Effect factors for language and memory dominance evaluation in patients with refractory epilepsy / 中华行为医学与脑科学杂志

Objective To investigate the effect factors for language and memory dominance testing in propofol Wada test in refractory epilepsy patients.Methods From January 2010 to August 2013,total of 23 patients underwent propofol Wada tests for language and memory dominance evaluation.According the performance in language test and memory test,the patients were divided into two groups,respectively:succeed with test or failed in test.The relevant factors including age,duration of epilepsy,handedness,FIQ (full scale of intelligence quotient),lateralization of lesions,language dominance,dose of propofol and the adverse effects of propofol were recorded as independent variables.Logistic regression was adopted to screen the effect factors for memory dominance evaluation.All statistical analyses were processed with SPSS software.Results All 23 patients succeeded with language test,but only 13 patients succeed with memory test.The difference of success ratios between language test and memory test was significant (P=0.001).For memory test,the difference of duration of epilepsy and FIQ in success group and failed group was significantly different (duration of epilepsy:(10.57±4.68) vs (18.30±9.30),P=0.032,FIQ:(81 ±25.33) vs (64.2±10.86),P=0.046).More grade Ⅱ adverse effects of propofol occured in the patients who failed in memory test (P=0.011).Logistic regression results indicated the grade Ⅱ adverse effects of propofol were the main risk factor for memory test failure (OR=28.0,P＜0.01).Conclusions Propofol Wada test is an effective method for language dominance evaluation.However,the effect factors for memory dominance evaluation are much more than language evaluation,such as duration of epilepsy,FIQ and grade Ⅱ adverse effects of propofol,and grade Ⅱ adverse effects of propofol may be the most significant risk factor.

Functional MRI Assessment of Hemispheric Language Dominance with Using a Lexical Decision Task

PURPOSE: We wanted to compare the fMRIs (functional magnetic resonance images) obtained during a lexical decision task and also during a word generation task, and we wanted to evaluate the usefulness of using a lexical decision task for the visualization of the brain language area and for the determination of language dominance. MATERIALS AND METHODS: Sixteen patients (9 women and 7 men) who had had undergone the Wada test were included in our study. All the patients were left dominant for language, as tested for on the Wada test. The functional maps of the brain language area were obtained in all the subjects during the performance of a lexical decision task and also during the performance of a word generation task. The MR examinations were performed with a 1.5 T scanner and with using the EPI BOLD technique. We used the SPM program for the postprocessing of the images. The threshold for significance was set at p<0.001 or p<0.01. A lateralization index was calculated from the number of activated pixels in each hemispheric region (the whole hemisphere, the frontal lobe and the temporoparietal lobe), and the hemispheric language dominance was assessed by the lateralization index; the results were then compared with those results of the Wada tests. The differences for the lateralization of the language area were analyzed with regard to the stimulation tasks and the regions used for the calculation of the lateralization indices. RESULTS: The number of activated pixels during the lexical decision task was significantly smaller than that of the word generation task. The language dominance based on the activated signals in each hemisphere, was consistent with the results of the Wada test for the word generation tasks in all the subjects. On the lexical decision task, the language dominance, as determined by the activated signals in each hemisphere and the temporoparietal lobe, correlated for 94% of the patients. The mean values of the lateralization index for the lexical decision task were higher than those mean values of the lateralization index of the word generation task. CONCLUSION: The lexical decision task allowed us to map the language area and to determine the language dominance. It could be a useful task for those patients who cannot perform the word generation task because of their cognitive retardation.

The Clinical Findings of Unitemporal and Bitemporal Glucose Hypometabolism in Mesial Temporal Lobe Epilepsy / 대한간질학회지

PURPOSE: To identify clinical characteristics in patients with unitemporal hypometabolism (UTH) or bitemporal hypometabolism (BTH) in mesial temporal lobe epilepsy (TLE). METHODS: We enrolled 95 patients with mesial TLE, 87 of whom subsequently had a surgery. Seizures, interictal and ictal EEG, brain MRI, Wada test, and neuropsychological test results were reviewed. (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) scans were visually interpreted. Patients were divided into two groups, UTH and BTH. RESULTS: There were 59 UTH patients and 36 BTH patients. Semiology showed that UTH had higher frequencies of aura and unilateral dystonic posturing than BTH, whereas BTH had higher frequencies of a non-lateralized bilateral ictal EEG pattern and of bilateral interictal spikes than UTH. Moreover, BTH had symmetric Wada memory scores more frequently than UTH, and white matter changes of the bilateral temporal lobes in brain MRI were more frequent in BTH than UTH. All UTH patients with bilateral TLE in scalp EEG showed unilateral seizure onset in intracranial EEG. CONCLUSION: The characteristic clinical findings of mesial TLE patients with BTH were more frequent non-lateralized ictal EEG pattern, bitemporal interictal spikes, symmetric Wada memory score, the presence of anterior temporal white matter changes, and less frequent aura, and unilateral dystonic posturing. Surgical outcomes were similar and good in both groups although surgery could not be performed in 8 (22.2%) BTH patients.

