Medline ® Abstracts for References 1-4

The prevalence of psychogenic non-epileptic seizures is difficult to estimate. We propose an estimate based on a calculation. We used the following data, which are known or have been estimated, and are generally accepted. A prevalence of epilepsy of 0.5-1%; a proportion of intractable epilepsy of 20-30%; a percentage of these referred to epilepsy centers of 20-50%; and a percentage of patients referred to epilepsy centers that are psychogenic non-epileptic seizures: 10-20%. Using the low estimates, the prevalence of psychogenic non-epileptic seizures would be 1/50 000. Using the high estimates, the prevalence of psychogenic non-epileptic seizures would be 1/3000. The prevalence of psychogenic non-epileptic seizures is somewhere between 1/50 000 and 1/3000, or 2 to 33 per 100 000, making it a significant neurologic condition.

This paper reports the results of a population study designed to assess the standards of epilepsy care within a geographical population in relation to diagnosis, seizure management and quality of life. One of the findings was the unexpectedly high frequency of the misdiagnosis of epilepsy. Forty-nine of 214 patients with a primary diagnosis of epilepsy were subsequently found to have been misdiagnosed following a specialist review and investigations. All except two have been withdrawn from antiepileptic medication. The diagnosis of epilepsy was disputed in a further 26 patients. Of the 49 patients, 20 were found to have cardiovascular or cerebrovascular pathology. Seven had only ever experienced a single seizure and a further 10 were found to have underlying psychopathology. Such observations support the view that epilepsy is frequently misdiagnosed and this paper discusses some of the implications of misdiagnosis.

We assessed the frequency, causes and consequences of erroneous diagnosis of epilepsy, and the outcome of patients referred with 'refractory epilepsy', by retrospective analysis of the case records of 324 patients. The sample was divided into those exposed to anti-epileptic drugs (n = 184), of whom 92 were said to have refractory seizures, and those who had not received treatment (n = 140). The latter group is reported elsewhere. The overall misdiagnosis rate was 26.1% (46/184), with incomplete history-taking and misinterpretation of the EEG equally responsible. Side-effects were reported by 19/40, while unnecessary driving restrictions and employment difficulties were encountered by 12/33 and 5/33, respectively. Of those labelled 'refractory epilepsy', 12 did not have epilepsy. Sixteen were rendered seizure-free and 25 significantly improved by the optimal use of anti-epileptic drugs or surgery. Diagnostic and management services for patients with suspected and established epilepsy are suboptimal, with psychological and socio-economic consequences for individual patients. The resulting economic burden on the health and welfare services is probably substantial.

We report a prospective series of 18 patients with a diagnosis of non-epileptic seizures (NES, pseudoseizures) identified in one unit. Sixteen patients agreed to complete a therapeutic programme. At the end of treatment eight were seizure free, three had only occasional NES and five were unchanged. At 1-year follow-up the situation remained similar regarding seizures, with responders demonstrating an improvement in social functioning and a marked reduction in demands on health service resources. Admission variables significantly associated with a poor outcome were an IQ of less than 80 and a past history of violent behaviour.