Ictal cognitive assessment of partial seizures and pseudoseizures

Diagnosis and management of functional neurological disorder

Functional neurological disorder (FND), previously regarded as a diagnosis of exclusion, is now a rule-in diagnosis with available treatments. This represents a major step toward destigmatizing the disorder, which was often doubted and deemed untreatable. FND is prevalent, generally affecting young and middle aged adults, and can cause severe disability in some individuals. An early diagnosis, with subsequent access to evidence based rehabilitative and/or psychological treatments, can promote recovery-albeit not all patients respond to currently available treatments. This review presents the latest advances in the use of validated rule-in examination signs to guide diagnosis, and the range of therapeutic approaches available to care for patients with FND. The article focuses on the two most frequently identified subtypes of FND: motor (weakness and/or movement disorders) and seizure type symptoms. Twenty two studies on motor and 27 studies on seizure type symptoms report high specificities of clinical signs (64-100%), and individual signs are reviewed. Rehabilitative interventions (physical and occupational therapy) are treatments of choice for functional motor symptoms, while psychotherapy is an emerging evidence based treatment across FND subtypes. The literature to date highlights heterogeneity in responses to treatment, underscoring that more research is needed to individualize treatments and develop novel interventions.

Shame in patients with psychogenic nonepileptic seizure: A narrative review

Psychogenic Nonepileptic Seizures (PNES) have been linked to dysregulated emotions and arousal. However, the question which emotions may be most relevant has received much less attention. In this multidisciplinary narrative review, we argue that the self-conscious emotion of shame is likely to be of particular importance for PNES. We summarize current concepts of the development of shame processing and its relationship with other emotional states. We demonstrate the potential of acute shame to cause a sudden disruption of normal cognitive function and trigger powerful behavioral, cognitive, physiological and secondary emotional responses which closely resemble key components of PNES. These responses may lead to the development of shame avoidance strategies which can become disabling in themselves. We discuss how excessive shame proneness and shame dysregulation are linked to several psychopathologies often associated with PNES (including depression and PTSD) and how they may predispose to, precipitate and perpetuate PNES disorders, not least by interacting with stigma. We consider current knowledge of the neurobiological underpinnings of shame and PNES. We explore how shame could be the link between PNES and a heterogeneous range of possible etiological factors, and how it may link historical aversive experiences with individual PNES events occurring much later and without apparent external trigger. We argue that, in view of the potential direct links between shame and PNES, the well-documented associations of shame with common comorbidities of this seizure disorder and the well-characterized relationship between chronic shame and stigma, there is a compelling case to pay greater attention to shame in relation to PNES. Its role in the treatment of patients with PNES is discussed in a separate, linked review incorporating case vignettes to highlight the complex interactions of different but interlinked shame-related issues in individual patients.

Psychogenic non-epileptic seizures (PNES) in the context of concurrent epilepsy – making the right diagnosis

Epilepsy is a risk factor for the development of psychogenic non-epileptic seizures (PNES) and comorbid epilepsy is recognized as a comorbidity in about 10–30% of patients with PNES. The combination of epileptic and nonepileptic seizures poses a particular diagnostic challenge. In patients with epilepsy, additional PNES may be suspected on the basis of their typical semiology. The possibility of additional PNES should also be considered if seizures fail to respond to antiepileptic drug treatment, in patients with frequent emergency admissions with seizures and in those who develop new types of seizures. The description of semiological details by patients and witnesses can suggest additional PNES. Home video recordings can support an initial diagnosis, however, especially in patients with mixed seizure disorders it is advisable to seek further diagnostic confirmation by capturing all habitual seizure types with video-EEG. The clinical features of PNES associated with epilepsy are similar to those in isolated PNES disorders and include longer duration, fluctuating course, asynchronous movements, pelvic thrusting, side-to-side head or body movement, persistently closed eyes and mouth, ictal crying, recall of ictal experiences and absence of postictal confusion. PNES can also present as syncope-like episodes with unresponsiveness and reduced muscle tone. There is no unique epileptological or brain pathology profile putting patients with epilepsy at risk of additional PNES. However, patients with epilepsy and PNES typically have lower educational achievements and higher levels of psychiatric comorbidities than patients with epilepsy alone. Psychological trauma, including sexual abuse, appears to be a less relevant aetiological factor in patients with mixed seizure disorders than those with isolated PNES, and the gender imbalance (i.e. the greater prevalence in women) is less marked in patients with PNES and additional epilepsy than those with PNES alone. PNES sometimes develop after epilepsy surgery. A diagnosis of ‘known epilepsy’ should never be accepted without (at least brief) critical review. This narrative review summarises clinical, electrophysiological and historical features that can help identify patients with epilepsy and additional PNES.

