Biomedical subjects

A M Murro

Publications and source records attributed to A M Murro.

At least 19 recordsLinked to original sources

PubMed2000

Prognostic implication of contralateral secondary electrographic seizures in temporal lobe epilepsy.

PURPOSE: Interhemispheric propagation of seizures in temporal lobe epilepsy is frequently noted during intracranial EEG monitoring. We hypothesized that a distinct secondary electrographic seizure (DSES) in the temporal lobe contralateral to primary seizure onset may be an unfavorable prognostic indicator. METHODS: We reviewed intracranial depth electrode EEG recordings, 1-year outcome, and medical records of 51 patients (M 29, F 22: age 15-64 years) who underwent anterior temporal lobectomy during 1988-96. We defined DSES as a seizure that spread to the contralateral temporal lobe and produced distinct contralateral EEG features. The distinct feature was focal involvement of one or two electrode contacts at onset, which starts and evolves independently from the ipsilateral temporal lobe. We considered DSES as the predominant seizure pattern when it occurred in more than one half of the patients' recorded seizures. RESULTS: Only nine of 19 (47%) patients with predominant DSES had a 1-year seizure-free outcome, whereas 27 of 32 (84%) patients without predominant DSES had a 1-year seizure-free outcome (p < 0.01). Bitemporal independent seizures were more common in patients with predominant DSES (9/19 versus 0/32; p < 0.001). CONCLUSION: Our results suggest that distinct contralateral secondary electrographic seizure is a predictor of unfavorable outcome and is also more likely to be associated with bitemporal seizures.

Adolescent↗

PubMed1999

Differential cognitive effects of carbamazepine and gabapentin.

PURPOSE: The cognitive effects of the newer antiepileptic drugs (AEDs) compared with the older standard AEDs are uncertain. METHODS: We directly compared the cognitive effects of carbamazepine (CBZ) and gabapentin (GBP) in 35 healthy subjects by using a double-blind, randomized crossover design with two 5-week treatment periods. During each treatment condition, subjects received either GBP, 2,400 mg/day, or CBZ (mean, 731 mg/day) adjusted to a dose to achieve midrange standard therapeutic blood levels (mean, 8.3 microg/ml). Subjects were tested at the end of each AED treatment period and in four drug-free conditions [two pretreatment baselines and two post-treatment washout periods (1 month after each AED)]. The neuropsychological test battery included 17 measures yielding 31 total variables. RESULTS: Direct comparison of the two AEDs revealed significantly better performance on eight variables for GBP, but none for CBZ. Comparison of CBZ and GBP to the nondrug average revealed significant statistical differences for 15 (48%) of 31 the variables. Pairwise follow-up analyses of the 15 variables revealed significantly better performance for nondrug average on 13 variables compared with CBZ, and on four compared with GBP. GBP was better than nondrug average on one variable. CONCLUSIONS: Although both CBZ and GBP produced some effects, GBP produced significantly fewer untoward cognitive effects compared with CBZ at the dosages used in this study.

Acetates↗

PubMed1999

A 13-year experience with epilepsy surgery.

Between 1985 and 1997, 563 therapeutic craniotomies were performed: 311 anterior temporal (ATL) and 158 extramesial temporal (XMT) resections, 67 callosotomies, 20 hemispherectomies and 7 multiple subpial transections. Sixty-seven percent of nonlesional ATL cases were seizure free (SF), and 76% of nonlesional ATL cases < or =18 years old were SF. Seventy-eight percent of lesional ATL cases with complete resection were SF. Seventy-three percent of lesional cases < or =18 were SF. Thirty-seven percent of nonlesional XMT cases were SF. Seventy percent of XMT lesional cases with complete resection were SF, and 82% of lesional XMT cases < or =18 were SF. Of the anterior callosotomy cases, there was a > or =90% decrease in generalized tonic-clonic seizures in 50% of patients, and in tonic seizures, drop attacks, absence and myoclonic seizures in approximately 60-70% of patients. Of 20 hemispherectomies, 65% were SF. Of 7 multiple subpial transections, 29% were SF.

Adult↗

PubMed1997

Wada memory and timing of stimulus presentation.

