Use of short term video EEG in the diagnosis of attack disorders

The effect of epilepsy self-management on productivity at work

BACKGROUND

Epilepsy is a significant public health concern and the most common neurological disorder. Lack of understanding of the disease may magnify the challenges faced by employees with epilepsy, including effective management of symptoms, and full participation in workplace and work productivity.

AIM

Study aimed to evaluate epilepsy self-management skills of working individuals with epilepsy and to determine the impact of it on productivity at work.

METHODS

The study adopted a cross-sectional design and involved 111 individuals with epilepsy. Data collection was carried out using a socio-demographic characteristics form, the "Epilepsy Self-Management Scale" and the "Endikot Work Productivity Scale."

RESULTS

The average age was 35.76 ± 3.39 in the study. The majority of the participants (57.7 %) were women. Additionally, 33.3 % were private sector employee, and 39.6 % held a bachelor's degree. The mean score of the Epilepsy Self Management Scale was 3.91 ± 0.15, the total score of Endikot Work Productivity Scale was 39.84 ± 6.33. A negative significant correlation was observed between epilepsy self management and work productivity. Moreover, women (3.94 ± 0.17) and healthcare workers (3.97 ± 0.06) had higher scores of epilepsy self management. While men (40.43 ± 0.15) demonstrated higher productivity scores, public servants (35.61 ± 0.34) had lower scores compared to others (p < 0.05).

CONCLUSIONS

The findings of this study suggest that improved self-management of epilepsy among working individuals leads to increased work productivity. The epilepsy-management skills of women and healthcare workers was higher. Furthermore, men exhibited lower productivity levels, while woman and public servants displayed higher.

Diagnostic yield and limitations of in-hospital documentation in patients with epilepsy

OBJECTIVE

To determine the diagnostic yield of in-hospital video-electroencephalography (EEG) monitoring to document seizures in patients with epilepsy.

METHODS

Retrospective analysis of electronic seizure documentation at the University Hospital Freiburg (UKF) and at King's College London (KCL). Statistical assessment of the role of the duration of monitoring, and subanalyses on presurgical patient groups and patients undergoing reduction of antiseizure medication.

RESULTS

Of more than 4800 patients with epilepsy undergoing in-hospital recordings at the two institutions since 2005, seizures with documented for 43% (KCL) and 73% (UKF).. Duration of monitoring was highly significantly associated with seizure recordings (p < .0001), and presurgical patients as well as patients with drug reduction had a significantly higher diagnostic yield (p < .0001). Recordings with a duration of >5 days lead to additional new seizure documentation in only less than 10% of patients.

SIGNIFICANCE

There is a need for the development of new ambulatory monitoring strategies to document seizures for diagnostic and monitoring purposes for a relevant subgroup of patients with epilepsy in whom in-hospital monitoring fails to document seizures.

Regional brain atrophy and aberrant cortical folding relate to anxiety and depression in patients with traumatic brain injury and psychogenic nonepileptic seizures

OBJECTIVE

Psychogenic nonepileptic seizures (PNES) are characterized by multifocal and global abnormalities in brain function and connectivity. Only a few studies have examined neuroanatomic correlates of PNES. Traumatic brain injury (TBI) is reported in 83% of patients with PNES and may be a key component of PNES pathophysiology. In this study, we included patients with TBI preceding the onset of PNES (TBI-PNES) and TBI without PNES (TBI-only) to identify neuromorphometric abnormalities associated with PNES.

METHODS

Adults diagnosed with TBI-PNES (n = 62) or TBI-only (n = 59) completed psychological questionnaires and underwent 3-T magnetic resonance imaging. Imaging data were analyzed by voxel- and surface-based morphometry. Voxelwise general linear models computed group differences in gray matter volume, cortical thickness, sulcal depth, fractal dimension (FDf), and gyrification. Statistical models were assessed with permutation-based testing at 5000 iterations with the Threshold-Free Cluster Enhancement toolbox. Logarithmically scaled p-values corrected for multiple comparisons using familywise error were considered significant at p < .05. Post hoc analyses determined the association between structural and psychological measures (p < .05).

RESULTS

TBI-PNES participants demonstrated atrophy of the left inferior frontal gyrus and the right cerebellum VIII. Relative to TBI-only, TBI-PNES participants had decreased FDf in the right superior parietal gyrus and decreased sulcal depth in the left insular cortex. Significant clusters were positively correlated with global assessment of functioning scores, and demonstrated varying negative associations with measures of anxiety, depression, somatization, and global severity of symptoms.