Improved ictal assessment performance in the epilepsy monitoring unit via standardization

OBJECTIVE

To determine whether the standardization and implementation of an ictal testing protocol in the Epilepsy Monitoring Unit (EMU) leads to improvements in ictal testing performance.

METHODS

Ictal assessments completed in the EMU from a single center were retrospectively reviewed over a two-month period. Each assessment was evaluated to determine whether 8 high-yield aspects of the ictal assessment were performed. Following observation of performance, a standardized ictal testing protocol was developed based on a root cause analysis and review of consensus guidelines. This protocol was disseminated to staff in conjunction with an annual epilepsy education seminar. Ictal assessment performance was re-assessed during the subsequent two months (short-term follow-up) and again during a five- to seven-month period (long-term follow-up) beyond the initial intervention. For sub-group analysis, event characteristics (event type, time of assessment) and patient characteristics (age, gender) were also evaluated and analyzed in relation to ictal testing performance.

RESULTS

All eight individual ictal testing elements were more likely to be assessed in short-term and long-term follow-up periods when compared to pre-intervention assessments. The cumulative difference in ictal testing was 20.4% (95% CI 3.7-37.2, p = 0.02) greater for the short-term period and 16.7% (95% CI -0.3% to 33.8%, p = 0.05) greater in the long-term period when compared to baseline testing.

CONCLUSIONS

Utilization of a standardized ictal testing battery in conjunction with staff education leads to an objective improvement in ictal assessment performance. Further research is warranted to assess the replicability of our findings.

Clinical differentiation of psychogenic non-epileptic seizure: a practical diagnostic approach

Background

Psychogenic non-epileptic seizure (PNES) has long been the counterpart of epileptic seizure (ES). Despite ample of evidence differentiating the two, PNES mistakenly diagnosed as ES was still common, resulting in unnecessary exposure to long-term antiepileptic medications and reduced patient’s and caregiver’s quality of life, not to mention the burgeoning financial costs.

Objectives

In this review, we aimed to elucidate various differences between PNES and epileptic seizure with respect to baseline characteristics, seizure semiology, EEG pattern, and other key hallmark features.

Methods

An unstructured search was carried out in PubMed, MEDLINE, and EMBASE using keywords pertinent to PNES and ES differentiation. Relevant information was subsequently summarized herein.

Results

PNES differs significantly with ES in terms of baseline characteristics, prodromal symptoms, seizure semiology, presence of pseudosleep, and other hallmark features (for instance provoking seizure with suggestion). The combined approach, if applied appropriately, can yield high diagnostic yield.

Conclusions

PNES can be clearly differentiated from ES via careful adherence to a set of valid clinical cues. The summarized clinical hallmarks is highly useful to prevent unnecessary ES diagnosis and treatment with AEDs.

Differential diagnosis between epileptic seizures and psychogenic nonepileptic seizures based on semiology

Psychogenic nonepileptic seizures present as paroxysmal symptoms and signs mimicking epileptic seizures. The gold standard test is the synchronous recording by video, electrocardiogram and electroencephalogram. However, video electroencephalogram is not available at many centers and not entirely independent of semiology. Recent studies have focused on semiological characteristics distinguishing these two circumstances. Clinical signs and symptoms provide important clues when making differential diagnosis. The purpose of this review is to help physicians differentiating psychogenic nonepileptic seizures better from epileptic seizures based on semiology, and improve care for those patients.

Machine learning as a diagnostic decision aid for patients with transient loss of consciousness

Background

Transient loss of consciousness (TLOC) is a common reason for presentation to primary/emergency care; over 90% are because of epilepsy, syncope, or psychogenic non-epileptic seizures (PNES). Misdiagnoses are common, and there are currently no validated decision rules to aid diagnosis and management. We seek to explore the utility of machine-learning techniques to develop a short diagnostic instrument by extracting features with optimal discriminatory values from responses to detailed questionnaires about TLOC manifestations and comorbidities (86 questions to patients, 31 to TLOC witnesses).

Methods

Multi-center retrospective self- and witness-report questionnaire study in secondary care settings. Feature selection was performed by an iterative algorithm based on random forest analysis. Data were randomly divided in a 2:1 ratio into training and validation sets (163:86 for all data; 208:92 for analysis excluding witness reports).

