How effective is surgery to cure seizures in drug-resistant temporal lobe epilepsy?

How are they doing as adults? Psychosocial and socioeconomic outcomes 11-30 years after pediatric epilepsy surgery

OBJECTIVE

Pediatric epilepsy surgery yields cure from epilepsy or complete seizure control with continued medication in many patients early in life. This study aimed to evaluate the long-term (>10 years) psychosocial and socioeconomic outcomes of pediatric epilepsy surgery and examine the role of comorbid disability, type of surgery, seizure freedom, and age at surgery.

METHODS

A novel ad hoc parent/patient questionnaire was used to assess educational and occupational attainment, marital/familial status, mobility, and other outcomes in patients who underwent unilobar or multilobar surgery for drug-refractory epilepsy during their childhood. The questionnaire also captured information on comorbid disability.

RESULTS

Of the 353 eligible patients, 203 could still be contacted and 101 of these (50%) returned appropriately filled-in questionnaires (follow-up intervals: 11-30 [mean: 19.6] years). The cure from epilepsy rate was 53%. Type of surgery was strongly confounded by comorbid disability. Patients with comorbid disabilities had significantly lower rates of regular school degrees, gainful employment, marriage, and driving license (N = 29; 12%, 4%, 0%, 3%) compared with non-disabled patients (N = 69; 89%, 80%, 43%, and 67%, respectively). Patients achieved lower school degrees than their siblings and parents. Non-disabled seizure-free patients had better employment and mobility outcomes compared with non-seizure-free patients. Age at surgery (<10 vs. ≥10 years of age) did not have any effect on any outcome in patients with preschool seizure onset.

SIGNIFICANCE

Pediatric epilepsy surgery can lead to permanent relief from epilepsy in many patients, but comorbid disability strongly impacts adult life achievement. In non-disabled patients, favorable outcomes in academic, occupational, marital, and mobility domains were achieved, approaching respective rates in the German population. Complete seizure freedom had additional positive effects on employment and mobility in this group. However, in case of chronic comorbid disability the overall life prospects may be limited despite favorable seizure outcomes.

Clinical adult outcome 11-30 years after pediatric epilepsy surgery: Complications and other surgical adverse events, seizure control, and cure of epilepsy

OBJECTIVE

Pediatric epilepsy surgery promises seizure freedom or even cure of epilepsy. We evaluated the long-term (≥10 years) adult clinical outcome including surgery-related adverse events and complications, which are generally underreported.

METHODS

A monocentric, single-arm, questionnaire study in now adult patients who underwent epilepsy surgery during childhood. A novel ad hoc parental/patient questionnaire, which addressed diverse outcome domains was applied.

RESULTS

From a total of 353 eligible patients, 203 could be contacted (3 patients died of causes unknown) and 101 (50%) returned appropriately filled-in surveys. No evidence for a survey-response bias was found. The rate of surgical complications according to the patient records was 9%. As regards the survey, half of the parents/patients reported surgical adverse events (expected and unexpected issues) and one-third reported permanent aversive sequels. Two-thirds of the patients were seizure-free during the last year before follow-up; 63% were Engel class 1A; favorable seizure outcomes (including auras only) were obtained in 73%; and 54% were seizure-free and off antiseizure medicine (ASM), that is, cured of epilepsy. In non-seizure-free patients, seizure relapse occurred at any time during the follow-up interval but 87% of those with a seizure-free first postoperative year were seizure-free at follow-up. One patient experienced a seizure relapse during the ASM withdrawal trial but became seizure-free again with ASMs. Eleven patients reported an increased number of ASMs as compared to the time before surgery. Earlier focal surgery did not affect the long-term clinical outcome.

SIGNIFICANCE

Pediatric epilepsy surgery was capable of curing epilepsy in about one-half of the children and to significantly control seizures in about three-fourths. Long-term success of focal surgery did not depend on age at surgery or duration of epilepsy. Surgical adverse events including complications may be underreported and must be assessed more thoroughly.

