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SLATER TF, SAWYER B, STRAEULI U. STUDIES ON SUCCINATE-TETRAZOLIUM REDUCTASE SYSTEMS. III. POINTS OF COUPLING OF FOUR DIFFERENT TETRAZOLIUM SALTS. BIOCHIMICA ET BIOPHYSICA ACTA 1963; 77:383-93. [PMID: 14089413 DOI: 10.1016/0006-3002(63)90513-4] [Citation(s) in RCA: 541] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
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Desmond JE, Sum JM, Wagner AD, Demb JB, Shear PK, Glover GH, Gabrieli JD, Morrell MJ. Functional MRI measurement of language lateralization in Wada-tested patients. Brain 1995; 118 ( Pt 6):1411-9. [PMID: 8595473 DOI: 10.1093/brain/118.6.1411] [Citation(s) in RCA: 331] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In this study the use of functional MRI (fMRI) for measuring language lateralization non-invasively was examined. The subjects were seven patients with histories of temporal lobe epilepsy who had undergone Wada testing for pre-surgical evaluation. Four patients were left-hemisphere-dominant and three were right-hemisphere-dominant for language. They received fMRI scans while they made semantic or perceptual judgments about visually presented words. Regions of the inferior frontal gyrus (pars triangularis and pars orbitalis) and neighbouring orbital cortex, corresponding to portions of Brodmann areas 45, 46 and 47, exhibited significant increases in activation during semantic relative to perceptual judgments. Lateralization of the increases in activation were consistent with the Wada test assessments of hemispheric language dominance in each of the seven patients. These results suggest that, in addition to providing a tool for investigating human cognitive processes, fMRI has significant clinical potential as a non-invasive measure of language lateralization.
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Anzola GP, Magoni M, Guindani M, Rozzini L, Dalla Volta G. Potential source of cerebral embolism in migraine with aura: a transcranial Doppler study. Neurology 1999; 52:1622-5. [PMID: 10331688 DOI: 10.1212/wnl.52.8.1622] [Citation(s) in RCA: 316] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The recently found association between patent foramen ovale (PFO) and transient global amnesia (TGA) has suggested that paradoxical microembolization in the terminal vertebrobasilar territory might underlie at least some TGA cases. Migraine with visual aura is another paroxysmal disturbance in which a sudden dysfunction of cortical areas fed by the terminal branches of the basilar artery is believed to trigger the attack. Therefore we investigated the prevalence of PFO in a consecutive unselected cohort of migraine patients. OBJECTIVE To investigate the prevalence of PFO in a consecutive unselected cohort of migraine patients to search for a possible mechanism for the reported association of migraine with stroke. METHODS AND RESULTS A total of 113 patients, consecutively referred by the Headache Outpatient Clinic for migraine with aura (MA+, mean age 34+/-12 years) were compared with 53 patients with migraine without aura (MA-, mean age 36+/-13 years) and with 25 age-matched nonmigraine subjects (mean age 31+/-10 years) selected from the hospital staff. PFO was assessed with transcranial Doppler sonography with IV injection of agitated saline, a technique that is 90% sensitive and 100% specific. The prevalence of PFO was 48% (54/113) in MA+ patients, 23% (12/53) in MA- patients, and 20% (5/25) in control subjects. The difference between MA+ and MA- patients was significant (odds ratio [OR] = 3.13, 95% confidence interval [CI] = 1.41 to 7.04, chi2 = 9.52,p = 0.002) as was the difference between MA+ patients and controls (OR = 3.66, 95% CI = 1.21 to 13.25, chi2 = 6.46, p = 0.01), whereas MA- patients did not differ from controls (OR = 1.17, 95% CI = 0.32 to 4.45, chi2 = 0.07). MRI was negative in 22 MA+ and 8 MA- patients. CONCLUSIONS Patency of the foramen ovale is associated with migraine with aura but not with migraine without aura. The increased risk of stroke found in epidemiologic studies in patients with migraine with aura may be explained by an increased propensity to paradoxical cerebral embolism.
