphere speech obtained right-ear advantages, while the patient with right hemisphere speech showed a left-ear advantage. As a group, patients with left-hemisphere speech obtained a statistically significant right-ear advantage for the lambda and lambda(*) indices, while the patient with right-hemisphere speech showed a left-ear advantage that was also significant for both lambda measures. Patients with bilateral speech, as a group, displayed a non-significant ear advantage. Some of the scores from the left-hemisphere group overlapped with those from patients with bilateral speech representation. Controlling for stimulus dominance effects using the lambda(*) measure did not improve classification accuracy for nature of speech representation based on FDWT scores. Finally, comparison of our data using the laterality index from a similar study, showed scores smaller in magnitude than that found in adults with epilepsy.

Adolescent↗

Memory performance on the intracarotid amobarbital procedure as a predicator of seizure focus.

The intracarotid amobarbital procedure (IAP) was performed on 56 patients with intractable complex-partial epilepsy who were candidates for temporal lobectomy. Seizure focus was lateralized to one hemisphere, as determined by surface EEG recordings and MRI evidence of temporal lobe disease. IAP memory items were presented following injection of 125 mg of sodium amytal into the internal carotid artery. Verbal, Nonverbal, Design, Pictorial, and Total memory scores were calculated based on recall/recognition of memory stimuli following drug recovery. Poorer memory was observed in the hemisphere ipsilateral to seizure focus on all memory scores. The Total Memory Score was the best memory measure, correctly classifying the largest number of patients. Using optimal cut-off scores on this measure, 75% of the patients with left hemisphere seizure focus and 79% of the patients with right seizure focus were correctly classified. There was a definite tendency for the dominant hemisphere to outperform the non-dominant. This must be taken into account in arriving at optimal cut-off points.

Adolescent↗

Prediction of presence of hippocampal sclerosis from intracarotid amobarbital procedure memory asymmetry scores and epilepsy on set age.

Identification of the pathological status of the hippocampus prior to surgery is important since the absence of hippocampal sclerosis (HS) carries risks to memory function following anterior temporal lobectomy (ATL). We studied 62 patients undergoing ATL (31 L, 31 R) for intractable epilepsy of temporal lobe origin in whom no pathology was identified apart from HS. An intracarotid amobarbital procedure (IAP) was performed as part of the preoperative evaluation. All patients were left hemisphere dominant for language. IAP memory testing was according to the protocol of Loring. We examined IAP memory asymmetry scores at four levels of difference (<2, > or =2, > or =4, > or =6) as a function of the presence (HS+) or absence (HS-) of HS. A logistic regression analysis was performed with HS+ as the dependent variable, and age at onset of epilepsy, age at time of surgery, gender, side of surgery and significant IAP memory asymmetry as independent variables. At each level of memory asymmetry, onset age and memory asymmetry were the only predictors of HS+. Younger age at onset was associated with HS+. Curves were constructed showing probability of HS+ for age at onset for each level of asymmetry. These can be used to predict the likelihood of presence of HS based on age at onset of epilepsy and the IAP memory asymmetry score. It is concluded that IAP memory asymmetry scores reflect the functional and pathological status of the hippocampus, and greater asymmetry increases the probability of finding HS in the resected hippocampus.

Adult↗

Usefulness of language and memory testing during intracarotid amobarbital testing: observations from an fMRI study.

