Publications (50)177.32 Total impact
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Article: Prognostic importance of risk factors for temporal lobe epilepsy in patients undergoing surgical treatment.
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ABSTRACT: To investigate the prognostic importance of an identified putative underlying risk factor in patients undergoing surgery for intractable temporal lobe epilepsy (TLE). A retrospective study of 400 consecutive patients who underwent TLE surgery between December 21, 1987, and September 11, 1996, was performed. Demographic characteristics, history of remote symptomatic neurologic disease, preoperative evaluation, and postoperative outcome data were extracted. Individuals without any risk factors were considered controls. Magnetic resonance imaging findings were used to identify mesial temporal sclerosis (MTS) before surgery. Seizure outcome was classified by a modified Engel classification. Two hundred eighty-one patients had a potential underlying etiology, and 143 patients had more than 1 risk factor. One hundred nineteen patients had no evidence of a putative symptomatic neurologic illness. There was a statistically significant association (P<.05) between the presence of MTS and a favorable operative outcome (odds ratio, 4.28; 95% CI, 2.67-6.87). A history of remote symptomatic neurologic disease was not of prognostic importance unless associated with the development of MTS. These results indicate that the preoperative identification of MTS by neuroimaging is the most important predictor of a favorable operative outcome in patients with TLE. These findings may be useful in the identification and counseling of potential candidates for epilepsy surgery.Mayo Clinic Proceedings 04/2013; 88(4):332-6. · 5.70 Impact Factor -
Article: Concealed Long QT Syndrome and Intractable Partial Epilepsy: A Case Report.
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ABSTRACT: Herein, we describe a patient with concealed type 2 long QT syndrome with concomitant electroencephalogram-documented epilepsy. Although syncope in patients with long QT syndrome is common and often secondary to cerebral hypoxia after a protracted ventricular arrhythmia, this article demonstrates the importance of avoiding "tunnel vision" as patients with long QT syndrome could also have a primary seizure disorder. Identification of the etiology underlying seizurelike activity is paramount in instituting effective therapy. Furthermore, we theorize that abnormal KCHN2-encoded potassium channel repolarization in the brain could result in epilepsy and arrhythmias in long QT syndrome.Mayo Clinic Proceedings 10/2012; · 5.70 Impact Factor -
Article: Use of Anterior Temporal Lobectomy for Epilepsy in a Community-Based Population.
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ABSTRACT: OBJECTIVE To assess the hypothesis that use of anterior temporal lobectomy (ATL) for temporal epilepsy has diminished over time. DESIGN Population-based cohort study. SETTING The Rochester Epidemiology Project based in Olmsted County, Minnesota. PARTICIPANTS Residents of Olmsted County. MAIN OUTCOME MEASURES Poisson regression was used to evaluate changes in ATL use over time by sex. RESULTS Over a 17-year period, from 1993 to 2009, 847 ATLs were performed with the primary indication of epilepsy (average, 50 procedures/y). Of these, 26 occurred among Olmsted County residents. The use rates declined significantly between 1993 and 2000 (8 years) and 2001 and 2009 (9 years) according to Poisson regression analysis, from 1.9 to 0.7 per 100 000 person-years (P = .01). The rate of ATL use among Olmsted County residents was 1.2 (95% CI, 0.9 to 2.4) per 100 000 person-years of follow-up over this 17-year period. The sex-specific rates were 1.6 (95% CI, 0.9 to 2.4) and 0.7 (95% CI, 0.2 to 1.3) per 100 000 person-years for females and males, respectively. CONCLUSIONS In this community-based cohort, the rate of ATL use was 1.2 per 100 000 person-years of follow-up. Use of this procedure has declined over time; the reasons for this are unknown but do not include referral pattern changes.Archives of neurology 08/2012; · 6.31 Impact Factor -
Article: Autoimmune Epilepsy: Clinical Characteristics and Response to Immunotherapy.
