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Abstracts presented at the annual general meeting of the British Branch of the International League Against Epilepsy, 19 May 1994, London, UK
Seizure 1994; 3:311-317
ABSTRACTS
Abstracts presented at the Annual General Meeting of the British Branch of the International League Against Epilepsy, 19 May 1994, London, UK The remission of epilepsy: the probability of newly diagnosed epilepsy achieving 3 and 5 year remission in the National General Practice Study of Epilepsy (NGPSE) Oliver C. Cockerell, Yvonne M. Hart, Josemir W. Sander, Simon D. Shorvon Epilepsy Research Group, The Institute of Neurology, Queen Square, London, and the Chalfont Centre for Epilepsy, Chalfont St Peter, Bucks, SL9 ORJ, UK Address for correspondence; Dr O.C. Cockerell, Epilepsy Research Group, The Chalfont Centre for Epilepsy, Chalfont St Peter, Bucks, SL9 0RJ, UK Population-based studies have suggested t h a t between 60-75% of patients with epilepsy will enter a period of remission lasting from 3 - 5 years at some time in t h e i r lives. However, there have been no prospective population-based studies t h a t have followed patients with newly diagnosed epilepsy from the onset of their epilepsy, and a n u m b e r of issues remain to be clarified, including the effect of early seizure patterns, the effect of underlying aetiology, and the factors t h a t led to relapses after remission. Patients were identified in the UK between 1984-87 as part of the NGPSE, which is the largest prospective community-based cohort study of newly diagnosed epilepsy, and follow-up h a s now reached up to 9 years. The remission p a t t e r n s were analysed in 564 patients who, at the time of the latest diagnostic panel review, had definite epilepsy, as well in 228 patients with possible or probable epilepsy. 60% of patients experienced a 3-year period of remission, and this figure was not greatly influenced by aetiology, seizure type, or age of onset. Detailed actuarial analysis will be presented, together with 5-year remission rates, and the terminal remission rates.
A comparative brain neuropharmacokinetic study of different anti-epileptic drugs in rat frontal cortex using microdialysis M.S. Alavijeh, W,T. Abed, M.C. Walker, S. Nagaki, M.T. O'Connell, P.N. Patsalos Epilepsy Research Group, Department of Clinical Neurology, Institute of Neuro/ogy, Queen Square, London The extracellu]ar environment is considered to reflect events at the neuronal level. Using microdialysis we have monitored the extracellular environment of rat frontal cortex after the administration of different anti-epileptic drugs (AEDs) and derived comparative neuropharmacokinetic constants for these drugs. Male S p r a g u e - D a w l e y rats (250-300 g) were anaesthetized and microdialysis probes were stereotaxically implanted into the frontal cortex. One day after surgery, rats were administered carbamazepine (CBZ, 60 mg/kg), phenobarbitone (PB, 30 mg/kg), phenytoin (PHT, 50 mg/kg) or valproic acid (VPA, 200 mg/kg) intraperitoneally. Dialysate of frontal cortex (2 ~l/min) were collected at 10-minute intervals over a 4 8 hour period and analysed for AED content using GC or HPLC. Neuropharmacokinetic constants were computed according to a first order one compartmental model using PCNONLIN. The following m e a n parameters were obtained for CBZ, PB, PHT and VPA respectively: Tma×(h)--l.39, 2.45, 0.25, 0.34; AUC(Fmolh/1)--55.45, 35.91, 5.43, 274.4; Tl/2(h)--l.54, 13.93, 1.16, 0.34. These data demonstrate the viability of microdialysis in studies ofAED neuropharmacokinetics and may pave the way for a better u n d e r s t a n d i n g of AED.mechanisms(s) of action.
An audit of epilepsy care in general practice Ann Jacoby, Gus Baker1-, David Chadwick*, Suzannah Graham-Jonest Centre for Hea/th Services Research, University of Newcastle-upon-Type, *Department of Neuroscience, Wa/ton Hospital Liverpool, and tDepartment of Genera/Practice, University of Liverpoo/ Correspondence to: Ann Jacoby, Senior Research Associate, Centre for Health Services Research, University of Newcastle-upon-Tyne, 21 Claremont Place, Newcastle-upon-Tyne NE2 4AA, UK Epilepsy fulfils a n u m b e r of criteria specified by Kessner e t al. ~ as necessary to make a condition a satisfactory tracer for audit. It is also a condition which, it h a s been argued z, is best cared for by the general practitioner in the majority of cases. As
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part of a larger community study of the quality of life and care of people with epilepsy, general practitioners in the Mersey Region have u n d e r t a k e n an audit of their care. A random sample of 31 practices, covering a total population of 177,700 patients, took part. J u s t over 1300 people with active epilepsy were identified from practice records, an overall prevalence of 0.8%. The prevalence within individual practices ranged from 0.6-1.2%, with the rural single-handed and small group practices producing the lowest. For each patient identified, information was collected about diagnosis, AED therapy and general practice and hospital contacts in the previous year, and findings from these various aspects of the audit will be summarized. Information from the audit exercise is being fed back to participating practices, together with information obtained through postal questionnaires to patients themselves. It is hoped t h a t feedback from the study will inform the setting of standards for the care of people with epilepsy in general practice.
REFERENCES 1. Kessner, D.M., Kalk, C.E. and Singer, J. Assessing h e a l t h quality; the case for tracers. New England Journal of Medicine 1977; 189:194 2. D e p a r t m e n t of Health and Social Security. Report of the Working Group on Services for People with Epilepsy. London: HMSO, 1986.
Epilepsy viewed from the gut Marta Elian, Amos D. Korczyn*, Miri Y. Neufeld*
Department of EEG, Oldchurch Hospital, Romford, Essex, UK and *Department of Neurology, Ichilov Hospital, TelAviv, Israel The search for an etiology of epilepsy started several thousand years ago and the suggested causes are manifold. It seems t h a t the first quarter of our present century has produced one of the most bizarre of all suspected causes and subsequent treatments. The purpose of this paper is to report on this hitherto untold story. It was observed t h a t people with epilepsy suffer from constipation, with or without anatomical changes in the gastrointestinal tract, leading to stasis and absorption of toxic agents. The search for this agent has led to identifying an organism, the Bacillus epilepticus, successfully t r a n s m i t t e d to experimental animals in whom seizures appeared thus satisfying Koch's postulates. The t r e a t m e n t ranged from diet through gastric lavage to colectomy. The success rate in abolishing seizures was enthusiastically reported on in respectable journals on both sides of the Atlantic. Uncontrolled t r e a t m e n t trials which disregard possible placebo effects are leading to uncritical acceptance of success. We conclude t h a t self-deception, placebo effect and uncontrolled clinical observations may lead to 'misfit' theories and t r e a t m e n t s which can only be avoided by controlled clinical studies.
