Shorter Duration Of Epilepsy Research Articles

The Clinical and Electrophysiological Characteristics of Temporal Lobe Epilepsy with Normal MRI

Background and PurposeTo identify the clinical and electrophysiological characteristics of temporal lobe epilepsy (TLE) with normal MRI.MethodsTwenty-six patients were diagnosed with TLE with normal MRI by stereotaxically implanted depth electrode EEG (SEEG) and quantitative MRI. We divided the patients into anterior or diffuse temporal groups by interictal EEG, into localized, hemispheric or non-lateralized onset groups by ictal scalp EEG, and into focal or regional onset groups by SEEG. The clinical and electrophysiological characteristics were compared with those of 25 TLE patients with unilateral hippocampal atrophy (HA) on MRI. Four patients of TLE with unilateral HA also underwent SEEG.ResultsPatients in the normal MRI group showed a significantly higher frequency of secondarily generalization (225±235, median 160 vs 68±48, median 50, p<0.05), shorter duration of epilepsy (16±10 yrs vs 25.9±7.8 yrs, p<0.001), and less favorable surgical outcome (50% vs 88%, p <0.05) than patients in the unilateral HA group. Also, patients with normal MRI frequently showed diffuse temporal (50% vs 20%, p<0.05) discharges on interictal EEG. The ictal seizure patterns of patients with normal MRI showed less localization to one temporal lobe on scalp EEG (28% vs 65%, p<0.001) and a higher frequency of regional onset on SEEG (68% vs 8%, p<0.001) than patients with unilateral HA.ConclusionsThe characteristics of TLE with normal MRI compared with TLE with unilateral HA are shorter duration of epilepsy, higher frequency of secondarily generalization, and less favorable surgical outcome, suggesting wider areas of temporal lobe involved compared with patients with unilateral HA.

Impact of Epilepsy Surgery on Developing Minds: How do we Weigh the Consequences?

Cognitive Function in Preschool Children after Epilepsy Surgery: Rationale for Early Intervention Freitag H, Tuxhorn I Epilepsia 2005;46(4):561–567 Purpose The detrimental effect of frequent early seizures on the cognitive potential of children is a significant clinical issue. Epilepsy surgery in childhood offers a good prognosis for seizure control and improved developmental outcome. We studied the postoperative outcome and the developmental velocity after surgery and analyzed risk factors for developmental delay in 50 consecutive preschool children treated surgically for severe epilepsy at ages 3 to 7 years. Methods Pre- and postoperative developmental quotients (DQs) were analyzed with analysis of variance; step-wise linear regressions were performed on preoperative DQs and on a difference score between post- and preoperative DQs to determine risk factors for preoperative development and factors influencing postoperative development. Results Of the 50 patients, 70% were retarded, with IQ &lt;70; 16% were of average intelligence, with IQ ranging from 85 to 115. Age at seizure onset and extent of lesion were predictive variables for preoperative cognitive development. Six to 12 months after surgery (early postoperative phase), 66% were seizure free (Engel outcome class I), 26% had substantial to worthwhile seizure reduction (classes II and III), and 8% were unchanged (class IV). Forty-one (82%) children showed stable velocity of development; three children showed gains of 15 IQ points; three had developmental decline (loss of 10 IQ points), which was transient in two children; and three children moved from not assessable to assessable. At last follow-up (6 months to 10 years after surgery), 11 children showed IQ/DQ gains of 15 IQ points. Gains in IQ were observed only in seizure-free children and were stable over time. Shorter duration of epilepsy was significantly associated with a postoperative increase in DQ. Conclusions (a) Substantial global mental delay is common in young children treated for epilepsy with surgery; (b) in most patients, postoperative development proceeded at a stable velocity; (c) catch-up development may occur but only in seizure-free patients; (d) substantial cognitive losses were noted in only one child; and (e) early seizure control stabilized developmental velocity in this patient cohort.

Value of non-invasive testing when there are independent bitemporal seizures in the scalp EEG

We investigated the value of non-invasive data for predicting the outcome of intracranial EEG and anterior temporal lobectomy (ATL) (follow-up > 1 year) in patients who have bitemporal independent seizures in the scalp EEG. No previous report has dealt with this patient group. Independent variables were duration of epilepsy, febrile seizures, interictal and ictal scalp EEG, ictal behavior, MRI, [18F]-fluorodeoxyglucose–PET (PET) and Wada test and dependent variables were surgical outcome (seizure free or not) and localized on intracranial EEG (finding all symptomatic seizures from one temporal lobe). Non-parametric statistics were used. Of 24 patients, 20 patients had IEEG, of which 12 were localized and 8 were not. Sixteen patients had ATL and, of these, 13 (81%) became seizure free and the remaining three improved. Lateralized findings on MRI and PET, a history of febrile convulsions and shorter duration of epilepsy were all associated with a focal onset on intracranial EEG, while there was a non-significant trend with ictal behavior. The non-invasive data did not predict surgical outcome. We conclude that some of these patients can do well with surgery. In most cases, intracranial EEG is necessary for localization of seizure focus, but if PET and MRI show focal abnormalities and there is a history of febrile convulsions no further evaluation could be needed. These findings need confirmation.

