ILAE Commission on the Burden of Epilepsy, Subcommission on the Economic Burden of Epilepsy: Final report 1998-2001

MicroRNA-33 regulates the synaptic plasticity-related gene ARC in temporal lobe epilepsy

This study aimed to elucidate the expression patterns of miR-33 and ARC in both a rat model of temporal lobe epilepsy (TLE) and human TLE patients, to explore the role of miR-33 in epilepsy onset through its regulation of ARC expression in the hippocampus. Our findings, supported by a Dual-Luciferase reporter assay, suggest that miR-33 can bind to the 3' UTR region of ARC. We observed that miR-33 levels were reduced at 1 hour and 60 days post-seizure, while ARC expression notably increased at these time points. In the hippocampal CA1 and CA3 regions of post-seizure rats, ARC expression significantly exceeded that of control groups. Following the transfection of HEK cells with a miR-33 mimic, there was a decrease in both ARC mRNA and protein levels, whereas the group treated with a miR-33 inhibitor displayed the opposite effect. RNA sequencing in TLE patients revealed a similar miR-33 and ARC interaction. The regulation of Arc expression by miR-33 suggests that Arc may be a target gene of miR-33 in the context of epilepsy. Our findings indicate that miR-33 downregulation could contribute to the dysregulation of Arc expression observed in TLE, potentially influencing the disease process. Further studies are required to establish the exact role of miR-33-mediated Arc regulation in the development of epilepsy.

Testing an online screening tool for epilepsy surgery evaluation

BACKGROUND

 Epilepsy surgery is recognized for its effectiveness in controlling seizures in a significant number of patients with drug-resistant epilepsy. Despite this, there remains a notable deficiency in referring these patients for video-electroencephalogram (EEG) monitoring and surgical evaluation. Addressing this gap, the Canadian Appropriateness of Epilepsy Surgery (CASES), an online tool for epilepsy surgery evaluation (www.epilepsycases.com), was developed to aid physicians in the referral process of patients with refractory epilepsy to surgical assessments.

OBJECTIVE

 The present study aimed to evaluate the utility of CASES in identifying candidates for epilepsy surgery, thereby facilitating clinical decision-making for patients with drug-resistant epilepsy.

METHODS

 A cross-sectional analysis was conducted using the CASES platform to assess surgical candidacy among individuals with epilepsy. Participants were selected among those receiving care at the Epilepsy Clinic of the Neurology Service, Hospital de Clínicas de Porto Alegre, Brazil, over a 3-month period. The study cohort included 211 patients. Data were systematically extracted from patient medical records or collected during clinical appointments.

RESULTS

 Of the evaluated cohort, 59.6% were identified as potential candidates for video-EEG monitoring and subsequent surgical evaluation. Factors significantly associated with recommendations for video-EEG and surgical assessment included seizure frequency, the number of antiseizure medications (ASMs) trialed, and the occurrence of drug-related adverse effects.

CONCLUSION

 The CASES showed significant potential in guiding recommendations for video-EEG monitoring and facilitating referrals for epilepsy surgery. This tool may not only enhance patient treatments and outcomes but also contribute to cost savings in epilepsy management in both the short and long term.

Missed, mistaken, stalled: Identifying components of delay to diagnosis in epilepsy

