Informing patients about the impact of provocation methods increases the rate of psychogenic nonepileptic seizures during EEG recording

Seizure provocation in EEG recordings: A data-driven approach

OBJECTIVE

Recording seizures on video-EEG has a high diagnostic value. However, bilateral convulsive seizures constitute a risk for the patients. Our aim was to investigate the diagnostic yield and associated risks of provocation methods in short-term video-EEGs.

METHODS

We extracted data on seizures and provocation methods from a large database of short-term video-EEGs with standardized annotations using SCORE (Standardized Computer-based Organized reporting of EEG).

RESULTS

2742 paroxysmal clinical episodes were recorded in 11 919 consecutive EEGs. Most epileptic seizures (54%) were provoked. Hyperventilation provoked most of typical absence seizures (55%), intermittent photic stimulation (IPS) provoked myoclonic seizures (25%) and most of bilateral convulsive seizures (55%), while 43% of focal seizures were precipitated by sleep. All but one of the 16 bilateral convulsive seizures were provoked by IPS or sleep. Latency between start of generalized photoparoxysmal EEG response and bilateral convulsive seizures were ≤3 s in all but one patient.

SIGNIFICANCE

The large, structured database provides evidence for the diagnostic utility of various provocation methods in short-term video-EEGs. The risk of bilateral convulsive seizures is relatively small, but it cannot be prevented by stopping IPS after 3 s. A priori knowledge about seizure semiology helps planning patient-tailored provocation strategy in short-term video-EEGs.

Routine and sleep EEG: Minimum recording standards of the International Federation of Clinical Neurophysiology and the International League Against Epilepsy

This article provides recommendations on the minimum standards for recording routine ("standard") and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy-related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Studies (QUADAS-2) was used to assess the risk of bias in technical and methodological studies. Where high-quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus-based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods.

Routine and sleep EEG: Minimum recording standards of the International Federation of Clinical Neurophysiology and the International League Against Epilepsy

This article provides recommendations on the minimum standards for recording routine ("standard") and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy-related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the risk of bias in technical and methodological studies. Where high-quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus-based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods.

The evaluation of psychogenic non-epileptic seizures (PNES) cases with saline injection method in video-EEG monitorization unit

BACKGROUND

It has been reported that 10 to 30% of patients sent to epilepsy centers with a diagnosis of refractory epilepsy are diagnosed with psychogenic non-epileptic seizure (PNES). A wide variety of provocative methods are used to assist PNES diagnosis.

OBJECTIVE

To investigate the effect of seizure induction on the diagnosis and prognosis of PNES.

METHODS

We retrospectively examined 91 patients with PNES complaints in our video-EEG laboratory. Intravenous saline was administered to all patients for induction of seizures.

RESULTS

Saline injection was performed in 91 patients referred to our EEG lab with PNES initial diagnosis, 57 of whom were female and 34 male. Saline injection triggered an attack in 82 patients (90%).

CONCLUSIONS

In this study we have concluded that provocative methods are practical, cheap and, most of all, effective for patient diagnosis. In clinical practice, explaining the diagnosis is the first and most important step of the treatment, and careful patient-doctor communication has a positive impact on patient prognosis.

Evidence-Based Practice for the Clinical Assessment of Psychogenic Nonepileptic Seizures: A Report From the American Neuropsychiatric Association Committee on Research