Results

Three hundred patients with proven diagnoses (100 each: epilepsy, syncope and PNES) were recruited from epilepsy and syncope services. Two hundred forty-nine completed patient and witness questionnaires: 86 epilepsy (64 female), 84 PNES (61 female), and 79 syncope (59 female). Responses to 36 questions optimally predicted diagnoses. A classifier trained on these features classified 74/86 (86.0% [95% confidence interval 76.9%-92.6%]) of patients correctly in validation (100 [86.7%-100%] syncope, 85.7 [67.3%-96.0%] epilepsy, 75.0 [56.6%-88.5%] PNES). Excluding witness reports, 34 features provided optimal prediction (classifier accuracy of 72/92 [78.3 (68.4%-86.2%)] in validation, 83.8 [68.0%-93.8%] syncope, 81.5 [61.9%-93.7%] epilepsy, 67.9 [47.7%-84.1%] PNES).

Conclusions

A tool based on patient symptoms/comorbidities and witness reports separates well between syncope and other common causes of TLOC. It can help to differentiate epilepsy and PNES. Validated decision rules may improve diagnostic processes and reduce misdiagnosis rates.

Classification of evidence

This study provides Class III evidence that for patients with TLOC, patient and witness questionnaires discriminate between syncope, epilepsy and PNES.

Structured testing during seizures: A practical guide for assessing and interpreting ictal and postictal signs during video EEG long term monitoring

BACKGROUND

Ictal and postictal testing carried out in long-term epilepsy monitoring units is often sub-optimal. Recently, a European consensus protocol for testing patients during and after seizures was developed by a joint taskforce of the International League Against Epilepsy - Commission on European Affairs and the European Epilepsy Monitoring Unit Association.

AIM

Using this recently developed standardised assessment battery as a framework, the goal of this narrative review is to outline the proposed testing procedure in detail and explain the rationale for each individual component, focusing on the underlying neurobiology. This is intended to serve as an educational resource for staff working in epilepsy monitoring units.

METHODS

A literature review of PubMed was performed; using the search terms "seizure", "ictal", "postictal", "testing", "examination", and "interview". Relevant literature was reviewed and relevant references were chosen. The work is presented as a narrative review.

RESULTS

The proposed standardised assessment battery provides a comprehensive and user-friendly format for ictal-postictal testing, and examines consciousness, language, motor, sensory, and visual function.

CONCLUSION

The standardised approach proposed has the potential to make full use of data recorded during video EEG increasing the diagnostic yield with regards to lateralisation and localisation, aiding both presurgical and diagnostic studies.

Dissociative (non-epileptic) seizures: tackling common challenges after the diagnosis

Dissociative (non-epileptic) seizures are one of the three major causes of transient loss of consciousness. As such, their treatment cannot be left to superspecialised experts. In this article I draw on personal experience to suggest ways to tackle some challenges that commonly arise after diagnosing dissociative seizures, focusing on three issues: “I want to know what is wrong with me,” “I hear what you are saying but it doesn’t apply to me” and “What if I have a seizure?” The suggestions detail both actions and words that may help at a crucial point in the patient’s journey. If handled well, the process can leave the patient better equipped to understand their seizures and to engage in further treatment; if handled badly, patients may be left more traumatised, angry and with additional disability.

Proposal for best practice in the use of video-EEG when psychogenic non-epileptic seizures are a possible diagnosis

The gold-standard for the diagnosis of psychogenic non-epileptic seizures (PNES) is capturing an attack with typical semiology and lack of epileptic ictal discharges on video-EEG. Despite the importance of this diagnostic test, lack of standardisation has resulted in a wide variety of protocols and reporting practices. The goal of this review is to provide an overview of research findings on the diagnostic video-EEG procedure, in both the adult and paediatric literature. We discuss how uncertainties about the ethical use of suggestion can be resolved, and consider what constitutes best clinical practice. We stress the importance of ictal observation and assessment and consider how diagnostically useful information is best obtained. We also discuss the optimal format of video-EEG reports; and of highlighting features with high sensitivity and specificity to reduce the risk of miscommunication. We suggest that over-interpretation of the interictal EEG, and the failure to recognise differences between typical epileptic and nonepileptic seizure manifestations are the greatest pitfalls in neurophysiological assessment of patients with PNES. Meanwhile, under-recognition of semiological pointers towards frontal lobe seizures and of the absence of epileptiform ictal EEG patterns during some epileptic seizure types (especially some seizures not associated with loss of awareness), may lead to erroneous PNES diagnoses. We propose that a standardised approach to the video-EEG examination and the subsequent written report will facilitate a clear communication of its import, improving diagnostic certainty and thereby promoting appropriate patient management.