A substantial proportion of individuals with newly diagnosed epilepsy report prior seizures, suggesting a missed opportunity for early epilepsy care and management. Consideration of the causes and outcomes of diagnostic delay is needed to address this issue. We aimed to review the literature pertaining to delay to diagnosis of epilepsy, describing the components, characteristics, and risk factors for delay. We undertook a systematic search of the literature for full-length original research papers with a focus on diagnostic delay or seizures before diagnosis, published 1998-2020. Findings were collated, and a narrative review was undertaken. Seventeen papers met the inclusion criteria. Studies utilized two measures of diagnostic delay: seizures before diagnosis and/or a study-defined time between first seizure and presentation/diagnosis. The proportion of patients with diagnostic delay ranged from 16% to 77%; 75% of studies reported 38% or more to be affected. Delays of 1 year or more were reported in 13%-16% of patients. Seizures prior to diagnosis were predominantly nonconvulsive, and usually more than one seizure was reported. Prior seizures were often missed or mistaken for symptoms of other conditions. Key delays in the progression to specialist review and diagnosis were (1) "decision delay" (the patient's decision to seek/not seek medical review), (2) "referral delay" (delay by primary care/emergency physician referring to specialist), and (3) "attendance delay" (delay in attending specialist review). There were few data available relevant to risk factors and virtually none relevant to outcomes of diagnostic delay. This review found that diagnostic delay consists of several components, and progression to diagnosis can stall at several points. There is limited information relating to most aspects of delay apart from prevalence and seizure types. Risk factors and outcomes may differ according to delay characteristics and for each of the key delays, and recommendations for future research include examining each before consideration of interventions is made.

MicroRNAs and target genes in epileptogenesis

Epilepsy is a chronic brain dysfunction. Current antiepileptic medicines cannot prevent epileptogenesis. Increasing data have shown that microRNAs (miRNAs) are selectively altered within the epileptic hippocampi of experimental models and human tissues, and these alterations affect the genes that control epileptogenesis. Furthermore, manipulation of miRNAs in animal models can modify epileptogenesis. As a result, miRNAs have been proposed as promising targets for treating epilepsy. We searched PubMed using the terms "microRNAs/miRNAs AND epilepsy", "microRNAs/miRNAs AND epileptogenesis", and "microRNAs/miRNAs AND seizure". We selected the articles in which the relationship between miRNAs and target gene(s) was validated and manipulation of miRNAs in in vivo epilepsy models modified epileptogenesis during the chronic phase via gene regulation. A total of 13 miRNAs were found in the present review. Based on the current analysis of miRNAs and their target gene(s), each miRNA has limitations as a potential epilepsy target. Importantly, miR-211 or miR-128 transgenic mice displayed seizures. These findings highlight new developments for epileptogenesis prevention. Developing novel strategies to modify epileptogenesis will be effective in curing epilepsy patients. This article provides an overview of the clinical application of miRNAs as novel targets for epilepsy.

Emergency hospital care for adults with suspected seizures in the NHS in England 2007-2013: a cross-sectional study

AIMS

To quantify the frequency, characteristics, geographical variation and costs of emergency hospital care for suspected seizures.

DESIGN

Cross-sectional study using routinely collected data (Hospital Episode Statistics).

SETTING

The National Health Service in England 2007-2013.

PARTICIPANTS

Adults who attended an emergency department (ED) or were admitted to hospital.

RESULTS

In England (population 2011: 53.11 million, 41.77 million adults), suspected seizures gave rise to 50 111 unscheduled admissions per year among adults (≥18 years). This is 47.1% of unscheduled admissions for neurological conditions and 0.71% of all unscheduled admissions. Only a small proportion of admissions for suspected seizures were coded as status epilepticus (3.5%) and there were a very small number of dissociative (non-epileptic) seizures. The median length of stay for each admission was 1 day, the median cost for each admission was £1651 ($2175) and the total cost of all admissions for suspected seizures in England was £88.2 million ($116.2 million) per year. 16.8% of patients had more than one admission per year. There was significant geographical variability in the rate of admissions corrected for population age and gender differences and some areas had rates of admission which were consistently higher than the average.

CONCLUSIONS

Our data show that suspected seizures are the most common neurological cause of admissions to hospital in England, that readmissions are common and that there is significant geographical variability in admission rates. This variability has not previously been reported in the published literature. The cause of the geographical variation is unknown; important factors are likely to include prevalence, deprivation and clinical practice and these require further investigation. Dissociative seizures are not adequately diagnosed during ED attendances and hospital admissions.

Cross-sectional study of the hospital management of adult patients with a suspected seizure (EPIC2)

OBJECTIVE

To determine the clinical characteristics, management and outcomes of patients taken to hospital by emergency ambulance after a suspected seizure.