Perfusion of the posterior cerebral artery and memory dysfunction during sodium amytal testing of patients with epilepsy N. Morton, R.G. Morris, C.E. Polkey, T. Cox Centre for Epilepsy at the Maudsley Hospital and Institute of Epileptology, Institute of Psychiatry, London, UK Angiographic filling of"the posterior cerebral artery (PCA) was assessed in 57 patients with unilateral temporal epileptic seizure foci, undergoing routine sodium amytal testing of memory function. The rationale of this procedure is to explore the memory capability of the hemisphere contralateral to the injected hemisphere. PCA filling predicts delivery of sodium amytal to medial temporal lobe structures thought to be important in memory. It is therefore an important question as to w h e t h e r PCA filling is associated with poorer memory functioning during the procedure? Memory was tested following injection of the internal carotid artery centralateral and ipsilateral to the side of seizure focus. In both cases, patients with PCA filling showed a greater memory deficit, although this effect was stronger with contralateral injections. In a sub-sample of patients with left hemisphere dominance for language, the effect of PCA filling on memory performance was only significant when the right hemisphere was injected. The implications of these findings are discussed in terms of the validity of the sodium amytal test and the different factors t h a t need to be t a k e n into account when interpreting IAP memory performance.
The development of a patient-based adverse drug event scale as a part of a health-related quality of life measure for people with epilepsy G.A. Baker, P. Francis, E. Middleton, A. Jacoby, B. Defalla, C. Young, D. Smith, D.W. Chadwick
University Department of Neurosciences, Walton Hospital, Rice Lane, Liverpool All anti-epileptic drugs affect brain function and carry some risk of adverse drug reactions, the most common of which are C and S dose-related reactions. Recent studies with patients receiving monotherapy fail to show significant effects on objective psychometric testing for several different AEDs. Despite this finding, patients treated with AEDs commonly describe sideeffects including sedation, fatigue, dizziness, double vision and difficulties with memory.
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In development of a n adverse drug event scale, 200 patients were asked to describe the common side effects associated with their treatment. A 20-item scale was constructed from the data. Factor analysis disclosed one scale with 16 items accounting for more than 45% of the variants. In terms of reliability, tEis scale had an acceptable level of internal consistency. Initial evidence of the validity of the scale was established by correlating it with an observer-based Reagan scale. Comparisons of a match control (n = 90) suggest that the scale is able to detect symptoms due to AEDs. Development of the adverse drug scale is part of a further refinement of the health-related Quality of Life model.
The variability in seizure patterns of complex partial seizures of temporal lobe origin--a retrospective videotape analysis A. Tajer, C.D. Binnie, R.D.C. Elwes, G. Alarcon, C.E. Polkey* Department of Clinical Neurophysiology and *Neurosurgical Unit, The Maudsley Hospital, Denmark Hill, London, UK Correspondence to: Dr Afsaneh Tajer, Department of Clinical Neurophysiology, The Maudsley Hospital, Denmark Hill, London SE5 8AZ, UK An identical seizure pattern, within a patient, is usually said to be a characteristic of epileptic seizures and a m a r k e r for differential diagnosis between epileptic and non-epileptic seizures. A n u m b e r of factors, however, influence the ictal pattern, including frequency of seizures, withdrawal or changes in anti-epileptic drugs and most important, the existence of multiple loci causing different types of seizures. In order to evaluate the variabilty of ictal patterns or signs, we analysed 38 complex partial seizures of temporal lobe origin, retrospectively, fl'om 12 patients using video-EEG telemetry archives, All these 12 patients have undergone surgery for epilepsy more t h a n 2 years ago and all have been seizure-free post-operatively, suggesting t h a t there was a single epileptic focus, removed by surgery. We will present the results and discuss the influence of changes in anti-epileptic drugs on seizure pattern and its clinical significance.
Psychiatric and cognitive changes after acute anti-epileptic drug withdrawal in epileptic patients A. Tajer, P.B. Fenwick*, C.D. Binnie, R.D.C. Elwes, C.E. Polkey-t Department of Clinical Neurophysiology, Weuropsychiatry and Epilepsy Unit, tNeurosurgical Unit, The Maudsley Hospital, Denmark Hill, London, UK Correspondence to: Dr Afsaneh Tajer, Department of Clinical Neurophysiology, The Maudsley Hospital, Denmark Hill, London SE5 8AZ, UK Drugs (i.e. polytherapy, drug toxicity, drug withdrawal, chronic medication and their side effects) are important aetiological factors in the psychopathology and cognitive impairment of epileptic patients. During evaluation for epilepsy surgery for intractable epilepsy, anti-epileptic drugs (AED) are usually withdrawn abruptly to increase the seizure frequency while the patient undergoes EEG telemetry with intracranial recording. We have studied the effect of abrupt withdrawal of different anti-epileptic drugs on psychiatric status and cognitive functioning of patients who have undergone abrupt AED withdrawal. These patients had been admitted for neurophysiological evaluation for possible epilepsy surgery in a neurosurgical ward in the Maudsley Hospital. The Present State Examination and the Maudsley Cognitive Test were performed on admission and Brief Psychiatric Rating and Mini-mental State E x a m i n a t i o n were done everyday to compare the mental and cognitive state of the patients, on-medication to off-medication. The results will be presented and the possible clinical consequences of the findings will be discussed.
Quantitative analysis and display of acute electrocorticogram G. Alarcon, C.D. Binnie, R.D.C. Elwes, J.J. Garcia Seoane*, J. Juler, C.E. Polkeyl Department of Clinical Neurophysiology, and *Neurosurgical Unit, Maudsley Hospital, and tDepartmento de Fisiologia, Facultad de Medicina, Universidad Complutense, Madrid 28020, Spain Although acute electrocorticography }]as been a standard procedure in the surgical t r e a t m e n t of epilepsy for many years. there is a lack of agreement concerning interpretation and application of the findings. Discussion has centred chiefly on the significance of the extent and rate of epileptiform discharge, the utility or otherwise of activation procedures, and the issue of w h e t h e r or not excision of all discharging areas is necessary to achieve a good surgical result. Our previously reported findings suggest t h a t the detailed topography and morphology of the electrocorticogram are predictive of the site and nature of pathology and relevant to p l a n n i n g of surgery. As an extension of this approach we have developed a system for intraoperative computer-assisted recognition of epileptiform transients and the presentation of topographic displays showing both their occurrence and temporal relationships.
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Preliminary findings suggest t h a t in planning the extent of surgical resection it is important to distinguish those discharging regions t h a t function as pacemakers and those in which ECoG spikes appear secondarily after a time delay.