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BRANCH C, MILNER B, RASMUSSEN T. Intracarotid Sodium Amytal for the Lateralization of Cerebral Speech Dominance. J Neurosurg 1964; 21:399-405. [PMID: 14168208 DOI: 10.3171/jns.1964.21.5.0399] [Citation(s) in RCA: 283] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Viñuela F, Dion JE, Duckwiler G, Martin NA, Lylyk P, Fox A, Pelz D, Drake CG, Girvin JJ, Debrun G. Combined endovascular embolization and surgery in the management of cerebral arteriovenous malformations: experience with 101 cases. J Neurosurg 1991; 75:856-64. [PMID: 1941114 DOI: 10.3171/jns.1991.75.6.0856] [Citation(s) in RCA: 245] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The authors describe their experience with 101 cerebral arteriovenous malformations (AVM's) treated by endovascular embolization followed by surgical removal. Fifty-three patients presented with intracranial hemorrhage and 35 had seizures. Based on the classification of Spetzler and Martin, two AVM's were Grade I, 13 were Grade II, 26 were Grade III, 43 were Grade IV, and 17 were Grade V. Fifty-six AVM's were in the right hemisphere, 28 were in the left hemisphere, 12 were in the corpus callosum, and five involved the cerebellum. In 50 cases, presurgical obliteration of 50% to 75% of the AVM nidus was achieved by embolization, and in 31 cases this percentage increased to between 75% and 90%. In 97 (96%) patients, complete surgical removal of the AVM was obtained. Morbidity resulting from preoperative endovascular embolization was classified as mild in 3.9% of the cases, moderate in 6.9%, and severe in 1.98%. The death rate related to embolization was 0.9%. The immediate postsurgical morbidity was classified as mild in 5.9% of the cases, moderate in 10.8%, and severe in 5.9%. The overall long-term morbidity was mild in 5.9% of the cases, moderate in 6.9%, and severe in 1.98%. Two patients (1.98%) died due to intractable intraoperative hemorrhage and two (1.98%) as a result of postsurgical pulmonary complications.
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Engel J, Rausch R, Lieb JP, Kuhl DE, Crandall PH. Correlation of criteria used for localizing epileptic foci in patients considered for surgical therapy of epilepsy. Ann Neurol 1981; 9:215-24. [PMID: 7013652 DOI: 10.1002/ana.410090303] [Citation(s) in RCA: 207] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Criteria for anterior temporal lobectomy, performed on seven patients with partial complex seizures, were derived from a battery of fourteen presurgical tests. Seven tests were routine studies aimed at identifying a focus of epileptic excitability, while seven were designed to reveal areas of focal functional deficit. Conflicting information was frequently obtained from the tests of epileptic excitability, suggesting that it is probably inaccurate to view patients with partial complex seizures as having a single epileptogenic focus. Presurgical evaluation must therefore be aimed at identifying the focus most responsible for the patient's habitual seizures. Tests of focal functional deficit provided useful nonconflicting confirmatory information in each of the seven patients studied. The most reliable information was obtained from depth electrode implantation, and this procedure should be considered essential except when all evidence of surface-recorded epileptic excitability, including ictal onset, and evidence of focal functional deficit agree.
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Papanicolaou AC, Simos PG, Castillo EM, Breier JI, Sarkari S, Pataraia E, Billingsley RL, Buchanan S, Wheless J, Maggio V, Maggio WW. Magnetocephalography: a noninvasive alternative to the Wada procedure. J Neurosurg 2004; 100:867-76. [PMID: 15137606 DOI: 10.3171/jns.2004.100.5.0867] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object. In this study the authors evaluated the sensitivity and selectivity of a noninvasive language mapping procedure based on magnetoencephalography (MEG), for determining hemispheric dominance for language functions.