DESIGN

Quantitative cross-sectional retrospective study of a consecutive series of patients.

SETTING

An acute hospital trust in a large city in England.

PARTICIPANTS

In 2012-2013, the regions' ambulance service managed 605 481 emergency incidents, 74 141/605 481 originated from Sheffield (a large city in the region), 2121/74 141 (2.9%) were suspected seizures and 178/2121 occurred in May 2012. We undertook detailed analysis of the medical records of the 91/178 patients who were transported to the city's acute hospital. After undertaking a retrospective review of the medical records, the best available aetiological explanation for the seizures was determined.

RESULTS

The best available aetiological explanation for 74.7% (68/91) of the incidents was an epileptic seizure, 11.0% (10/91) were psychogenic non-epileptic seizures and 9.9% (9/91) were cardiogenic events. The epileptic seizures fall into the following four categories: first epileptic seizure (13.2%, 12/91), epileptic seizure with a historical diagnosis of epilepsy (30.8%, 28/91), recurrent epileptic seizures without a historical diagnosis of epilepsy (20.9%, 19/91) and acute symptomatic seizures (9.9%, 9/91). Of those with seizures (excluding cardiogenic events), 2.4% (2/82) of patients were seizing on arrival in the Emergency Department (ED), 19.5% (16/82) were postictal and 69.5% (57/82) were alert. 63.4% (52/82) were discharged at the end of their ED attendance and 36.5% (19/52) of these had no referral or follow-up.

CONCLUSIONS

Most suspected seizures are epileptic seizures but this is a diagnostically heterogeneous group. Only a small minority of patients require emergency medical care but most are transported to hospital. Few patients receive expert review and many are discharged home without referral to a specialist leaving them at risk of further seizures and the associated morbidity, mortality and health services costs of poorly controlled epilepsy.

Joint reconstruction of Ictal/inter-ictal SPECT data for improved epileptic foci localization

PURPOSE

To improve the performance for localizing epileptic foci, we have developed a joint ictal/inter-ictal SPECT reconstruction method in which ictal and inter-ictal SPECT projections are simultaneously reconstructed to obtain the differential image.

METHODS

We have developed a SPECT reconstruction method that jointly reconstructs ictal and inter-ictal SPECT projection data. We performed both phantom and patient studies to evaluate the performance of our joint method for epileptic foci localization as compared with the conventional subtraction method in which the differential image is obtained by subtracting the inter-ictal image from the co-registered ictal image. Two low-noise SPECT projection datasets were acquired using ^99m Tc and a Hoffman head phantom at two different positions and orientations. At one of the two phantom locations, a low-noise dataset was also acquired using a ^99m Tc-filled 3.3-cm sphere with a cold attenuation background identical to the Hoffman phantom. These three datasets were combined and scaled to mimic low-noise clinical ictal (three different lesion-to-background contrast levels: 1.25, 1.55, and 1.70) and inter-ictal scans. For each low-noise dataset, 25 noise realizations were generated by adding Poisson noise to the projections. The mean and standard deviation (SD) of lesion contrast in the differential images were computed using both the conventional subtraction and our joint methods. We also applied both methods to the 35 epileptic patient datasets. Each differential image was presented to two nuclear medicine physicians to localize a lesion and specify a confidence level. The readers' data were analyzed to obtain the localized-response receiver operating characteristic (LROC) curves for both the subtraction and joint methods.

RESULTS

For the phantom study, the difference between the mean lesion contrast in the differential images obtained using the conventional subtraction versus our joint method decreases as the iteration number increases. Compared with the conventional subtraction approach, the SD reduction of lesion contrast at the 10^th iteration using our joint method ranges from 54.7% to 68.2% (P < 0.0005), and 33.8% to 47.9% (P < 0.05) for 2 and 4 million total inter-ictal counts, respectively. In the patient study, our joint method increases the area under LROC from 0.24 to 0.34 and from 0.15 to 0.20 for the first and second reader, respectively. We have demonstrated improved performance of our method as compared to the standard subtraction method currently used in clinical practice.