The misdiagnosis of epilepsy and the diagnosis of funny turns D. Smith, E. Dafella, D.W. Chadwick
The Department of Neuroscience, The Walton Centre for Neurology and Neurosurgery, Rice Lane, Liverpool L9 1AE, UK Patients with 'funny turns' are often referred to neurological clinics with a previous or possible diagnosis of epilepsy. Although widely recognized by neurologists, no systematic study has examined the frequency of, factors contributing to and implications of, a misdiagnosis of epilepsy. A retrospective analysis of the case records of 317 patients, with a previous or possible diagnosis of epilepsy, was conducted. The sample was divided into those exposed to AEDs IEpilepsy for Management, #z = 1951 and those who had not received this t r e a t m e n t cFunny Turns for Diagnosis, n = 122t. An erroneous diagnosis of epilepsy was observed in 25.1cA with inadequate history-taking and misinterpretation of EEG equally responsible for misdiagnosis. Epilepsy was an uncommon, and syncope a common cause of undiagnosed funny turns but this was not reflected in referral letters. Diagnosis is usually achieved on clinical grounds alone except in patients with pseudoseizures who are taking AEDs, 58cA of whom required investigation to refute the diagnosis of epilepsy. Most patients with funny t u r n s will present to a GP or physician. The misdiagnosis of epilepsy may be reduced by education emphasizing careful history taking, the diagnostic limitations of inter-ictal EEG and the inadvisability of trials of AEDs. This could diminish the psychosocial implications of a erroneous diagnosis of epilepsy and have beneficial economic implications for the NHS.
Prognosis in newly diagnosed childhood epilepsy E. Hughes, M. de Silva, B.G.R. Neville, A.L. Johnson, E.H. Reynolds The Centre for Epilepsy, The Maudsley Hospital, London SE 5, Paediatric Neurology, Guy's Hospital, London and MRC Biostatistics Unit, Cambridge We conducted a prospective, comparative monotherapy trial of four anti-epileptic drugs (phenobarbitone, phenytoin, carbamazepine and sodium valproate) in 167 children (aged 3 - 1 6 years) with newly diagnosed epilepsy. At the point of entry into the study, they had experienced two or more tonic-clonic seizures, or partial seizures with or without secondary generalization. At the time of our initial report these children had been followed for a median of 44 months. We did not find any difference in efficacy between the four drugs. We now present the outcome for this group of patients over a median follow-up period of 88 months (range: 8 months to 152 months), with regard to relative efficacy of the four drugs studied and factors other t h a n drug therapy influencing seizure prognosis.
Prognosis in newly diagnosed adult epilepsy J. Stewart, A. Heller, A.L. Johnson, E.H. Reynolds
The Centre for Epilepsy, The Maudsley Hospital, London SE 5, and MRC Biostatistics Unit, Cambridge We have previously reported a multicentre prospective comparative monotherapy trial of four anti-epileptic drugs (phenobarbitone, phenytoin, carbamazepine and sodium v a l p r o a t e / i n 241 adults (aged over 16 years), followed for a median of 30 months, with newly diagnosed previously untreated epilepsy, i.e. a m i n i m u m of two or more tonic--clonic seizures or partial seizures with or without secondary generalization. We did not find any difference in efficacy between the four drugs. At 36 months, 75~ of the patients had achieved a 1-year remission: We have now extended the follow up of the 127 patients who were recruited in the London area to the end of 1992, i.e. by an additional 45 monthsl In this group we examined multiple factors which influence prognosis for prolonged remission.
An audit of lamotrigine and vigabatrin chronic therapy in outpatients with refractory epilepsy G.J. Schapel, D.W. Chadwick
Department of Neurological Science, The Walton Centre for Neurology and Neurosurgery, Rice Lane, Liverpool L9 1AE, UK Lamotrigine (LTG) and vigabatrin (GVG) are chemically novel anti-epileptic drugs (AEDs), recently introduced into clinical practice in Europe. An audit of LTG and GVG t r e a t m e n t was performed of the case notes of 356 patients attending the outpatient clinic of a tertiary referral epilepsy service draining a population source of 4 million in the northwest of Britain. Two-thirds of patients were chronologically treated for localization-related epilepsy and one-third for idiopathic generalized epilepsy for 1-50 months. LTG was still being t a k e n by 60~ (16c~ on monotherapyl and GVG by 4 3 ~ (4% on
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monotherapyl of patients, with 42~ on LTG and 2 1 ~ on GVG showing a 50% or greater decrease in seizure frequency and 8~ of patients on both drugs being seizure-free. Adverse effects (e.g. skin rash) resulted in LTG discontinuation in 12% and in GVG withdrawal in 13%/e.g. personality disturbance, drowsiness and weight gain). It is concluded t h a t LTG and GVG are clinically effective safe drugs for the longterm t r e a t m e n t of a wide range of patients with refractory epilepsy.
Neurophysiology and callosal surgery for epilepsy A.T. King, S. Delamonte, C.E. Polkey, C.D. Binnie The Maudsley Hospital, Denmark Hill, London, UK Callosal section is an empirical t r e a t m e n t for epilepsy which can relieve significantly atonic(drop) attacks and episodes of status epilepticus. In 24 patients undergoing partial callosal section we have used pre-operative carotid amytal tests to assess bilateral secondary synchrony and intra-operative electrocorticography to indicate the effectivness of the callosal section during the procedure. We have evaluated the benefit of each of these techniques. E i g h t e e n patients had pre-operative amytal investigation. In eight of these the test suggested one hemisphere was driving the other. Four of these patients obtained fit reduction including two with unilateral hemisphere disease. There was F U of more t h a n 1 year for 22 of these 24 patients. Overall, 12 of these 22 patients gained benefit in terms of fit reduction from the surgery. Three of the seven patients with unilateral hemisphere disease benefitted, the other four patients subsequently underwent major resection. Intra-operative electrocorticography was attempted on 23 patients, but useful data was obtained in only 13 patients. Among these 13 there was a good correlation between ECoG desynchronization and eventual outcome in eight patients.
Neuroimaging in Rasmussen's disease P. lyengar, D. Bailey, C.E. Polkey, T.C.S. Cox The Maudsley Hospital, Denmark Hill, London, UK The brain imaging studies available in a series of 20 patients with Rasmussen's encephalitis have been reviewed. In 19 cases the diagnosis had been made histologically in the r e m a i n i n g patient the clinical history, examination and radiological findings were consistent with t h a t diagnosis. A smaller group of four patients were identified in which there were unilateral changes in the caudate nucleus which appeared early in the disease and were more marked t h a n the atrophic changes in the r e m a i n d e r of t h a t hemisphere.