Psychogenic Explanations of Physical Illness

In some patients with chronic physical complaints, detailed examination fails to reveal a well-recognized underlying disease process. In this situation, the physician may suspect a psychological cause. In this review, we critically evaluated the evidence for this causal claim, focusing on complaints presenting as neurological disorders. There were four main conclusions. First, patients with these complaints frequently exhibit psychopathology but not consistently more often than patients with a comparable “organic” diagnosis, so a causal role cannot be inferred. Second, these patients report a high incidence of adverse life experiences, but again, there is insufficient evidence to indicate a causal role for any particular type of experience. Third, although psychogenic illnesses are believed to be more responsive to psychological interventions than comparable “organic” illnesses, there is currently no evidence to support this claim. Finally, recent evidence suggests that biological and physical factors play a much greater causal role in these illnesses than previously believed. We conclude that there is currently little evidential support for psychogenic theories of illness in the neurological domain. In future research, researchers need to take a wider view concerning the etiology of these illnesses.

Value of patient-reported symptoms in the diagnosis of transient loss of consciousness

OBJECTIVE

Epileptic seizures, syncope, and psychogenic nonepileptic seizures (PNES) account for over 90% of presentations with transient loss of consciousness (TLOC). The patient's history is crucial for the diagnosis, but the diagnostic value of individual semiologic features is limited. This study explores the diagnostic potential of a comprehensive questionnaire focusing on TLOC-associated symptoms.

METHODS

A total of 386 patients with proven epilepsy, 308 patients with proven PNES, and 371 patients with proven syncope were approached by post to recruit 100 patients in each diagnostic group. Symptoms were self-reported on an 86-item questionnaire (the Paroxysmal Event Profile [PEP]) using a 5-point Likert scale (always to never). Data were subjected to exploratory factor analysis (EFA) followed by confirmatory factor analysis (CFA). Factors were used to differentiate between diagnoses by pairwise and multinomial regression.

RESULTS

Patients with PNES reported more and more frequent TLOC-associated symptoms than those with epilepsy or syncope (p < 0.001). EFA/CFA identified a 5-factor structure based on 74/86 questionnaire items with loadings ≥0.4. Pairwise logistic regression analysis correctly classified 91% of patients with epilepsy vs those with syncope, 94% of those with PNES vs those with syncope, and 77% of those with epilepsy vs those with PNES. Multinomial logistic regression analysis yielded a similar pattern.

CONCLUSIONS

Clusters of self-reported TLOC symptoms can be used to direct patients to appropriate investigation and treatment pathways for syncope on the one hand and seizures on the other, although additional information is required for a reliable distinction, especially between epilepsy and PNES.

Nonepileptic seizures - subjective phenomena

Psychogenic nonepileptic seizures (PNES) superficially resemble epileptic seizures or syncope and most patients with PNES are initially misdiagnosed as having one of the latter two types of transient loss of consciousness. However, evidence suggests that the subjective seizure experience of PNES and its main differential diagnoses are as different as the causes of these three disorders. In spite of this, and regardless of the fact that PNES are considered a mental disorder in the current nosologies, research has only given limited attention to the subjective symptomatology of PNES. Instead, most phenomenologic research has focused on the visible manifestations of PNES and on physiologic parameters, neglecting patients' symptoms and experiences. This chapter gives an overview of qualitative and quantitative studies providing insights into subjective symptoms associated with PNES, drawing on a wide range of methodologies (questionnaires, self-reports, physiologic measures, linguistic analyses, and neuropsychologic experiments). After discussing the scope and limitations of these approaches in the context of this dissociative phenomenon, we discuss ictal, peri-ictal and interictal symptoms described by patients with PNES. We particularly focus on impairment of consciousness. PNES emerges as a clinically heterogeneous condition. We conclude with a discussion of the clinical significance of particular subjective symptoms for the engagement of patients in treatment, the formulation of treatment, and prognosis.