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ABSTRACT: OBJECTIVE: To describe clinical characteristics and immunotherapy responses in patients with autoimmune epilepsy. DESIGN: Observational, retrospective case series. SETTING: Mayo Clinic Health System. Patients Thirty-two patients with an exclusive (n = 11) or predominant (n = 21) seizure presentation in whom an autoimmune etiology was suspected (on the basis of neural autoantibody [91%], inflammatory cerebrospinal fluid [31%], or magnetic resonance imaging suggesting inflammation [63%]) were studied. All had partial seizures: 81% had failed treatment with 2 or more antiepileptic drugs and had daily seizures and 38% had seizure semiologies that were multifocal or changed with time. Head magnetic resonance imaging was normal in 15 (47%) at onset. Electroencephalogram abnormalities included interictal epileptiform discharges in 20; electrographic seizures in 15; and focal slowing in 13. Neural autoantibodies included voltage-gated potassium channel complex in 56% (leucine-rich, glioma-inactivated 1 specific, 14; contactin-associated proteinlike 2 specific, 1); glutamic acid decarboxylase 65 in 22%; collapsin response-mediator protein 5 in 6%; and Ma2, N-methyl-d-aspartate receptor, and ganglionic acetylcholine receptor in 1 patient each. Intervention Immunotherapy with intravenous methylprednisolone; intravenous immune globulin; and combinations of intravenous methylprednisolone, intravenous immune globulin, plasmapheresis, or cyclophosphamide. Main Outcome Measure Seizure frequency. RESULTS: After a median interval of 17 months (range, 3-72 months), 22 of 27 (81%) reported improvement postimmunotherapy; 18 were seizure free. The median time from seizure onset to initiating immunotherapy was 4 months for responders and 22 months for nonresponders (P < .05). All voltage-gated potassium channel complex antibody-positive patients reported initial or lasting benefit (P < .05). One voltage-gated potassium channel complex antibody-positive patient was seizure free after thyroid cancer resection; another responded to antiepileptic drug change alone. CONCLUSION: When clinical and serological clues suggest an autoimmune basis for medically intractable epilepsy, early-initiated immunotherapy may improve seizure outcome.Archives of neurology 03/2012; · 6.31 Impact Factor -
Article: Should patients be routinely assessed for cerebral vasospasm after temporal lobe epilepsy surgery?
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ABSTRACT: Temporal lobe epilepsy (TLE) is the most common form of epilepsy that is resistant to antiepileptic drug treatment. Resective epilepsy surgery offers a substantially greater prospect of achieving seizure control than continued medical therapy, and is associated with better quality of life outcomes.(1) The nature of the resection performed in patients undergoing epilepsy surgery for drug-resistant TLE varies among centers and surgeons. The most common type of resection is an "anterior temporal lobectomy" based on the procedure developed by Falconer and colleagues in the 1960s.(2) This involves the excision of the mesial temporal structures, the anterior temporal pole, and 3-6.5 cm of the lateral temporal neocortex (usually sparing the superior temporal gyrus). More recently, some surgeons have adopted the "selective amygdalohippocampectomy" approach, first described by Wieser and Yasargil.(3) This procedure attempts to restrict the resection to the mesial temporal structures, via a pterional craniotomy and transsylvian approach, while minimizing the possibility of reduced function due to resection of anterior and lateral temporal structures,(3) especially neurocognitive deficits, as compared to the standard anterior temporal lobectomy procedure.(4) However, performing a selective amygdalohippocampectomy is technically challenging, and patients undergoing this procedure have a high incidence of cerebral vasospasm (CVS), possibly as a result of mechanical irritation of blood vessels and increased intracranial bleeding. CVS may occur in up to 50% of patients following a selective amygdalohippocampectomy, and can be associated with increased neurologic morbidity.(5) However, CVS may also occur following anterior temporal lobectomy(6); the incidence or clinical consequences have not been directly compared between the 2 types of epilepsy surgery procedures.Neurology 03/2012; 78(16):1196-7. · 8.31 Impact Factor -
Article: Scalp and intracranial EEG in medically intractable extratemporal epilepsy with normal MRI.