Multiple subpial transection--a useful technique? C.D. Binnie, C.E. Polkey The Maudsley Hospital, Denmark Hill, London Multiple subpiaI transection was first conceived and developed by Morrell in Chicago. This technique has now been used in our practice in operations on over 20 patients for a variety of reasons. Eighteen patients had refractory epilepsy, the r e m a i n i n g three patients had L a n d a u - K l e f f e r Syndrome (acquired aphasia). There were structural abnormalities on MRI on eight patients and pathological examination of biopsy or resection specimens from the 18 patients showed Rasmussen's syndrome in six, cortical dysplasia in six cases, tumour in one and non-specific changes in the r e m a i n i n g five. There is a follow-up period of 1 - 5 years for 12 of the epileptic patients. In five patients there was a decrease in seizure frequency and in four a decrease in severity. None of the patients developed a p e r m a n e n t neurological deficit which could be attributed to the MST. In the three patients with LKS there has been recovery of speech in two cases.
Psychiatric and psychosocial evaluation of temporal lobe surgery for epilepsy C.J.B. McEvedy, D.H. Ffytche, R.D.C. Elwes, C.E. Polkey, PB.C. Fenwick The Maudsley Hospital, Denmark Hill, London, UK 150 patients who had undergone temporal lobe resection for intractible epilepsy were assessed for psychiatric outcome using a combination of GP survey, review of psychiatric casenotes and questionnaire sent to involved psychiatrists. A high prevalence of psychiatric morbidity (35%) was found over the 8-year follow-up period, mainly affective disorder, and this is
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compared with t h a t of a matched control group drawn from the hospital's epilepsy clinic. The other striking finding from the study was an association between r i g h t sided lesion/operation and post-operative affective disorder.
Precipitating and inhibiting epileptic seizures; a survey of adults with poorly controlled epilepsy S. Spector, L.H. Goldstein, C. Cull, P. Fenwick, T.E. Reynolds
The Maudsley Hospital, Denmark Hill, London, UK Studies have shown t h a t epileptic seizures do not occur at random. They may occur in response to a yariety of internal and external stimuli. In addition, some individuals can induce or inhibit t h e i r seizures. In our study we interviewed 87 patients with epilepsy, using the Maudsley Hospital Questionnaire. The subjects were adults (18-65 years) with a history of at least 3 years of poorly controlled epilepsy, experiencing at least four seizures per month. Information was collected regarding the various seizure precipitants, the n a t u r e of the different methods some patients develop to inhibit and induce t h e i r seizures, and drug compliance. Over 87% of the subjects could report at least one seizure precipitant, the commonest ones being stress, depression, feeling tired or angry and being overexcited. 50% of the subjects reported being able to stop a seizure from happening. Methods for seizure control include voluntary changes of thoughts, emotions or behaviour. Only 17% of the subjects said they have on one or more occasions induced a seizure, by not t a k i n g t h e i r drugs, or in other ways. Our data are discussed in the light of other similar surveys.
Sudden death in epilepsy: risk assessment in different patient groups L. Nashef, S. Garner, O.C. Cockerell, D. Fish, J.W.A.S. Sander, S.D. Shorvon Epilepsy Research Group, Institute of Neurology, Queen Square, London and Chalfont Centre for Epilepsy, Chalfont St Peter, Bucks, UK Sudden unexpected deaths in epilepsy, where post-mortem examination fails to reveal a n anatomical or toxicological cause for death, have been recognized since the last century. Evidence for a n associated seizure is found in some 50% of cases. Risk estimates in patients with chronic epilepsy vary from 1:200 to l : i 200 per year with young adults bearing the highest risk: Our group has previously published data regarding the risk among adult patients with chronic epilepsy in long-term residential care ~. We present further data outlining the risk in other patient groups. In a n outpatient cohort with chronic epilepsy at a tertiary referral centre (n = 601 patients, 1849 patient years), the incidence was of the order of 1:200 sudden deaths per year. A m i n i m u m incidence of l:400/year has so far been found in a young cohort with epilepsy and educational difficulty (n = 310, 4228.5 person years). On the other hand, no such cases have been reported to the National General Practice Study of Epilepsy which includes newly diagnosed epileptic seizures (definite and possible) in a general population (> 5000 patient years). Characteristics of each cohort, including age distribution, and other factors t h a t may be implicated in defining risk will be discussed.
REFERENCE 1. Klenerman, P. Sander, J.W.A.S., Shorvon, S.D. Mortality in patients with epilepsy: a study of patients in long-term residential care. J N N P 1993; 56: 149-152.
The relationship between MRI hippocampal morphology and the intracarotid sodium amytal test in the presurgical evaluation of patients for temporal Iobectomy Sallie A. Baxendale, Mark Cook, Simon Shorvon, Pamela J. Thompson, Elizabeth K. Warrington
Epilepsy Research Group, Institute of Neurology, Queen Square, London The increasing sophistication of MRI volumetric m e a s u r e m e n t has led to speculation t h a t it may supersede the intracarotid sodium amytal test in the presurgical screening for bilateral abnormalities in prospective temporal lobectomy patients.t We report on 50 presurgical cases who underwent the intracarotid sodium amytal test and morphometric analysis of hippocampal sclerosis identified by MRI scan. The predictive power of each technique is compared and contrasted with respect to presurgical seizure lateralization and post-surgical seizure control and changes in memory function. We conclude t h a t the combination of functional and structural measures provides valuable information in the presurgical assessment of patients for temporal lobectomy.
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REFERENCE 1. Trenerry, M.R. et al. MRI hippocampal volumes and memory function before and after temporal lobectomy. Neurology 1993; 43: 1800-1805.