We compared Wada memory performance for stimuli presented at two timing intervals following amobarbital injection in 47 non-lesional patients with complex partial seizures (L = 26; R = 21). A significant interaction between seizure focus and timing of presentation was present (P < 0.03). Memory performance for objects whose presentation began approximately 50-55 s following amobarbital administration differed as a function of ipsilateral vs. contralateral injection at a very high level of statistical significance (P < 0.00001). Items presented approximately 4 min, 30 s post injection were also related to seizure onset literality, but at a lower statistical level (P < 0.01). Presentation of Wada memory stimuli earlier during hemispheric anaesthesia yields results that are more sensitive to lateralized temporal lobe seizure onset than does presentation of items later during the procedure.

Adult↗

PubMed1997

Results of lesional vs. nonlesional frontal lobe epilepsy surgery.

Fifty-three seizure focus resections limited to the frontal lobe were performed. Forty-nine had adequate follow-up. Five of 17 (29%) nonlesional (NL) cases and 21 of 32 (66%) lesional (L) cases were seizure free (SF) at 1 year postoperatively. Eight of 9 (89%) L cases < or = 18 years old vs. 13 of 23 (57%) > 18 years old were SF. Eight of 10 (80%) tumor vs. 13 of 22 (59%) nontumor L cases were SF. Sixteen NL cases were localized by invasive recording. Five (31%) were SF. Ictal localization was obtained in 4 of 32 L cases. Three of 4 (75%) were SF. Eighteen of 24 (64%) L cases without ictal localization were SF. Nine of 12 (75%) lateral resections, 7 of 12 (58%) lobectomies, and 2 of 13 (15%) mesial resections were SF. Three of 20 cases with at least 90% reduction in seizures became SD > or = 2 years postresection. No case with < 90% seizure reduction at one year showed improvement with longer follow-up.

Adolescent↗

PubMed1996

The significance of ictal depth EEG patterns in patients with temporal lobe epilepsy.

We reviewed 187 depth recorded seizures in 33 patients with non-lesional temporal lobe complex partial seizures. All patients had a minimum of 1 year follow-up following temporal lobectomy. We classified seizure onset pattern as rhythmic activity, attenuation, or repetitive spikes or spike wave complexes. The most common pattern of seizure onset was rhythmic activity and the next most common pattern was repetitive spikes. Seventy-five seizures (49%) had only one seizure onset pattern, and 79 seizures (51%) had a combination of seizure onset patterns. The degree of hippocampal gliosis strongly predicted the type of seizure onset pattern (Chi square = 24.07, 2 d.f., P < 0.01). The rhythmic activity pattern was associated with mild gliosis, and the repetitive spike pattern was associated with severe gliosis. We classified seizure onset as focal or regional based on the number of electrode contacts that were involved by the ictal EEG. A focal seizure onset was associated with an excellent outcome following temporal lobectomy.

Brain↗

PubMed1995

Precision of dipole localization in a spherical volume conductor: a comparison of referential EEG, magnetoencephalography and scalp current density methods.

In this study, we determined the influence of dipole orientation, dipole location, and number of recording sites on the precision of dipole localization in a spherical volume conductor. We compared localization from referential EEG (R-EEG), scalp current density EEG (SCD-EEG) and magnetoencephalography (MEG). Dipole orientation had a small influence on the precision of dipole localization for R-EEG and SCD-EEG. Dipole location relative to the recording sites, dipole depth, and number of recording channels strongly influenced the precision of dipole localization. Assuming equal signal to noise conditions for each recording method, MEG and SCD-EEG had a similar precision for dipole localization of a single tangential dipole source and both methods were more precise than R-EEG. However, SCD-EEG was inferior to MEG for distinguishing a single tangential current source from a pair of deeper radial current sources. In summary, these results suggest that the MEG will be most useful for localization of multiple simultaneous dipole sources.

Brain↗

PubMed1995

Multichannel magnetoencephalography in ablative seizure surgery outside the anteromesial temporal lobe.

Magnetoencephalography (MEG) was used to evaluate 40 candidates for seizure surgery thought to have foci outside the anteromesial temporal lobe. Of 29 cases with electrographic data suggesting a convexity focus, MEG spikes were recorded from 28. In 21, MEG and electrographic data were localized to the same area. Invasive studies were, or could have been, avoided in 13 cases based on MEG and other noninvasive data. MEG was not localizing value in 4 orbitofrontal or 7-depth-nonlocalized cases. Seventeen patients with MEG epileptiform data have had postoperative follow-up. Eight of 13 with electrographic and MEG data localized to the same area are seizure free. None of 4 with spatial discordance of MEG electrographic data are seizure free.

Electroencephalography↗

PubMed1995

Wada memory asymmetries predict verbal memory decline after anterior temporal lobectomy.