Methods. Magnetic activation profiles of the brain were obtained from 100 surgical candidates (age range 8–56 years) with medically intractable seizure disorder by using a whole-head MEG system within the context of a word recognition task. The degree of language-specific activity was indexed according to the number of consecutive sources (modeled as single, moving current dipoles) in perisylvian brain areas. Only activity sources that were observed with a high degree of spatial and temporal overlap in two split-half data sets were used to compute the MEG laterality index. Independently, all patients underwent Wada testing for the determination of hemispheric dominance for language.
Independent clinical judgments based on MEG and Wada data showed a high degree of concordance (87%). Magnetoencephalography laterality judgments had an overall sensitivity of 98%, but a lower selectivity of 83%, which was due to the fact that MEG detected more activity in the nondominant hemisphere than was predicted based on the Wada test. A number of objective criteria were derived based on this large patient series to ensure data quality and bolster the clinical usefulness of MEG for language mapping.
Conclusions. Although the availability of MEG is still limited across epilepsy surgery centers, this study method may be substituted for the Wada procedure in assessing hemispheric dominance for language in select cases.
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Rutten GJM, Ramsey NF, van Rijen PC, Alpherts WC, van Veelen CWM. FMRI-determined language lateralization in patients with unilateral or mixed language dominance according to the Wada test. Neuroimage 2002; 17:447-60. [PMID: 12482097 DOI: 10.1006/nimg.2002.1196] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Due to the reported variability of the language laterality index (LI) across fMRI studies, reliable distinction between patients with unilateral and mixed language dominance is currently not possible, preventing clinical implementation of fMRI as a replacement for the invasive Wada test. Variability of the LI may be related to differences in experimental and control tasks, and statistical methodology. The goal of this study was to improve detection power of fMRI for hemispheric language dominance by using a combined analysis of four different language tasks (CTA), that has previously shown more reliable and robust Lls in groups of normal volunteers than individual task analyses (see Ramsey et al). The CTA targets brain areas that are common to different language tasks, thereby focusing on areas that are critical for language processing. Further advantage of the CTA is that it is relatively independent of specific task and control conditions. 18 patients with typical (i.e., left-sided, n = 11) and atypical (i.e., right-sided or mixed, respectively, n = 3 and n = 4) language dominance according to the Wada test underwent fMRI (groups respectively denoted as WadaL, WadaR, and WadaM patients). Statistical methodology (including thresholding of activity maps) was fixed to assure a user-independent approach. CTA yielded better results than any of the individual task analyses: it was more robust (on average 2.5 times more brain activity was detected due to its higher statistical power) and more reliable (concordance for WadaL, WadaM and WadaR patients was respectively 10/11 (91%), 3/4 (75%), and 2/3 patients (67%)). Overall, a significant correlation was observed between frontal and temporoparietal LIs. Remarkably, brain activity for WadaM patients was significantly lower than for WadaL or WadaR patients, and a dissociation in lateralization was observed between frontal (right-sided) and temporoparietal (left-sided) activity in three of four patients. Of the individual task analyses, the verb generation task yielded best results for patients with unilateral language dominance (same concordance as CTA). However, in contrast to CTA results, the verb generation task was unable to identify WadaM patients (concordance in one of four patients). In conclusion, the CTA is a promising approach for clinical implementation of fMRI for the prediction of hemispheric language dominance.
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SERAFETINIDES EA, HOARE RD, DRIVER M. INTRACAROTID SODIUM AMYLOBARBITONE AND CEREBRAL DOMINANCE FOR SPEECH AND CONSCIOUSNESS. Brain 1965; 88:107-30. [PMID: 14282892 DOI: 10.1093/brain/88.1.107] [Citation(s) in RCA: 152] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
1. Paraquat and diquat produce only a slight increase in the oxygen uptake of rat liver mitochondria, and it is likely that they do not penetrate the mitochondrial membrane. 2. In mitochondrial fragments inhibited by antimycin A or by Amytal, both substances stimulate oxygen uptake with NADH or beta-hydroxybutyrate as substrate but not with succinate. The NADH dehydrogenase of the respiratory chain appears to be involved, at a site only partially inhibited by Amytal. 3. An NADPH oxidase activity is stimulated in rat liver microsomes by diquat, and to a smaller extent by paraquat; diquat also causes an NADH oxidase activity to develop. The effect is not inhibited by carbon monoxide or p-chloromercuribenzoate, and it is probable that a flavoprotein is involved by a mechanism not requiring thiol groups. 4. One molecule of oxygen can oxidize two molecules of NADPH in the stimulated microsomal system, the hydrogen peroxide produced being broken down by a catalase activity in the microsomes. 5. Diquat can stimulate NADH oxidase and NADPH oxidase activity in the postmicrosomal soluble fraction; the enzyme involved may be DT-diaphorase. 6. The mechanism of these reactions and their significance in relation to the toxicity of the dipyridilium compounds are discussed.