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ABSTRACT: Purpose. To investigate EEG and SPECT in the surgical outcome of patients with normal MRI (nonlesional) and extratemporal lobe epilepsy. Methods. We retrospectively identified 41 consecutive patients with nonlesional extratemporal epilepsy who underwent epilepsy surgery between 1997 and 2007. The history, noninvasive diagnostic studies (scalp EEG, MRI, and SPECT) and intracranial EEG (iEEG) monitoring was reviewed. Scalp and iEEG ictal onset patterns were defined. The association of preoperative studies and postoperative seizure freedom was analyzed using Kaplan-Meier analysis, log-rank test, and Cox proportional hazard. Results. Thirty-six of 41 patients had adequate information with a minimum of 1-year followup. Favorable surgical outcome was identified in 49% of patients at 1 year, and 35% at 4-year. On scalp EEG, an ictal onset pattern consisting of focal beta-frequency discharge (>13-125 Hz) was associated with favorable surgical outcome (P = 0.02). Similarly, a focal fast-frequency oscillation (>13-125 Hz) on iEEG at ictal onset was associated with favorable outcome (P = 0.03). Discussion. A focal fast-frequency discharge at ictal onset identifies nonlesional MRI, extratemporal epilepsy patients likely to have a favorable outcome after resective epilepsy surgery.ISRN neurology. 01/2012; 2012:942849. -
Article: Effect of general anesthesia in patients with cerebral palsy at the turn of the new millennium: a population-based study evaluating perioperative outcome and brief overview of anesthetic implications of this coexisting disease.
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ABSTRACT: The severity of preoperative cerebral palsy appears to correlate directly with postoperative complications. The primary aim of this study was to characterize the frequency of perioperative morbidity and mortality in cerebral palsy patients undergoing anesthesia. This was accomplished by undertaking a systematic review of the Mayo Database. The risk for perioperative adverse events was 63.1% (95% confidence interval 59.8%-66.5%). However, it deserves clarification that hypothermia and clinically significant yet non-life-threatening hypotension represented the majority (80%) of these complications. When these 2 events are excluded, the rate of adverse perioperative events was 13.1% (95% confidence interval 10.8%-15.5%). Risk factors associated with increased risk included American Society of Anesthesiologists physical status score exceeding 2, history of seizures, upper airway hypotonia, general surgery procedures, and adults. Our findings are useful to counsel patients with cerebral palsy, their caregivers, and their guardians regarding the risk of general anesthesia.Journal of child neurology 12/2011; 27(7):859-66. · 1.59 Impact Factor -
Article: Effect of general anesthesia in patients with epilepsy: a population-based study.
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ABSTRACT: General anesthesia may be required for particular diagnostic and therapeutic procedures in patients with seizure disorders. There is concern regarding the safety of anesthetic drugs in these individuals because of the reported proconvulsant effect of selected medications. Potentially, general anesthesia may be associated with perioperative seizures or increased adverse effects in people with epilepsy. The rationale for the present study was to evaluate the outcome of general anesthesia in a population-based cohort with seizure disorders undergoing interventions that were unlikely to alter the seizure tendency, for example, magnetic resonance imaging study. Seizures were observed in only 6 of 297 (2%) anesthetic procedures, and intravenous therapy was required in only one patient. None of the patients had any reported adverse effect from general anesthesia. The current findings may be useful in counseling and guiding patients with seizure disorders, their caregivers, and their guardians regarding the risk of general anesthesia.Epilepsy & Behavior 11/2009; 17(1):87-9. · 2.34 Impact Factor -
Article: Electrocorticography-guided resection of temporal cavernoma: is electrocorticography warranted and does it alter the surgical approach?