Surgical outcome and predictive factors in adult patients with intractable epilepsy and focal cortical dysplasia

To determine the surgical outcome and prognostic factors in adult patients with intractable epilepsy and focal cortical dysplasia (FCD). We retrospectively studied the operative outcome in 21 consecutive adult patients with FCD who underwent surgical treatment for intractable partial epilepsy. The mean age at surgery was 32.7 years (range, 18-58 years). The median post-operative follow-up was 2.5 years. The FCD was extratemporal in 11 patients, involved the temporal lobe in 10 patients, and was multilobar in eight patients. Eleven patients (52%) were rendered seizure-free, four patients (19%) had >95% reduction in seizures, and two patients (10%) had an 80-94% reduction in seizures. A seizure-free outcome was associated with shorter duration of epilepsy (P = 0.02). Adult patients with FCD may be candidates for surgical treatment of intractable partial epilepsy. Most individuals have neocortical, extrahippocampal seizures and approximately 50% of patients are rendered seizure-free.

Clinical Features of Patients with Posterior Cortex Epilepsies and Predictors of Surgical Outcome

Posterior cortex epilepsies (PCEs) encompass a group of epilepsies originating from the occipital, parietal, or occipital border of the temporal lobe, or from any combination of these regions. When their seizures are refractory to pharmacologic treatment, these patients are usually referred for surgery. The aim of our study was to analyze clinical characteristics of all PCE patients referred for surgery from 1994 to 2003, and to search for predictors of surgical outcome. We performed a retrospective analysis of clinical and laboratory data from 81 consecutive refractory PCE patients referred for surgery. Surgical and nonsurgical groups of patients were compared, and detailed analyses of all variables of the surgical cases were performed in the search for predictors of seizure outcome. Risk factors for PCEs included gliosis (34.56%), malformations of cortical development (33.33%), tumors (8.64%), brain trauma (3.70%), Sturge-Weber disease (4.93%), vascular malformations (3.70%), family history of epilepsy (3.70%), history of CNS infections (2.46%), and low IQ (2.46%). Of the 81 patients, 44 were submitted to surgery at the time of the completion of this study. Surgical treatment was highly effective in improving seizures (p<0.001) when compared with previous pharmacologic treatment alone. Twenty-eight (65.11%) patients became seizure free after surgery versus none in the nonsurgical group. Regarding outcome predictors, patients with shorter duration of epilepsy and those without neurologic abnormalities on clinical examination had higher chances of favorable evolution. Surgical treatment is effective for the treatment of PCEs and superior to pharmacologic therapy alone. In our series, shorter duration of epilepsy and normal neurologic examination were the only independent variables that predicted better surgical outcome.

Cognitive Function in Preschool Children after Epilepsy Surgery: Rationale for Early Intervention

The detrimental effect of frequent early seizures on the cognitive potential of children is a significant clinical issue. Epilepsy surgery in childhood offers a good prognosis for seizure control and improved developmental outcome. We studied the postoperative outcome and the developmental velocity after surgery and analyzed risk factors for developmental delay in 50 consecutive preschool children treated surgically for severe epilepsy at ages 3 to 7 years. Pre- and postoperative developmental quotients (DQs) were analyzed with analysis of variance; stepwise linear regressions were performed on preoperative DQs and on a difference score between post- and preoperative DQs to determine risk factors for preoperative development and factors influencing postoperative development. Of the 50 patients, 70% were retarded, with IQ < 70; 16% were of average intelligence, with IQ ranging from 85 to 115. Age at seizure onset and extent of lesion were predictive variables for preoperative cognitive development. Six to 12 months after surgery (early postoperative phase), 66% were seizure free (Engel outcome class I), 26% had substantial to worthwhile seizure reduction (classes II and III), and 8% were unchanged (class IV). Forty-one (82%) children showed stable velocity of development; three children showed gains of >/=15 IQ points; three had developmental decline (loss of >/=10 IQ points), which was transient in two children; and three children moved from not assessable to assessable. At last follow-up (6 months to 10 years after surgery), 11 children showed IQ/DQ gains of >/=15 IQ points. Gains in IQ were observed only in seizure-free children and were stable over time. Shorter duration of epilepsy was significantly associated with a postoperative increase in DQ. (a) Substantial global mental delay is common in young children treated for epilepsy with surgery; (b) In most patients, postoperative development proceeded at a stable velocity; (c) Catch-up development may occur but only in seizure-free patients; (d) Substantial cognitive losses were noted in only one child. and (e) Early seizure control stabilized developmental velocity in this patient cohort.