BACKGROUND: Several procedures for testing language lateralization and memory function exist during the intracarotid amobarbital test (IAT). The use of functional magnetic resonance imaging (fMRI) gives the opportunity to assess the validity of some of these procedures, or at least to inspect the neuronal correlates. A comprehensive fMRI protocol was tested, aimed at addressing aspects of lateralization of language, as well as testing memory in relation to activation of mesiotemporal regions. Here we report observations with possible consequences for the current IAT procedures. MATERIALS AND METHODS: The protocol consisted of three language tasks (overt naming, semantic decision and silent word generation) and two memory tasks (encoding and retrieving visual scenes). The paradigms used a block-related procedure in nine right-handed normal volunteers. During the procedure dynamic weighted full brain images were acquired which are sensitive to the blood oxygenation activation effect. RESULTS: Encoding showed symmetrical bilateral activation in the mesiotemporal regions, specifically the hippocampus, parahippocampal gyrus and fusiform gyrus. With a retrieval task activation of the mesiotemporal areas was restricted to the posterior hippocampal area. Overt object naming showed results, similar to encoding tasks with bilateral activation of hippocampal areas. Silent word generation showed much stronger ability to lateralize than the other two language-related tasks and especially object naming. CONCLUSION: Activation revealed by fMRI activation shows that IAT procedures, using active semantic language processing or comprehensive procedures with multiple language tasks have the highest guarantee for individual activation lateralization. Simple object naming does not guarantee a lateralized language fMRI activation pattern. Of the different memory procedures during IAT, the procedures (Interview and the Montreal) demanding encoding processing will be related to larger areas of bilateral hippocampal activation than procedures (Seattle) exclusively requiring retrieval. Moreover, tasks using recognition of previously presented language items (naming objects) are equally effective for assessing hippocampal activation compared with presenting separate memory items.

Adult↗

Material-specific memory changes after anterior temporal lobectomy as predicted by the intracarotid amobarbital test.

PURPOSE: The intracarotid amobarbital test (IAT) has been shown to predict verbal memory changes after anterior temporal lobectomy (ATL). Seeking to extend these findings, we examined two questions: (a) What is the relationship between material-specific aspects of IAT memory and material-specific memory changes after ATL? and (b) Which IAT memory score(s) optimally predict memory changes after surgery, the memory score after injection ipsilateral to the seizure focus, the memory score after injection contralateral to the seizure focus, or the IAT asymmetry score, comprising the ipsilateral minus contralateral injection scores? METHODS: Seventy left hemisphere language-dominant patients undergoing ATL for treatment of medically refractory seizures were administered a verbal and visuospatial recognition memory test before surgery and 3 weeks after surgery. IAT memory recognition scores for words and designs were used to predict verbal and visuospatial memory changes after surgery. RESULTS: After surgery, left ATL patients declined in verbal memory, whereas right ATL patients declined in visuospatial memory. IAT total recognition memory scores (collapsed across all types of materials) and IAT word memory scores were associated with postoperative verbal memory decline. This relationship was significant for the IAT ipsilateral injection memory scores and the IAT hemispheric asymmetry scores. IAT memory performances were not related to visuospatial memory changes. CONCLUSIONS: Results indicate IAT memory measures to be related to postoperative verbal, but not visuospatial, memory change. A specific relationship was found between postoperative verbal memory change and IAT verbal memory after injection ipsilateral to the seizure focus, when relying primarily on the contralateral hemisphere. This finding is consistent with the functional reserve model of memory change in ATL.

Adult↗

Heart rate and heart rate variability changes in the intracarotid sodium amobarbital test.

PURPOSE: Changes in heart rate and heart rate variability have been found in prior studies performed during the intracarotid sodium amobarbital (ISA) test. However, these results are not entirely consistent with current models of differential cerebral involvement in the modulation of the heart. This study was designed to re-investigate this topic with a larger N than has heretofore been used. METHODS: The electrocardiogram was recorded during left and right ISAs in 73 subjects. Raw heart rate and heart rate variability were calculated. RESULTS: Raw heart rate increased during inactivation of either hemisphere, but more so for the right hemisphere. Heart rate variability changes consistent with decreasing parasympathetic tone also were found to occur during either ISA, but to a significant degree, only during right ISA. CONCLUSIONS: The right hemisphere appears to have a greater role in cerebral regulation of cardiac function, perhaps by virtue of the modification of parasympathetic effects.

Adolescent↗

Focal functional deficits in temporal lobe epilepsy on PET scans and the intracarotid amobarbital procedure: comparison of patients with unitemporal epilepsy with those requiring intracranial recordings.