CONCLUSION

The proposed joint ictal/inter-ictal reconstruction method yields better performance for epileptic foci localization than the conventional subtraction method.

Welfare cost of childhood- and adolescent-onset epilepsy: A controlled national study

OBJECTIVES

Epilepsy is associated with a significant burden to patients and society. We calculated the factual excess in direct and indirect costs associated with childhood- and adolescent-onset epilepsy.

METHODS

Using records from the Danish National Patient Registry (1998-2002), we identified 3123 and 5018 patients with epilepsy aged 0-5years and 6-20years at the time of diagnosis, respectively. The two age groups of patients with epilepsy were matched to 6246 and 10,036 control persons without epilepsy, respectively, by gender, age, and geography. The controls were randomly chosen from the Danish Civil Registration System. Welfare costs included outpatient services, inpatient admissions, and emergency room visits based on the Danish National Patient Registry and information from the primary health-care sector based on data from the Danish Ministry of Health. This allowed the total health-care cost of epilepsy to be estimated. The use and costs of drugs were based on data from the Danish Medicines Agency. The frequencies of visits to outpatient clinics and hospitalizations and costs from primary sectors were based on data obtained from the National Patient Registry.

RESULTS

Children with epilepsy had higher welfare costs than controls. The highest cost was found one year after diagnosis, with higher costs up to 10years after diagnosis compared with controls. Children aged 0-5years incurred greater health-care costs than those aged 6-20years.

CONCLUSION

Epilepsy has major socioeconomic consequences for the individual person with epilepsy and for society.

Addressing the burden of epilepsy: Many unmet needs

Epilepsy is a heterogeneous clinical condition characterized by recurrent unprovoked seizures, their causes and complications. The incidence, prevalence and mortality of epilepsy vary with age, place and time contributing to a variable extent to the burden of the disease. Diagnostic misclassification may have strong impact on personal and societal reflections of the disease in light of its clinical manifestations and the need for chronic treatment. Epilepsy accounts for a significant proportion of the world's disease burden ranking fourth after tension-type headache, migraine and Alzheimer disease. Among neurological diseases, it accounts for the highest disability-adjusted life year rates both in men and in women. Although epilepsy is self-remitting in up to 50% of cases, variable long-term prognostic patterns can be identified based on the response to the available treatments. Epilepsy carries an overall increased risk of premature mortality with variable estimates across countries. Premature mortality predominates in patients aged less than 50 years, with epilepsies due to structural/metabolic conditions, with generalized tonic-clonic seizures, and seizures not remitting under treatment. Among deaths directly attributable to epilepsy or seizures, included are sudden unexpected death in epilepsy (SUDEP), status epilepticus, accidents, drowning, unintentional injuries, and suicide. Somatic and psychiatric disorders prevail in patients with epilepsy than in people without epilepsy. Asthma, migraine and cerebral tumors tend to occur more frequently in younger adults while cardiovascular disorders, stroke, dementia and meningioma predominate in the elderly. As being a fairly common clinical condition affecting all ages and requiring long-term (sometimes lifelong) treatment, epilepsy carries high health care costs for the society. Direct costs peak in the first year after diagnosis and then vary according to the severity of the disease, the response to treatment, and the presence of comorbidity. Although in several countries the costs of epilepsy are met by the national health systems, out-of-pocket costs may be a relevant fraction of the overall costs, especially in countries where the public management of health care is suboptimal or non-existent. Epilepsy strongly affects patients' independence, psychological health and emotional adjustment. Epilepsy impairs all aspects of health-related quality of life. Awareness and attitudes of the public about epilepsy may significantly affect the burden of the disease. All these factors add to the burden of the disease. However, many of the factors implicated in the onset of epilepsy, its course and treatment can be favorably addressed with appropriate strategic plans. More research is needed to investigate and manage the medical and psychosocial implications of epilepsy.