Temporal Lobectomy for Refractory Epilepsy in the U.S. Military

To determine the characteristics, seizure outcomes, and quality-of-life outcomes for military beneficiaries undergoing partial temporal lobectomy for refractory epilepsy at the only U.S. military medical center with a comprehensive epilepsy surgery program. The records of all 84 patients treated with partial temporal lobectomy between 1986 and 2000 at Walter Reed Army Medical Center were retrospectively reviewed. Outcome measures included seizure frequency according to the Engel classification system, driving, employment, anticonvulsant use, and military service. The study cohort consisted of 72 military dependents, 10 active duty military members, and 2 military retirees. Two years after surgery, 65 (92%) of 71 patients had seizure improvement (Engel classes I-III) and 46 (66%) of 71 had seizure remission (Engel class I). Driving and employment rates increased after surgery, whereas anticonvulsant use decreased. Five (50%) of 10 active duty patients achieved seizure remission postoperatively and continued to serve in the Armed Forces. Active duty patients had a later age of seizure onset, shorter duration of epilepsy, and greater proportion of lesional epilepsy, compared with nonactive duty patients. Epilepsy surgery outcomes in the U.S. military are similar to those reported from nonmilitary centers, with the majority of patients experiencing seizure remission and improvements in quality-of-life measures. Complete seizure remission after successful anterior temporal lobectomy enables some active duty military members to continue service in the U.S. Armed Forces.

Stress and epilepsy: a patient perception survey

A questionnaire was administered to patients in the Montefiore Medical Center outpatient epilepsy department to assess perceptions about stress, seizures, and stress reduction. Eighty-nine patients completed the questionnaire. Overall, 64% of patients reported the belief that stress increased the frequency of their seizures. This belief was not significantly associated with gender, age, location of care, epilepsy classification, or seizure control, but was significantly associated with a shorter duration of epilepsy ( P=0.04). Thirty-two percent of subjects had tried stress reduction modalities for epilepsy. Of those who had not, 53% were willing to try, and this willingness was significantly associated with a greater number of seizures in the prior 2 months ( P=0.006) and the belief that stress was associated with seizures ( P=0.04). Both major and minor stressors were reported with equal frequency. The majority of our study population believe that stress and seizures are related, and are willing to try stress reduction techniques for seizure control. We believe that these findings indicate a need for a prospective study to evaluate the role of stress and stress reduction as an additional potential therapeutic modality for epilepsy.

Short duration of benign partial epilepsy in infancy.

It has previously been reported that benign partial epilepsy in infancy constitutes up to 29% of the epilepsies presenting in the first 2 years of life. To determine the proportion of benign partial epilepsy in our epilepsy population, we retrospectively reviewed 331 patients with greater than two afebrile seizures in the first 2 years of life between 1993 and 2000. Inclusion criteria were (1) partial seizures with or without secondary generalization, (2) normal development, (3) no other neurologic abnormalities, (4) normal interictal electroencephalograms (EEGs), and (5) good response to treatment. Exclusion criteria included seizures that (1) were caused by acute central nervous system insult, (2) occurred only within the first month of life, and (3) lasted longer than 30 minutes. Of 331 patients, 22 (6.6%) fulfilled the criteria with a minimum of 2 years and a mean of 4 years of follow-up off antiepilepsy drug treatment. Six (27%) had complex partial seizures, and 16 (73%) had complex partial seizures with secondary generalization. Neuroimaging studies were normal in all patients. Of the 6 patients with ictal EEGs, 3 had a temporal lobe focus, 1 had an occipital lobe focus, and the remaining 2 had dual foci. Median onset was 4.0 months (range 0.8-9.3). Seizures remitted within 4 months in 20 (91%). Mean duration of seizure persistence was 2.1 months (range 0-8.3) and was longer in treated patients. Median age at last seizure was 6.4 months (range 2-18). Nineteen were treated with antiepilepsy drugs. At last follow-up (mean duration of 52.2 months), all patients were seizure free and off antiepilepsy drugs. Benign partial epilepsy in infancy is an epilepsy syndrome of short duration and is easily recognized using accepted classification criteria. Benign partial epilepsy in infancy appears to be an idiopathic localization-related epilepsy with a favorable prognosis. The incidence in our population is not as common as previously reported. Based on our findings, we suggest weaning of antiepilepsy drugs 6 months after seizure onset.