We examined Wada memory and neuropsychological memory function in 34 nonlesional patients who underwent anterior temporal lobectomy (ATL) and who were seizure free at 1-year follow-up. Patients who displayed a decline on verbal memory measures that exceeded 1 SD after left ATL had significantly smaller left/right Wada memory asymmetries than left ATL patients without a significant verbal memory decline. When Wada memory asymmetries were used to predict verbal memory decline after left ATL in individual patients, similar statistically significant effects were present. No significant relationship between Wada memory and postoperative memory was present in right ATL patients, and postoperative memory function was not related to Wada memory performance after either left hemisphere or right hemisphere injection alone. We conclude that Wada memory asymmetries provide one measure of the risk to material-specific decline in verbal memory after left ATL.

Analysis of Variance↗

PubMed1994

Stimulus timing effects on Wada memory testing.

OBJECTIVE: To determine the effects of presenting Wada memory stimuli at different times after intracarotid amobarbital injection on Wada memory asymmetries. DESIGN: Wada memory asymmetries from three timing series were related to the laterality of eventual temporal lobectomy. SETTING: Academic institution epilepsy surgery program. PATIENTS: Forty-three patients with complex partial seizures who later underwent anterior temporal lobectomy (left temporal lobectomy, 24 patients; right temporal lobectomy, 19 patients). No patient included had abnormalities on magnetic resonance imaging scans to suggest a lesion other than gliosis. RESULTS: Memory performance for objects whose presentation began approximately 45 seconds after amobarbital administration differentiated laterality of seizure onset. Memory for items presented later and after partial return of language (on average 3 minutes 40 seconds postinjection) also differed as a function of ipsilateral vs contralateral injection, but at a lower level of statistical significance. Memory for items presented last during the procedure (on average 6 minutes postinjection) discriminated seizure groups at a still lower level of statistical significance. When used to predict lateralized temporal lobe impairment in individual patients, early object memory performance was significantly better than memory performance employing either middle (56%) or late (43%) stimulus presentation timings. CONCLUSION: The results of early object memory testing are superior to those obtained from stimulus presentation later in the procedure in documenting temporal lobe dysfunction associated with a lateralized seizure onset.

Adult↗

PubMed1994

A method for imaging of intracranial EEG electrodes using magnetic resonance imaging.

In this study, we describe a method for imaging intracerebral electrodes within a three-dimensional reconstructed image of the brain. A three-dimensional image of the brain was reconstructed from serial magnetic resonance images. The locations of intracerebral electrodes were determined from anterior-posterior and lateral skull X-rays performed after intracerebral electrode implantation. The three-dimensional reconstruction of the brain including electrode locations was displayed using IRIS Explorer Software (Silicon Graphics, Mountainview, CA). This method might improve the interpretation of electrical patterns of seizure activity recorded from intracerebral electrodes.

Brain↗

PubMed1994

Do dichotic word listening asymmetries predict side of temporal lobe seizure onset?

Dichotic word listening asymmetries are thought to be useful in predicting side of temporal lobe dysfunction. However, little direct evidence exists to support this assumption in practice, especially in patients with subtle epileptogenic lesions. To determine if word listening ear asymmetries are valid predictors of side of temporal lobe seizure onset, we examined the preoperative dichotic word listening performance of 80 patients with either left (N = 41) or right (N = 39) temporal lobe (TL) seizure foci. On a group level, patients showed a statistically significant 'lesion effect' as evidenced by a relative deficit in the ear contralateral to the side of lesion. Prediction of side of seizure focus in individual cases, however, was poor: depending upon the criteria used, 61% to 80% of epileptics with unilateral temporal lobe foci did not show the expected contralateral ear deficit. Results suggest that caution be exercised when inferring side of temporal lobe seizure focus through dichotic word listening asymmetries in individual temporal lobe epilepsy cases.

Adult↗

PubMed1994

Use of scalp-sphenoidal EEG for seizure localization in temporal lobe epilepsy.

We determined the accuracy and sensitivity of scalp-sphenoidal EEG for seizure focus localization in 50 patients who became seizure-free or had rare seizures following temporal lobectomy. EEG localization was based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters. All patients became seizure-free or had rare seizures following temporal lobectomy. Localization from EEG disagreed with the side of surgery in only 1 (2%) of 50 patients. We identified 3 distinct patient groups with a low, moderate, and high likelihood of having a focal ictal EEG pattern during a seizure. These groups comprised 31% (low likelihood), 44% (moderate likelihood), and 25% (high likelihood) of patients. A model based on these results suggests that with multiple ictal EEG recordings, accurate localization from scalp-sphenoidal EEG is possible in approximately up to 65-70% of patients with temporal lobe epilepsy.