Stereotactic craniotomy for cavernous angiomas
A.T.H. Casey, D.G.T. Thomas, W.F. Harkness The National Hospital for Neurology and Neurosurgery, UK With the wider availability of magnetic resonance imaging angiographically occult vascular malformations are being recognized with increasing frequency in those patients presenting with medically refractory epilepsy. Surgical resection is the treatment of choice. However, because these lesions are often small and can be located in eloquent areas stereotactically guided resection should be considered. Stereotactically guided resection of pathologically confirmed lesions has been performed in nine patients in this series presenting with epilepsy (seven males, three females mean age 34 years). Eight patients presented with medically refractory epilepsy (five complex partial seizures, three grand real seizures) the remaining patient experiencing repeated intracerebral haemorrhages and epileptic seizures. All patients had normal neurological examinations. Patients were assessd by CT scan, MRI and angiogram. Operative resection was guided by either CRW or Leksell frame, Peroperative ECoG, cortical stimulation with speech mapping and ultrasonography were employed in selected cases. MRI typically consisted of mixed T1 and T2 signals with a rim of low density suggestive of haemosiderin deposition. Pathological findings were also indicative of repeated haemorrhagic episodes. Following resection of these lesions all patients experienced improved seizure control (Enge] I-III) with a mean follow-up of 19.6 months. We conclude that stereotactic localization of these lesions offers significant advantages. The surgical indications for operation include medically refractory epilepsy, repeated haemorrhagic episodes, and in those cases where diagnostic uncertainty exists:
ABSTRACTS
Abstracts presented at the Annual General Meeting of the British Branch of the International League Against Epilepsy, 19 May 1994, London, UK The remission of epilepsy: the probability of newly diagnosed epilepsy achieving 3 and 5 year remission in the National General Practice Study of Epilepsy (NGPSE) Oliver C. Cockerell, Yvonne M. Hart, Josemir W. Sander, Simon D. Shorvon Epilepsy Research Group, The Institute of Neurology, Queen Square, London, and the Chalfont Centre for Epilepsy, Chalfont St Peter, Bucks, SL9 ORJ, UK Address for correspondence; Dr O.C. Cockerell, Epilepsy Research Group, The Chalfont Centre for Epilepsy, Chalfont St Peter, Bucks, SL9 0RJ, UK Population-based studies have suggested t h a t between 60-75% of patients with epilepsy will enter a period of remission lasting from 3 - 5 years at some time in t h e i r lives. However, there have been no prospective population-based studies t h a t have followed patients with newly diagnosed epilepsy from the onset of their epilepsy, and a n u m b e r of issues remain to be clarified, including the effect of early seizure patterns, the effect of underlying aetiology, and the factors t h a t led to relapses after remission. Patients were identified in the UK between 1984-87 as part of the NGPSE, which is the largest prospective community-based cohort study of newly diagnosed epilepsy, and follow-up h a s now reached up to 9 years. The remission p a t t e r n s were analysed in 564 patients who, at the time of the latest diagnostic panel review, had definite epilepsy, as well in 228 patients with possible or probable epilepsy. 60% of patients experienced a 3-year period of remission, and this figure was not greatly influenced by aetiology, seizure type, or age of onset. Detailed actuarial analysis will be presented, together with 5-year remission rates, and the terminal remission rates.
A comparative brain neuropharmacokinetic study of different anti-epileptic drugs in rat frontal cortex using microdialysis M.S. Alavijeh, W,T. Abed, M.C. Walker, S. Nagaki, M.T. O'Connell, P.N. Patsalos Epilepsy Research Group, Department of Clinical Neurology, Institute of Neuro/ogy, Queen Square, London The extracellu]ar environment is considered to reflect events at the neuronal level. Using microdialysis we have monitored the extracellular environment of rat frontal cortex after the administration of different anti-epileptic drugs (AEDs) and derived comparative neuropharmacokinetic constants for these drugs. Male S p r a g u e - D a w l e y rats (250-300 g) were anaesthetized and microdialysis probes were stereotaxically implanted into the frontal cortex. One day after surgery, rats were administered carbamazepine (CBZ, 60 mg/kg), phenobarbitone (PB, 30 mg/kg), phenytoin (PHT, 50 mg/kg) or valproic acid (VPA, 200 mg/kg) intraperitoneally. Dialysate of frontal cortex (2 ~l/min) were collected at 10-minute intervals over a 4 8 hour period and analysed for AED content using GC or HPLC. Neuropharmacokinetic constants were computed according to a first order one compartmental model using PCNONLIN. The following m e a n parameters were obtained for CBZ, PB, PHT and VPA respectively: Tma×(h)--l.39, 2.45, 0.25, 0.34; AUC(Fmolh/1)--55.45, 35.91, 5.43, 274.4; Tl/2(h)--l.54, 13.93, 1.16, 0.34. These data demonstrate the viability of microdialysis in studies ofAED neuropharmacokinetics and may pave the way for a better u n d e r s t a n d i n g of AED.mechanisms(s) of action.
An audit of epilepsy care in general practice Ann Jacoby, Gus Baker1-, David Chadwick*, Suzannah Graham-Jonest Centre for Hea/th Services Research, University of Newcastle-upon-Type, *Department of Neuroscience, Wa/ton Hospital Liverpool, and tDepartment of Genera/Practice, University of Liverpoo/ Correspondence to: Ann Jacoby, Senior Research Associate, Centre for Health Services Research, University of Newcastle-upon-Tyne, 21 Claremont Place, Newcastle-upon-Tyne NE2 4AA, UK Epilepsy fulfils a n u m b e r of criteria specified by Kessner e t al. ~ as necessary to make a condition a satisfactory tracer for audit. It is also a condition which, it h a s been argued z, is best cared for by the general practitioner in the majority of cases. As
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part of a larger community study of the quality of life and care of people with epilepsy, general practitioners in the Mersey Region have u n d e r t a k e n an audit of their care. A random sample of 31 practices, covering a total population of 177,700 patients, took part. J u s t over 1300 people with active epilepsy were identified from practice records, an overall prevalence of 0.8%. The prevalence within individual practices ranged from 0.6-1.2%, with the rural single-handed and small group practices producing the lowest. For each patient identified, information was collected about diagnosis, AED therapy and general practice and hospital contacts in the previous year, and findings from these various aspects of the audit will be summarized. Information from the audit exercise is being fed back to participating practices, together with information obtained through postal questionnaires to patients themselves. It is hoped t h a t feedback from the study will inform the setting of standards for the care of people with epilepsy in general practice.
REFERENCES 1. Kessner, D.M., Kalk, C.E. and Singer, J. Assessing h e a l t h quality; the case for tracers. New England Journal of Medicine 1977; 189:194 2. D e p a r t m e n t of Health and Social Security. Report of the Working Group on Services for People with Epilepsy. London: HMSO, 1986.
Epilepsy viewed from the gut Marta Elian, Amos D. Korczyn*, Miri Y. Neufeld*
Department of EEG, Oldchurch Hospital, Romford, Essex, UK and *Department of Neurology, Ichilov Hospital, TelAviv, Israel The search for an etiology of epilepsy started several thousand years ago and the suggested causes are manifold. It seems t h a t the first quarter of our present century has produced one of the most bizarre of all suspected causes and subsequent treatments. The purpose of this paper is to report on this hitherto untold story. It was observed t h a t people with epilepsy suffer from constipation, with or without anatomical changes in the gastrointestinal tract, leading to stasis and absorption of toxic agents. The search for this agent has led to identifying an organism, the Bacillus epilepticus, successfully t r a n s m i t t e d to experimental animals in whom seizures appeared thus satisfying Koch's postulates. The t r e a t m e n t ranged from diet through gastric lavage to colectomy. The success rate in abolishing seizures was enthusiastically reported on in respectable journals on both sides of the Atlantic. Uncontrolled t r e a t m e n t trials which disregard possible placebo effects are leading to uncritical acceptance of success. We conclude t h a t self-deception, placebo effect and uncontrolled clinical observations may lead to 'misfit' theories and t r e a t m e n t s which can only be avoided by controlled clinical studies.