Need of Immediate Drug Reduction after Epilepsy Surgery - A Prospective Observational Study

Background

Patients undergoing epilepsy surgery are on polytherapy. Drug tapering is usually done after 1 year in adults and after 6 months in children. Sometimes, drugs have to be altered during the perioperative period, which is more commonly seen in hemispherotomy (HS) patients. The present study was done to compare perioperative drug alterations between HS and temporal (TL) lobectomy patients.

Materials and Methods

Prospective analysis of postoperative HS and TL patients was done. Primary outcomes were drug number, dosage changes, and seizure outcome. Secondary outcome studied was a change in intelligence quotient (IQ) in the two groups.

Results

At total of 71 patients were included. Perioperative drug stopping (clobazam - CLB) was needed in 3/38 patients in the HS group, due to sedation. Dosage was reduced in 23/38 (60.52%) in HS group, and in 2/33 (6%) in TL group P < 0.001. The most common drug was CLB, with reduction in 21/27 (77.77%) patients, with a mean reduction of 41.21 ± 4.01%. Two patients required drug substitution in the HS group. About 64/71 (90.1%) patients achieved Class I outcome at a 1-year postoperative time point (TL - 90.9%, HS - 89.47%). There was no change in IQ in any of the groups.

Conclusion

Perioperative drug alteration is often needed in the HS patients as compared to TL patients. Benzodiazepines have to be reduced to maintain alertness in the HS patients. The increased sedation postoperatively can be due to decreased cortical drive over the reticular activating system, gamma-aminobutyric acid (GABA) receptor denervation hypersensitivity, or increased activity of drugs over the remaining active hemisphere.

Does early postoperative drug regimen impact seizure control in patients undergoing temporal lobe resections?

OBJECTIVE

To evaluate the impact of postoperative antiepileptic drug (AED) load on seizure control in patients who underwent surgical treatment for pharmacoresistant mesiotemporal lobe epilepsy during the first two postoperative years.

PATIENTS AND METHODS

532 consecutive patients (48.7% males and 51.7% females) who underwent surgical treatment for mesiotemporal lobe epilepsy were retrospectively evaluated regarding effects of AED load on seizures control during the first 2 years following epilepsy surgery. We analyzed whether postoperative increases in postoperative AED load are associated with better seizure control in patients initially not seizure free, and if postoperative decreases in postoperative AED load would increase the risk for seizure persistence or recurrence. For statistical analyses, Fisher's exact and Wilcoxon test were applied.

RESULTS

68.9, 64.0 and 59.1% of patients were completely seizure free (Engel Ia) at 3, 12 and 24 months after surgery, respectively. Patients in whom daily drug doses were increased did not have a higher rate of seizure freedom at any of the three follow-up periods. Of 16 patients achieving secondary seizure control at 12 months after surgery, only one did so with an increase in drug load in contrast to 15 patients who experienced a running down of seizures independent of drug load increases. Decreases in drug load did not significantly increase the risk for seizure recurrence. Of postoperatively seizure free patients at 3 months after surgery in whom AED were consequently reduced, 85% remained completely seizure free at 1 year and 76% at 1 year after surgery, respectively, as opposed to 86% each when AED was not reduced (differences n.s.). Mean daily drug load was significantly lower in seizure free patients at 12 and 24 months compared to patients with ongoing seizures.

CONCLUSION

In this large patient cohort stratified to the epilepsy syndrome neither did a postoperative reduction in drug load significantly increase the risk for seizure relapse nor did increases in drug dosages lead to improved seizure control. Mean drug load was on average lower in seizure free- than non-seizure free patients at 12 and 24 months of follow-up. Secondary seizure control after initial postoperative seizures in > 90% of cases occurred as a running down, independent of an AED increase. Thus, the effect of the surgical intervention rather than the postoperative drug regimen was the key determinant for seizure control. This finding supports a curative role of temporal lobe surgery rather than an effect rendering the majority of patients' pharmacoresponsive with a critical role of the antiepileptic drug regime for seizure control.