Towards precision medicine in epilepsy surgery

Up to a third of all patients with epilepsy are refractory to medical therapy even in the context of the introduction of new antiepileptic drugs (AEDs) with considerable advantages in safety and tolerability over the last two decades. It has been widely accepted that epilepsy surgery is a highly effective therapeutic option in a selected subset of patients with refractory focal seizure. There is no doubt that accurate localization of the epileptogenic zone (EZ) is crucial to the success of resection surgery for intractable epilepsy. The pre-surgical evaluation requires a multimodality approach wherein each modality provides unique and complimentary information. Accurate localization of EZ still remains challenging, especially in patients with normal features on MRI. Whereas substantial progress has been made in the methods of pre-surgical assessment in recent years, which widened the applicability of surgical treatment for children and adults with refractory seizure. Advances in neuroimaging including voxel-based morphometric MRI analysis, multimodality techniques and computer-aided subtraction ictal SPECT co-registered to MRI have improved our ability to identify subtle structural and metabolic lesions causing focal seizure. Considerable observations from animal model with epilepsy and pre-surgical patients have consistently found a strong correlation between high frequency oscillations (HFOs) and epileptogenic brain tissue that suggest HFOs could be a potential biomarker of EZ. Since SEEG emphasizes the importance to study the spatiotemporal dynamics of seizure discharges, accounting for the dynamic, multidirectional spatiotemporal organization of the ictal discharges, it has greatly deep our understanding of the anatomo-electro-clinical profile of seizure. In this review, we focus on some state-of-the-art pre-surgical investigations that contribute to the precision medicine. Furthermore, advances also provide opportunity to achieve the minimal side effects and maximal benefit individually, which meets the need for the current concept of precision medicine in epilepsy surgery.

Costs of epilepsy and cost-driving factors in children, adolescents, and their caregivers in Germany

OBJECTIVE

To provide first data on the cost of epilepsy and cost-driving factors in children, adolescents, and their caregivers in Germany.

METHODS

A population-based, cross-sectional sample of consecutive children and adolescents with epilepsy was evaluated in the states of Hessen and Schleswig-Holstein (total of 8.796 million inhabitants) in all health care sectors in 2011. Data on socioeconomic status, course of epilepsy, and direct and indirect costs were recorded using patient questionnaires.

RESULTS

We collected data from 489 children and adolescents (mean age ± SD 10.4 ± 4.2 years, range 0.5-17.8 years; 264 [54.0%] male) who were treated by neuropediatricians (n = 253; 51.7%), at centers for social pediatrics ("Sozialpaediatrische Zentren," n = 110, 22.5%) and epilepsy centers (n = 126; 25.8%). Total direct costs summed up to €1,619 ± €4,375 per participant and 3-month period. Direct medical costs were due mainly to hospitalization (47.8%, €774 ± €3,595 per 3 months), anticonvulsants (13.2%, €213 ± €363), and ancillary treatment (9.1%, €147 ± €344). The total indirect costs amounted to €1,231 ± €2,830 in mothers and to €83 ± €593 in fathers; 17.4% (n = 85) of mothers and 0.6% (n = 3) of fathers reduced their working hours or quit work because of their child's epilepsy. Independent cost-driving factors were younger age, symptomatic cause, and polytherapy with anticonvulsants. Older age, active epilepsy, symptomatic cause, and polytherapy were independent predictors of higher antiepileptic drug (AED) costs, whereas younger age, longer epilepsy duration, symptomatic cause, disability, and parental depression were independent predictors for higher indirect costs.

SIGNIFICANCE

Treatment of children and adolescents with epilepsy is associated with high direct costs due to frequent inpatient admissions and high indirect costs due to productivity losses in mothers. Direct costs are age-dependent and higher in patients with symptomatic epilepsy and polytherapy. Indirect costs are higher in the presence of a child's disability and parental depression.