Interhemispheric Reorganization of Memory Function Assessed by Wada Test in Patients with Mesial Temporal Lobe Epilepsy

BACKGROUND: We investigate an interhemispheric reorganization of memory functions using Wada test in patients with unilateral mesial temporal lobe epilepsy (MTLE). METHODS: We included 70 patients with unilateral MTLE and 37 with neocortical epilepsy (NE). The Wada memory stimuli were composed of 10 items. Scores for each injection were calculated with 1 and 0.5 points assigned for each correct free recall and recognition, respectively. A cut-off asymmetry score for lateralization of memory deficit was defined as 2 points. We statistically analyzed the proportion of memory asymmetry and the average memory score according to the type of epilepsy and the lateralization of seizure focus. RESULTS: The lateralizations of memory deficit determined by Wada memory asymmetry were evenly distributed in the left MTLE (n=34): left in 12 (36%), right in 11 (32%), and undetermined in 11 (32%). However, most (92%) of the right MTLE (n=36) were correctly lateralized to the side of seizure focus. More than 90% of patients with NE were lateralized to right hemisphere regardless of the seizure laterality. The average total (left plus right) memory score were not significantly different between each group. However, right memory score in left MTLE or left memory score in right MTLE were significantly higher than those in NE. The earlier age at seizure onset and the longer duration of epilepsy were observed in patients with left MTLE who had ipsilateral memory deficit comparing to those who had contralateral memory deficit. CONCLUSIONS: A pure interhemispheric reorganization of memory functions could occur in some patients with MTLE. It may be influenced by age at the onset of a seizure and the duration of epilepsy.

Interhemispheric Reorganization of Memory Function Assessed by Wada Test in Patients with Mesial Temporal Lobe Epilepsy

BACKGROUND: We investigate an interhemispheric reorganization of memory functions using Wada test in patients with unilateral mesial temporal lobe epilepsy (MTLE). METHODS: We included 70 patients with unilateral MTLE and 37 with neocortical epilepsy (NE). The Wada memory stimuli were composed of 10 items. Scores for each injection were calculated with 1 and 0.5 points assigned for each correct free recall and recognition, respectively. A cut-off asymmetry score for lateralization of memory deficit was defined as 2 points. We statistically analyzed the proportion of memory asymmetry and the average memory score according to the type of epilepsy and the lateralization of seizure focus. RESULTS: The lateralizations of memory deficit determined by Wada memory asymmetry were evenly distributed in the left MTLE (n=34): left in 12 (36%), right in 11 (32%), and undetermined in 11 (32%). However, most (92%) of the right MTLE (n=36) were correctly lateralized to the side of seizure focus. More than 90% of patients with NE were lateralized to right hemisphere regardless of the seizure laterality. The average total (left plus right) memory score were not significantly different between each group. However, right memory score in left MTLE or left memory score in right MTLE were significantly higher than those in NE. The earlier age at seizure onset and the longer duration of epilepsy were observed in patients with left MTLE who had ipsilateral memory deficit comparing to those who had contralateral memory deficit. CONCLUSIONS: A pure interhemispheric reorganization of memory functions could occur in some patients with MTLE. It may be influenced by age at the onset of a seizure and the duration of epilepsy.