Research and Clinical Application of Three-Dimensional Location of Amygdaloid Body

Accurately representing the spatial location of the amygdaloid body can lay an anatomical basis for the neurosurgery operation for amputation of the amygdaloid body through lateral fissure approach. As we know, there are a number of nerve nucleuses and essential structures locating around amygdaloid body in our brain, especially optic tract. However, only few research had been done to protect these tissues or nerve nucleuses. Thus, we reconstructed the three-dimensional images of the amygdaloid body of the human brain and established a coordinate system. The morphological parameters of the amygdaloid body and the three-dimensional coordinate data were measured. The spherical coordinates (R, θ, ϕ) were constructed by calculating the azimuth angle, elevation angle, and the distance from the coordinates origin to each amygdaloid body centroid. Sixty people brain MRI images without any visible organic disease were used in our research to investigate the average level of related parameters. The authors selected a proper coordinate origin and measured the value of anteroposterior diameter, right-and-left diameter, vertical diameter of the amygdaloid body, and the distance from the optic tract to amygdaloid body. The authors also measured the three-dimensional coordinate data of each centroid of the amygdaloid body in order to provide anatomical suggestion for surgery. The authors confirmed the nearest point from the foremost edge of the brain ventricle temporal horn to the lateral fissure, then viewed it as the coordinate origin. By means of coordinate translation, the authors got various morphological parameters and the coordinate values of each centroid of the amygdaloid body. Spherical coordinates were calculated from the three-dimensional coordinate values. The distances between the different layers of the amygdaloid body and the optic tract were also measured. The reconstruction of the three-dimensional coordinates of amygdaloid body is part of the digital engineering of the human body. The measurement of the parameters provides an important theoretical basis for the clinical amygdaloid body destruction surgery. Finally, the authors get conclusions as follows. There are no significant differences in the measured values of r1, r2, and r3 between the upper and lower diameters, the left and right diameters, the anteroposterior diameter of the amygdaloid body. The measured values of men and women are not statistically significant (P > 0.05). Spherical coordinates (R, θ, ϕ) calculated from the three-dimensional coordinate values and values from different sexes of the amygdaloid body are not statistically significant, either (P > 0.05). The distance between the different levels of the amygdaloid body and the optic tract (h1, h2, h3, h4, h5, h6, and h7) are not statistically significant (P > 0.05).

Treatment issues for children with epilepsy transitioning to adult care

This is the third of three papers that summarize the second symposium on Transition in Epilepsies held in Paris in June 2016. This paper focuses on treatment issues that arise during the course of childhood epilepsy and make the process of transition to adult care more complicated. Some AEDs used during childhood, such as stiripentol, vigabatrin, and cannabidiol, are unfamiliar to adult epilepsy specialists. In addition, new drugs are being developed for treatment of specific childhood onset epilepsy syndromes and have no indication yet for adults. The ketogenic diet may be effective during childhood but is difficult to continue in adult care. Regional adult epilepsy diet clinics could be helpful. Polytherapy is common for patients transitioning to adult care. Although these complex AED regimes are difficult, they are often possible to simplify. AEDs used in childhood may need to be reconsidered in adulthood. Rescue medications to stop prolonged seizures and clusters of seizures are in wide home use in children and can be continued in adulthood. Adherence/compliance is notoriously difficult for adolescents, but there are simple clinical approaches that should be helpful. Mental health issues including depression and anxiety are not always diagnosed and treated in children and young adults even though effective treatments are available. Attention deficit hyperactivity disorder and aggressive behavior disorders may interfere with transition and successful adulthood but these can be treated. For the majority, the adult social outcome of children with epilepsy is unsatisfactory with few proven interventions. The interface between pediatric and adult care for children with epilepsy is becoming increasingly complicated with a need for more comprehensive transition programs and adult epileptologists who are knowledgeable about special treatments that benefit this group of patients.

Natural course of treated epilepsy and medico-social outcomes. Turku studies. Part II

Introduction. Population-based data on the prognosis of childhood-onset epilepsy were almost nonexistent in the 1960s. This prompted me to start an epidemiological prospective study on children with epilepsy.