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Loring DW, Meador KJ, Lee GP, Murro AM, Smith JR, Flanigin HF, Gallagher BB, King DW. Cerebral language lateralization: evidence from intracarotid amobarbital testing. Neuropsychologia 1990; 28:831-8. [PMID: 2247209 DOI: 10.1016/0028-3932(90)90007-b] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cerebral language lateralization was investigated in 103 patients undergoing intracarotid amobarbital testing as part of their diagnostic work-up for epilepsy surgery. Inclusion criteria included adequate bilateral intracarotid amobarbital studies and no radiologic lesion in areas other than the temporal lobe. Language was evaluated with respect to strict presence or absence of language representation, in which a patient was considered to have bilateral language despite potentially having asymmetric language representation, and with respect to forced relative hemispheric dominance, in which a single side could be considered dominant despite bilateral language representation. Seventy-nine patients displayed exclusive left hemisphere language representation, two patients showed exclusive right hemisphere language representation, and 22 patients had language represented in each hemisphere. In the 22 patients with bilateral language, an asymmetry was present in 17 cases (13 L greater than R, 4 R greater than L). These data indicate that language restricted only to the right hemisphere is rare, and that in the absence of purely left hemisphere language, most patients exhibit bilateral representation. Previously reported incidence of exclusive right hemisphere language may be an artifact of dichotomizing a continuous variable.
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Mailis-Gagnon A, Giannoylis I, Downar J, Kwan CL, Mikulis DJ, Crawley AP, Nicholson K, Davis KD. Altered central somatosensory processing in chronic pain patients with "hysterical" anesthesia. Neurology 2003; 60:1501-7. [PMID: 12743239 DOI: 10.1212/wnl.60.9.1501] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The authors hypothesized that central factors may underlie sensory deficits in patients with nondermatomal somatosensory deficits (NDSD) and that functional brain imaging would reveal altered responses in supraspinal nuclei. BACKGROUND Patients with chronic pain frequently present with NDSD, ranging from hypoesthesia to complete anesthesia in the absence of substantial pathology and often in association with motor weakness and occasional paralysis. Patients with pain and such pseudoneurologic symptoms can be classified as having both a pain disorder and a conversion disorder (Diagnostic and Statistical Manual of Mental Disorders-IV classification). METHODS The authors tested their hypothesis with functional MRI (fMRI) of brush and noxious stimulation-evoked brain responses in four patients with chronic pain and NDSD. RESULTS The fMRI findings revealed altered somatosensory-evoked responses in specific forebrain areas. Unperceived stimuli failed to activate areas that were activated with perceived touch and pain: notably, the thalamus, posterior region of the anterior cingulate cortex (ACC), and Brodmann area 44/45. Furthermore, unperceived stimuli were associated with deactivations in primary and secondary somatosensory cortex (S1, S2), posterior parietal cortex, and prefrontal cortex. Finally, unperceived (but not perceived) stimuli activated the rostral ACC. CONCLUSIONS Diminished perception of innocuous and noxious stimuli is associated with altered activity in many parts of the somatosensory pathway or other supraspinal areas. The cortical findings indicate a neurobiological component for at least part of the symptoms in patients presenting with nondermatomal somatosensory deficits.