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ABSTRACT: Cavernous hemangiomas associated with epilepsy present an interesting surgical dilemma in terms of whether one should perform a pure lesionectomy or tailored resection, especially in the temporal lobe given the potential for cognitive damage. This decision is often guided by electrocorticography (ECoG), despite the lack of data regarding its value in cavernoma surgery. The purpose of the present study was several-fold: first, to determine the epilepsy outcome following resection of cavernomas in all brain regions; second, to evaluate the usefulness of ECoG in guiding surgical decision making; and third, to determine the optimum surgical approach for temporal lobe cavernomas. The authors identified from their surgical database 173 patients who had undergone resection of cavernomas. One hundred two of these patients presented with epilepsy, and 61 harbored temporal lobe cavernomas. Preoperatively, all patients were initially evaluated by an epileptologist. The mean follow-up was 37 months. Regardless of the cavernoma location, surgery resulted in an excellent seizure control rate: Engel Class I outcome in 88% of patients at 2 years postoperatively. Of 61 patients with temporal lobe cavernomas, the mesial structures were involved in 35. Among the patients with temporal lobe cavernomas, those who underwent ECoG typically had a more extensive parenchymal resection rather than a lesionectomy (p < 0.0001). The use of ECoG in cases of temporal lobe cavernomas resulted in a superior seizure-free outcome: 79% (29 patients) versus 91% (23 patients) of patients at 6 months postresection, 77% (22 patients) versus 90% (20 patients) at 1 year, and 79% (14 patients) versus 83% (18 patients) at 2 years without ECoG versus with ECoG, respectively. The surgical removal of cavernomas most often leads to an excellent epilepsy outcome. In cases of temporal lobe cavernomas, the more extensive the ECoG-guided resection, the better the seizure outcome. In addition to upholding the concept of kindling, the data in this study support the use of ECoG in temporal lobe cavernoma surgery in patients presenting with epilepsy.Journal of Neurosurgery 02/2009; 110(6):1179-85. · 2.96 Impact Factor -
Article: When drugs and surgery don't work.
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ABSTRACT: Epilepsy is a chronic disorder characterized by recurrent and unprovoked seizures (Dreifuss, 1987; Hauser & Hesdorffer, 1990). It is one of the most common neurologic disorders in the adult. The lifetime risk of developing epilepsy is 3.2% (Mattson, 1992). Approximately 90% of the incident cases in adults have symptomatic partial or localization-related epilepsy (Camfield & Camfield, 1996; Hauser & Hesdorffer, 1990; Hauser, 1992). The medial temporal lobe is the most epileptogenic region of the brain (Luby et al., 1995; Jeong et al., 1999; Wiebe et al., 2001). Pathologic lesions underlying the epileptogenic zone include mesial temporal sclerosis (MTS), tumor, vascular anomaly, malformations of cortical development (MCDs), and head trauma (Cascino et al., 1993; Radhakrishnan et al., 1998). The initial response to medication is of prognostic importance (Hauser, 1992). Patients with a remote symptomatic neurologic disease, foreign-tissue lesion, developmental delay, or abnormal neurologic examination are less likely to be rendered seizure-free. The goals of treatment are to render the individual seizure-free without producing antiepileptic drug (AED) toxicity, allowing the individual to become a participating and productive member of society (Engel & Ojemann, 1993). Despite the introduction of "newer" AEDs, nearly one-half of patients with partial epilepsy will not attain a seizure remission with pharmacotherapy (Kwan & Brodie, 2003). This discussion focuses on management of the adult patient with intractable partial seizure disorders that are medically refractory and may not be surgically remediable. It is estimated that 400,000 of the 2 million individuals with partial epilepsy in the United States have a medically refractory partial seizure disorder (Hauser & Hesdorffer, 1990; Hauser, 1992). An estimated 1,500 patients in the United States undergo epilepsy surgery each year. A UK study indicated that 30,000 patients develop epilepsy each year and approximately 6,000 have medically refractory seizures (Lhatoo et al., 2003). However, there are only about 400 epilepsy surgeries performed annually in the UK. Therefore, the number of patients with intractable partial epilepsy that is both medically refractory and possibly not a surgically remediable epileptic syndrome is significant.Epilepsia 12/2008; 49 Suppl 9:79-84. · 3.96 Impact Factor -
Article: Intracranial electroencephalography seizure onset patterns and surgical outcomes in nonlesional extratemporal epilepsy.