Rates and predictors of seizure freedom in resective epilepsy surgery: an update

Epilepsy is a debilitating neurological disorder affecting approximately 1 % of the world's population. Drug-resistant focal epilepsies are potentially surgically remediable. Although epilepsy surgery is dramatically underutilized among medically refractory patients, there is an expanding collection of evidence supporting its efficacy which may soon compel a paradigm shift. Of note is that a recent randomized controlled trial demonstrated that early resection leads to considerably better seizure outcomes than continued medical therapy in patients with pharmacoresistant temporal lobe epilepsy. In the present review, we provide a timely update of seizure freedom rates and predictors in resective epilepsy surgery, organized by the distinct pathological entities most commonly observed. Class I evidence, meta-analyses, and individual observational case series are considered, including the experiences of both our institution and others. Overall, resective epilepsy surgery leads to seizure freedom in approximately two thirds of patients with intractable temporal lobe epilepsy and about one half of individuals with focal neocortical epilepsy, although only the former observation is supported by class I evidence. Two common modifiable predictors of postoperative seizure freedom are early operative intervention and, in the case of a discrete lesion, gross total resection. Evidence-based practice guidelines recommend that epilepsy patients who continue to have seizures after trialing two or more medication regimens should be referred to a comprehensive epilepsy center for multidisciplinary evaluation, including surgical consideration.

Health plan paid cost of epilepsy in 2009 in the U.S

Our objectives were to estimate the health plan paid cost of epilepsy and to show major cost driver(s) of these costs. The health insurance claims and membership data from six U.S. health plans were analyzed. To prepare two comparison groups, individuals with epilepsy (n=5810) were match-paired with individuals without epilepsy (n=5810) using propensity scores derived from logistic regression using gender, age group, health plan product, and length of enrollment in the health plans. Total health plan paid cost per member per year (PMPY) was $11,232 for the epilepsy group and $3026 for the controls (p<0.001). The estimated cost PMPY for treatment of epilepsy was $8206. Relative distribution (%) of health plan paid costs ($) by cost driver category based on place of service (POS) indicated that the treatment of epilepsy places a larger cost burden in inpatient POS than in outpatient hospital or MD office POS compared to controls.

Evaluation of health-care utilization among adult patients with epilepsy in Germany

This study evaluated the resource use of patients with epilepsy in the German district of Marburg-Biedenkopf. A cross-sectional cohort of consecutive adults with epilepsy, irrespective of seizure severity, duration of illness and epilepsy syndrome, was investigated in all health-care sectors. Costs of inpatient and outpatient treatment were derived from billing data of participating hospitals and office-based physicians. Data on socioeconomic status, course of epilepsy and further direct and indirect costs were recorded using patient questionnaires. We enrolled 366 patients from the district of Marburg-Biedenkopf and calculated annual epilepsy-specific costs of €7738 per patient. Direct costs contributed 31.1% (€2406) and indirect costs 68.9% (€5332) of the total costs. Direct medical costs were mainly due to hospitalization (33.2% of total direct costs) and anticonvulsants (26.7%). Costs of admissions were due to status epilepticus (24.4%), video-EEG monitoring (14.8%), newly diagnosed patients (14.4%) and seizure-related injuries (8.8%). Indirect costs were mainly due to early retirement (38.0%), unemployment (35.9%) and days off due to seizures (26.2%). The mean costs of epilepsy found in our study were lower than those found in studies conducted at European epilepsy centers due to the inclusion of patients in all health-care sectors.

Caregiver measures for seizure control, efficacy, and tolerability of antiepileptic drugs for childhood epilepsy: results of a preference survey

We sought to identify and quantify caregiver-defined characteristics of efficacy related to the perceived success of antiepileptic drug (AED) use. A 22-question survey was designed using physician input, focus groups, and clinical trial endpoints. Responses were pooled and analyzed with regard to seizure type and treatment, categorized as controlled (exposure to 1 AED), adjunctive (exposure to 2 AEDs), or refractory (exposure to ≥3 AEDs). Two hundred ninety-five surveys were completed: 109 (37%) controlled, 84 (28%) adjunctive, and 102 (35%) refractory. Seizure freedom and median seizure reduction >90% maintained for >1 year were reported as the most important indicators of medication efficacy by the majority of respondents. These measures were the same regardless of seizure type or treatment category. Our results demonstrate that current trial design may be inadequate to address the expectations of patients. Incorporating patient-defined AED efficacy measures may improve satisfaction and informed decision making regarding epilepsy treatment.