Neurologic diagnostic criteria for functional neurologic disorders

The diagnosis of functional neurologic disorders can be challenging. In this chapter we review the diagnostic criteria and rating scales reported for functional/psychogenic sensorimotor disturbances, psychogenic nonepileptic seizures (PNES) and functional movement disorders (FMD). A recently published scale for sensorimotor signs has some limitations, but may help in the diagnosis, and four motor and two sensory signs have been reported as highly reliable. There is good evidence using eight specific signs for the differentiation of PNES from seizures. Recently, diagnostic criteria were developed for PNES; their sensitivity and specificity need to be evaluated. The definitive diagnosis of PNES can be made by recording typical positive features during the spells, and in a low proportion of cases, where the distinction with an organic etiology cannot easily be done, a normal electroencephalogram suggests the diagnosis. FMD diagnosis relies on diagnostic criteria, which have been refined over time and may be supplemented by laboratory tests in some phenotypes. Rating scales for PNES and FMD could be useful for severity measures, but several limitations remain to be addressed.

Epilepsy and driving: potential impact of transient impaired consciousness

Driving is an important part of everyday life for most adults, and restrictions on driving can place a significant burden on individuals diagnosed with epilepsy. Although sensorimotor deficits during seizures may impair driving, decreased level of consciousness often has a more global effect on patients' ability to respond appropriately to the environment. Better understanding of the mechanisms underlying alteration of consciousness in epilepsy is important for decision-making by people with epilepsy, their physicians, and regulators in regard to the question of fitness to drive. Retrospective cohort and cross-sectional studies based on surveys or crash records can provide valuable information about driving in epilepsy. However, prospective objective testing of ictal driving ability during different types of seizures is needed to more fully understand the role of impaired consciousness and other deficits in disrupting driving. Driving simulators adapted for use in the epilepsy video-EEG monitoring unit may be well suited to provide both ictal and interictal data in patients with epilepsy. Objective information about impaired driving in specific types of epilepsy and seizures can provide better informed recommendations regarding fitness to drive, potentially improving the quality of life of people living with epilepsy.

Consciousness of seizures and consciousness during seizures: are they related?

Recent advances have been made in the network mechanisms underlying impairment of consciousness during seizures. However, less is known about patient awareness of their own seizures. Studying patient reports or documentation of their seizures is currently the most commonly utilized mechanism to scientifically measure patient awareness of seizures. The purpose of this review is to summarize the available evidence regarding the accuracy of patient seizure counts and identify the variables that may influence unreliable seizure reporting. Several groups looking at patient documentation of seizures during continuous EEG monitoring show that patients do not report as many as 50% of their seizures. These studies also suggest that seizures accompanied by loss of consciousness, arising from the left hemisphere or the temporal lobe, or occurring during sleep are associated with significantly reduced reporting. Baseline memory performance does not appear to have a major influence on the accuracy of seizure report. Further prospective studies using validated ictal behavioral testing as well as using correlation with newer electrophysiological and neuroimaging techniques for seizure localization are needed to more fully understand the mechanisms of underreporting of seizures. Better methods to alert caregivers about unrecognized seizures and to improve seizure documentation are under investigation.

Prospective assessment of ictal behavior using the revised Responsiveness in Epilepsy Scale (RES-II)

Impaired consciousness in epilepsy has a significant negative impact on patients' quality of life yet is difficult to study objectively. Here, we develop an improved prospective Responsiveness in Epilepsy Scale-II (RES-II) and report initial results compared with the earlier version of the scale (RES). The RES-II is simpler to administer and includes both verbal and non-verbal test items. We evaluated 75 seizures (24 patients) with RES and 34 seizures (11 patients) with RES-II based on video-EEG review. The error rate per seizure by test administrators improved markedly from a mean of 2.01 ± 0.04 with RES to 0.24 ± 0.11 with RES-II. Performance during focal seizures showed a bimodal distribution, corresponding to the traditional complex partial vs. simple partial seizure classification. We conclude that RES-II has improved accuracy and testing efficiency compared with the original RES. Prospective objective testing will ultimately lead to a better understanding of the mechanisms of impaired consciousness in epilepsy.

Intact vs. impaired ictal sensorium: does it affect outcome of psychogenic nonepileptic events following disclosure of diagnosis?