Brain↗

PubMed1994

Role of multichannel magnetoencephalography in the evaluation of ablative seizure surgery candidates.

Magnetic source imaging (MSI) was performed on 30 ablative epilepsy surgery candidates. The technique involved high resolution multiplanar MRI images with lipid fiducials attached to the patient's head to define a head-based 3D coordinate space. Magnetoencephalography (MEG) was performed after digitizing the same fiducial points. A 37-channel magnetometer obtained data at two to five sites over each hemisphere. MEG epileptiform data were obtained with and without EEG triggering. A single equivalent current dipole model was used to determine orientation and location of a dipole generator whose surface isocontour map most closely fits the measured dipolar data for each event. The MEG data were then transformed to MRI images for source localization. In five of seven cases with ictal anterior temporal lobe foci, MSI data were localized to the same temporal lobe but did not provide additional spatial data. In 10 of 11 cases with convexity foci, MSI provided additional spatial localizing data. MSI did not verify depth electrode localization in one anterior temporal-orbital frontal and three orbitofrontal cases. In seven of eight cases in which depth EEG recordings were nonlocalizing, MSI provided insufficient localizing data. MSI appears to provide additional spatial localizing data in most cases with a convexity epileptic focus.

Analog-Digital Conversion↗

PubMed1994

Wada memory performance predicts seizure outcome following anterior temporal lobectomy.

We examined the ability of Wada memory testing to predict seizure outcome 1 year following anterior temporal lobectomy. Asymmetry scores for Wada memory performance, using amobarbital doses of 125 mg or less, were calculated for 55 patients under the age of 45 years who had no radiologic evidence of structural lesions other than gliosis. Wada memory asymmetries were significantly greater (p < 0.02) in patients who were seizure free compared with those who continued to experience seizures. Furthermore, patients with Wada memory score asymmetries of at least three objects (maximum = 8) were more likely to be seizure free compared with patients with Wada memory asymmetries less than three (p < 0.01). Of the 36 patients who had Wada memory score asymmetries of at least three objects, 32 (89%) were seizure free. In contrast, of the 19 patients whose Wada memory score asymmetries were less than three, only 12 (63%) were seizure free. These data suggest that Wada memory performance is related to seizure outcome following anterior temporal lobectomy.

Adult↗

PubMed1993

Localization of temporal lobe seizures with quantitative EEG.

In this study, we describe a quantitative EEG method for localization of seizure onset in 29 patients with temporal lobe epilepsy. We used right-left differences in relative power and a logistic regression to predict the side of seizure onset. The optimum bipolar channels were T4-T6/T3-T5 and the optimum frequency band was 4-10.5 Hz. Using a threshold probability of 0.75 for classification, the best quantitative EEG method classified 23 patients (79%) correctly, 2 patients (7%) incorrectly, and 4 patients (14%) as undetermined localization. In comparison, 3 electroencephalographers visually interpreted these same EEGs and classified 20-25 patients (69-86%) correctly, 1 patient (3%) incorrectly and 3-8 patients (10-28%) as undetermined localization. In the 8 patients classified as undetermined localization by at least one interpreter, the quantitative EEG method classified 5 patients correctly, 1 patient incorrectly and 2 patients as undetermined localization. These results suggest that quantitative EEG might improve the reliability of ictal EEG localization and potentially reduce the need for invasive intracranial EEG monitoring.

Adolescent↗

PubMed1993

Seizure localization in temporal lobe epilepsy: a comparison of scalp-sphenoidal EEG and volumetric MRI.

We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for seizure focus localization in 20 patients with temporal lobe epilepsy. All patients became seizure-free or had rare seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG localization criteria, six (30%) met MRI localization criteria alone, three (15%) met EEG localization criteria alone, and two patients (10%) did not meet either localization criteria. In the 18 patients meeting MRI or EEG localization criteria, the predicted localization agreed with the side of temporal lobectomy. These results suggest that a noninvasive approach combining MRI and EEG will correctly localize the side of seizure onset in most patients with temporal lobe epilepsy.

Adolescent↗

PubMed1993

Wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy.

We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate seizure localization in 20 patients with complex partial seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery.

Adult↗