Seizure outcome after surgery for epilepsy due to focal cortical dysplastic lesions.

Neocortical development is a highly complex process encompassing cellular proliferation, neuronal migration and cortical organization. At any time this process can be interrupted or modified by genetic or acquired factors causing malformations of cortical development (MCD). Epileptic seizures are the most common type of clinical manifestation, besides developmental delay and focal neurological deficits. Seizures due to MCD are frequently pharmacoresistant, especially those associated to focal cortical dysplasia (FCD). Surgical therapy results have been reported since 1971, however, currently available data from surgical series are still limited, mainly due to small number of patients, distinct selection of candidates and surgical strategies, variable pathological diagnosis and inadequate follow-up. This study addresses the possibilities of seizure relief following resection of focal cortical dysplasia, and the impact of presurgical evaluation, extent of resection and pathological findings on surgical outcome. We included 41 patients, 22 adults and 19 children and adolescents, with medically intractable seizures operated on from 1996 to 2002. All were submitted to standardized presurgical evaluation including high-resolution MRI, Video-EEG monitoring and ictal SPECT. Post-surgical seizure outcome was classified according to Engel's schema. Univariate and multivariate analysis were performed. Fifteen patients had temporal and 26 extratemporal epilepsies. Of the total 26 patients (63.4%) reached seizure-free status post-operatively. There was no correlation between outcome and age at surgery, duration of epilepsy, frequency of seizures, and pathological findings. There was, however, a clear correlation with topography of FCD (temporal versus extratemporal) and regional ictal EEG onset, on univariate as well as multivariate analysis.     

Seizure outcome after extratemporal epilepsy surgery in childhood

Aim The aim of the study was to describe seizure outcome following surgery for focal extratemporal epilepsy and identify factors associated with prolonged postsurgical freedom from seizures. Method In this retrospective cohort study, children with drug‐resistant focal extratemporal epilepsy were treated surgically and followed up in a single tertiary care centre between 1997 and 2008. Results Eighty children were identified for inclusion in the study (42 males, 38 females; median age 9y 1mo, range 3mo–18y 7mo). The aetiology was identified as focal cortical dysplasia (n=37), low‐grade tumour (n=22), tuberous sclerosis (n=9), or non‐specific (n=12). Children were followed for a median of 3 years 1 month (range 8mo–10y 7mo) after surgery. Overall, at last follow‐up, 50% of the children had been completely seizure free since surgery (Engel class Ia); of these 40 individuals, 15 had discontinued all antiepileptic drugs. Several presurgical factors were associated with a favourable outcome. However, after controlling for confounding factors, aetiology appeared to be the only determinant of long‐term seizure outcome as non‐specific lesion pathology was associated with seizure recurrence (hazard ratio 10.43; 95% confidence interval 3.26–33.39). Interpretation In 50% of cases, children with surgically treated drug‐resistant extratemporal epilepsies have an excellent long‐term outcome. The aetiology of the epileptogenic lesion appears to be the only significant determinant of surgical outcome in this population of children. It is difficult to correctly identify non‐specific pathology on presurgical magnetic resonance imaging.     

Seizure outcome after epilepsy surgery in children and adolescents

Few epilepsy surgery outcome data are available from series of pediatric patients. We studied seizure outcome in 136 pediatric patients who had surgery for intractable epilepsy at The Cleveland Clinic between January 1990 and June 1996, with a postoperative follow-up of 1 to 7.5 years (mean, 3.6 years). Sixty-two children (3 months to 12 years old at time of surgery) were compared with 74 adolescents (13–20 years old). Extratemporal or multilobar resections and hemispherectomies were similarly frequent among children (50%) and adolescents (44%), but these procedures strongly predominated in infancy (90% of patients 0–2 years of age). The remaining patients had temporal resection. Cortical dysplasia and low-grade tumor were the most common causes and hippocampal sclerosis was rare. Seizure-free outcome was achieved for 69% of adolescents, 68% of children, and 60% of the infant subgroup, overall; for 23 (74%) of 31 children and 33 (80%) of 41 adolescents after temporal resection; for 11 (58%) of 19 children and 15 (52%) of 29 adolescents after extratemporal or multilobar resection; and for 8 (67%) of 12 children and 3 (75%) of 4 adolescents after functional hemispherectomy. Seizure-free outcome was more frequent after temporal resection (56 of 72, 78%) than after extratemporal or multilobar resection (26 of 48, 54%; 41 of 48 with a focal lesion on magnetic resonance imaging), and among patients with tumor (36 of 44, 82%) versus cortical dysplasia (16 of 31, 52%). The frequency of seizure-free outcome after epilepsy surgery was similar for infants, children, and adolescents, and comparable with results from adult series. Most patients in each age, surgery type, and causal group were free from seizures after surgery. These results suggest that children should be considered for surgical evaluation at whatever age they manifest with severe, intractable, disabling localization-related epilepsy.     