Seizure prediction and its applications

Epilepsy is characterized by intermittent, paroxysmal, hypersynchronous electrical activity that may remain localized and/or spread and severely disrupt the brain's normal multitask and multiprocessing function. Epileptic seizures are the hallmarks of such activity. The ability to issue warnings in real time of impending seizures may lead to novel diagnostic tools and treatments for epilepsy. Applications may range from a warning to the patient to avert seizure-associated injuries, to automatic timely administration of an appropriate stimulus. Seizure prediction could become an integral part of the treatment of epilepsy through neuromodulation, especially in the new generation of closed-loop seizure control systems.

Knowledge, attitudes, and practice toward epilepsy (KAPE): a survey of Chinese and Vietnamese adults in the United States

We conducted, in four languages, the first national cross-sectional survey of the knowledge, attitudes, and practice with respect to epilepsy of Chinese- and Vietnamese-American adults. We used a convenience sampling method to recruit 2831 adults in seven states. Eighty-four percent had heard or read of epilepsy and 58% had seen a seizure, whereas only 34% knew someone with epilepsy. Forty-two percent would object to their children marrying a person with epilepsy, and 43% would not knowingly hire someone with epilepsy. We examined bivariate associations for questions of knowledge, attitudes, and practice with age, gender, ethnicity, nativity, language, and education. chi(2) analyses showed differences in knowledge of and attitudes toward epilepsy by age group, gender, ethnicity, and education. Although misconceptions and negative views about epilepsy are held by Chinese and Vietnamese populations living in the United States, our results show noteworthy differences in attitudes and practice in relation to previous studies in Asian countries.

A cost comparison of alternative regimens fortreatment-refractory partial seizure disorder: An econometric analysis

BACKGROUND

Partial seizure disorder is typically treated by monotherapy with antiepileptic drugs (AEDs). However, when the condition is refractory to the initial treatment regimen, patients may be switched to monotherapy with another AED or to combination therapy with the initial AED plus a second AED.

OBJECTIVES

The purpose of this study was to examine the economic costs associated with treatment-refractory partial seizure disorder and to compare the costs of 2 alternative approaches: a switch to oxcarbazepine (OXC) monotherapy or the addition to the regimen of another AED (AED add-on).

METHODS

Adult patients with a diagnosis of partial seizure disorder who received initial AED monotherapy between January 1, 2000, and March 31, 2003, were identified from the PharMetrics Patient-Centric Database, a health plan administrative claims database. The medical and pharmacy history of these patients was analyzed from 6 months before a change to either OXC monotherapy or AED add-on therapy through 12 months after the change in treatment. Total health care resource utilization and the associated costs were compared within each cohort before and after the change, as well as between cohorts, with statistical differences tested using Wilcoxon rank sum tests. Multivariate econometric analyses were performed to examine the impact of age, sex, geographic location, Charlson Comorbidity Index, and the presence of specific comorbidities.

RESULTS

Demographic and clinical characteristics 102 were similar between the OXC monotherapy cohort (n = 259) and the AED add-on cohort (n = 795). Annual direct treatment costs increased in both groups in the period after the failure of initial monotherapy, increasing from 10,462 US dollars to 11,360 US dollars in the OXC cohort and from 10,137 US dollars to 12,201 US dollars in the AED add on cohort (P < 0.01). Increased pharmacy costs were the primary driver behind cost increases in both cohorts. Patients in the AED add-on cohort were significantly more likely to have an emergency department visit during the period after the failure of initial monotherapy compared with the OXC monotherapy cohort (odds ratio = 1.52; P < 0.05).

CONCLUSION

Despite limitations, the results of retrospective analysis of claims data suggest that the care of patients with treatment-refractory partial seizure disorder is costly and may vary significantly based on the pattern of care.

Localizing Value of Ictal-Interictal SPECT Analyzed by SPM (ISAS)

PURPOSE

The goal of neuroimaging in epilepsy is to localize the region of seizure onset. Single-photon emission computed tomography with tracer injection during seizures (ictal SPECT) is a promising tool for localizing seizures. However, much uncertainty exists about how to interpret late injections, or injections done after seizure end (postictal SPECT). A widely available and objective method is needed to interpret ambiguous ictal and postictal scans, with changes in multiple brain regions.

METHODS

Ictal or postictal SPECT scans were performed by using [99mTc]-labeled hexamethyl-propylene-amine-oxime (HMPAO), and images were analyzed by comparison with interictal scans for each patient. Forty-seven cases of localized epilepsy were studied. We used methods that can be implemented anywhere, based on freely downloadable software and normal SPECT databases (http://spect.yale.edu). Statistical parametric mapping (SPM) was used to localize a single region of seizure onset based on ictal (or postictal) versus interictal difference images for each patient. We refer to this method as ictal-interictal SPECT analyzed by SPM (ISAS).

RESULTS

With this approach, ictal SPECT identified a single unambiguous region of seizure onset in 71% of mesial temporal and 83% of neocortical epilepsy cases, even with late injections, and the localization was correct in all (100%) cases. Postictal SPECT, conversely, with injections performed soon after seizures, was very poor at localizing a single region based on either perfusion increases or decreases, often because changes were similar in multiple brain regions. However, measuring which hemisphere overall had more decreased perfusion with postictal SPECT, lateralized seizure onset to the correct side in approximately 80% of cases.

CONCLUSIONS

ISAS provides a validated and readily available method for epilepsy SPECT analysis and interpretation. The results also emphasize the need to obtain SPECT injections during seizures to achieve unambiguous localization.

Effect of comorbidities on medical care use and cost among refractory patients with partial seizure disorder

PURPOSE

The goal of this work was to assess the effect of comorbidities on medical care use and costs among patients with partial seizure disorder who are also refractory to initial antiepileptic drug (AED) monotherapy.

METHODS

Retrospective data from the PharMetrics managed care claims database were collected for adult patients treated with AED monotherapy between January 1, 2000 and March 31, 2002. The associations of comorbidity, specifically the Charlson Comorbidity Index (CCI) and incidence of specific comorbid conditions, with total costs and with hospitalization were analyzed via econometric analysis and logistic regression.

RESULTS

Five hundred forty-nine patients were identified and analyzed. The odds of hospitalization were 3.7 times greater among patients with a CCI1, than for patients without comorbidities (OR=3.7, 95% CI=1.7-7.9), while treatment costs for all medical care were 136% higher (P<0.05). Depression had the largest marginal effect on costs and on the likelihood of hospitalization.

CONCLUSIONS

For patients refractory to initial AED monotherapy, the presence of comorbidities, especially depression, is associated with a substantial increase in medical care use and costs.

Epileptic seizure prediction and control

Epileptic seizures are manifestations of epilepsy, a serious brain dynamical disorder second only to strokes. Of the world's approximately 50 million people with epilepsy, fully 1/3 have seizures that are not controlled by anti-convulsant medication. The field of seizure prediction, in which engineering technologies are used to decode brain signals and search for precursors of impending epileptic seizures, holds great promise to elucidate the dynamical mechanisms underlying the disorder, as well as to enable implantable devices to intervene in time to treat epilepsy. There is currently an explosion of interest in this field in academic centers and medical industry with clinical trials underway to test potential prediction and intervention methodology and devices for Food and Drug Administration (FDA) approval. This invited paper presents an overview of the application of signal processing methodologies based upon the theory of nonlinear dynamics to the problem of seizure prediction. Broader application of these developments to a variety of systems requiring monitoring, forecasting and control is a natural outgrowth of this field.