Sturge-Weber syndrome: correlation between clinical course and FDG PET findings.

To determine whether the extent and degree of glucose hypometabolism defined by PET correlate with seizure characteristics, cognitive function, and interictal EEG abnormalities in children with unilateral cerebral involvement of Sturge-Weber syndrome (SWS). 2-Deoxy-2[18F]fluoro-D-glucose (FDG) PET was performed in 13 children (age range 0.7 to 15.1 years; five boys, eight girls) with unilateral SWS. Based on asymmetries between homologous cortical areas in FDG PET images, cortical areas of mildly (10% to 20% decrease), and severely (>20% decrease) asymmetric cortical metabolism were defined. These areas were normalized to the size of the ipsilateral hemisphere and correlated with clinical seizure characteristics, full-scale IQ, and interictal EEG abnormalities. Both seizure frequency (p = 0.027) and lifetime number of seizures (p = 0.017) showed a positive correlation with the area (expressed as the percentage of cortical area of ipsilateral hemisphere) of mildly asymmetric cortical metabolism. Patients with higher IQ had a shorter duration of epilepsy (p = 0.044) and a larger area of severely asymmetric cortical metabolism (p = 0.044). Patients with bilateral interictal EEG abnormalities had larger lifetime number of seizures (p = 0.042), lower IQ (p = 0.024), and smaller area of severely asymmetric cortical metabolism (p = 0.019) than those with only ipsilateral EEG abnormalities. Association of severely asymmetric cortical metabolism with relatively preserved cognitive function in SWS suggests that functional reorganization occurs more readily when cortex is severely rather than mildly damaged. Therefore, the area of mildly asymmetric cortical metabolism may exert a nociferous effect on the remaining of the brain. Thus, the extent and degree of glucose asymmetry detected by PET are sensitive markers of seizure severity and cognitive decline in SWS.

Glioneuronal tumors and medically intractable epilepsy: a clinical study with long-term follow-up of seizure outcome after surgery

The present study intends to identify factors that predict postoperative clinical outcome in patients with gangliogliomas (GG) and dysembryoplastic neuroepithelial tumors (DNT). We evaluated the medical records of 45 patients with GG and 13 patients with DNT, treated surgically between 1985 and 1995. We assessed several clinical and histopathological features and analyzed the data statistically. At 5 years postoperatively, 63% of patients with GG and 58% of patients with DNT were seizure-free (Engel's class I). Younger age at surgery ( P<0.01 for GG and P<0.05 for DNT), total resection ( P<0.01 for GG), shorter duration of epilepsy ( P<0.01), absence of generalized seizures ( P<0.01 for GG; P<0.05 for DNT) and absence of epileptiform discharge in the post-operative EEG ( P<0.01 for GG; P=0.01 for DNT) predicted a better postoperative seizure outcome. Tumor recurrence with malignant progression occurred in eight histologically benign GG and two anaplastic GG and was associated which older age at surgery ( P=0.01) and subtotal resection of the tumor ( P<0.01). Our results indicate that a prompt diagnosis, relatively soon after seizure onset, followed by complete resection of glioneuronal tumors provides the best chance for curing epilepsy and preventing their malignant transformation.

Ganglioglioma and intractable epilepsy: clinical and neurophysiologic features and predictors of outcome after surgery.

To review the clinical, neurophysiologic, and radiological data of patients with ganglioglioma who had undergone evaluation and surgery in our Epilepsy Program. The medical and neurophysiologic records of 38 patients with intractable epilepsy and ganglioglioma were reviewed. Data underwent statistical analysis. There were 28 temporal and 10 extratemporal resections, with a mean age at seizure onset of 10.5 years and mean age at surgery of 22 years. Five tumor resections performed earlier were recorded. Twenty-nine patients had auras and 20 had secondarily generalized seizures. All 28 patients with temporal tumor had complex partial seizures. Preoperative MRI demonstrated the tumor in 36 of 36 patients: 17 of 29 demonstrated gadolinium enhancement, and 17 of 36 had mass effect. Scalp interictal sharp waves were present in 32 patients, and in 15 they were multiregional. In two patients, scalp EEG seizure onset was from the hemisphere contralateral to the tumor. Postoperatively, 79% of patients (30 of 38) were seizure-free (Engel's class I) at 6 months, 72% at 1 year (26 of 36), and 63% at 2 years (20 of 32). Excellent outcome was associated with a lower age at operation (p = 0.008), shorter duration of epilepsy (p = <0.01), absence of generalized seizures (p = <0.01), and no epileptiform discharges on a postoperative EEG (p = 0.01). Good surgical outcome is expected in patients with ganglioglioma despite years of medically resistant seizures. Good outcome may be achieved despite EEG findings that may conflict with tumor location, and is more likely when surgery is performed relatively soon after epilepsy onset.