Seizure prediction in patients with focal hippocampal epilepsy

Objective

We evaluated the performance of our previously developed seizure prediction approach on thirty eight seizures from ten patients with focal hippocampal epilepsy.

Seizure outcome after epilepsy surgery in patients with normal preoperative MRI

OBJECTIVE: To determine outcome after epilepsy surgery in patients with normal preoperative magnetic resonance imaging (MRI). METHODS: 24 adult and paediatric patients with normal preoperative MRIs were studied. They underwent epilepsy surgery between 1994 and 2001 and had at least one year of follow up. RESULTS: At the most recent follow up, nine patients (37%) were seizure-free and 18 (75%) had at least a 90% reduction in seizure frequency with weekly or monthly seizures. Seizure freedom was not significantly different after resections in frontal (5/9) or temporal regions (4/13) (p = 0.24, Fisher's exact test), or among patients with or without localising features on EEG, PET, or ictal SPECT. Subdural grids, used in 15 of 24 patients, helped tailor resections but were not associated with differences in outcome. Histopathology showed cortical dysplasia in 10 patients (42%), non-specific findings in 13 (54%), and hippocampal sclerosis in one (4%). Cortical dysplasia was seen in seven patients with frontal resection (78%) and non-specific findings in nine (69%) with temporal resection. Seizure outcome did not differ on the basis of location of resection or histopathology. CONCLUSIONS: While these results were less favourable than expected for patients with focal epileptogenic lesions seen on MRI, they represented worthwhile improvement for this patient population with high preoperative seizure burden. In this highly selected group, no single test or combination of tests further predicted postoperative seizure outcome.     

Seizure anticipation in pediatric epilepsy: use of Kolmogorov entropy

The purpose of this paper is to demonstrate feasibility of using trends in Kolmogorov entropy to anticipate seizures in pediatric patients with intractable epilepsy. Surface and intracranial recordings of preseizure and seizure activity were obtained from five patients and subjected to time series analysis using Kolmogorov entropy. This metric was compared with correlation dimension and power indices, both known to predict seizures in some adult patients. We used alarm levels and introduced regression analysis as a quantitative approach to the analysis of trends. Surrogate time series evaluated data nonlinearity, as a precondition to the use of nonlinear measures. Seizures were anticipated before clinical or electrographic seizure onset for three of the five patients from the intracranial recordings, and in two of five patients from the scalp recordings. Anticipation times varied between 2 and 40 minutes. This is the first report in which simultaneous surface and intracranial recording are used for seizure prediction in children. We conclude that the Kolmogorov entropy and power indices were as effective as the more commonly used correlation dimension in anticipating seizures. Further, regression analysis of the Kolmogorov entropy time series is feasible, making the analysis of data trends more objective.     

Seizure outcome of intractable partial epilepsy in children

The intractable partial epilepsy outcome information is important in determining not only when epilepsy surgery evaluation should begin but also in deciding who would benefit and what is the likelihood of any benefit from surgery. Medical records of 50 children diagnosed with nontumor-related partial seizures, confirmed by video-electroencephalography (video-EEG), had at least one seizure per week and were followed for at least 2 consecutive years after video-EEGs were reviewed. There were 30 patients who continued with antiepileptic drug treatment after video-EEG. The seizure outcome analysis revealed a significant improvement of seizure control in the first year of follow-up but no difference between the first year and the following 3 years. Only 30% had excellent long-term outcome (seizure free or less than one seizure per 6 months). The presence of focal lesions on neuroimaging was the only risk factor of poor outcome. The other 20 patients underwent epilepsy surgery after video-EEG; 60% attained excellent outcome despite the fact that 90% had focal neuroimaging abnormality. Children whose partial epilepsy remained intractable after 1 year of antiepileptic drug treatment should be evaluated for candidacy of epilepsy surgery, particularly those who have focal lesions on neuroimaging.     