It remains uncertain whether particular ictal manifestations of psychogenic nonepileptic events (PNEE) can reflect distinctive psychological processes or prognostic outcomes. We hypothesize that the integrity of ictal sensorium may affect the clinical outcome of PNEE following disclosure of diagnosis. We prospectively studied 47 veterans who were diagnosed with video-EEG-confirmed PNEE, presented with the diagnosis utilizing a standardized communication strategy, and followed for their clinical progress. When compared to patients with intact ictal sensorium, significantly smaller proportion of patients with impaired ictal sensorium endorsed improvement of either PNEE frequency or intensity across both the initial 1- to 3-month (p=0.005) and ensuing 6- to 9-month (p=0.01) follow-ups. However, improvement among patients with impaired ictal sensorium was more significantly associated with their level of understanding for the PNEE diagnosis across both the initial (rho=0.41, p=0.017) and ensuing (rho=0.43, p=0.015) follow-ups. Our study presents preliminary evidence underscoring the potential clinical significance of ictal sensorial integrity when evaluating patients with PNEE.

Psychogenic nonepileptic seizures

Treatment for PNES must be individualized. A combination of approaches is probably the most beneficial for improvement. Treatment should not simply emphasize removing maladaptive PNES behaviour, but should also focus on learning new coping skills and removing secondary gains. If PNES persist, therapy should be re-evaluated.

Impaired consciousness in epilepsy investigated by a prospective responsiveness in epilepsy scale (RES)

PURPOSE

Impaired consciousness in epileptic seizures has a major negative impact on patient quality of life. Prior work on epileptic unconsciousness has mainly used retrospective and nonstandardized methods. Our goal was to validate and to obtain initial data using a standardized prospective testing battery.

METHODS

The responsiveness in epilepsy scale (RES) was used on 52 patients during continuous video-electroencephalography (EEG) monitoring. RES begins with higher-level questions and commands, and switches adaptively to more basic sensorimotor responses depending on patient performance. RES continues after seizures and includes postictal memory testing. Scoring was conducted based on video review.

KEY FINDINGS

Testing on standardized seizure simulations yielded good intrarater and interrater reliability. We captured 59 seizures from 18 patients (35% of participants) during 1,420 h of RES monitoring. RES impairment was greatest during and after tonic-clonic seizures, less in partial seizures, and minimal in auras and subclinical seizures. In partial seizures, ictal RES impairment was significantly greater if EEG changes were present. Maximum RES impairment (lowest ictal score) was also significantly correlated with long postictal recovery time, and poor postictal memory.

SIGNIFICANCE

We found that prospective testing of responsiveness during seizures is feasible and reliable. RES impairment was related to EEG changes during seizures, as well as to postictal memory deficits and recovery time. With a larger patient sample it is hoped that this approach can identify brain networks underlying specific components of impaired consciousness in seizures. This may allow the development of improved treatments targeted at preventing dysfunction in these networks.

Ictal characteristics of psychogenic nonepileptic seizures: what we have learned from video/EEG recordings--a literature review

Psychogenic nonepileptic seizures (PNES) are highly prevalent in selected populations, with a strong impact in terms of morbidity and social cost. The gold standard for PNES diagnosis is video/EEG recording of a typical attack. However this technique is costly and not always available. In addition, many patients are treated with antiepileptic drugs for several years before undergoing video/EEG recording. The diagnosis is further complicated by concomitant epileptic seizures in some patients with PNES. Therefore, a good knowledge of PNES semiology is important for early screening of patients for video/EEG recording and for correct interpretation of the examination. We reviewed the literature on video/EEG studies reporting ictal PNES semiology to identify features indicative of psychogenic or epileptic seizures. Several features appeared to be useful in the clinical setting.

Definition of the postictal state: when does it start and end?

The postictal state is the abnormal condition occurring between the end of an epileptic seizure and return to baseline condition. Applying this definition operationally can be difficult, especially for complex partial seizures, where cognitive and sensorimotor impairments merge imperceptibly into the postictal state. Many patients are unaware of even having had a seizure. Electroencephalography sometimes helps to distinguish ictal from postictal periods, but may demonstrate focal slowing both during and after a seizure. Epileptiform electroencephalographic changes do not always correspond precisely to behavioral changes, especially with scalp recordings. The postictal state ends at the interictal state, but this too can be ambiguous. Interictal spikes and spike-waves can be associated with cognitive and behavioral impairments, suggesting that they may represent fragments of ictal episodes. Except where boundaries are clear, it is better to describe a sequence of behaviors and electroencephalographic changes, without labeling arbitrary stages as being ictal or postictal.