SIGNIFICANCE

The diagnosis of PNES was associated with brain atrophy and reduced cortical folding in regions implicated in emotion processing, regulation, and response inhibition. Cortical folds primarily develop during the third trimester of pregnancy and remain relatively constant throughout the remainder of one's life. Thus, the observed aberrations in FDf and sulcal depth could originate early in development. The convergence of environmental, developmental, and neurobiological factors may coalesce to reflect the neuropathophysiological substrate of PNES.

Psychogenic non-epileptic seizures: Chronology of multidisciplinary team approach to diagnosis and management

While the diagnosis and management of psychogenic non-epileptic seizures (PNES) remain challenging, certain evidence-based guidelines exist, which can help to optimize patient care. A multidisciplinary team approach appears to have many benefits. Current recommendations exist for some aspects of diagnosis and management of PNES, including levels of diagnostic certainty as proposed by the International League Against Epilepsy's expert Task Force on PNES. Other aspects of clinical still care lack clear consensus, including use of suggestion techniques for recording PNES and optimal terminology, since the term "functional seizures" has recently been proposed as a possible term to replace "PNES". The present article aims to (1) review current recommendations and (2) discuss our own team's experience in managing patients with PNES. This is organized chronologically in terms of the roles of the neurologist, psychiatrist and psychologist, and discusses diagnostic issues, psychiatric assessment and treatment, and psychotherapeutic approaches.

Minimum standards for inpatient long-term video-EEG monitoring: A clinical practice guideline of the international league against epilepsy and international federation of clinical neurophysiology

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events (see Table S1). For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and establish its clinical utility.

Minimum standards for inpatient long-term video-electroencephalographic monitoring: A clinical practice guideline of the International League Against Epilepsy and International Federation of Clinical Neurophysiology

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events. For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and to establish its clinical utility.

Diagnostic Yield of 8-Hour Video-EEG in Detecting Psychogenic Non-Epileptic Seizures (PNES)

To evaluate the diagnostic yield of the first 8 hours of video-EEG (vEEG) monitoring in detecting Psychogenic Non-Epileptic Seizures (PNES) during the Epilepsy Monitoring Unit (EMU) admission. We performed a retrospective chart review of patients ages ≥4 years who were admitted to the EMU between 2011 and 2018 (n = 616). We calculated the proportion of patients diagnosed with PNES within the first 8 hours of EEG recording and studied the associated risk factors for patients diagnosed with PNES and patients with epileptic seizures (ES). Out of the total 616 patients, 24% (149) patients had an EMU diagnosis of PNES. Of these, 44.3% had at least one typical event within the first 8 hours of vEEG monitoring. A higher incidence was seen within the pediatric subgroup (54.8% had an event within 8 hours). A diagnosis of chronic pain disorder was more common with PNES compared to ES (48.3% versus 16.5%, p < 0.001). A suspicion for PNES documented during an office visit was noted in a high proportion of patients (68.5%) who eventually had a PNES event during EMU. Our study suggests that in a well-selected group of patients (such as a high suspicion of PNES during a physician/neurology office visit), an outpatient 8-hour vEEG could open new avenues for a prompt diagnosis. This could especially be beneficial in hospital settings where there is either a lack of an EMU or a delay in admission to the EMU.

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.

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.

Suggestive seizure induction for inpatients with suspected psychogenic nonepileptic seizures

OBJECTIVE

To determine the utility of suggestive seizure induction for inpatient work-up of suspected psychogenic nonepileptic seizures (PNES).

METHODS

Prospective study of epilepsy center inpatient admissions with suspected PNES. Patients were randomized to undergo suggestive induction first (group A) and then, if necessary, long-term video-electroencephalography (EEG) monitoring, or vice versa (group B). Diagnostic pathways were compared. Potential clinical predictors for diagnostic success were evaluated.

RESULTS

Length of in-hospital stay did not significantly differ between groups. Suspicion of PNES was confirmed in 43 of 77 (56%) patients, evenly distributed between group A (22 of 39) and group B (21 of 38). In nine patients, recorded habitual seizures were epileptic and in 25 cases, no diagnostic event could be recorded. Diagnosis of PNES was ascertained primarily by recording a typical seizure through suggestive induction in 24 patients and through long-term monitoring in 19 patients. In group A (induction first), monitoring was not deemed necessary in 21% of cases. In group B (monitoring first), 13% would have remained inconclusive without suggestive induction. Patients who reported triggers to their habitual seizures were not more likely to have spontaneous or provoked PNES during monitoring or suggestive inducion, respectively. Patients with subjective seizure prodromes (auras) were significantly more likely to have a PNES during suggestive induction than those without (odds ratio [OR] 3.4, 95% confidence interval [CI] 1.1-10.4). There was no significant difference in seizure frequency between patients with spontaneous PNES during long-term monitoring and those with nondiagnostic monitoring sessions.