Seizure outcome for surgery of extratemporal epilepsy

Over a 10-year period, 64 surgical operations were carried out on 55 patients suffering from refractory extratemporal epilepsy. Patient class outcome 3 years after the final surgical procedure showed that 9 patients (16%) were completely seizure free and 21 patients (38%) had less than a 50% reduction in seizure outcome. Corpus callosal section as a surgical procedure had the highest percentage (57%) of patients with a class 4 outcome. Corpus callosotomy as a final operation resulted in reduction in frequency and severity of ‘drop attacks’ in all patients. Gliosis without atrophy was the most common histopathology. There were no deaths as a result of surgery, although 4 patients died postsurgery; 2 died in status epilepticus. Multiple lobectomy was the most successful surgical procedure, with a Prognostic Index of 2.0, followed by 2.5 for extratemporal tumour resection. Corpus callosotomy and cystectomy had a Prognostic Index of 3.3 and 3.1, respectively.     

Seizure clusters in drug‐resistant focal epilepsy

We investigated clinical factors associated with seizure clustering in patients with drug‐resistant focal epilepsy and any association between seizure clustering and outcome after surgery. We performed a retrospective study including patients with a diagnosis of drug‐resistant focal epilepsy who underwent epilepsy surgery. Patients were prospectively registered in a database from 1986 until 2015. Seizure cluster was defined as two or more seizures occurring within 2 days. Potential risk factors for seizure clustering were assessed. To investigate any potential association between seizure clusters and seizure outcome after surgery, time to event analysis was used to produce a Kaplan‐Meier estimate of seizure recurrence. We studied 764 patients. Seizure clusters were reported in 23.6% of patients with temporal lobe epilepsy (TLE) and 16.9% of extratemporal patients (p = 0.2). We could not identify any significant clinical factors associated with seizure clustering. Among patients with TLE, those who had history of seizure clusters fared better after surgery (p < 0.01). We found that seizure clusters relate to prognosis after temporal lobe surgery in drug‐resistant TLE. These data may provide added value for surgical prognostication when combined with other data types. A better understanding of the neurobiology underlying seizure clusters is needed.     

Seizure outcome in patients with juvenile absence epilepsy

The purpose of this study was to identify seizure outcome and factors potentially predictive for seizure outcome in patients with juvenile absence epilepsy (JAE). In this case–control study all patients with JAE were recruited at the outpatient epilepsy clinic at Shiraz University of Medical Sciences from 2008 till 2012. All patients had to be under the care of the epileptologist for at least 18 months. We divided the patients into two groups: patients who were seizure free in the last 12 months of their follow-up period and those who had any seizures. During the study period, 2750 patients with epilepsy were registered at our epilepsy clinic; 641 patients (23.3 %) had idiopathic generalized epilepsy (IGE). Among patients with IGE, 81 patients (12.6 %) were diagnosed as having JAE and of these, 33 patients (20 women and 13 men) were eligible to enter into the study. Ten patients (30.3 %) were seizure free in the last 12 months of their follow-up and 23 (69.6 %) patients reported at least one seizure of any type. We could not identify any factor to be associated with seizure outcome in these patients. All studies in the literature suffer from small number of patients; so does our study. Besides, they used different methodologies. A large multicenter study is required to explore the variables that predict seizure outcome in patients with juvenile absence epilepsy. This is particularly needed to provide an appropriate counselling for patients and their families and also to formulate better individualized treatment plans for the patients.     

Seizure outcome after surgery for epilepsy due to malformation of cortical development

PURPOSE: To explore seizure outcome after surgery for focal epilepsy due to malformation of cortical development (MCD), with focus on the role of MRI. METHODS: Thirty-five patients who had surgery for intractable focal epilepsy due to MCD identified by preoperative MRI and confirmed by histopathologic analysis of resected tissue were studied. Patients were aged 3 months to 47 years (median, 14 years) at the time of surgery. Duration of follow-up was 1 to 7.9 (mean, 3.4) years. RESULTS: At latest follow-up, 17 patients (49%) had Engel Class I outcome with no seizures or auras only; eight patients (23%) had Class II outcome, with rare disabling seizures; seven patients (20%) had worthwhile improvement; and three patients (9%) had no improvement. Seizure-free outcome tended to be more frequent among patients who had complete resection of unilateral MCD (excluding hemimegalencephaly) based on postoperative MRI (7/12; 58%), compared with patients with unilateral MCD who had incomplete resection (3/11; 27%), but the difference was not significant. The frequency of seizure-free outcome did not differ significantly between children (8/14; 57%), adolescents (7/15; 47%) or adults (2/6; 33%); between patients who had daily (12/24; 50%), weekly (4/9; 44%), or monthly (1/2; 50%) seizures preoperatively; between patients who had temporal (2/6; 33%) or extratemporal or multilobar resections (14/28; 50%); or between patients who were (9/16; 56%) or were not (8/19; 42%) studied with subdural electrodes. Results for all analyses were similar when analyzed at latest available follow-up or at 1 year after surgery. CONCLUSIONS: Surgery can offer seizure-free outcome for approximately one half of carefully selected patients with intractable focal epilepsy due to MCD. Complete resection of the MRI-apparent lesion may improve the likelihood for favorable outcome. MRI evidence of hemimegalencephaly or bilateral MCD suggests a low likelihood for postoperative freedom from seizures.     