Preoperative clinical, EEG, and imaging findings do not predict seizure outcome following temporal lobectomy in childhood.

Although certain clinical, electroencephalographic (EEG), magnetic resonance imaging (MRI), and pathologic findings in adults with intractable temporal lobe epilepsy predict seizure outcome following temporal lobectomy, predictors of seizure outcome have not been studied systematically in pediatric temporal lobectomy series. We retrospectively analyzed preoperative clinical, EEG, and neuroimaging findings with reference to seizure outcome (seizure free or non-seizure free) in 33 children (mean age, 9.3 years) who underwent tailored temporal lobe resections for intractable temporal lobe epilepsy. Trends were apparent with (1) younger age at seizure onset, younger age at surgery, shorter duration of epilepsy, localized unilateral temporal lesions on MRI, and right-sided surgery more frequently associated with a seizure-free outcome, and (2) significant prior history, daily preoperative seizures, generalized motor seizures, mental retardation, and localized unilateral temporal epileptiform EEG activity more frequently associated with a non-seizure-free outcome. However, none of these findings, alone or in combination, correlated with postoperative seizure status at a statistically significant level. Submitting the four variables generally considered to be most predictive of favorable outcome (ie, normal intelligence, unilateral ictal and interictal EEG discharges, and focal temporal MRI lesion) to a multiple-cutoff procedure did not predict seizure freedom. Our data indicate that predictors of outcome of temporal lobectomy in adults may not apply in children, perhaps due to inherent neurobiologic differences in the etiology and expression of temporal lobe epilepsy, and should therefore not be used as sole determinants of surgical candidacy in children.

Clobazam in long-term epilepsy treatment: sustained responders versus those developing tolerance.

Clobazam (CLB) is a structurally unique benzodiazepine (BZD) that has anticonvulsant activity in all types of refractory seizures. The main drawback to CLB, as to other BZDs, is the occurrence of tolerance. To date, there has been no way to predict which patients will develop tolerance. We compared clinical features and treatment variables between two groups of patients whose seizures were initially well controlled with CLB: patients with a sustained response and patients who developed tolerance. We retrospectively identified a group of 50 very good responders from among 173 consecutive patients with uncontrolled epilepsy treated with CLB. Very good responders were defined as patients with > 75% reduction in seizures after the addition of CLB who continued CLB treatment for at least 1 month. At a mean follow-up of 37.5 +/- 12.8 months, 25 patients continued to respond and 25 developed tolerance (mean follow-up 17.0 +/- 15.7 months). Tolerance was defined as a relapse to a level > or = 50% of pre-CLB seizure frequency after an initial very good response for a minimum period of 1 month, despite constant CLB dose and, when available, serum levels. There was no change in concomitant medication. Significant differences were noted between the two groups. The sustained response group had a shorter duration of epilepsy (mean 16.5 vs. 24.5 years, p = 0.015), a greater proportion of individuals with a known etiology for their epilepsy (48 vs. 16%, p = 0.006), and higher CLB levels (0.50 vs. 0.22 microM, p = 0.017), but no significant difference in N-desmethyl-CLB levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognosis of partial epilepsy.

The prognosis of partial epilepsy in childhood (excluding cases of benign partial epilepsy) was studied; the average follow up period was 7.4 years. Improvement rate of seizure status was 82.3%. We studied favourable prognostic factors and found that those most often associated with seizure improvement were familial convulsions and idiopathic forms, no generalised seizures before partial onset, low frequency of seizures after 12 months of treatment, short duration of epilepsy, and no background activity abnormalities on electroencephalography. We also observed such factors as mental retardation, neurological abnormalities, and behaviour and cognitive disorders. Factors that determined the prognosis for social adjustment were similar to those for seizure improvement. We discuss the favourable prognosis of partial seizures in childhood and the predictive factors.