Aim. To study the medical and social outcome of children with epilepsy.

Methods. The most important personal data on the natural course and outcome were reviewed and compared with the relevant data of other investigators.

Results and discussion. The natural course of treated epilepsy is remitting, uninterrupted by relapse (in 48%); a remitting-relapsing course (interrupted by relapses, in terminal remission) (19%); worsening course (early or late remission followed by drug-resistant epilepsy) (14%); and never in ≥5-year remission (drug resistance) (19%) The medical and social outcomes based on my unique, five decades followed cohort show that most subjects are in 10-year remission without medications, which is the definition of resolved epilepsy. Normal or subnormal IQ, non-symptomatic etiology, and low seizure frequency both in the first year of AED treatment and prior to medication appear to be clinical predictors of cure in childhood-onset epilepsy. Subjects with 1-year remission during the first five years form onset of treatment have more than 10-fold chance for entering 5-year terminal remission vs those who have no 1-year remission during the first five years. Even about one fourth of difficult-to-treat subjects become seizure free on medication and more than half of them enter one or more 5-year remissions. Epilepsy has a substantial impact on quality of life even in those who are seizure free off medication for many years and particularly those not in remission or in remission but still on medication.

Conclusions. The prognosis is excellent for medical and social outcome. The successful outcome is confirmed by several longitudinal studies from recent decades. Good response to early drug therapy does not necessarily guarantee a favorable seizure outcome, and even a late good response may still predict a successful prognosis. Our life-cycle study is being continued and targets to answer the question whether or not childhood-onset epilepsy is a risk factor for premature and/or increased incidence of mental impairment and dementia.

Long-term seizure and psychosocial outcomes after resective surgery for intractable epilepsy

Resective surgery is considered an effective treatment for refractory localization-related epilepsy. Most studies have reported seizure and psychosocial outcomes of 2-5 years postsurgery and a few up to 10 years. Our study aimed to assess long-term (up to 15 years) postsurgical seizure and psychosocial outcomes at our epilepsy center. The Henry Ford Health System Corporate Data Store was accessed to identify patients who had undergone surgical resection for localization-related epilepsy from 1993 to 2011. Demographics including age at epilepsy onset and surgery, seizure frequency before surgery, and pathology were gathered from electronic medical records. Phone surveys were conducted from May 2012 to January 2013 to determine patients' current seizure frequency and psychosocial metrics including driving and employment status and use of antidepressants. Surgical outcomes were based on Engel's classification (classes I and II=favorable outcomes). McNemar's tests, chi-square tests, two sample t-tests, and Wilcoxon two sample tests were used to analyze the relationships of psychosocial and surgical outcomes with demographic and surgical characteristics. A total of 470 patients had resective epilepsy surgery, and of those, 50 (11%) had died since surgery. Of the remaining, 253 (60%) were contacted with mean follow-up of 10.6±5.0years (27% of patients had follow-up of 15 years or longer). Of the patients surveyed, 32% were seizure-free and 75% had a favorable outcome (classes I and II). Favorable outcomes had significant associations with temporal resection (78% temporal vs 58% extratemporal, p=0.01) and when surgery was performed after scalp EEG only (85% vs 65%, p<0.001). Most importantly, favorable and seizure-free outcome rates remained stable after surgery over long-term follow-up [i.e., <5 years (77%, 41%), 5-10 years (67%, 29%), 10-15 years (78%, 38%), and >15 years (78%, 26%)]. Compared to before surgery, patients at the time of the survey were more likely to be driving (51% vs 35%, p<0.001) and using antidepressants (30% vs 22%, p=0.013) but less likely to be working full-time (23% vs 42%, p<0.001). A large majority of patients (92%) considered epilepsy surgery worthwhile regardless of the resection site, and this was associated with favorable outcomes (favorable=98% vs unfavorable=74%, p<0.001). The findings suggest that resective epilepsy surgery yields favorable long-term postoperative seizure and psychosocial outcomes.