Should patients with psychogenic nonepileptic seizures be allowed to drive? Recommendations of German experts

In the absence of evidence-based regulations on the driving ability of patients with psychogenic nonepileptic seizures (PNES), we asked 41 German epileptologists via e-mail for their recommendations on driving with PNES. This survey was modeled on an earlier study by Benbadis et al. in the United States and was compared with it. Thirty-four (82.9%) epileptologists responded. Three responses were possible: (A) same restrictions as stipulated for patients with epilepsy, answered by 11 epileptologists (32.4%); (B) no restrictions at all, which no German expert gave as an answer (0%); (C) decision on an individual basis, answered by 23 experts (67.6%). The divergent approaches reflect the poor data on motor vehicle accidents of patients with PNES and the great variability of PNES with respect to semiology, psychiatric morbidity, and prognosis. In the study by Benbadis et al., 49% chose A, 32% B, and 19% C. The considerable national differences may be explained by differences between the two countries with respect to driving regulations and cultural aspects.

Psychogenic nonepileptic seizures: answers and questions

Psychogenic nonepileptic seizures (PNES) superficially resemble epileptic seizures, but are not associated with ictal electrical discharges in the brain. PNES constitute one of the most important differential diagnoses of epilepsy. However, despite the fact they have been recognized as a distinctive clinical phenomenon for centuries and that access to video/EEG monitoring has allowed clinicians to make near-certain diagnoses for several decades, our understanding of the etiology, underlying mental processes, and, subsequently, subdifferentiation, nosology, and treatment remains seriously deficient. Emphasizing the clinical picture throughout, the first part of this article is intended to "look and look again" at what we know about the epidemiology, semiology, clinical context, treatment, and prognosis of PNES. The second part is dedicated to the questions that remain to be answered. It argues that the most important reason our understanding of PNES remains limited is the focus on the visible manifestations of PNES or the seizures themselves. In contrast, subjective seizure manifestations and the biographic or clinical context in which they occur have been relatively neglected.

Sensitivity and specificity of procedures for the differential diagnosis of epileptic and non-epileptic seizures: a systematic review

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> or =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.

Auditory event-related potentials (P300) in the identification of psychogenic nonepileptic seizures

The feasibility and conceivable value of postictal event-related potential (ERP) recordings were studied in patients with nonepileptic seizures (NES) admitted for long-term video/EEG monitoring. Ten patients with NES underwent preictal (on hospital admission) and postictal (< or =6 hours after seizure) ERP recordings of an auditory oddball paradigm. Additionally, 10 temporal lobe epilepsy (TLE) patients with partial seizures and secondary generalization underwent preictal, postictal (< 6 hours after seizures), and interictal (7-48 hours after seizure) ERP recordings. We recently reported that ERPs recorded in TLE patients with partial epilepsy undergo a temporary change postictally, while returning to their preictal state during interictal recordings. In the current study intraclass correlations, transformed into z scores, are used to determine test-retest validity of repeated ERP recordings. An independent sample t test with z scores for the comparison of preictal and postictal recordings showed that ERP activation differed between NES and TLE patients (P=0.009). More specifically, ERP recordings in the preictal and postictal states were similar in NES patients, but dissimilar in TLE patients. On the other hand, this dissimilarity in ERPs disappeared when comparing z scores for the preictal and postictal recordings in NES patients with z scores for the preictal and interictal recordings in TLE patients. This further supports the notion that identical waveforms during preictal and postictal recordings in NES patients reflect nonepileptic seizure activity. The current findings suggest that postictal ERP recordings are useful in the diagnosis of NES and differentiate TLE from NES.

Controversies in the diagnosis and management of psychogenic pseudoseizures

Since the advent of video-EEG telemetry studies (V-EEG) neurologists have become increasingly aware of psychogenic pseudoseizures (PPS) given the relatively high prevalence of these events among patients seen in epilepsy centers. The use of V-EEG has been accepted as the gold standard study in establishing this diagnosis; some clinicians, however, have suggested that the clinical phenomena of PPS are so obvious in many patients that V-EEG may not be necessary. This is one of many controversial points that clinicians face when evaluating patients suspected of having PPS. In this article, we review some of these controversies, specifically the need for a video-EEG monitoring study in all patients suspected of having PPS and the role of induction protocols in the evaluation of PPS, the question of whether patients have any control over their events, and finally some of the therapeutic strategies for PPS including the need to limit these patients' driving privileges.