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ABSTRACT: Patients with normal MR imaging (nonlesional) findings and medically refractory extratemporal epilepsy make up a disproportionate number of nonexcellent outcomes after epilepsy surgery. In this paper, the authors investigated the usefulness of intracranial electroencephalography (iEEG) in the identification of surgical candidates. Between 1992 and 2002, 51 consecutive patients with normal MR imaging findings and extratemporal epilepsy underwent intracranial electrode monitoring. The implantation of intracranial electrodes was determined by seizure semiology, interictal and ictal scalp EEG, SPECT, and in some patients PET studies. The demographics of patients at the time of surgery, lobar localization of electrode implantation, duration of follow-up, and Engel outcome score were abstracted from the Mayo Rochester Epilepsy Surgery Database. A blinded independent review of the iEEG records was conducted for this study. Thirty-one (61%) of the 51 patients who underwent iEEG ultimately underwent resection for their epilepsy. For 28 (90.3%) of the 31 patients who had epilepsy surgery, adequate information regarding follow-up (> 1 year), seizure frequency, and iEEG recordings was available. Twenty-six (92.9%) of 28 patients had frontal lobe resections, and 2 had parietal lobe resections. The most common iEEG pattern at seizure onset in the surgically treated group was a focal high-frequency discharge (in 15 [53.6%] of 28 patients). Ten (35.7%) of the 28 surgically treated patients were seizure free. Fourteen (50%) had Engel Class I outcomes, and overall, 17 (60.7%) had significant improvement (Engel Class I and IIAB with > or =80% seizure reduction). Focal high-frequency oscillation at seizure onset was associated with Engel Class I surgical outcome (12 [85.7%] of 14 patients, p = 0.02), and it was uncommon in the nonexcellent outcome group (3 [21.4%] of 14 patients). A focal high-frequency oscillation (> 20 Hz) at seizure onset on iEEG may identify patients with nonlesional extratemporal epilepsy who are likely to have an Engel Class I outcome after epilepsy surgery. The prospect of excellent outcome in nonlesional extratemporal lobe epilepsy prior to intracranial monitoring is poor (14 [27.5%] of 51 patients). However, iEEG can further stratify patients and help identify those with a greater likelihood of Engel Class I outcome after surgery.Journal of Neurosurgery 12/2008; 110(6):1147-52. · 2.96 Impact Factor -
Article: History and seizure semiology in distinguishing frontal lobe seizures and temporal lobe seizures.
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ABSTRACT: This study aimed to determine the reliability of clinical history and seizure semiology for distinguishing between frontal lobe seizures (FLS) and temporal lobe seizures (TLS). FLS patients (n=23) were consecutively identified through an epilepsy surgery database. TLS patients (n=27) were selected randomly from 238 patients who had undergone temporal lobe surgery for epilepsy. The criterion standard for seizure localization was the location of resective epilepsy surgery that controlled seizures for a minimum of 2 years. Blinded comparisons of 13 historical information items (HII) and 19 video-recorded semiologic features (VSF) were made. We identified 3 HII (sex, history of febrile convulsions, and history of generalized tonic-clonic seizures) and 2 VSF (fencing posturing and postictal confusion) that significantly distinguished between FLS and TLS. The multivariate analysis model correctly identified 87% of FLS patients and 74% of TLS patients. No single HII or VSF is sufficient for distinguishing between FLS and TLS. A model integrating multiple HII and VSF may assist in this differentiation, but some patients still may be misclassified.Epilepsy research 10/2008; 82(2-3):177-82. · 2.48 Impact Factor -
Article: Intracranial electroencephalography with subdural grid electrodes: techniques, complications, and outcomes.
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ABSTRACT: Intracranial subdural grid monitoring is a useful diagnostic technique for surgical localization in patients with intractable partial epilepsy. The rationale for the present study was to assess the morbidity of intracranial recordings and the surgical outcomes. We retrospectively reviewed the clinical data for 189 unique patients undergoing 198 intracranial subdural grid monitoring sessions between 1996 and 2004 at a tertiary epilepsy center. The mean age of patients undergoing monitoring was 28 +/- 14 years. An average of 63 +/- 23 electrodes were inserted. The mean duration of monitoring was 8 +/- 4 days. Localization of an epileptogenic zone occurred in 156 sessions (79%) resulting in 136 resections (69%). There were 13 major complications (6.6%), including five infections and six hematomas. Three patients (1.5%) developed permanent deficits related to implantation. Sixty-two (47%) of 136 patients undergoing resection were seizure-free after resection. An additional 38 patients (28%) had a significant reduction in seizures. The mean follow-up was 51 +/- 30 months. The duration of monitoring, bone flap replacement, number of electrodes, and perioperative corticosteroids were not associated with infection or complication. Subdural grid monitoring for identification an epileptogenic focus is high yield, revealing a focus in 79% of monitoring sessions. Complications rarely result in permanent morbidity (1.5%). Surgical outcome indicated that 74% of patients experienced a favorable reduction in seizure tendency.Neurosurgery 10/2008; 63(3):498-505; discussion 505-6. · 2.79 Impact Factor -
Article: Neuroimaging in epilepsy: diagnostic strategies in partial epilepsy.