Outcomes after Epilepsy Surgery

Epilepsy surgery is a highly effective and durable treatment for specific types of drug resistant epilepsy such as temporal lobe epilepsy. assessment of outcomes is essential in epilepsy surgery, which is an irreversible intervention for a chronic condition. Excellent short-term results of resective epilepsy surgery have been established. In the last years more information regarding long term outcomes have been published. This article reviews the best available evidence about the best measures to assess outcomes and the most important evidence. The outcomes reviewed in this article are the following: seizure outcome, social and psychiatric outcomes, complications and mortality.

Clinical conditions of long-term cure in childhood-onset epilepsy: a 45-year follow-up study

Clinical conditions of long-term cure in childhood-onset epilepsy, defined as sustained remission off antiepileptic drug (AED) treatment, are not well known. To address that clinically important question, we determined clinical factors predictive of long-term seizure cure in a population-based cohort of 133 patients followed up since their first seizure before the age of 16 years. At the end of the 45-year follow-up (mean=39.8, median=44, range=11-47), 81 (61%) of the 133 patients had entered at least 5-year remission off AEDs, meeting our definition of cure. The 81 patients were seizure-free off AEDs for a mean of 34.4 (median=38, range=6-46) years and 59 (73%) of the 81 patients following the first standard medication until the end of follow-up (mean=36.5, median=39, range=14-46 years). Four independent factors were found to be associated with cure compared with having seizures while on AEDs: seizure frequency less than weekly during the first 12 months of AED treatment (p=0.002), pretreatment seizure frequency less than weekly (p=0.002), higher IQ (>70; p=0.021), and idiopathic or cryptogenic vs. symptomatic etiology (p=0.042). Patients with seizure frequency of less than once a week during early treatment and idiopathic etiology had a ninefold chance to of being cured since the onset of the first adequate antiepileptic therapy until the end of follow-up compared with patients who a symptomatic etiology had at least weekly seizures while on AEDs (RR=8.7, 95% CI=2.0-37.0; p<0.001). In conclusion, IQ, etiology, and seizure frequencies both in the first year of AED treatment and prior to medication appear to be clinical predictors of cure in childhood-onset epilepsy.

Long-term seizure and psychosocial outcomes of epilepsy surgery

Most results reported in studies focusing on long-term outcomes of epilepsy surgery resemble those reported in studies with shorter follow-up, indicating that many of the surgical results are enduring. In general, about 60% of patients with temporal epilepsy and 25% to 40% of those with extratemporal epilepsy achieve long-term seizure freedom after epilepsy surgery. Over a long term, about 20% of patients discontinue antiepileptic drugs, whereas 41% continue monotherapy and 31% use polytherapy. Evidence concerning the impact of epilepsy surgery on mortality is inconclusive, but some data support a reduction in the risk of death if patients become seizure-free. The information regarding long-term cognitive outcomes is limited but is similar to that derived from short-term studies. Decline in verbal memory occurs frequently after resections of the left temporal lobe; better memory outcomes are reported in seizure-free patients, and memory decline has been documented in patients with intractable epilepsy who do not undergo surgery. However, important confounders such as the effects of antiepileptic drugs, practice effects, and regression to the mean have not been adequately accounted for in these studies. All uncontrolled long-term studies report improved psychosocial outcomes with epilepsy surgery, including employment, education, driving status, satisfaction, and quality of life, but the results of the few existing controlled studies are less persuasive.

Long term outcome in patients not initially seizure free after resective epilepsy surgery

PURPOSE

To assess the long-term seizure outcome and find predictors of outcome for patients who were not initially seizure free 6 months after epilepsy surgery.

METHODS

We retrospectively reviewed all adult patients who underwent epilepsy surgery at the Epilepsy Center Bethel, between 1992 and 2003. There were 266 patients included in this analysis.