Effective Memory Stimulus Type and Score Measurement of Wada Memory Test in Lateralization of Temporal Lobe Epilepsy

BACKGROUND: The Wada test is not yet standardized among epilepsy surgery centers, which makes it difficult to dis-cern the differences between its results. The objectives of this study were to examine the effects of memory stimulus types in the Wada test and the methods of score measurement of results. METHODS: We examined the Wada test in 59 patients with temporal lobe epilepsy who had language dominancy in left hemispheres. They underwent surgical treat-ment and were seizure-free for at least until the 1-year follow up. The Wada test was done on the patients using three different protocols during the presurgical evaluations: 1) protocol A; sixteen cards displaying eight line drawings of common objects and eight words, 13 patients, 2) protocol B; eight line drawings of abstract figures, 14 patients, and 3) protocol C; four line drawings of common objects and four line drawings of abstract figures, 32 patients. RESULTS: Thirty-three patients with RTL (right temporal lobectomy) and 26 patients with LTL (left temporal lobectomy) were not significantly different in demographic and disease characteristics such as age and sex, age at onset, risk factors before 2 years old, epilepsy duration, and Korean Wechsler Adult Intelligence Scale- IQ scores. Patients with RTL rec-ognized significantly more words and line drawings of common objects with a right injection than those with a left injection. Patients with LTL recognized significantly more line drawings of abstract figures and common objects fol-lowing a left injection versus a right injection. Correct rates obtained through discriminant function analysis (100% (A), 64% (B) and 84% (C) were higher than that obtained through cutoff criteria (memory asymmetry scores (3)25%: 82% (A), 62% (B) and 56% (C) ). CONCLUSIONS: Our study shows that line drawings of common objects as Wada memory stimuli are more useful for the lateralization of the epileptogenic hemisphere than line drawings of abstract figures and words. Discriminant function analysis is also a more effective score measurement than cutoff criteria.

Factors Affecting Impaired Reaction in Wada Test

BACKGROUND: The Wada test is an essential part of the preoperative evaluations in candidates for epilepsy surgery. Impaired reactions (IR) to intracarotid sodium amytal infusions include: confusion, disorientation, and decreased respon-siveness, thereby confounding test results. We retrospectively analyzed the factors affecting the impaired reactions (IR) regarding both individual and methodologic factors. METHODS: Subjects included 202 patients (age;28.5+/-9.48, range:8 to 64 years, M:F=113:89) with intractable epilepsy. Patients with IR (IR group) and those without IR (Non-IR group) were compared with respect to individual factors such as: age, sex, epilepsy syndromes, injected hemispheres, dominan-cy as well as methodologic factors including amobarbital doses. With regards to the dose of amobarbital, the total accu-mulated dose as well as the initial injected dose, were used. RESULTS: IR was observed in 50 patients (24.7%). Compared to the non-IR group, the IR group had more prolonged, contralateral weakness and total test times, but the same duration of EEG changes. IR occurred more frequently with injections into the left hemisphere (p<0.001), the dominant hemi-sphere (p<0.0001), and contralateral hemisphere of epileptic focus (p<0.07). The IR group received significantly higher amounts of amobarbital than the non-IR group (p<0.05). Considering the oversedation as well as the undersedation of amobarbital together, 100mg of amobarbital was the most appropriate dose in the Wada test. CONCLUSIONS: These results suggest that dominant hemisphere injections and usage of higher doses of amobarbital can frequently produce IR in the Wada test. The ideal dose of amobarbital in the Wada test for Korean patients should be 100mg.

Memory Functions of Temporal Lobe Epileptic Patients in the Intracarotid Amobarbital Procedure:I. Lateralizing Value

BACKGROUNDS: To examine the effects of seizure laterality and stimulus type on Wada memory performance in patients with temporal lobe epilepsy(TLE). METHODS: The subjects were 43 patients with medically intractable TLE (left TLE 26, Right TLE 17) who had no or rare seizures after surgery. The memory stimuli were concrete figures for some subjects and abstract figures for the other subjects. RESULTS: A clinical criterion of at least 2-points difference between left and right injections correctly classified 31(72%) patients into left and right TLE groups, with 4(9%) patients falsely classified. A discriminant function analysis(DFA) based on left and right injection scores allowed for a correct classification of 37(86%) patients into left and right TLE groups. When the memory stimuli were concrete figures, the correct classification rate was greater for right than left TLE patients. In contrast, with abstract figures, the correct classification rate was greater for left than right TLE patients. CONCLUSIONS: The Wada memory test is a valuable diagnostic aid in lateralizing temporal epileptogenic foci. Stimulus type as well as seizure lateralization is a major determinant of Wada memory asymmetries.