The American Neuropsychiatric Association's Committee on Research assigned the task of defining the most helpful clinical factors and tests in establishing the diagnosis of psychogenic nonepileptic seizures (PNES) during a neuropsychiatric assessment. A systematic review of the literature was conducted using three search engines and specified search terms for PNES and the predetermined clinical factors and diagnostic tests, followed by a selection process with specific criteria. Data extraction results from selected articles are presented for clinical factors (semiology, psychiatric comorbidities, medical comorbidities, psychological traits) and diagnostic tests (EEG, psychometric and neuropsychological measures, prolactin level, clinical neuroimaging, autonomic testing). Semiology with video EEG (vEEG) remains the most valuable tool to determine the diagnosis of PNES. With the exception of semiology, very few studies revealed the predictive value of a clinical factor for PNES, and such findings were isolated and not replicated in most cases. Induction techniques, especially when coupled with vEEG, can lead to a captured event, which then confirms the diagnosis. In the absence of a captured event, postevent prolactin level and personality assessment can support the diagnosis but need to be carefully contextualized with other clinical factors. A comprehensive clinical assessment in patients with suspected PNES can identify several clinical factors and may include a number of tests that can support the diagnosis of PNES. This is especially relevant when the gold standard of a captured event with typical semiology on vEEG cannot be obtained.

Use of suggestive seizure manipulation methods in the investigation of patients with possible psychogenic nonepileptic seizures-An international ILAE survey

Video‐encephalographic (vEEG) seizure recordings make essential contributions to the differentiation of epilepsy and psychogenic nonepileptic seizures (PNES). The yield of vEEG examinations can be increased through suggestive seizure manipulation (SSM) (ie, activation/provocation/cessation procedures), but its use has raised ethical concerns. In preparation for guidelines on the investigation of patients with PNES, the ILAE PNES Task Force carried out an international survey to investigate practices of and opinions about SSM. An online questionnaire was developed by the ILAE PNES Task Force. Questions were asked at clinical unit or individual respondent level. All ILAE chapters were encouraged to send questionnaires to their members. The survey was open from July 1, 2019, to August 31, 2019. A total of 487 clinicians from 411 units across 94 countries responded. Some form of SSM was used in 296/411 units (72.0%). Over 90% reported the use of verbal suggestion, over 80% the use of activation procedures also capable of eliciting epileptic activity (hyperventilation or photic stimulation). Only 26.3% of units used techniques specifically intended to provoke PNES (eg, saline injection). Fewer than 10% of units had established protocols for SSM, only 20% of units required written patient consent, in 12.2% of units patients received explicitly false information to provoke seizures. Clinicians using SSM tended to perceive no ethical problems, whereas those not using SSM were likely to have ethical concerns about these methods. We conclude that the use of invasive nocebo techniques intended to provoke PNES in diagnostic settings has declined, but SSM is commonly combined with activation procedures also capable of eliciting epileptic activity. While research suggests that openness about the use of PNES‐specific nocebo techniques does not reduce diagnostic yield, very few units have suggestion protocols or seek patient consent. This could be addressed through establishing consensus guidance for the practice of SSM.

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.

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.

Nonepileptic seizures: an updated review

Psychogenic nonepileptic seizures (PNES) are a functional neurological disorder/conversion disorder subtype, which are neurobehavioral conditions at the interface of neurology and psychiatry. Significant advancements over the past decade have been made in the diagnosis, management, and neurobiological understanding of PNES. This article reviews published PNES research focusing on semiologic features that distinguish PNES from epileptic seizures, consensus diagnostic criteria, the intersection of PNES and other comorbidities, neurobiological studies, evidence-based treatment interventions, and outcome studies. Epidemiology and healthcare utilization studies highlight a continued unmet medical need in the comprehensive care of PNES. Consensus guidelines for diagnostic certainty are based on clinical history, semiology of witnessed typical event(s), and EEG findings. While certain semiologic features may aid in the diagnosis of PNES, the gold standard remains capturing a typical event on video electroencephalography (EEG) showing the absence of epileptiform activity with history and semiology consistent with PNES. Medical-neurologic and psychiatric comorbidities are prevalent in PNES; these should be assessed in diagnostic evaluations and integrated into treatment interventions and prognostic considerations. Several studies, including a pilot, multicenter, randomized clinical trial, have now demonstrated that a cognitive behavioral therapy-informed psychotherapy is an efficacious treatment for PNES, and additional efforts are necessary to evaluate the utility of pharmacologic and other psychotherapy treatments. Neuroimaging studies, while requiring replication, suggest that PNES may occur in the context of alterations within and across sensorimotor, emotion regulation/processing, cognitive control, and multimodal integration brain systems. Future research could investigate similarities and differences between PNES and other somatic symptom disorders.