RESULTS

Of the 266 patients who were included in this study, the probability of becoming seizure free was 12% (95%CI 8-16%) after 2 years, 19.5% (95%CI 15-24%) after 5 years and 34.7% (95%CI 28-41%) after 10 years. In patients who had auras only, the probability of being seizure free was 18.2% after 2 years, 25.5% after 5 years, and 39.1% after 10 years. In the multiregression analysis, the EEG carried out 2 years after surgery, a psychic aura, the frequency of postoperative focal seizures and hypermotor seizures predicted seizure remission in the long-term outcome.

CONCLUSIONS

The frequency and type of postoperative seizures are critical determinants for long-term outcome. Seizure semiology may be the clue to a precise diagnosis and long-term prognosis of epilepsy.

Epilepsy surgery: a critical review

The objective of surgical treatment of epilepsy is seizure control and improvement of quality-of-life of patients with medically intractable epilepsy. Confirmation of the diagnosis of epilepsy and its medical intractability is the essential prerequisite for epilepsy surgery. After excluding nonepileptic events such as psychogenic pseudoseizures, the clinician must establish that adequate drug trials, including verification of compliance, have been performed. A careful diagnostic evaluation is mandatory to localize the epileptogenic zone. In this review we discuss the role of different diagnostic methods with respect to patient selection and surgical outcome. Furthermore, experimental approaches are mentioned and the reasons for failures of epilepsy surgery are critically discussed.

Modern management of epilepsy: a practical approach

The epilepsies are among the most common serious brain disorders, can occur at all ages, and are characterized by a variety of presentations and causes. Diagnosis of epilepsy remains clinical, and neurophysiological investigations support the diagnosis of the syndrome. Brain imaging is able to identify many of the structural causes of the epilepsies. Current antiepileptic drugs (AEDs) block seizures without influencing the underlying tendency to generate seizures, and are effective in 60-70% of individuals. Several modern drugs are as efficacious as the older medications, but have important advantages including the absence of adverse drug interactions and hypersensitivity reactions. Epilepsy is associated with an increased prevalence of mental health disorders including anxiety, depression, and suicidal thoughts. An understanding of the psychiatric correlates of epilepsy is important to the adequate management of people with epilepsy. Anticipation of common errors in the diagnosis and management of epilepsy is important. Frequent early diagnostic errors include nonepileptic psychogenic seizures, syncope with myoclonus, restless legs syndrome, and REM behavioral disorders, the last mostly in elderly men. Overtreatment with too rapid titration and too high doses or too many AEDs should be avoided. For people with refractory focal epilepsy, vagus nerve stimulation offers palliative treatment with possible mood improvement and neurosurgical resection offers the possibility of a life-changing cure. Potential advances in the management of epilepsy are briefly discussed. This short review summarizes the authors' how-to-do approach to the modern management of people with epilepsy.

Long-term follow-up outcome after surgical treatment for lesional temporal lobe epilepsy

OBJECTIVES

Lateral or neocortical temporal lobe epilepsy (TLE) is regarded as a distinct clinical entity from medial TLE. Surgery for neocortical TLE can be considered as a viable treatment option; however, there is very limited information available on aspects such as long-term seizure outcome. Thus, we retrospectively reviewed our ten surgical cases of lateral TLE with a minimum 2 year follow-up outcome.

METHODS

The series comprised four male and six female patients, ranging in age from 3 to 46 years (mean: 28.8 years). Seven cases were found to be drug-resistant. Invasive pre-surgical evaluation for intractable epilepsy was performed in six patients.

RESULTS

The pathologic lesions were removed completely in nine cases. Lesionectomy alone was performed in four cases and total epileptogenic focus resection was confirmed in four cases. The epileptogenic regions within eloquent areas were preserved in two cases. The medial temporal structure was intact and preserved in all cases. Neuropathologic diagnoses were cavernoma in three cases, astrocytoma (grade 2) in two cases, arteriovenous malformation in two cases, gliosis in two cases and ganglioglioma in one case. The mean duration of follow-up was 6.5 years (range: 2.2-9.3 years). Outcomes categorized according to Engel classes were class I (E1) in six cases and class II (E2) in four cases. Patients who had post-operative seizures may also achieve long-term seizure decrease or freedom in three cases: case 5 (E4-E2), case 6 (E4-E2) and case 7 (E3-E1). Thus, worthwhile improvement was achieved in 100% of the cases in this series, with 60% of patients being seizure-free during the followed-up period.