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ABSTRACT: The diagnostic evaluation of the patient with partial or localization-related epilepsy is designed to identify treatment strategies that will permit the individual to be seizure-free. The use of magnetic resonance imaging (MRI) has been pivotal in elucidating the presence of an epileptogenic pathological alteration that may coexist with the site of seizure onset. There are compelling data that MRI is of significant diagnostic and prognostic importance in patients with partial epilepsy. Patients with MRI-negative partial epilepsy may be candidates for additional neuroimaging techniques including positron emission tomography, MR spectroscopy, and single photon emission tomography. Contemporary innovations with peri-ictal imaging may allow identification of the epileptogenic zone in patients with normal MRI scans. This discussion will focus on the management of the adult patient with seizures and epilepsy, emphasizing the neuroimaging evaluation and treatment of patients with medically refractory seizure disorders.Seminars in Neurology 10/2008; 28(4):523-32. · 1.64 Impact Factor -
Article: Influence of subtraction ictal SPECT on surgical management in focal epilepsy of indeterminate localization: a prospective study.
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ABSTRACT: The impact of functional imaging tests on the decision-making and planning process for epilepsy surgery has never been prospectively assessed. We prospectively evaluated 50 consecutively eligible patients whose noninvasive evaluations showed nonlocalized findings and determined how their SISCOM (subtraction ictal SPECT [single photon emission computed tomography] co-registered to MRI [magnetic resonance imaging]) data altered consensus decisions for epilepsy surgery. At an epilepsy surgery conference where each patient was discussed, consensus decisions were documented after a standardized presentation of data from the noninvasive evaluation (SISCOM findings initially were excluded). Consensus decisions were again documented after presentation of SISCOM data. Consensus decisions changed for 10 of 32 patients (31%) with localizing SISCOM results, whereas the decision changed in only 1 of 18 patients (6%) with nonlocalizing SISCOM results (P<.05). Changes in consensus decisions were as follows: (1) intracranial electrode implantation (IEI) was obviated and resective surgery was recommended (n=2); (2) resective surgery or further evaluation for patients initially not considered surgical candidates (n=2); (3) IEI in patients for whom it was not recommended initially (n=3); (4) increased IEI coverage (n=3); and (5) antiepileptic drug trial or vagal nerve stimulation was recommended instead of IEI (n=1). For some patients whose noninvasive evaluations did not clearly localize a surgical focus, SISCOM data can have a major impact on decisions to recommend resective epilepsy surgery or IEI.Epilepsy research 09/2008; 82(2-3):190-3. · 2.48 Impact Factor -
Article: Breast cancer at site of implanted vagus nerve stimulator.
Neurology 03/2007; 68(9):703. · 8.31 Impact Factor -
Article: Subtraction ictal single-photon emission computed tomography coregistered to magnetic resonance imaging in evaluating the need for repeated epilepsy surgery.