Transcranial magnetic stimulation and sedation as treatment for functional neurologic disorders

Functional neurologic disorder (FND), also known as conversion disorder, is common and often associated with a poor prognosis. It has been relatively neglected by research and as such there is a conspicuous lack of evidence-based treatments. Physical and psychologic therapies are the main treatment modalities, over and above reassurance and sensitive explanation of the diagnosis. However there are two other historic treatments that have seen a recent resurgence of interest and use. The first is electric stimulation, which was initially pioneered with direct stimulation of nerves but now used indirectly (and therefore noninvasively) in the form of transcranial magnetic stimulation (TMS). The second is (therapeutic) sedation, previously known as "abreaction," where it was mostly used in the context of psychologic investigation and treatment, but now increasingly advocated during rehabilitation as a way to therapeutically demonstrate reversibility of symptoms. This chapter introduces the background of these treatment modalities, their evolution into their current applications before critically evaluating their current evidence base and exploring possible mechanisms of action. It also tentatively suggests when they should be considered in current practice and briefly considers their future potential. In summary there is encouraging preliminary evidence to suggest that both TMS and sedation may be effective treatments for FNDs.

Psychogenic nonepileptic seizures: EEG and investigation

In the investigation of psychogenic nonepileptic seizures (PNES), the main differential diagnoses are between convulsive PNES and tonic-clonic seizures, between swoon PNES and syncope, and between pseudoabsence PNES and absence seizures. For the best diagnostic certainty, events must be captured, ideally using video-electroencephalogram (EEG), including an electrocardiographic channel. The "video" part of video-EEG allows EEG changes (or lack of them) to be interpreted in the appropriate clinical context. When the diagnosis is based on less good data (e.g., video alone or EEG alone), then the limitations and constraints of the tests should borne in mind, and a lesser degree of certainty must be accepted. Tests such as serum prolactin (PRL) level and postictal EEG should be regarded as adjunctive rather than definitive. Excluding additional epilepsy with a good probability is not possible using investigations alone. In particular, one standard interictal EEG recording is of little value in excluding additional epilepsy, though multiple or prolonged recordings may offer additional sensitivity.

Hyperventilation and photic stimulation are useful additions to a placebo-based suggestive seizure induction protocol in patients with psychogenic nonepileptic seizures

The early and definitive diagnosis of psychogenic nonepileptic seizures is a common challenge in epileptology practice. Suggestive seizure induction is a valuable tool to aid the differentiation between epileptic and psychogenic nonepileptic seizures, especially when long-term video-EEG monitoring is inconclusive or unavailable. In this retrospective analysis, we compared the diagnostic yield of a classical, placebo-based induction protocol with that of an extended protocol that includes hyperventilation and photic stimulation as means of suggestion while also implementing more open, standardized patient information. We investigated whether the diversification of suggestive seizure induction has an effect on diagnostic yield and whether it preempts the administration of placebo. Data from 52 patients with confirmed psychogenic nonepileptic seizures were analyzed. While suggestive seizure induction using only placebo-based suggestion provoked a typical event in 13 of 20 patients (65%), the extended protocol was positive in 27 of 34 cases (84%); this improvement was not significant (p=0.11). Noninvasive suggestion techniques accounted for 78% of inductions, avoiding placebo administration in a majority of patients. Still, placebo remains an important part of suggestive seizure induction, responsible for 22% (6 out of 27) of successful inductions using our extended protocol. Our study demonstrates that the diversification of suggestive seizure induction is feasible and beneficial for both patients and diagnosticians.