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Golby AJ, Poldrack RA, Illes J, Chen D, Desmond JE, Gabrieli JDE. Memory lateralization in medial temporal lobe epilepsy assessed by functional MRI. Epilepsia 2002; 43:855-63. [PMID: 12181004 DOI: 10.1046/j.1528-1157.2002.20501.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine the utility of functional magnetic resonance imaging (fMRI) in preoperative lateralization of memory function in patients with medial temporal lobe epilepsy (MTLE). METHODS Nine patients with MTLE underwent standard preoperative assessment including video-EEG and intracarotid amytal testing (IAT). fMRI was performed while subjects encoded four types of stimuli (patterns, faces, scenes, and words). Activation maps were created for each subject representing areas more active for novel than for repeated stimuli. Regions of interest were drawn around the MTL in individual subjects, suprathreshold voxels were counted, and an asymmetry index was calculated. RESULTS In eight of nine subjects, lateralization of memory encoding by fMRI was concordant with that obtained from the IAT. Group-level analysis demonstrated greater activation in the MTL contralateral to the seizure focus such that in the left MTLE group, verbal encoding engaged the right MTL, whereas in the right MTLE group, nonverbal encoding engaged the left MTL. CONCLUSIONS fMRI is a valid tool for assessing of memory lateralization in patients with MTLE and may therefore allow noninvasive preoperative evaluation of memory lateralization. FMRI revealed that memory encoding may be reorganized to the contralateral MTL in patients with MTLE.
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Zatorre RJ. Perceptual asymmetry on the dichotic fused words test and cerebral speech lateralization determined by the carotid sodium amytal test. Neuropsychologia 1989; 27:1207-19. [PMID: 2480551 DOI: 10.1016/0028-3932(89)90033-x] [Citation(s) in RCA: 129] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The rhymed fused dichotic words test was administered to 61 epileptic patients whose lesions were atrophic and predominantly unilateral. Subjects were categorized according to the side of speech representation, as determined by intracarotid sodium Amytal injection (left-hemisphere representation, 35 subjects; right-hemisphere representation, 4 subjects; bilateral representation, 22 subjects). Results indicated that 33 of the patients with left-hemisphere speech representation obtained right-ear advantages, and all four of the patients with right-hemisphere speech representation obtained left-ear advantages. The distribution of scores for patients with bilateral speech straddled the zero ear-advantage point, but overlapped both of the other two groups to some extent. Neither handedness, familial handedness, sex, nor side of epileptogenic focus had any significant effect on the observed asymmetries. It was also found that stimulus dominance effects have an important influence on the results, and must be taken into account in the interpretation of dichotic listening asymmetries. It is concluded that this test yields valid estimates of speech lateralization; it is also apparent that the magnitude of ear advantage may be an important variable insofar as the more extreme asymmetries appear to be exclusively associated with speech dominance of the contralateral hemisphere, whereas small-magnitude asymmetries are often associated with bilateral speech representation.
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Jooma R, Yeh HS, Privitera MD, Gartner M. Lesionectomy versus electrophysiologically guided resection for temporal lobe tumors manifesting with complex partial seizures. J Neurosurg 1995; 83:231-6. [PMID: 7616267 DOI: 10.3171/jns.1995.83.2.0231] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Complex partial seizures associated with tumors and other mass lesions are readily diagnosed by modern imaging techniques but their optimum surgical treatment remains unresolved. Lesionectomy has been reported to produce seizure outcomes equal to outcomes after resection that ablates the epileptogenic cortex with the lesion. However, some evidence suggests that when the lesion is in the temporal lobe, simple excision of the tumor or lesion more often fails to control seizures. After retrospectively reviewing the records of 30 patients with complex partial seizures and temporal lobe tumors who underwent surgical treatment at the University of Cincinnati hospitals (1985-1992), the authors divided them into two groups: Group A (16 patients) underwent lesionectomy only and Group B (14 patients) received surgical treatment for seizures with electroencephalographic delineation of the epileptogenic zone and resection of the lesion. Seizure control was best achieved in Group B patients with 13 (92.8%) seizure free at follow up (mean 52 months). Only three (18.8%) of the Group A patients became seizure free after lesionectomy at follow up (mean 33 months). In eight Group A patients, who underwent temporal lobectomy as a second procedure after lesionectomy failed to control seizures, five (62.5%) became seizure free. Group B patients had a longer duration of seizures and were more likely to have lesions smaller than 2.5 cm compared with Group A. Analysis of covariance demonstrated that the differences in outcome between the groups remained significant even with adjustment for the variation in duration of seizures (p = 0.0006) and size of tumor (p = 0.0001). Based on this study, the authors found that the probable relief from seizures caused by a temporal lobe lesion is greater if the region of epileptogenicity, usually the amygdalohippocampal complex, is resected along with the tumor in a temporal lobectomy.