Perfusion of the posterior cerebral artery and memory dysfunction during sodium amytal testing of patients with epilepsy N. Morton, R.G. Morris, C.E. Polkey, T. Cox Centre for Epilepsy at the Maudsley Hospital and Institute of Epileptology, Institute of Psychiatry, London, UK Angiographic filling of"the posterior cerebral artery (PCA) was assessed in 57 patients with unilateral temporal epileptic seizure foci, undergoing routine sodium amytal testing of memory function. The rationale of this procedure is to explore the memory capability of the hemisphere contralateral to the injected hemisphere. PCA filling predicts delivery of sodium amytal to medial temporal lobe structures thought to be important in memory. It is therefore an important question as to w h e t h e r PCA filling is associated with poorer memory functioning during the procedure? Memory was tested following injection of the internal carotid artery centralateral and ipsilateral to the side of seizure focus. In both cases, patients with PCA filling showed a greater memory deficit, although this effect was stronger with contralateral injections. In a sub-sample of patients with left hemisphere dominance for language, the effect of PCA filling on memory performance was only significant when the right hemisphere was injected. The implications of these findings are discussed in terms of the validity of the sodium amytal test and the different factors t h a t need to be t a k e n into account when interpreting IAP memory performance.
The development of a patient-based adverse drug event scale as a part of a health-related quality of life measure for people with epilepsy G.A. Baker, P. Francis, E. Middleton, A. Jacoby, B. Defalla, C. Young, D. Smith, D.W. Chadwick
University Department of Neurosciences, Walton Hospital, Rice Lane, Liverpool All anti-epileptic drugs affect brain function and carry some risk of adverse drug reactions, the most common of which are C and S dose-related reactions. Recent studies with patients receiving monotherapy fail to show significant effects on objective psychometric testing for several different AEDs. Despite this finding, patients treated with AEDs commonly describe sideeffects including sedation, fatigue, dizziness, double vision and difficulties with memory.
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In development of a n adverse drug event scale, 200 patients were asked to describe the common side effects associated with their treatment. A 20-item scale was constructed from the data. Factor analysis disclosed one scale with 16 items accounting for more than 45% of the variants. In terms of reliability, tEis scale had an acceptable level of internal consistency. Initial evidence of the validity of the scale was established by correlating it with an observer-based Reagan scale. Comparisons of a match control (n = 90) suggest that the scale is able to detect symptoms due to AEDs. Development of the adverse drug scale is part of a further refinement of the health-related Quality of Life model.
The variability in seizure patterns of complex partial seizures of temporal lobe origin--a retrospective videotape analysis A. Tajer, C.D. Binnie, R.D.C. Elwes, G. Alarcon, C.E. Polkey* Department of Clinical Neurophysiology and *Neurosurgical Unit, The Maudsley Hospital, Denmark Hill, London, UK Correspondence to: Dr Afsaneh Tajer, Department of Clinical Neurophysiology, The Maudsley Hospital, Denmark Hill, London SE5 8AZ, UK An identical seizure pattern, within a patient, is usually said to be a characteristic of epileptic seizures and a m a r k e r for differential diagnosis between epileptic and non-epileptic seizures. A n u m b e r of factors, however, influence the ictal pattern, including frequency of seizures, withdrawal or changes in anti-epileptic drugs and most important, the existence of multiple loci causing different types of seizures. In order to evaluate the variabilty of ictal patterns or signs, we analysed 38 complex partial seizures of temporal lobe origin, retrospectively, fl'om 12 patients using video-EEG telemetry archives, All these 12 patients have undergone surgery for epilepsy more t h a n 2 years ago and all have been seizure-free post-operatively, suggesting t h a t there was a single epileptic focus, removed by surgery. We will present the results and discuss the influence of changes in anti-epileptic drugs on seizure pattern and its clinical significance.
Psychiatric and cognitive changes after acute anti-epileptic drug withdrawal in epileptic patients A. Tajer, P.B. Fenwick*, C.D. Binnie, R.D.C. Elwes, C.E. Polkey-t Department of Clinical Neurophysiology, Weuropsychiatry and Epilepsy Unit, tNeurosurgical Unit, The Maudsley Hospital, Denmark Hill, London, UK Correspondence to: Dr Afsaneh Tajer, Department of Clinical Neurophysiology, The Maudsley Hospital, Denmark Hill, London SE5 8AZ, UK Drugs (i.e. polytherapy, drug toxicity, drug withdrawal, chronic medication and their side effects) are important aetiological factors in the psychopathology and cognitive impairment of epileptic patients. During evaluation for epilepsy surgery for intractable epilepsy, anti-epileptic drugs (AED) are usually withdrawn abruptly to increase the seizure frequency while the patient undergoes EEG telemetry with intracranial recording. We have studied the effect of abrupt withdrawal of different anti-epileptic drugs on psychiatric status and cognitive functioning of patients who have undergone abrupt AED withdrawal. These patients had been admitted for neurophysiological evaluation for possible epilepsy surgery in a neurosurgical ward in the Maudsley Hospital. The Present State Examination and the Maudsley Cognitive Test were performed on admission and Brief Psychiatric Rating and Mini-mental State E x a m i n a t i o n were done everyday to compare the mental and cognitive state of the patients, on-medication to off-medication. The results will be presented and the possible clinical consequences of the findings will be discussed.
Quantitative analysis and display of acute electrocorticogram G. Alarcon, C.D. Binnie, R.D.C. Elwes, J.J. Garcia Seoane*, J. Juler, C.E. Polkeyl Department of Clinical Neurophysiology, and *Neurosurgical Unit, Maudsley Hospital, and tDepartmento de Fisiologia, Facultad de Medicina, Universidad Complutense, Madrid 28020, Spain Although acute electrocorticography }]as been a standard procedure in the surgical t r e a t m e n t of epilepsy for many years. there is a lack of agreement concerning interpretation and application of the findings. Discussion has centred chiefly on the significance of the extent and rate of epileptiform discharge, the utility or otherwise of activation procedures, and the issue of w h e t h e r or not excision of all discharging areas is necessary to achieve a good surgical result. Our previously reported findings suggest t h a t the detailed topography and morphology of the electrocorticogram are predictive of the site and nature of pathology and relevant to p l a n n i n g of surgery. As an extension of this approach we have developed a system for intraoperative computer-assisted recognition of epileptiform transients and the presentation of topographic displays showing both their occurrence and temporal relationships.
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Preliminary findings suggest t h a t in planning the extent of surgical resection it is important to distinguish those discharging regions t h a t function as pacemakers and those in which ECoG spikes appear secondarily after a time delay.
