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Summary Objectives: Non-epileptic seizures (NES) present a considerable challenge in clinical practice. This paper reviews published evidence for the reliability of a number of procedures for the differential diagnosis of NES and epilepsy. Methods: Papers identified from MEDLINE and PsychInfo Databases (1980–2001) and additional hand searches were independently reviewed using methods for evaluating evidence in systematic reviews [Liddle, J., Williamson, M. Irwig, L. Method for evaluating research guideline evidence . New South Wales Department of Health; 1996 [State Health publication no. (CEB) 96–204]; SIGN. An introduction to SIGN methodology for the development of evidence based clinical guidelines . Scottish Intercollegiate Network; 1999]. Included studies had to have an NES group and a control group of people with epilepsy (each n ≥10), allocated using EEG linked video-recording of concurrent behaviour, and sensitivity and specificity values had to be stated or be calculable. Results: Thirty-three papers were identified, of which 13 satisfied criteria. Excluded studies are briefly described. Those retained comprised a range of procedures [seizure induction, MMPI assessment, physiological assessment (prolactin, SPECT), pre-ictal pseudosleep, and ictal/post-ictal characteristics]. No procedure emerged with both high sensitivity and specificity and adequately replicated findings, although high levels of specificity were more commonly reported than high levels of sensitivity. This suggests that procedures were generally better at excluding a possible diagnosis. Conclusions: No procedure attains reliability equivalent to EEG video-telemetry. Further rigorous evaluation, using standardised and replicable methodologies, is required. The range of symptoms presented in NES suggests that a multi-method approach may be required. This too would require evaluation.

Summary Objective Our purpose was to present and discuss the psychiatric diagnoses of patients who presented psychogenic non-epileptic seizures (PNES) during video-electroencephalographic monitoring (VEEG). Methods Out of 98 patients, a total of 28 patients presented PNES during the diagnostic procedure. In those cases in which the PNES that occurred during VEEG were validated by clinical history (clinical validation), and by showing the recorded event on video to an observer close to the patient (observer validation), was defined psychogenic non-epileptic seizure disorder (PNESD). Psychiatric diagnoses were made according to DSM-IV. Results In 27, psychogenic non-epileptic seizures disorder was diagnosed. Fourteen patients presented only with psychogenic non-epileptic seizure disorder, 13 with both psychogenic non-epileptic seizures disorder and epilepsy, and one patient with epilepsy only. Psychiatric diagnoses were: 17 (63%) patients with conversion disorder, five (19%) with somatization disorder, two (7%) with dissociative disorder NOS, two (7%) with post-traumatic stress disorder and one (4%) with undifferentiated somatoform disorder. Conclusions Dissociative-conversion non-epileptic seizures are the most frequent finding, representing the pseudoneurological manifestation of mental disorders that have these symptoms as a common feature. Provisionally, they may be defined as dissociative-conversion non-epileptic seizure disorders.

Patients with psychogenic non-epileptic seizures (pseudoseizures) have been diagnosed as having conversion disorder or dissociative disorder. Pseudoseizure patients frequently report a history of physical and sexual abuse, and traumatic experience is considered part of the mechanism for producing dissociation. Pseudoseizures may be a manifestation of dissociative disorder, especially when a history of sexual or physical abuse is documented. A common mechanism involving traumatic experience may be present in both pseudoseizures and dissociative disorders. A complete neurodiagnostic evaluation along with an awareness of this relationship is needed to provide appropriate care for this patient population.

The purpose of this study was to examine the incidence of patients with NES vs. NES and concomitant epilepsy in an epilepsy centre and to present a diagnostic algorithm. We collected and reviewed the data of 322 patients consecutively referred to the adult ward of our epilepsy centre in 1 year. The results of our study reveal that 44 (14%) of all patients referred had NES. Of these, nine proved to have concomitant epilepsy. Of 44 patients with NES, 20 were treated with AED on admission. In 14 cases this unnecessary antiepileptic drug treatment was stopped. In six remaining patients with NES and concomitant epilepsy, the total number of AEDs could be reduced until discharge. The maximum duration of AED treatment among patients with NES only, had been longer than 360 months (median 72 months).Much has been written about whether the diagnosis of psychogenic non-epileptic events is overused. According to our experience however, the fact that many patients with so-called ‘pharmacoresistant epilepsy’, suspected NES or other diagnoses are referred to a centre of excellence much too late, proves to be the key problem in diagnosis and treatment of NES.We conclude that early admission of so-called ‘pharmacoresistant epilepsy’ to an epilepsy centre, establishing a standard work-up and clarifying the medical terminology will improve diagnosis and lead to adequate therapy of NES as well as prevent unnecessary drug treatment.

The aim of the study was to assess whether post-ictal symptoms can help distinguish patients who have epileptic seizures from those with non-epileptic seizures (NES). We reviewed the spontaneous responses to the question ‘What symptoms do you have after a seizure?’ in 16 patients with epileptic seizures (predominantly focal with secondary generalization or generalized tonic–clonic) and 23 NES patients. Six of the 16 patients (38%) vs. only one of 23 NES patients (4.3%) noted post-ictal headache (P= 0.008). Nine epilepsy patients (56%) vs. three NES patients (13%) reported post-ictal fatigue (P= 0.004). Confusion or other symptoms did not distinguish epilepsy patients from those with NES. All epilepsy patients had at least one post-ictal symptom while 12 NES patients (52%) had none (P= 0.001). Therefore, patients evaluated for epileptic vs. non-epileptic seizures who have post-ictal fatigue or headache, are more likely to have epileptic seizures. Patients with a diagnosis of NES who note post-ictal fatigue or headache should be investigated further.

Studies of patients with psychogenic non-epileptic seizures (NES) typically focus upon the phenomenology and outcome of NES episodes. Little is known, however, about the frequency and nature of other somatic symptoms such as pain, in this population. To assess the frequency, location and severity of symptoms of pain among NES patients, we administered structured interviews to 56 patients, 6 or more months following the diagnosis of psychogenic non-epileptic seizures (NES). Patients were recruited from a tertiary hospital-based epilepsy monitoring unit. Seventy-seven percent of patients suffered from moderate to severe pain, most commonly headache (61%), while neck pain and backache were also common. Twenty-six of 27 patients with persistent NES vs. 17 of 29 patients whose NES resolved experienced moderate to severe pain (P< 0.001). Pain is an under-recognized problem that occurs frequently and with significant severity among NES patients. Pain symptoms are more common among patients with persistent NES than those whose NES resolve.