Seizure outcome after temporal lobectomy for temporal lobe epilepsy: a Kaplan-Meier survival analysis

OBJECTIVE: To determine seizure outcome and its predictors in patients with medically refractory temporal lobe epilepsy (TLE) after temporal lobectomy (TL). BACKGROUND: TL is the most common surgical procedure performed in adolescents and adults for the treatment of medically refractory TLE. Seizure outcome has been reported extensively during the first few postoperative years, but little is known beyond that time. METHODS: The authors analyzed seizure outcome in 79 patients who underwent TL for epilepsy at the Duke University Medical Center from 1962 through 1984. Patients with less than 2 years of follow-up and degenerative disorders were excluded. Predictors of seizure outcome were analyzed using Kaplan-Meier survival analyses. RESULTS: The mean follow-up was 14 years (range, 2.1 to 33.6 years). Using Engel's classification, 65% of patients were class I, 15% were class II, 11% were class III, and 9% were class IV. At least one postoperative seizure occurred in 55% of subjects. The majority of recurrences (86%) took place within 2 years of surgery. Later recurrences tended not to lead to medical intractability. Higher monthly preoperative seizure frequency was associated with poor seizure outcome. A seizure-free state at 2 years was found to be a better predictor of long-term outcome than the 6-, 12-, and 18-month landmarks. CONCLUSIONS: TL provides sustained, long-term benefit in patients with medically refractory TLE. Seizure-free status at 2 years from the time of surgery is predictive of long-term remission.     

Psychiatric comorbidity in patients with pharmacoresistant focal epilepsy and psychiatric outcome after epilepsy surgery

There are only a few studies in which both preoperative psychiatric comorbidity in pharmacoresistant focal epilepsy and its outcome after epilepsy surgery have been investigated. In this study, 144 patients evaluated for epilepsy surgery received psychiatric examination, 84 proceeding to intervention were reassessed postoperatively. Preoperatively, 60% met criteria for ICD-10- or epilepsy-specific psychiatric diagnosis. Twenty-seven percent, predominantly female, suffered from dysphoric disorder (DD) associated with temporal epileptogenic foci. Prevalence of DD correlated with complex partial seizure frequency and presence of ictal fear suggesting limbic-cortical dysregulation. Psychotic syndromes were linked to a history of febrile convulsions and left-sided temporomesial epileptogenic foci. High seizure frequency and early epilepsy onset predisposed to the development of personality disorders. Postoperative assessment revealed 18% of patients with "de novo" interictal affective disorders after surgery. Symptoms in 48% of patients with preoperative affective syndromes and 60% of patients with DD remitted after surgery. Seizure freedom and improved psychosocial status predicted remission of preoperative psychopathology.     

Multiple hippocampal transections for intractable hippocampal epilepsy: Seizure outcome

PurposeThe purpose of this study was to evaluate the seizure outcomes after transverse multiple hippocampal transections (MHTs) in 13 patients with intractable TLE.MethodsThirteen patients with normal memory scores, including 8 with nonlesional hippocampi on MRI, had temporal lobe epilepsy (TLE) necessitating depth electrode implantation. After confirming hippocampal seizure onset, they underwent MHT. Intraoperative monitoring was done with 5–6 hippocampal electrodes spaced at approximately 1-cm intervals and spike counting for 5–8 min before each cut. The number of transections ranged between 4 and 7. Neuropsychological assessment was completed preoperatively and postoperatively for all patients and will be reported separately.ResultsDuration of epilepsy ranged between 5 and 55 years. There were no complications. Intraoperatively, MHT resulted in marked spike reduction (p = 0.003, paired t-test). Ten patients (77%) are seizure-free (average follow-up was 33 months, range 20–65 months) without medication changes. One of the 3 patients with persistent seizures had an MRI revealing incomplete transections, another had an additional neocortical seizure focus (as suggested by pure aphasic seizures), and the third had only 2 seizures in 4 years, one of which occurred during antiseizure medication withdrawal. Verbal and visual memory outcomes will be reported separately. Right and left hippocampal volumes were not different preoperatively (n = 12, p = 0.64, Wilcoxon signed-rank test), but the transected hippocampal volume decreased postoperatively (p = 0.0173).ConclusionsMultiple hippocampal transections provide an effective intervention and a safe alternative to temporal lobectomy in patients with hippocampal epilepsy.     