PURPOSE: To analyze the relationship between the intracarotid amobarbital procedure (IAP) and positron emission tomography (PET) and study the lateralizing value of these tests in patients with unitemporal epilepsy and those requiring intracranial recordings. METHODS: We compared 51 patients with unitemporal epilepsy (group1) with 26 patients in whom surface recordings failed to reveal a distinct unitemporal focus, necessitating invasive recordings (group 2). RESULTS: The brain magnetic resonance imaging (MRI) scans for group 1 showed mesial temporal sclerosis in 70.5% of the patients. PET showed unilateral temporal hypometabolism in 88%. In addition, 74.5% of the patients in group 1 had impaired memory on the epileptogenic side on the IAP, and 89.4% of those patients also had ipsilateral temporal hypometabolism on PET scans. All the group 1 patients underwent temporal resections. The pathologic examination showed hippocampal sclerosis in 72% of the patients. Eighty percent of group 1 patients became seizure free, and 16% had rare seizures (follow-up, 2-7 years). MRIs for group 2 showed mesial temporal sclerosis in 31% of the patients; PET scans showed temporal hypometabolism in 39%. The IAP was lateralized in 47.8%. Sixty-nine percent had temporal lobe resections. The pathologic examination showed hippocampal sclerosis in 44% of the patients. Forty-four percent of group 2 patients became seizure free, and 27.7% had rare seizures (follow-up, 2-8 years). CONCLUSIONS: Ninety-six percent of the patients with unitemporal foci had focal functional deficits on the epileptogenic side on 18-fluorodeoxyglucose-(FDG) PET scans, the IAP, or both. The results of the FDG-PET were predictive of impaired memory on the IAP. Memory impairment contralateral to the temporal hypometabolism found on the PET scans was never seen. These patients had an excellent outcome. In contrast, <50% of the patients requiring intracranial recordings had focal functional deficits, suggesting that more a diffuse pathology may account for their less favorable outcome.

Adolescent↗

[The determination of cerebral speech dominance with the intracarotid amobarbital test].

In neuropsychological diagnostics of lateralisation of cognitive functions, the intracarotid amobarbital procedure (IAP) is a well established method for the determination of cerebral language dominance. In this review, different frameworks of classification of dominance patterns are discussed, ranging from the simple left/right/bilateral-dominance framework to a quantitative analysis according to a computed lateralisation index. Evidence from IAP studies concerning the cerebral organisation of linguistic subfunctions like naming and reading are discussed. A critical evaluation of rivalling approaches like electrical stimulation mapping or visual hemifield studies suggests that these methods mainly yield results complementary to IAP data and hence should not be taken as substitutes of that procedure.

Amobarbital↗

Crossed aphasia in a patient with complex partial seizures: evidence from intracarotid amobarbital testing, functional cortical mapping, and neuropsychological assessment.

We report a right-handed patient who became transiently aphasic following a right temporal lobectomy for control of intractable complex partial seizures. Preoperative intracarotid amobarbital testing revealed right-hemisphere language dominance, although bilateral language representation was present. Memory testing during unilateral electrical hippocampal simulation with depth electrodes indicated reliance on left-hemisphere mesial temporal lobe structures for verbal memory. Functional mapping for language during surgery established several right perisylvian regions that, when stimulated, produced speech arrest and/or paraphasic substitution. One-year follow-up neuropsychological assessment demonstrated an increase in verbal learning and decrease in visual memory, a pattern associated with patients who have undergone right temporal lobectomy. These data demonstrate that (1) right cerebral language dominance can be observed when ipsilateral seizure onset is present (2) verbal memory and language dominance are not necessarily linked, and (3) some reported cases of crossed aphasia may in fact have bilateral language representation.

Adult↗

Case report of an intracarotid amobarbital procedure performed for a deaf patient.

The intracarotid amobarbital procedure (IAP) was conducted with a profoundly deaf young man prior to right anteromedial temporal lobectomy for pharmacologically refractory partial complex seizures. The IAP required considerable modification in order to take into account the use of varying sign language methods and related issues. Visual memory, American Sign Language, signed English, and finger-spelling functioning were all assessed. The patient manifested left hemisphere dominance for all these abilities, performing well under right hemisphere anesthesia. In contrast, no ability to function on these tasks was detectable when the left hemisphere was anesthetized. This demonstrates that an intact left temporal lobe and related structures are sufficient to support sign language functioning. The development of a deaf adaptation of the IAP is of methodological significance, as the IAP is thereby rendered accessible for deaf patients.

Adult↗

Affective self-report during the intracarotid sodium amobarbital test.