Cut-off Value of Wada Memory Score in Verbal and Visual Memory Domain

BACKGROUND: The cut-off value which determine pass or fail in Wada memory test has not been thoroughly studied, especially in regard to modality-specific memory domains. To investigate the optimal cut-off value, we tried to know what value is appropriate to forecast good postoperative memory outcome in verbal and visual memory domains. METHODS: Eighteen temporal lobe epilepsy patients underwent preoperative Wada test and pre- and postoperative neuropsychological evaluation. Corrected Wada memory score (cWMS) was calculated by ipsilateral Wada retention score divided by pre-Wada score. As a measure of postoperative memory outcome, neuropsycholgical asymmetry index (NPAI) was defined as [(postoperative memory score ? Preoperative memory score) / their mean] and analyzed in verbal and visual memory domains respectively. We made six arbitrary cut-off cWMS values (40, 50, 60, 70, 80, and 90%) and dichotomized the patients into pass or fail group at each arbitrary cut-off value. Verbal and visual NPAIs were compared statistically between two groups. RESULTS: Verbal NPAIs were significantly different between pass and fail groups at 80% cut-off value (p=0.044). Visual NPAIs were significantly different between two groups at 50% (p=0.043) and 60% (p=0.003) cut-off values. CONCLUSIONS: Higher cut-off values may be better for differentiating good and poor postoperative memory outcomes in verbal memory domain, and, in contrast, lower cut-off values may be better in visual memory domain. The verbal and visual memory in Wada test should be analyzed with different cut-off values.

Effect of Material-specificity on the Wada Memory Test in Medial Temporal Lobe Epilepsy with Hippocampal Sclerosis

BACKGROUNDS: The Wada test is a useful method in predicting the laterality of a epileptogenic zone. However, past research reveals that material specificity has an influence on the lateralization We examined the material-specificity of memory and its change in epileptic patients to discover reasonable items on the Wada test for the proper lateralization of the epileptogenic zone. METHODS: We analyzed 45 patients with video-EEG-confirmed medial temporal lobe epilepsy (mTLE) and definite hippocampal atrophy by an MRI. Eight items were presented during the Wada test including 3 common objects, 1 geometric object, 1 color, 1 word, 1 phrase, and 1 math expression. We checked recognition memo-ry after recovery of hemiparesis and normalization of EEG. RESULTS: For the right mTLE group, recognition memory following a right hemisphere injection was significantly better than a left hemisphere injection for all categories. For the left mTLE group, a significant difference of scores was found for the left versus right hemisphere injection for common objects. When injected to the left hemisphere, all the items helped lateralization, but when injected to the right hemisphere, a phrase did not help with lateralization. CONCLUSIONS: Items with strong unilateral encodings do not help lateralizing the epileptogenic zone.

Determination of Dominant Hemishere for Language: Comparison of fMRI and Wada Test

PURPOSE: To evaluate the usefulness of functional MR imaging(fMRI) for determination of language dominance compared with Wada test and to assess the lateralization of activated signals according to stimulation task of activated area. MATERIALS AND METHODS: Functional maps were obtained during word generation task and reading task in twenty patients(16 epilepsy, 4tumor; 17 right-handed, 1 left-handed, 2 ambidextrous). MR examinations were performed at 1.5T scanner with EPI BOLD technique during word generation and word reading tasks. We used SPM program for the postprocessing of image. The threshold for significance was set at p<0.0001 or p<0.001. A lateralization index(LI) was calculated from the number of activated pixels in three hemispheric areas(whole hemisphere, frontal lobe, and temporoparietal lobe. The LIs of fMRI and Wada test were compared according to stimulation task and area for calculation of LI. RESULTS: During the Wada test, sixteen patients had the left language dominance and four patients had right dominance. The language dominance determined by LI of fMRI in each hemisphere was concordant with the result of Wada in 19(95%) by word generation task and in 15(75%) by reading task. At word generation task, the concordance rate was higher with LI calculated on whole hemisphere than that on frontal(80%) or temporoparietal lobe(90%). Correlation between the LIs of Wada and fMRI was significant(r=0.74) CONCLUSION: In fMRI word generation task produced stronger activation of language areas and showed more accurate lateralization reading task. The concordance rate of and Wada test was higher with LI calculated on whole hemisphere than on frontal or temporoparietal lobe.