SIGNIFICANCE

Our results support the notion that suggestive seizure induction can reduce the number of inconclusive inpatient workups, and can obviate resource-intensive long-term monitoring in one fifth of cases. Patients who are aware of prodromes might have a higher chance of having seizures induced through suggestion.

Can short-term video-EEG substitute long-term video-EEG monitoring in psychogenic nonepileptic seizures? A prospective observational study

BACKGROUND

Psychogenic nonepileptic seizures (PNES), the commonest nonepileptic event, represent 20-30% of drug-resistant epilepsy. Correct identification of PNES avoids unnecessary hospitalization and exposure of antiepileptic drugs (AEDs), and helps implement appropriate psychological treatment. Long-term video-electroencephalography (LTVEEG) is the gold standard test to diagnose PNES. However, in a poor-resource country like India, hypothetically, short-term video-electroencephalography (STVEEG) may substitute it, as its usefulness is established in attack disorders.

OBJECTIVE

The objective of this study was to evaluate effectiveness of STVEEG in PNES and to look into their clinical profile and outcome.

DESIGN/METHODS

Consecutive cases of PNES diagnosed with STVEEG or LTVEEG during 2015-16 (two years) were enrolled. All cases were followed for 12 months or more. Detailed clinical evaluation was done including demography, semiology, coexisting anxiety/depressive disorders, and seizure frequency at time of first diagnosis and follow-up. The PNES were classified as Type I hypermotor, type II hypomotor, and type III unclassified/mixed. Favorable outcome was defined as seizure freedom or >50% reduction in seizure frequency while unfavorable outcome was defined as <50% reduction in seizure frequency on follow-up at 6 and 12 months.

RESULTS

Among 57 patients with PNES [median age of onset 24 years (10-69 years), F:M ratio = 7:3)], STVEEG ± induction could record event(s) in 80.7% while the rest required LTVEEG to confirm diagnosis. Among 82 events analyzed, the mean ± 2 standard deviation (SD) duration of events was 5'14″ ± 13'4″. Sixty-two (75.6%) and 10 (12.1%) events were hypermotor and hypomotor respectively, while 10 (12.1%) were unclassified/mixed. Forty-five (79%) patients had pure PNES, while 12 (21%) had coexistent epilepsy. Forty-nine (86%) and 54 (94.7%) patients had statistically significant reduction of seizure frequency (favorable outcome), at 6 and 12 months of follow-up respectively, while the rest had an unfavorable outcome.

CONCLUSIONS

The STVEEG has a remarkably good yield in diagnosing PNES, and it may be used when LTVEEG is not feasible. However, further studies are needed to show if it can substitute LTVEEG in PNES.

Psychogenic non-epileptic seizures: aetiology, diagnosis and management

Psychogenic non-epileptic seizures (PNES) have a significant impact on most patients in terms of distress, disability, loss of income and iatrogenic harm. Three-quarters of patients with PNES are initially misdiagnosed and treated for epilepsy. Misdiagnosis exposes patients to multiple iatrogenic harms and prevents them from accessing psychological treatment. In most cases, the patient's history (and witness accounts) should alert clinicians to the likely diagnosis of PNES. Since this diagnosis may be resisted by patients and may involve ‘un-diagnosing’ epilepsy, video-electroencephalogram recording of typical seizures is often helpful. The underlying causes of PNES are diverse: a model combining predisposing, precipitating and perpetuating factors is a useful way of conceptualising their aetiology. The initial step of treatment should be to limit iatrogenic harm. There is some evidence for the effectiveness of psychotherapy.

Clinical utility of serum lactate levels for differential diagnosis of generalized tonic-clonic seizures from psychogenic nonepileptic seizures and syncope

BACKGROUND

The differential diagnosis of generalized tonic-clonic seizures (GTCS), psychogenic nonepileptic seizures (PNES), and syncope constitutes a major challenge. Misdiagnosis rates up to 20 to 30% are reported in the literature.

PURPOSE

To assess the clinical utility of serum lactate levels for differentiation of GTCS, PNES, and syncope based on gender differences.

METHODS

Data from 270 patients were evaluated retrospectively. Only patients ≥18 years old with the final diagnosis of GTCS, PNES, or syncope in their chart were recruited. Serum lactate levels were measured in the first 2h of the index event.