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ABSTRACT: The aim of this study was to determine whether ictal single-photon emission computed tomography (SPECT) is useful in localizing the site of seizure onset in patients in whom surgery for intractable epilepsy failed and who are being considered for repeated surgery. Subtraction ictal SPECT coregistered to magnetic resonance imaging (SISCOM) studies were retrospectively analyzed in 58 patients who were being evaluated for possible repeated resection for intractable partial epilepsy between January 1, 1996, and October 31, 1999. All patients had persistent seizures subsequent to an initial resection and underwent another excision. The SISCOM-demonstrated abnormalities were classified as concordant, discordant, or indeterminate, compared with the localization of the epileptogenic zone revealed on video electroencephalography monitoring. The ability of SISCOM to predict operative outcome was also determined in patients who had undergone repeated surgical procedures. The SISCOM studies revealed a localized hyperperfused alteration in 46 (79%) of 58 patients. Forty-one (89%) of these 46 patients had a SISCOM-demonstrated alteration in the hemisphere of the previous epilepsy surgery. Imaging changes in 33 (72%) of the 46 patients were at the site of the previous focal cortical resection. Eight (17%) of the 46 had SISCOM-demonstrated abnormalities remote from the lobe in which surgery had been performed but in the ipsilateral hemisphere. The hyperperfusion focus was in the contralateral hemisphere in the remaining five patients (11%). The site of the epileptogenic zone was concordant with the SISCOM focus in 32 (70%) of 46 patients. Twenty-six patients underwent repeated resection and were followed up for a mean of 44 months thereafter; 11 of these patients (42%) had a significant reduction in seizure tendency. Only five patients (19%) were seizure free. Ten (50%) of 20 patients with a concordant SISCOM focus compared with none (0%) of three patients with a discordant focus had a favorable surgical outcome (p = 0.23). The SISCOM method might be useful in the evaluation of, and the surgical planning for, patients with intractable partial epilepsy in whom previous resective treatment has failed and who are being considered for reoperation.Journal of Neurosurgery 08/2006; 105(1):71-6. · 2.96 Impact Factor -
Article: Elevations of troponin in patients with epileptic seizures? What do they mean?
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ABSTRACT: Cardiac troponin concentrations are important sensitive and specific markers for myocardial injury in clinical medicine. Troponin (TnT) elevations have been noted in some series in the setting of acute neurologic disease. We have previously reported that solitary seizures do not evoke elevations in TnT. The importance of this negative finding is exemplified by a patient who arrived at our clinic following a new onset seizure and in whom the cardiac TnT level was observed to rise. Triggered by this observation and by the knowledge that seizures alone would not do this, a subsequent targeted cardiologic workup documented what was believed to be an extension of a previously unrecognized myocardial infarction, with a seizure as its clinical presentation. Elevations of troponin should not be considered to be due to isolated seizures. This case illustrates the importance of having data concerning the response of troponin in various emergency and clinical situations.Clinical Cardiology 08/2006; 29(7):325-6. · 2.15 Impact Factor -
Article: Altered expression of connexin subtypes in mesial temporal lobe epilepsy in humans.
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ABSTRACT: The causes of epileptic events remain unclear. Much in vitro and in vivo experimental evidence suggests that gap junctions formed by connexins (Cxs) between neurons and/or astrocytes contribute to the generation and maintenance of seizures; however, few experiments have been conducted in humans, and those completed have shown controversial data. The authors designed a study to compare the level of expression of Cxs in hippocampi from epileptic and nonepileptic patients to assess whether an alteration of gap junction expression in epileptic tissue plays a role in seizure origin and propagation. The expression of Cxs32, -36, and -43 was studied in 47 consecutive samples of hippocampi obtained from epileptic patients who had undergone an amygdalohippocampectomy for the treatment of intractable seizure. These expression levels were compared with those in hippocampi obtained in nonepileptic patients during postmortem dissection. Immunostaining was performed to create one slide for each of the three Cxs. Each slide demonstrated multiple cells from each of six regions (CA1, CA2, CA3, CA4, dentate gyrus, and subiculum). Two independent reviewers rated each Cx-region combination according to an immunoreactive score. Across all three measures-that is, staining intensity, percentage of positively stained cells, and immunoreactive score-Cx32 appeared to be expressed at a significantly lower level in the epileptic patients compared with controls (p < 0.001 for each measure), whereas Cx43 appeared to be expressed more among the epileptic patients (p < 0.001 for each measure). There was no evidence of any differential expression of Cx36. There was, however, regional variation within each Cx subtype. For Cx36, the staining intensity was higher in the CA2 region in the epilepsy group. The increase in Cx43, decrease in Cx32, and preservation of Cx36 expression in hippocampi from epileptic persons could play a role in the development of seizures in patients with temporal sclerosis. Additional studies must be completed to understand this mechanism better.Journal of Neurosurgery 07/2006; 105(1):77-87. · 2.96 Impact Factor -
Article: Long-term outcome of epilepsy surgery among 399 patients with nonlesional seizure foci including mesial temporal lobe sclerosis.