Changes in internal affective state were investigated in patients undergoing the intracarotid sodium amobarbital test. It was found that when the left hemisphere was inactivated, patients rated their mood as significantly more negative than during baseline conditions. No significant change in affective state was observed during the inactivation of the right hemisphere. The findings are interpreted in terms of a differential lateralization model of emotion, in which the right hemisphere is more involved in the more powerful and salient negative affects.

Adolescent↗

Objective criteria for reporting language dominance by intracarotid amobarbital procedure.

We propose a standardized method for reporting language lateralization by intracarotid amobarbital procedure (IAP). We retrospectively reviewed 165 IAPs, and classified language lateralization as left, right, or bilateral by three different methods, all based on the duration of speech arrest following each injection: absolute duration, side-to-side difference, and a "laterality index" defined as (L-R/L+R). Cutoff values were obtained by studying a pure subgroup of left hemisphere dominant right-handed subjects. In 142 patients (86%), the classification remained unchanged among all three methods: left in 112 (79%), right in 19 (13%), and bilateral in 11 (8%). In the other 23 patients (14%), language classification varied among the three criteria used. The change of category was never between left and right, and always involved bilateral language. Thus, this index may be helpful in standardizing and comparing IAP results from different series.

Adolescent↗

Promotion by sodium barbital of renal cortical and transitional cell tumors, but not intestinal tumors, in F344 rats given methyl(acetoxymethyl)nitrosamine, and lack of effect of phenobarbital, amobarbital, or barbituric acid on development of either renal or intestinal tumors.

Comparative effects of four barbiturates, phenobarbital (PB), amobarbital (AB), sodium barbital (NaBB), and barbituric acid (BA) on the development of neoplasms in the intestinal tract and other organs were investigated in rats following initiation with methyl(acetoxymethyl)nitrosamine (DMN-OAc). Four-week-old F344/NCr male rats were given a single i.p. injection of 0.05 nmol DMN.OAc in 5 ml sterile phosphate buffered saline/kg body weight. Two weeks after DMN.OAc treatment, the animals were provided with either tap water or drinking water containing 500 p.p.m. of PB, NaBB, AB, or BA for the remaining experimental period. Control groups received a single i.p. injection of 5 ml of sterile phosphate buffer/kg body weight and 2 weeks later were given either tap water or drinking water containing 500 p.p.m. of one of the barbiturates listed above. Rats were killed at 52 weeks or 80 weeks after DMN.OAc injection. DMN.OAc induced multiple intestinal tumors that occurred mostly in the mucosa of the small intestine, especially the terminal ileum. None of the barbiturates had any effect on either incidence or multiplicity of intestinal tumors. PB significantly enhanced the development of hepatocellular tumors as well as thyroid follicular cell neoplasms in DMN.OAc initiated rats, while the subsequent administration of NaBB, but not other barbiturates, resulted in the development of renal cortical and pelvic transitional cell tumors. This is the first demonstration of promotion of carcinogenesis in renal pelvic transitional epithelium, a cell type not previously recognized as vulnerable to initiation by DMN.OAc given i.p. NaBB without prior administration of DMN.OAc induced severe nephropathy and focal hyperplasia of both renal cortical tubular and pelvic transitional cell epithelium. No such effects were observed with either PB, AB, or BA. Our results failed to confirm the earlier findings of others that intestinal epithelial carcinogenesis could be promoted by continuous oral administration of NaBB. However, these results strongly support and extend our previous conclusions that some barbiturates have broad organ specificities and promote epithelial carcinogenesis in more than one organ and tissue.

Adenoma↗

Chance discovery of multiple personality disorder in a depressed patient by amobarbital interview.

Although the diagnosis of multiple personality disorder (MPD) has been receiving renewed interest in the literature, it presents a number of clinical problems and challenges. A case study is reported in which this diagnosis was uncovered by chance during an amobarbital interview on a psychotically depressed young male patient. The patient had previously been only minimally responsive to pharmacotherapy for a major depressive episode with mood-congruent psychotic features. When the multiple personality disorder was diagnosed, treatment emphasis shifted toward psychotherapeutic modalities with marked clinical improvement. Several unique aspects of the case, including diagnostic methodology, results of serial dexamethasone suppression tests, and psychosomatic symptomatology, are discussed as well as the implications of this case within a larger clinical context.

Adult↗