Seizure control and educational outcome in childhood-onset epilepsy.

Patients with epilepsy are more prone to have learning disabilities. This study investigated the therapeutic and educational outcome of 102 epileptic children. Analyzed data included age at onset, etiology, presence of underlying brain lesions, seizure type, and electroencephalographic (EEG) patterns. Cryptogenic seizures, remote symptomatic seizures, and underlying brain lesions were found in 29, 26, and 14 patients, respectively, whereas 47 patients had idiopathic seizures. Eighty-three patients achieved seizure control (46 remained seizure free), and 19 patients remained poorly controlled. Sixty-five patients were in regular schools, and 37 required special education (17 with mental retardation). Predictors for poor seizure control were remote symptomatic seizures, underlying brain lesions, and (when grouped together) hypsarrhythmia and mixed EEG patterns (P < .001). Predictors for special education needs were young age at onset, remote symptomatic seizures, underlying brain lesions, hypsarrhythmia and mixed EEG patterns, and poor seizure control (P < .001). We conclude that in childhood epilepsy, the need for special education is substantial and more common than treatment failure.     

Seizure outcome of infantile spasms with focal cortical dysplasia

Purpose: This study sought to evaluate the seizure outcome of infantile spasms (IS) with focal cortical dysplasia (FCD). Methods: We retrospectively reviewed infantile spasms patients with FCD from 2004 to 2010. We investigated seizure outcome from antiepileptic drug (AED), ketogenic diet (KD), resective surgery, and analyzed the results according to individual imaging studies. Results: Among 404 patients of IS, FCD was confirmed in 51 patients. In retrospective review of brain MRI, only 21 patients (41.2%) were suspected of FCD before 1 year of age, but 45 patients (88.2%) became confirmed to FCD by MRI after the age of 1 year. Once the spasms were not controlled by 1 or 2 AEDs, the chance of becoming seizure free with additional third or more drugs was very low (2.3%). The seizure free rate was 33.3% (7/21) in patients treated with ketogenic diet, and 73.3% (22/30) in surgical patients, who were both intractable to AEDs. There were no significant differences in seizure free rate in both ketogenic diet and surgical patients, between MRI negative and positive patients prior to 1 year of age. Conclusions: KD and surgery should be considered in medically refractory IS with FCD.     

Social competence in pediatric epilepsy: insights into underlying mechanisms

This study compared parent-based Child Behavior Checklist (CBCL) social competence scores of 90 children with complex partial seizures (CPS) and 62 with absence epilepsy (CAE) of average intelligence with scores of 91 healthy children. It also examined the role of seizure-related, cognitive, behavioral, linguistic, social communication, and demographic variables on these measures. When differences in cognitive, linguistic, and demographic variables were controlled for, the CPS and CAE groups had significantly lower scores in the school, but not in the social interaction and activities domains compared with the healthy control group. Among the patients, lower Full Scale IQ externalizing behaviors, disruptive disorders, minority status, and impaired social communication, but not seizure variables, predicted lower social competence scores. These findings demonstrate the importance of controlling for cognitive, behavioral, and demographic variables in social competence studies of children with CPS and CAE and the need to assess cognition and behavior when parents report school and social problems in these children.     

Seizure exacerbation in two patients with focal epilepsy following marijuana cessation

While animal models of epilepsy suggest that exogenous cannabinoids may have anticonvulsant properties, scant evidence exists for these compounds' efficacy in humans. Here, we report on two patients whose focal epilepsy was nearly controlled through regular outpatient marijuana use. Both stopped marijuana upon admission to our epilepsy monitoring unit (EMU) and developed a dramatic increase in seizure frequency documented by video-EEG telemetry. These seizures occurred in the absence of other provocative procedures, including changes to anticonvulsant medications. We review these cases and discuss mechanisms for the potentially anticonvulsant properties of cannabis, based on a review of the literature.