Psychogenic nonepileptic seizures: review and update

The population incidence of psychogenic nonepileptic seizures (PNES) may be only 4% that of epilepsy, but many patients with PNES have a tendency to seek medical attention, and PNES make up a larger share of the workload of neurologists and emergency and general physicians. Although a great number of publications describe how PNES can be distinguished from epileptic seizures, it usually takes several years to arrive at this diagnosis, and three-quarters of patients (with no additional epilepsy) are treated with anticonvulsants initially. However, the management of PNES as epileptic seizures can lead to significant iatrogenic harm. Moreover, the failure to recognize the psychological cause of the disorder detracts from addressing associated psychopathology and enhances secondary somatization processes. This review provides an overview of studies of the diagnosis, etiology, treatment, and prognosis of PNES. Physicians should always consider PNES in the differential diagnosis of a seizure disorder. If a diagnosis of PNES is possible, or a diagnosis of epilepsy in doubt, a clear diagnostic categorization should be sought. This should involve the assessment of the patient by a physician versed in the diagnosis of seizure disorders and, in many cases, the documentation of a typical seizure by video-EEG. Outcome may be improved if the diagnosis is more actively sought, made earlier, and communicated more convincingly.

Psychogenic, nonepileptic seizures associated with video-EEG-verified sleep

PURPOSE

Nonepileptic seizures (NES) are expressions of a psychiatric disease state, usually conversion disorder, that mimic epileptic seizures (ES) but are not associated with the neurophysiologic changes of epilepsy. Conversion has not been demonstrated to emerge from the sleeping state. Emergence out of sleep is usually considered a virtual exclusion criterion for NES, signifying the presence instead of ES. We sought to test this hypothesis.

METHODS

We retrospectively reviewed the video-EEG of all patients admitted to our epilepsy unit over a 3-year period, who were suspected of manifesting NES. We examined the relation between NES and the patients' sleep/wake state in this cohort. Two epileptologists blindly reviewed an intermixture of cases suspected to represent NES emerging out of sleep, together with control cases. Classification of each case was made independently.

RESULTS

We found that in a small minority of patients (<1%), NES began either while the patient was sleeping, or within several seconds of arousal, well before a plan to simulate a seizure could likely have been formulated in the wakeful state.

CONCLUSIONS

In some cases, NES are not the product of the awake mind, but rather represent a psychiatric condition that can be manifest in sleep.

The experience of earthquakes by patients with epileptic and psychogenic nonepileptic seizures

PURPOSE

We sought to understand better the experience of seizures by studying differences in the subjective experience of being in an earthquake between patients with epileptic (EP) and nonepileptic (NES) seizures.

METHODS

Forty-eight patients with CCTV/EEG-documented EP or NES who were in the Seattle metropolitan area during the February 28, 2001 Nisqually earthquake were randomly selected for telephone interviews on their earthquake experiences, including whether they thought they were having a seizure during the event.

RESULTS

Twenty-three percent of EP patients spontaneously volunteered that they initially thought they were having a seizure during the earthquake as compared with none of the NES individuals (p = 0.03). However, 35% of EP and 23% of NES patients thought they were having a seizure during it when asked directly (p = 0.37). The most common reasons given, regardless of seizure type, were shaking and feelings of losing control. Of those responding negatively, 100% of EP and 47% of NES patients said that movement of their environment indicated that it was not a seizure (p = 0.001). EP patients took an average of 42 s to realize that the earthquake was not a seizure compared with 105 s for the NES group (p = 0.06). The earthquake precipitated seizures in both groups (11.5% EP, 9.1% NES).

CONCLUSIONS

EP patients were more likely to mistake the earthquake spontaneously for a seizure. This indicates these two experiences are similar and provides a glimpse into the subjective experience of a seizure for those who have never had one but have experienced an earthquake.

An international survey of long-term video/EEG services

To determine current practices in the provision of video-EEG services, the authors conducted an international survey by post. The aim of the survey was to evaluate, by reference to other centres, how and why certain things are done, be assured that their own center is providing a quality service, identify weaknesses in their service, and from this, set improvement goals and objectives. A purposive sampling method was used by sending questionnaires to 78 hospitals where it was believed a long-term video-EEG monitoring service existed. Completed survey questionnaires were returned from 42 centers. Although the survey mechanism may have resulted in self-selection bias, evaluation of the responses provides information on patient management, staffing levels, equipment, and equipment management. Ultimately, these data may aid in identifying a minimum set of requirements for the provision of a video-EEG telemetry service.