The misdiagnosis of epilepsy and the diagnosis of funny turns D. Smith, E. Dafella, D.W. Chadwick
The Department of Neuroscience, The Walton Centre for Neurology and Neurosurgery, Rice Lane, Liverpool L9 1AE, UK Patients with 'funny turns' are often referred to neurological clinics with a previous or possible diagnosis of epilepsy. Although widely recognized by neurologists, no systematic study has examined the frequency of, factors contributing to and implications of, a misdiagnosis of epilepsy. A retrospective analysis of the case records of 317 patients, with a previous or possible diagnosis of epilepsy, was conducted. The sample was divided into those exposed to AEDs IEpilepsy for Management, #z = 1951 and those who had not received this t r e a t m e n t cFunny Turns for Diagnosis, n = 122t. An erroneous diagnosis of epilepsy was observed in 25.1cA with inadequate history-taking and misinterpretation of EEG equally responsible for misdiagnosis. Epilepsy was an uncommon, and syncope a common cause of undiagnosed funny turns but this was not reflected in referral letters. Diagnosis is usually achieved on clinical grounds alone except in patients with pseudoseizures who are taking AEDs, 58cA of whom required investigation to refute the diagnosis of epilepsy. Most patients with funny t u r n s will present to a GP or physician. The misdiagnosis of epilepsy may be reduced by education emphasizing careful history taking, the diagnostic limitations of inter-ictal EEG and the inadvisability of trials of AEDs. This could diminish the psychosocial implications of a erroneous diagnosis of epilepsy and have beneficial economic implications for the NHS.
Prognosis in newly diagnosed childhood epilepsy E. Hughes, M. de Silva, B.G.R. Neville, A.L. Johnson, E.H. Reynolds The Centre for Epilepsy, The Maudsley Hospital, London SE 5, Paediatric Neurology, Guy's Hospital, London and MRC Biostatistics Unit, Cambridge We conducted a prospective, comparative monotherapy trial of four anti-epileptic drugs (phenobarbitone, phenytoin, carbamazepine and sodium valproate) in 167 children (aged 3 - 1 6 years) with newly diagnosed epilepsy. At the point of entry into the study, they had experienced two or more tonic-clonic seizures, or partial seizures with or without secondary generalization. At the time of our initial report these children had been followed for a median of 44 months. We did not find any difference in efficacy between the four drugs. We now present the outcome for this group of patients over a median follow-up period of 88 months (range: 8 months to 152 months), with regard to relative efficacy of the four drugs studied and factors other t h a n drug therapy influencing seizure prognosis.
Prognosis in newly diagnosed adult epilepsy J. Stewart, A. Heller, A.L. Johnson, E.H. Reynolds
The Centre for Epilepsy, The Maudsley Hospital, London SE 5, and MRC Biostatistics Unit, Cambridge We have previously reported a multicentre prospective comparative monotherapy trial of four anti-epileptic drugs (phenobarbitone, phenytoin, carbamazepine and sodium v a l p r o a t e / i n 241 adults (aged over 16 years), followed for a median of 30 months, with newly diagnosed previously untreated epilepsy, i.e. a m i n i m u m of two or more tonic--clonic seizures or partial seizures with or without secondary generalization. We did not find any difference in efficacy between the four drugs. At 36 months, 75~ of the patients had achieved a 1-year remission: We have now extended the follow up of the 127 patients who were recruited in the London area to the end of 1992, i.e. by an additional 45 monthsl In this group we examined multiple factors which influence prognosis for prolonged remission.
An audit of lamotrigine and vigabatrin chronic therapy in outpatients with refractory epilepsy G.J. Schapel, D.W. Chadwick
Department of Neurological Science, The Walton Centre for Neurology and Neurosurgery, Rice Lane, Liverpool L9 1AE, UK Lamotrigine (LTG) and vigabatrin (GVG) are chemically novel anti-epileptic drugs (AEDs), recently introduced into clinical practice in Europe. An audit of LTG and GVG t r e a t m e n t was performed of the case notes of 356 patients attending the outpatient clinic of a tertiary referral epilepsy service draining a population source of 4 million in the northwest of Britain. Two-thirds of patients were chronologically treated for localization-related epilepsy and one-third for idiopathic generalized epilepsy for 1-50 months. LTG was still being t a k e n by 60~ (16c~ on monotherapyl and GVG by 4 3 ~ (4% on
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monotherapyl of patients, with 42~ on LTG and 2 1 ~ on GVG showing a 50% or greater decrease in seizure frequency and 8~ of patients on both drugs being seizure-free. Adverse effects (e.g. skin rash) resulted in LTG discontinuation in 12% and in GVG withdrawal in 13%/e.g. personality disturbance, drowsiness and weight gain). It is concluded t h a t LTG and GVG are clinically effective safe drugs for the longterm t r e a t m e n t of a wide range of patients with refractory epilepsy.
Neurophysiology and callosal surgery for epilepsy A.T. King, S. Delamonte, C.E. Polkey, C.D. Binnie The Maudsley Hospital, Denmark Hill, London, UK Callosal section is an empirical t r e a t m e n t for epilepsy which can relieve significantly atonic(drop) attacks and episodes of status epilepticus. In 24 patients undergoing partial callosal section we have used pre-operative carotid amytal tests to assess bilateral secondary synchrony and intra-operative electrocorticography to indicate the effectivness of the callosal section during the procedure. We have evaluated the benefit of each of these techniques. E i g h t e e n patients had pre-operative amytal investigation. In eight of these the test suggested one hemisphere was driving the other. Four of these patients obtained fit reduction including two with unilateral hemisphere disease. There was F U of more t h a n 1 year for 22 of these 24 patients. Overall, 12 of these 22 patients gained benefit in terms of fit reduction from the surgery. Three of the seven patients with unilateral hemisphere disease benefitted, the other four patients subsequently underwent major resection. Intra-operative electrocorticography was attempted on 23 patients, but useful data was obtained in only 13 patients. Among these 13 there was a good correlation between ECoG desynchronization and eventual outcome in eight patients.
Neuroimaging in Rasmussen's disease P. lyengar, D. Bailey, C.E. Polkey, T.C.S. Cox The Maudsley Hospital, Denmark Hill, London, UK The brain imaging studies available in a series of 20 patients with Rasmussen's encephalitis have been reviewed. In 19 cases the diagnosis had been made histologically in the r e m a i n i n g patient the clinical history, examination and radiological findings were consistent with t h a t diagnosis. A smaller group of four patients were identified in which there were unilateral changes in the caudate nucleus which appeared early in the disease and were more marked t h a n the atrophic changes in the r e m a i n d e r of t h a t hemisphere.