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ABSTRACT: The authors reviewed the long-term outcome of focal resection in a large group of patients who had intractable partial nonlesional epilepsy, including mesial temporal lobe sclerosis (MTS), and who were treated consecutively at a single institution. The goal of this study was to evaluate the long-term efficacy of epilepsy surgery and the preoperative factors associated with seizure outcome. This retrospective analysis included 399 consecutive patients who underwent epilepsy surgery at Mayo Clinic in Rochester, Minnesota, between 1988 and 1996. The mean age of the patients at surgery was 32 +/- 12 years (range 3-69 years), and the mean age at seizure onset was 12 +/- 11 years (range 0-55 years). There were 214 female (54%) and 185 male (46%) patients. The mean duration of epilepsy was 20 +/- 12 years (range 1-56 years). The preceding values are given as the mean +/- standard deviation. Of the 399 patients, 237 (59%) had a history of complex partial seizures, 119 (30%) had generalized seizures, 26 (6%) had simple partial seizures, and 17 (4%) had experienced a combination of these. Preoperative evaluation included a routine and video-electroencephalography recordings, magnetic resonance imaging of the head according to the seizure protocol, neuropsychological testing, and a sodium amobarbital study. Patients with an undefined epileptogenic focus and discordant preoperative studies underwent an intracranial study. The mean duration of follow up was 6.2 +/- 4.5 years (range 0.6-15.7 years). Seizure outcome was categorized based on the modified Engel classification. Time-to-event analysis was performed using Kaplan-Meier curves and Cox regression models to evaluate the risk factors associated with outcomes. Among these patients, 372 (93%) underwent temporal and 27 (7%) had extratemporal resection of their epileptogenic focus. Histopathological examination of the resected specimens revealed MTS in 113 patients (28%), gliosis in 237 (59%), and normal findings in 49 (12%). Based on the Kaplan-Meier analysis, the probability of an Engel Class I outcome (seizure free, auras, or seizures related only to medication withdrawal) for the overall patient group was 81% (95% confidence interval [CI] 77-85%) at 6 months, 78% (CI 74-82%) at 1 year, 76% (CI 72-80%) at 2 years, 74% (CI 69-78%) at 5 years, and 72% (CI 67-77%) at 10 years postoperatively. The rate of Class I outcomes remained 72% for 73 patients with more than 10 years of follow up. If a patient was in Class I at 1 year postoperatively, the probability of seizure remission at 10 years postoperatively was 92% (95% CI 89-96%); almost all seizures occurred during the 1st year after surgery. Factors predictive of poor outcome from surgery were normal pathological findings in resected tissue (p = 0.038), male sex (p = 0.035), previous surgery (p < 0.001), and an extratemporal origin of seizures (p < 0.001). The response to epilepsy surgery during the 1st follow-up year is a reliable indicator of the long-term Engel Class I postoperative outcome. This finding may have important implications for patient counseling and postoperative discontinuation of anticonvulsant medications.Journal of Neurosurgery 05/2006; 104(4):513-24. · 2.96 Impact Factor
Top co-authors
Top Journals
- Epilepsia (7)
- Journal of Neurosurgery (7)
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- Mayo Clinic Proceedings (2)
- Neurology (2)
Institutions
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1996–2013
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Mayo Clinic - Rochester
- • Department of Neurology
- • Department of Neurosurgery
Rochester, MN, USA
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2008–2012
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Royal Melbourne Hospital
Melbourne, Victoria, Australia
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2002–2011
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Mayo Foundation for Medical Education and Research
- • Department of Anesthesiology
- • Department of Neurology
Jacksonville, FL, USA -
University of Melbourne
Melbourne, Victoria, Australia
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