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Sabbah P, Chassoux F, Leveque C, Landre E, Baudoin-Chial S, Devaux B, Mann M, Godon-Hardy S, Nioche C, Aït-Ameur A, Sarrazin JL, Chodkiewicz JP, Cordoliani YS. Functional MR imaging in assessment of language dominance in epileptic patients. Neuroimage 2003; 18:460-7. [PMID: 12595199 DOI: 10.1016/s1053-8119(03)00025-9] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The value of functional MR Imaging (fMRI) in assessing language lateralization in epileptic patients candidate for surgical treatment is increasingly recognized. However few data are available for left-handed patients. Moreover determining factors for atypical dominance in patients investigated with contemporary imaging have not been reported. We studied 20 patients (14 males, 6 females; 9 right handed, 11 left handed) aged from 9 to 48 years, investigated for intractable partial epilepsy. Epileptic focus location was temporal in 14 cases, extratemporal in 6, and lateralized in the left hemisphere in 11/20. Hemispheric dominance for language was evaluated by both Wada test and fMRI using a silent word generation paradigm in all patients. Furthermore, a postictal speech test was performed in 15 patients. An fMRI language lateralization index was calculated from the number of activated pixels (Student's t test, P < 0.0001) in the right and left hemispheres. The Wada test showed a right hemispheric dominance in 8 patients (6 were left handed and 2 right handed) and a left hemispheric dominance in 12 patients (5 were left handed and 7 right handed). These results were concordant with clinical postictal examination in 11/15 patients (73%). Clinical status did not allow a conclusion about hemispheric dominance for the remaining 4 patients. FMRI was concordant with the Wada test in 19/20 cases. For one left-handed patient, fMRI showed bilateral activation, whereas the Wada test demonstrated a right hemispheric dominance. Right language lateralization was significantly correlated with left lateralized epilepsy (P < 0.05) but was not correlated with age at epilepsy onset, early brain injury (before 6 years), and lobar localization of epileptogenic focus. However the lack of a significant relationship between these factors and atypical language lateralization may be related to the small sample size.
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Jennum P, Friberg L, Fuglsang-Frederiksen A, Dam M. Speech localization using repetitive transcranial magnetic stimulation. Neurology 1994; 44:269-73. [PMID: 8309572 DOI: 10.1212/wnl.44.2.269] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
To evaluate whether repetitive transcranial magnetic stimulation (RTMS) may be used for speech localization, we compared the results from RTMS with the intracarotid amobarbital test (IAT) in 21 patients undergoing surgical treatment (amygdalohippocampectomy or anterior temporal lobe resection) for medically intractable partial epilepsy. None of the patients had aphasia. We stimulated the temporal and frontal cortex on each side at a frequency of 30 Hz for 1 second and increased the intensity until speech was inhibited. A list of words and forward and backward counting were used to test speech function. The IAT was performed on the hemisphere of proposed surgery by unilateral injection and simultaneous regional cerebral blood flow (rCBF) recordings. In one patient, there was doubt about hemisphere dominance and a second bilateral IAT was performed. Fifteen patients had left-sided speech dominance; one, left-sided dominance and a moderate right-sided speech inhibition; two, right-sided speech dominance; and one, bilateral speech representations (bilateral injection at the IAT) with both techniques. One patient showed bilateral with right-sided speech dominance by RTMS and showed right-sided speech inhibition with right-sided injection only at the IAT procedure. One patient differed from the rest, showing bilateral representations with right-sided speech dominance with RTMS and left-sided speech inhibition by IAT with left-sided injection only. The concordance was 95%. None of the patients had seizures provoked by the procedure. We conclude that speech localization with RTMS shows a high concordance with the results from the IAT and may be useful in addition to traditional techniques in speech localization.(ABSTRACT TRUNCATED AT 250 WORDS)