Multiple subpial transection--a useful technique? C.D. Binnie, C.E. Polkey The Maudsley Hospital, Denmark Hill, London Multiple subpiaI transection was first conceived and developed by Morrell in Chicago. This technique has now been used in our practice in operations on over 20 patients for a variety of reasons. Eighteen patients had refractory epilepsy, the r e m a i n i n g three patients had L a n d a u - K l e f f e r Syndrome (acquired aphasia). There were structural abnormalities on MRI on eight patients and pathological examination of biopsy or resection specimens from the 18 patients showed Rasmussen's syndrome in six, cortical dysplasia in six cases, tumour in one and non-specific changes in the r e m a i n i n g five. There is a follow-up period of 1 - 5 years for 12 of the epileptic patients. In five patients there was a decrease in seizure frequency and in four a decrease in severity. None of the patients developed a p e r m a n e n t neurological deficit which could be attributed to the MST. In the three patients with LKS there has been recovery of speech in two cases.
Psychiatric and psychosocial evaluation of temporal lobe surgery for epilepsy C.J.B. McEvedy, D.H. Ffytche, R.D.C. Elwes, C.E. Polkey, PB.C. Fenwick The Maudsley Hospital, Denmark Hill, London, UK 150 patients who had undergone temporal lobe resection for intractible epilepsy were assessed for psychiatric outcome using a combination of GP survey, review of psychiatric casenotes and questionnaire sent to involved psychiatrists. A high prevalence of psychiatric morbidity (35%) was found over the 8-year follow-up period, mainly affective disorder, and this is
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compared with t h a t of a matched control group drawn from the hospital's epilepsy clinic. The other striking finding from the study was an association between r i g h t sided lesion/operation and post-operative affective disorder.
Precipitating and inhibiting epileptic seizures; a survey of adults with poorly controlled epilepsy S. Spector, L.H. Goldstein, C. Cull, P. Fenwick, T.E. Reynolds
The Maudsley Hospital, Denmark Hill, London, UK Studies have shown t h a t epileptic seizures do not occur at random. They may occur in response to a yariety of internal and external stimuli. In addition, some individuals can induce or inhibit t h e i r seizures. In our study we interviewed 87 patients with epilepsy, using the Maudsley Hospital Questionnaire. The subjects were adults (18-65 years) with a history of at least 3 years of poorly controlled epilepsy, experiencing at least four seizures per month. Information was collected regarding the various seizure precipitants, the n a t u r e of the different methods some patients develop to inhibit and induce t h e i r seizures, and drug compliance. Over 87% of the subjects could report at least one seizure precipitant, the commonest ones being stress, depression, feeling tired or angry and being overexcited. 50% of the subjects reported being able to stop a seizure from happening. Methods for seizure control include voluntary changes of thoughts, emotions or behaviour. Only 17% of the subjects said they have on one or more occasions induced a seizure, by not t a k i n g t h e i r drugs, or in other ways. Our data are discussed in the light of other similar surveys.
Sudden death in epilepsy: risk assessment in different patient groups L. Nashef, S. Garner, O.C. Cockerell, D. Fish, J.W.A.S. Sander, S.D. Shorvon Epilepsy Research Group, Institute of Neurology, Queen Square, London and Chalfont Centre for Epilepsy, Chalfont St Peter, Bucks, UK Sudden unexpected deaths in epilepsy, where post-mortem examination fails to reveal a n anatomical or toxicological cause for death, have been recognized since the last century. Evidence for a n associated seizure is found in some 50% of cases. Risk estimates in patients with chronic epilepsy vary from 1:200 to l : i 200 per year with young adults bearing the highest risk: Our group has previously published data regarding the risk among adult patients with chronic epilepsy in long-term residential care ~. We present further data outlining the risk in other patient groups. In a n outpatient cohort with chronic epilepsy at a tertiary referral centre (n = 601 patients, 1849 patient years), the incidence was of the order of 1:200 sudden deaths per year. A m i n i m u m incidence of l:400/year has so far been found in a young cohort with epilepsy and educational difficulty (n = 310, 4228.5 person years). On the other hand, no such cases have been reported to the National General Practice Study of Epilepsy which includes newly diagnosed epileptic seizures (definite and possible) in a general population (> 5000 patient years). Characteristics of each cohort, including age distribution, and other factors t h a t may be implicated in defining risk will be discussed.
REFERENCE 1. Klenerman, P. Sander, J.W.A.S., Shorvon, S.D. Mortality in patients with epilepsy: a study of patients in long-term residential care. J N N P 1993; 56: 149-152.
The relationship between MRI hippocampal morphology and the intracarotid sodium amytal test in the presurgical evaluation of patients for temporal Iobectomy Sallie A. Baxendale, Mark Cook, Simon Shorvon, Pamela J. Thompson, Elizabeth K. Warrington
Epilepsy Research Group, Institute of Neurology, Queen Square, London The increasing sophistication of MRI volumetric m e a s u r e m e n t has led to speculation t h a t it may supersede the intracarotid sodium amytal test in the presurgical screening for bilateral abnormalities in prospective temporal lobectomy patients.t We report on 50 presurgical cases who underwent the intracarotid sodium amytal test and morphometric analysis of hippocampal sclerosis identified by MRI scan. The predictive power of each technique is compared and contrasted with respect to presurgical seizure lateralization and post-surgical seizure control and changes in memory function. We conclude t h a t the combination of functional and structural measures provides valuable information in the presurgical assessment of patients for temporal lobectomy.
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REFERENCE 1. Trenerry, M.R. et al. MRI hippocampal volumes and memory function before and after temporal lobectomy. Neurology 1993; 43: 1800-1805.
Stereotactic craniotomy for cavernous angiomas
A.T.H. Casey, D.G.T. Thomas, W.F. Harkness The National Hospital for Neurology and Neurosurgery, UK With the wider availability of magnetic resonance imaging angiographically occult vascular malformations are being recognized with increasing frequency in those patients presenting with medically refractory epilepsy. Surgical resection is the treatment of choice. However, because these lesions are often small and can be located in eloquent areas stereotactically guided resection should be considered. Stereotactically guided resection of pathologically confirmed lesions has been performed in nine patients in this series presenting with epilepsy (seven males, three females mean age 34 years). Eight patients presented with medically refractory epilepsy (five complex partial seizures, three grand real seizures) the remaining patient experiencing repeated intracerebral haemorrhages and epileptic seizures. All patients had normal neurological examinations. Patients were assessd by CT scan, MRI and angiogram. Operative resection was guided by either CRW or Leksell frame, Peroperative ECoG, cortical stimulation with speech mapping and ultrasonography were employed in selected cases. MRI typically consisted of mixed T1 and T2 signals with a rim of low density suggestive of haemosiderin deposition. Pathological findings were also indicative of repeated haemorrhagic episodes. Following resection of these lesions all patients experienced improved seizure control (Enge] I-III) with a mean follow-up of 19.6 months. We conclude that stereotactic localization of these lesions offers significant advantages. The surgical indications for operation include medically refractory epilepsy, repeated haemorrhagic episodes, and in those cases where diagnostic uncertainty exists: