The pathogenesis of tumour associated epilepsy

Tumour associated epilepsy (TAE) is a poorly understood manifestation of many gliomas, meningiomas and metastatic brain tumours that has important clinical and social implications. Etiological mechanisms underlying tumour associated epilepsy include theories invoking peritumoural amino acid disturbances, local metabolic imbalances, cerebral oedema, pH abnormalities, morphological changes in the neuropil, changes in neuronal and glial enzyme and protein expression and altered immunological activity. It has also been suggested that the pathology involves perturbations in distribution and function of the NMDA subclass of glutamate receptors. The often capricious response of the seizure disorder following removal of the causative neoplasms suggests multiple factors are involved. Further understanding about the pathogenesis of TAE will await the development and characterisation of suitable animal models that demonstrate the clinical manifestations and physiological changes comparable to those seen in human cerebral tumours. With such a model it is hoped that progress may one day be made in understanding and subsequently treating this debilitating clinical problem.

Epilepsy, vagal nerve stimulation by the NCP system, all-cause mortality, and sudden, unexpected, unexplained death

PURPOSE

This report concerns the 2-year extension of the study of mortality and sudden, unexpected, unexplained death in epilepsy (SUDEP) in the cohort of patients receiving vagal nerve stimulation by the NCP System for the treatment of epilepsy.

METHODS

A cohort of 1,819 individuals was followed 3,176.3 person-years from implantation. The 25 deaths that occurred during NCP System activation were reviewed for SUDEP by a panel.

RESULTS

The mortality rates were lower [standardized mortality ratio (SMR = 3.6)] with the extended follow-up compared to the previous finding (SMR = 5.3). The SUDEP rates (4.1 vs. 4.5 per 1,000 person-years) were similar to those in the previous study of this cohort. When the vagal nerve stimulation experience is stratified by duration of use, the rate of SUDEP was 5.5 per 1,000 over the first 2 years, but only 1.7 per 1,000 thereafter.

CONCLUSIONS

The mortality and SUDEP rates are similar to those reported from clinical trials of new drugs and cohorts of severe epilepsy. The lower SUDEP rates after 2 years of follow-up are intriguing, but require further investigation.

An evaluation of the management of epilepsy by primary health care nurses in Chitungwiza, Zimbabwe

In order to design an effective training program for nurses on the management of epilepsy in Zimbabwe, the drug management of epilepsy by community health nurses without prior training in epilepsy management was evaluated. Epilepsy patients in Chitungwiza, a high-density suburb of Harare, were routinely managed at four health clinics run by nurses. The patients also attended a monthly epilepsy support group (ESG) program, which provided them with vocational and social rehabilitative support. Neurologists evaluated the drug therapy of all patients attending this support group program over a 2-year period. The specialist interventions required to drug therapy in patients with inadequate seizure control or drug side effects were noted. A total of 114 epilepsy patients (age range 8-56 years, M:F=1:1.2) were seen, of these 84.2% had generalized seizures, 40.3% of patients had been seizure-free for at least 6 months, 71.9% of patients were on phenobarbitone, while 59.6% were on monotherapy. No drug intervention was required to on-going drug therapy in 43% of patient consultations. The most important intervention in patients with inadequate seizure control was an increase in drug dose, required in 29% of consultations. Of serum drug level estimations in clinically indicated cases, 58% were below the therapeutic ranges. This tendency to sub-therapeutic dosing with AED amongst nurses implied that a written AED drug therapy protocol specifying optimal maintenance doses and dose increment schedules may be beneficial to the community-based nursing management of epilepsy.

Cerebellar stimulation for cerebral palsy spasticity, function, and seizures

Chronic cerebellar stimulation (CCS) applied to the superio-medial cortex reduces generalized cerebral spasticity, athetoid movements, and seizures. Eighteen clinics have reported on 600 cerebral palsy (CP) patients who comprise 90% of those treated with CCS. CP patients have varying degrees of limited abilities interfered with by spasticity (primitive reflexes, increased muscle tone, co-contractions, and spasms) and by athetoid movements in two-thirds of the patients. With CCS, spasticity reduction occurred in 85% (marked 25%, moderate 34%, mild 27%) and resulted in improvements in patient drooling, speech, respiration, posture, motor performance, gait, joint range of motion, and mood states. Radiofrequency (RF)-linked stimulators were used initially with serious equipment and calibration problems; 68% of 422 patients improved. When totally implantable controlled-currrent stimulators were used, 86% of 178 patients improved. Our double-blind study of 20 CP patients using this implantable stimulator showed 12 (60%) improved in motor performance, joint range of motion, and profile of mood states when the stimulator was ON. When abilities are graded (1: poor to 9: best), the seven patients with the higher functioning grades (5-8) all improved (99% confidence level). Intractable seizures occurred in 27 (8%) of our CP patients. At a 17-year follow-up, 19 patients contacted were using or had used CCS with 10 (53%) seizure-free and 6 (32%) with reduced seizures. CCS should be given by a totally implanted controlled-current stimulator (1-4 microCoulombs/sq. cm. /phase, 150-200 Hz) applied intermittently to the superio-medial cerebellar cortex for safe, effective, and continuous results.

Vagus nerve stimulation for epilepsy: a review

Vagus nerve stimulation is an empirically based method for treatment of epilepsy by repeated stimulation of the left vagus nerve through implanted electrodes. Despite studies in animals and man, which show changes in brain electrophysiology, metabolism and neurochemistry, the mode of action remains unknown. Clinical testing has presented methodological challenges, as it is difficult to assess under double blind conditions a treatment which requires surgery and produces a sensation every time the stimulator comes on. This has nevertheless been successfully addressed in parallel design, controlled trials comparing high and low stimulation schedules. These have been performed in adults with medically intractable partial seizures, and demonstrated efficacy, safety and good tolerability. Efficacy, both in the controlled trials and in numerous reports arising from the considerable post-marketing experience is modest. Some 30% of patients achieve a 50% seizure reduction after 3 months of treatment, but this proportion progressively increases to about 50% after 18 months. Side-effects comprise: discomfort in the face or neck when the stimulator is activated, coughing, breathlessness on exertion and hoarseness of voice. All are related to intensity of stimulation and rapidly habituate in most subjects. In those patients who respond, a stimulus level can therefore generally be found which is acceptable to the subject. No indication other than refractory partial seizures in adults has been the subject of controlled trials, but post-marketing experience and uncontrolled reports indicate comparable efficacy and safety in a wide range of epilepsies, partial and generalized, idiopathic, cryptogenic, or symptomatic, in patients of all ages.

New antiepileptic drugs and non-pharmacological treatments

Many new drugs and therapies can now be offered to patients with epilepsy. The problem is that we do not know just how much better these new and more expensive therapies are compared with the old ones, nor do we know the full range of side-effects. This review focuses on the major clinical studies that have been published in the past year with emphasis on information as to tolerability and efficacy, especially when there is some information comparing different drugs or therapies. The topics include vigabatrin, lamotrigine, gabapentin, felbamate, topiramate, tiagabine, oxcarbazepine, levetiracetam, vagus nerve stimulation and the ketogenic diet. It is encouraging that some of the newly published double-blinded placebo-controlled studies now include children and the elderly, patient groups that have previously been neglected.

Vagus nerve stimulation therapy for epilepsy in older adults

The authors assessed the efficacy, safety, and tolerability of vagus nerve stimulation (VNS) for refractory epilepsy in 45 adults 50 years of age and older. They determined seizure frequency, adverse effects, and quality of life. At 3 months, 12 patients had a >50% decrease in seizure frequency; at 1 year, 21 of 31 studied individuals had a >50% seizure decrease. Side effects were mild and transient. Quality of life scores improved significantly with time.

Case-control and qualitative study of attrition in a community epilepsy programme in rural India

Dropout from epilepsy programmes is a serious problem in developing countries and has not been systematically studied before. We set up a community-based programme for children with epilepsy in rural India. The aim of this study was to assess reasons for dropout. We assessed medical and sociodemographic variables for their effect on dropout at 12 months using an unmatched case-control design on 32 cases and 62 controls. We also interviewed the parents of 32 children who dropped out of treatment, using a topic schedule. Two-thirds of the dropouts occurred within the first 6 months of treatment. Severely impaired children were more likely to drop out (odds ratio 4.60, 95% CI: 1.0-21.0) and families who had tried AEDs before were less likely to do so (odds ratio 0.12, 95% CI: 0.015-0.88). Denial of diagnosis, access problems and symptom resolution were the other main reasons underlying attrition. Active ascertainment methods should be reconsidered in community programmes. Very poor families without a male head or with long journey times are at high risk of dropout. People with severe impairments need appropriate integrated rehabilitation.

A questionnaire survey about doctor-patient communication, compliance and locus of control among south Indian people with epilepsy

To date, very few studies have investigated patients' views on the information they receive from the doctor concerning epilepsy and its management. Little information is available about the influence of doctor-patient communication and locus of control on the compliance of persons with epilepsy. We investigated, through a questionnaire-interview design, among patients attending the epilepsy clinic of a tertiary referral center in South India, their views about the provision of information by the doctor, and their compliance and locus of control. We also determined the interrelation between doctor-patient communication, compliance and locus of control. Our subjects comprised 200 adult persons with epilepsy, 113 males and 87 females, mean age 30.5 (range 18-67) years. Over one-third of the subjects received from the doctor insufficient information about epilepsy and its treatment. There was a significant positive correlation between effective doctor-patient communication and compliance. A majority of our patients had an external locus of control, which negatively influenced the compliance. Even in a comprehensive epilepsy clinic of a model tertiary referral center in a developing country, a significant proportion of patients do not receive optimal information about epilepsy from the doctor. Knowledge about their disease will encourage people with epilepsy to make informed choices, and achieve better compliance and personal control of their problems. Educating primary and secondary care physicians about the importance of doctor-patient communication in the management of epilepsy and educating the public about the positive aspects of life in epilepsy cannot be overemphasized.