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Strauss E, Satz P, Wada J. An examination of the crowding hypothesis in epileptic patients who have undergone the carotid amytal test. Neuropsychologia 1990; 28:1221-7. [PMID: 2290496 DOI: 10.1016/0028-3932(90)90057-u] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epileptic patients who had undergone the carotid amytal test were assessed on a variety of measures of verbal and non-verbal ability. All patients had left hemisphere dysfunction of early onset. Patients with atypical speech patterns performed as well as patients with left hemisphere speech on most, though not all, measures of language function. Transfer of language to the right hemisphere, however, occurred at a heavy cost. Patients with atypical speech patterns performed more poorly than their left hemisphere speech counterparts on a wide variety of non-verbal tests. These results are discussed in terms of the "crowding" hypothesis.
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Hirata M, Kato A, Taniguchi M, Saitoh Y, Ninomiya H, Ihara A, Kishima H, Oshino S, Baba T, Yorifuji S, Yoshimine T. Determination of language dominance with synthetic aperture magnetometry: comparison with the Wada test. Neuroimage 2004; 23:46-53. [PMID: 15325351 DOI: 10.1016/j.neuroimage.2004.05.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Revised: 05/07/2004] [Accepted: 05/11/2004] [Indexed: 11/19/2022] Open
Abstract
Cerebral dominance for language function was investigated with synthetic aperture magnetometry (SAM). The results were compared with those of the Wada test. SAM is a spatial filtering technique that enables demonstration of the spatiotemporal distribution of oscillatory changes (synchronization and desynchronization) in magnetoencephalography (MEG) signals elicited by specific brain activation. MEG was conducted during a silent reading task in 20 consecutive preoperative neurosurgical patients who also underwent a Wada test. The spatial distribution of oscillatory changes related to silent reading was shown tomographically with SAM as statistical images. Language dominance was estimated by the laterality index, which scales the lateralization of the beta (13-25 Hz) and low gamma (25-50 Hz) band desynchronizations in the inferior frontal gyrus (IFG) or middle frontal gyrus (MFG). Oscillatory changes were distributed multifocally and bilaterally in the occipital cortex, IFG or MFG, and temporo-parieto-occipital border regions. In 19 patients (95%), language lateralization estimated by the laterality index was congruent with the result of the Wada test. In left-handed patients, SAM analysis clearly differentiated language dominance (left, right, or bilateral), and the findings were confirmed by the Wada test. Lateralization of beta or low gamma band desynchronizations in the IFG or MFG is a good indicator of the side of language dominance. Reliability of MEG imaging with SAM is sufficient to evaluate language dominance preoperatively in neurosurgical patients.
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Abstract
Our purpose was to review the current role of invasive and semi-invasive EEG in the presurgical evaluation of candidates for epilepsy surgery. The use of stereotactically implanted intracranial depth (stereo-EEG), subdural strip and grid, and foramen ovale electrodes, as well as intraoperative electrocorticography and electrical brain stimulation ("functional mapping") at the Epilepsy Center University Hospital Zurich, from 1984 to 1998, is analyzed. Advantages and disadvantages of the various intracranial EEG techniques are critically discussed. Out of 422 selective amygdalohippocampectomies performed in Zurich, 54% had non-invasive, 32% had semi-invasive, and 14% had invasive presurgical EEG evaluation. Because patients currently referred to our center increasingly present with a complex history of disease, i.e., constitute so-called "difficult cases", there is trend to combine several invasive and semi-invasive, pre- and intraoperative neurophysiological techniques.
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