CONCLUSIONS

The controlled long-term follow-up results suggested that surgery for lesional TLE can be considered as a viable treatment option to control seizure with a low morbidity rate and good outcomes.

Proportional Feedback Stimulation for Seizure Control in Rats

PURPOSE

A responsive electrical brain stimulation system using control feedback was investigated for the treatment of seizures.

METHODS

A proportional feedback stimulation system was designed. Penicillin-induced episodic seizures were created in rat primary motor cortex. Both intracranial (proximal to seizure focus) and extracranial EEGs were monitored. Current stimulation was applied at the seizure focus by using the intracranial EEG as the current-stimulus template. Different gains (H) for determining feedback stimulus amplitudes were tested.

RESULTS

The effect of feedback stimulation on seizures was initially assessed by measuring change in variance of the amplitude histogram of the intracranial EEG before and during stimulation. Mean reduction in amplitude variance during seizure activity was significant, with variance during stimulation progressively reduced as feedback gain was increased, indicating that overall suppression of seizure amplitude depended on H. Further increases in feedback gain typically produced saturating oscillations, indicating that this level of H resulted in instability. Frequency analysis of seizure and stimulation periods for each of the effective levels of H demonstrated close correlation across a large frequency domain, suggesting that the reduction in EEG seizure amplitude during feedback stimulation was possibly because of shunting of neuronal currents near electrodes as opposed to an alteration of neuronal dynamics. Although the frequency and energy responses during seizures before or during feedback stimulation remained well correlated in the delta band, this correlation progressively decreased across the theta, alpha, and beta bands.

CONCLUSIONS

These results demonstrate that proportional feedback stimulation holds the promise of suppressing seizure activity. More-complicated control algorithms for generating feedback stimulation may provide further improvements in seizure suppression.

Neurosurgery for the treatment of epilepsy

PURPOSE OF REVIEW

Epilepsy is a common condition that is estimated to afflict 0.5-1.0% of the world's population. Frequently commencing in childhood, it is often associated with life-long disability. Approximately one-third of patients with epilepsy are refractory to antiepileptic drug therapy and many of these patients are candidates for surgical treatment. A growing body of evidence supports the safety and efficacy of surgery for the treatment of selected patients with epilepsy. Little information is available in the anesthesia literature regarding the presurgical assessment of candidates for surgical treatment.

RECENT FINDINGS

The presurgical identification of suitable candidates involves a multidisciplinary approach to assessment. Recent advances, particularly in neuroimaging techniques, are dramatically enhancing the capacity to accurately identify patients who are most likely to benefit from surgery. Epilepsy surgery is underused worldwide and in developed countries. In view of current efforts to increase opportunities to provide surgical treatment to more patients and to offer surgery earlier in the course of the disorder, the number of patients requiring specialized perioperative anesthetic care is expected to increase.

SUMMARY

This article provides anesthesiologists with an overview of the assessment process, investigation techniques and current rationale that influence the selection of appropriate candidates for surgical treatment and the associated need for specialized anesthetic care.

Protective effect of vineatrol against kainic acid induced seizures, oxidative stress and on the expression of heat shock proteins in rats

The aim of the present study was to evaluate the effect of an antioxidant vineatrol against kainic acid-induced seizures, markers of oxidative stress and expression of heat shock protein in brain. In rats, kainic acid (10 mg/kg i.p.) induced long lasting seizures, associated behavioral symptoms and brain damage and significantly increased level of brain malondialdehyde (MDA) (283 +/- 42 nmol/g wet tissue) as compared to control (173.3 +/- 10.2 nmol/g wet tissue). Pretreatment (5 min) of vineatrol (10, 20 and 40 mg/kg i.p.) could not inhibit the convulsions though the latency was significantly increased with 20 and 40 mg/kg. However when the drug was administrated 5 min prior and repeated at 30 and 90 min after kainic acid there was significant reduction in incidence of convulsions. The brain MDA levels were also found to be significantly attenuated, however the glutathione levels were not different in control, kainic acid and vineatrol treated animals. Expression of heat shock protein (HSP) 72 was observed in the kainic acid per se group indicating neurotoxicity as compared to the control group and was reduced by vineatrol. The study suggests the potential use of vineatrol in status epilepticus.

Antiepileptic Drug Withdrawal after Successful Surgery for Intractable Temporal Lobe Epilepsy

PURPOSE

To investigate the prognosis related to antiepileptic drug (AED) discontinuation after successful surgery for intractable temporal lobe epilepsy.

METHODS

The clinical courses after temporal lobectomies (TLs) were retrospectively analyzed in 88 consecutive patients. All the patients had TLs as the only surgical procedure, and they had been followed up for longer than 3 years. AED discontinuation was attempted if the patient had been seizure free without aura for >or=1 year during the follow-up period.

RESULTS

Sixty-six (75%) patients achieved complete seizure freedom for >or=1 year; 28 patients were seizure free immediately after surgery (immediate success); and 38 patients became seizure free after some period of recurrent seizures (delayed success). AED discontinuation was attempted in 60 (91%) of 66 patients with a successful outcome. In 13 (22%) patients, seizure relapse developed during AED reduction (n=60), and in seven (12%) patients after discontinuation of AEDs (n=38). The seizure recurrence rate was not different between the immediate-and delayed-success groups. Among 20 patients with seizure relapse related to AED tapering, nine (45%) of them regained seizure freedom after reinstitution of AED treatment, and AEDs were eventually discontinued in six of them. Seizures that recurred after complete AED discontinuation had a better prognosis than did the seizures that recurred during AED reduction (seizure freedom in 86% vs. 23%). At the final assessment, 54 (61%) patients had been seizure free >or=1 year; 37 without AEDs and 17 with AEDs. The successful discontinuation of AEDs was more frequent for patients with a younger age at the time of surgery and for those patients with shorter disease duration.

CONCLUSIONS

Our results suggest that seizure freedom without aura at >or=1 year is a reasonable indication for the attempt at AED discontinuation. The subsequent control of recurrent seizures was excellent, especially if seizures relapsed after the complete discontinuation of AEDs. Younger age at the time of surgery and a shorter disease duration seem to affect successful AED discontinuation for a long-term period.

The impact of temporal lobe surgery on cure and mortality of drug-resistant epilepsy: summary of a workshop

The Third International Spring Epilepsy Research Conference took place in Georgetown, Cayman Islands from April 26 to May 3, 2003. One workshop discussed the impact of epilepsy surgery on seizure outcome and mortality of antiepileptic drug (AED)-resistant temporal lobe epilepsy. This article summarizes the information presented at this workshop. Although two-thirds of adult patients undergoing epilepsy surgery become seizure-free with continued AED treatment, current clinical experience shows that seizure recurrence occurs in one-third of patients when AEDs are withdrawn under medical supervision. Additional seizure recurrence occurring after AED taper, poor drug compliance and even while patients continue on AEDs after surgery leave only approximately one-third of patients cured after temporal lobe resection. Mostly because so many patients prefer to stay on AEDs although they are free of disabling seizures after surgery, a randomised controlled trial of AED discontinuation is needed to determine if in fact only one-third of patients are cured after surgery. Based on the functional anatomy of temporal lobe surgery two hypotheses are presented why only a minority of patients are cured after surgery. The type and the prognostic significance of seizures after surgery is discussed. Recent studies have suggested that successful temporal lobe surgery may be able to normalize the increased standard mortality ratio (SMR) of drug-resistant temporal lobe epilepsy. However, pre-existing differences in SMR between those cured and those not cured by temporal lobe surgery and other unresolved methodological issues make it difficult at present to fully evaluate the impact of surgery on mortality. Future studies are thus warranted to specifically address the impact of temporal lobe surgery on cure and mortality.