Two cases of selective posterior cerebral artery sodium amytal test in temporal lobe epilepsy

Wada test has been used as the presurgical evaluation method of memory function in epileptic patient. We report experiences with selective posterior cerebral artery sodium amytal test in two intractable temporal lobe epilepsy patients who showed poor performance in conventional Wada test for the presurgical evaluation. Our procedure consisted of injection of sodium amytal via a microcatheter into the P1 distal segment of the posterior cerebral artery and verbal and visual memory test before and after the injection. We also performed Tc-99m ECD SPECT during the procedure. In one patient showed good memory function during the procedure so operation was performed. But the other patient showed poor memory function so we discharged him without operation.

Predictive Values of Four Wada Memory Asymmetry Indices in Postsurgical Memory Outcome

BACKGROUND: The interpretation of Wada memory test is various in different epilepsy centers. Four types of Wada memory score (WMS) were defined by four different criteria to determine the best WMS in predicting postsurgical memory outcome. METHODS: Twenty temporal lobe epilepsy patients underwent Wada test before surgery and pre- and post-operative neuropsychological tests. WMS was obtained by four ways; including 1) total stimulating items, 2) items presented between one and two minutes after amobarbital injection, 3) items presented before ipsilateral EEG slowing decreased to 50%, 4) items presented until EEG slowing disappeared. Wada memory asymmetry index (WAI) was determined by [(WMS of normal side ? WMS of epileptic side)/their mean]. Logical and visual memory tests were performed before and after operation. Neuropsychological asymmetry index (NPAI) was defined as [(postsurgical score ? Presurgical score)/their mean]. Spearman correlation coefficients were obtained between WAIs and NPAIs. RESULTS: WAIs obtained by method 2) and 3) showed relatively good correlation with NPAIs. Visual memory outcome was correlated with WMS better than logical memory both in non-dominant and dominant hemisphere epilepsy groups. The lateralizing value of memory dominance in non-dominant hemisphere epilepsy group was greater than that of dominant group. CONCLUSIONS: Early presented stimuli during Wada test had a better predictive value of postoperative memory outcome.

MRI-Based Lateralization of Anterior Speech Area

Speech lateralization by Wada is a necessary step in the presurgical evaluation of patients with intractable epilepsy. It, however, is invasive. We studied the usefulness of a noninvasive technique: MRI-based volumetric and anatomical analysis of the anterior speech area as compared to Wada test. Thirty nine patients with intractable epilepsy under presurgical evaluation includding Wada test for hemispheric lateralization for language, were studied: patients with left language dominance(n=20) and right language dominance (n=19). Sagittal and coronal T1-weighted turbo FLASH scans were acquired. Every image in each patient was reconstructed and inferior frontal gyrus was identified on the 3D-surface rendered brain. Then cortical gray matter of inferior frontal gyrus in each image was segmented and reconstructed using a 3D software(Allegro, ISG, Toronto, Canada). Sulcal and gyral patterns of the inferior frontal gyrus were evaluated and classified comparing with the normotive data of Steinmetz. Total volume of inferior frontal gyrus(ifg), regional volumes of pars triangularis(tr) and pars opercularis(op) were obtained. Asymmetry Quotient(AQ) of inferior frontal gyrus, (right-left)/0.5(right+left), between left and right were calculated in each patient. AQ from both groups of patients were compared and data was analysed. Complicated gyral pattern and presentation of a diagonal sulcus in the pars opercularis were prominent in the left side in patients with the left hemispheric dominance for language(p<0.006, p<0.02), and in the right side in patients with the right hemispheric dominance(p<0.002, p<0.03). In patients with language dominance in the left hemisphere, AQ of each portion of anterior speech area showed significant leftward asymmetry(M: Mean, SEM: Standard Error of Mean, Mifg=-.24; SEMifg=0.04, Mtr=-.19; SEMtr=0.09, Mop=-.26; SEMop=0.06). In patients with language dominance in the right hemisphere, AQ showed mild rightward asymmetry or no asymmetry(Masa=0.21; SEMifg=0.06, Mtr=0.15; SEMtr=0.08, Mop=0.24; SEMop=0.09). Fisher's Exact test demonstrated significant value of AQ in each portion of inferior frontal gyrus correlated with hemispheric dominance for language with confidence index(CI)in 95%. Interestingly, AQ of pars triangularis plus pars opercularis showed the highest value(p=0.00001) in predicting the language dominant hemisphere. MRI-based sulcal, gyral patterns and volumetric asymmetry of inferior frontal gyrus correlate with speech lateralization on Wada test. This is a promising noninvasive technique in hemispheric lateralization for language.