Effect of Sahaja yoga meditation on auditory evoked potentials (AEP) and visual contrast sensitivity (VCS) in epileptics

The effect of Sahaja yoga meditation on 32 patients with primary idiopathic epilepsy on regular and maintained antiepileptic medication was studied. The patients were randomly divided into 3 groups: group I practiced Sahaja Yoga meditation twice daily for 6 months under proper guidance; group II practiced postural exercises mimicking the meditation for the same duration; and group III was the control group. Visual Contrast Sensitivity (VCS), Auditory Evoked Potentials (AEP), Brainstem Auditory Evoked Potentials (BAEP), and Mid Latency Responses (MLR) were recorded initially (0 month) and at 3 and 6 months for each group. There was a significant improvement in VCS following meditation practice in group I participants. Na, the first prominent negative peak of MLR and Pa, the positive peak following Na did not register changes in latency. The Na-Pa amplitude of MLR also showed a significant increase. There were no significant changes in the absolute and interpeak latencies of BAEP. The reduced level of stress following meditation practice may make patients more responsive to specific stimuli. Sahaja Yoga meditation appears to bring about changes in some of the electrophysiological responses studied in epileptic patients.

Epilepsy in rural South African children--prevalence, associated disability and management

OBJECTIVE

To determine the prevalence of epilepsy and its associated disabilities in rural South African children aged 2-9 years.

SETTING

Eight villages in the district of Bushbuckridge, Northern Province, South Africa.

DESIGN

A two-phase design was used. The first phase involved screening children on a house-to-house basis by interviewing mothers or caregivers using an internationally validated questionnaire for detecting childhood disability in developing countries. The second phase consisted of a paediatric/neurodevelopmental assessment of the children who screened positive.

RESULTS

A total of 6,692 children were screened; 722 (10.8%) had a paediatric evaluation and 49 (0.73%) had epilepsy. The lifetime and active prevalences of epilepsy in these children were 7.3/1,000 and 6.7/1,000 respectively. Associated developmental disability was recorded in 35 affected children (71.4%), including 8 (16.3%) in whom this was moderate to severe. More than a half of the children with epilepsy (57.1%) did not receive anticonvulsant medication.

CONCLUSION

The prevalence of epilepsy in the rural childhood population investigated is higher than that recorded in most similar studies from sub-Saharan Africa, and the poor utilisation of appropriate anticonvulsant treatment is cause for concern. This study highlights the paucity of relevant information on the epidemiology of epilepsy in South Africa and that the system available for its management, especially in rural areas, appears to have functional deficiencies. Appropriate research is needed to identify the problems in service delivery and to enable the planning and implementation of an appropriate primary health care-based system for the diagnosis and management of epilepsy in children.

Can district-wide audits improve primary care epilepsy management? An audit of seizure frequency recording

A district-wide epilepsy audit in general practice showed that levels of seizure frequency recording were too low to evaluate the quality of control of epilepsy. A repeat audit after multi-faceted interventions showed an improvement in seizure frequency recording of 13.2% (CI = 8.9 to 17.6) from 54.7% to 68%. This illustrates the difficulties of evaluating quality of care using routine records and the problems of implementing changes in general practice.

Vagus nerve stimulation: a new tool for brain research and therapy

Biological psychiatry has a long history of using somatic therapies to treat neuropsychiatric illnesses and to understand brain function. These methods have included neurosurgery, electroconvulsive therapy, and, most recently, transcranial magnetic stimulation. Fourteen years ago researchers discovered that intermittent electrical stimulation of the vagus nerve produces inhibition of neural processes, which can alter brain electrical activity and terminate seizures in dogs. Since then, approximately 6000 people worldwide have received vagus nerve stimulation for treatment-resistant epilepsy. We review the neurobiology and anatomy of the vagus nerve and provide an overview of the vagus nerve stimulation technique. We also describe the safety and potential utility of vagus nerve stimulation as a neuroscience research tool and as a putative treatment for psychiatric conditions. Vagus nerve stimulation appears to be a promising new somatic intervention that may improve our understanding of brain function and has promise in the treatment of neuropsychiatric disorders.