RESULTS

Serum lactate levels in patients with GTCS (n=157) were significantly higher than in the patients with PNES (n=25) (p<0.001) and syncope (n=88) (p<0.001). When compared with the females, serum lactate levels in patients with GTCS were significantly higher in the male subgroup (p=0.004). In male patients the ROC analysis yielded a serum lactate value of 2.43mmol/l with a sensitivity of 0.85 and a specificity of 0.88 as the optimal cut-off value to distinguish GTCS from other events. The ROC analysis for the AUC yielded a high estimate of 0.94 (95% confidence interval: 0.91-0.98). When a cut-off value of 2.43mmol/l was chosen for the females, which was an optimal value for male patients, the specificity was 0.85, however, the sensitivity was 0.64.

CONCLUSION

We propose that serum lactate level when measured in the first 2h after the index event has a high clinical utility in the differential diagnosis of GTCS, PNES, and syncope. With concomitant clinical signs and physical examination findings besides neuroimaging and EEG, elevated levels of lactate should be taken into account when evaluating a patient with impaired consciousness. On the other hand, the suggested cut-off value 2.43mmol/l might not have a discriminative effect between GTCS, PNES, and syncope in female patients. This finding should be verified in a prospectively designed study with a larger patient population.

Diagnostic Utility of Wireless Video-Electroencephalography in Unsedated Dogs

BACKGROUND

Poor agreement between observers on whether an unusual event is a seizure drives the need for a specific diagnostic tool provided by video-electroencephalography (video-EEG) in human pediatric epileptology.

OBJECTIVE

That successful classification of events would be positively associated with increasing EEG recording length and higher event frequency reported before video-EEG evaluation; that a novel wireless video-EEG technique would clarify whether unusual behavioral events were seizures in unsedated dogs.

ANIMALS

Eighty-one client-owned dogs of various breeds undergoing investigation of unusual behavioral events at 4 institutions.

METHODS

Retrospective case series: evaluation of wireless video-EEG recordings in unsedated dogs performed at 4 institutions.

RESULTS

Electroencephalography achieved/excluded diagnosis of epilepsy in 58 dogs (72%); 25 dogs confirmed with epileptic seizures based on ictal/interictal epileptiform discharges, and 33 dogs with no EEG abnormalities associated with their target events. As reported frequency of the target events decreased (annually, monthly, weekly, daily, hourly, minutes, seconds), EEG was less likely to achieve diagnosis (P < 0.001). Every increase in event frequency increased the odds of achieving diagnosis by 2.315 (95% confidence interval: 1.36-4.34). EEG recording length (mean = 3.69 hours, range: 0.17-22.5) was not associated (P = 0.2) with the likelihood of achieving a diagnosis.

CONCLUSIONS AND CLINICAL IMPORTANCE

Wireless video-EEG in unsedated dogs had a high success for diagnosis of unusual behavioral events. This technique offered a reliable clinical tool to investigate the epileptic origin of behavioral events in dogs.

Diagnosing psychogenic nonepileptic seizures: Video-EEG monitoring, suggestive seizure induction and diagnostic certainty

Psychogenic nonepileptic seizures (PNES) can remain undiagnosed for many years, leading to unnecessary medication and delayed treatment. A recent report by the International League Against Epilepsy Nonepileptic Seizures Task Force recommends a staged approach to the diagnosis of PNES (LaFrance, et al., 2013). We aimed to investigate its practical utility, and to apply the proposed classification to evaluate the role of long-term video-EEG monitoring (VEEG) and suggestive seizure induction (SSI) in PNES workup. Using electronic medical records, 122 inpatients (mean age 36.0±12.9years; 68% women) who received the diagnosis of PNES at our epilepsy center during a 4.3-year time period were included. There was an 82.8% agreement between diagnostic certainty documented at discharge and that assigned retroactively using the Task Force recommendations. In a minority of cases, having used the Task Force criteria could have encouraged the clinicians to give more certain diagnoses, exemplifying the Task Force report's utility. Both VEEG and SSI were effective at supporting high level diagnostic certainty. Interestingly, about one in four patients (26.2%) had a non-diagnostic ("negative") VEEG but a positive SSI. On average, this subgroup did not have significantly shorter mean VEEG recording times than VEEG-positive patients. However, VEEG-negative/SSI-positive patients had a significantly lower habitual seizure frequency than their counterparts. This finding emphasizes the utility of SSI in ascertaining the diagnosis of PNES in patients who do not have a spontaneous habitual event during VEEG due to, for example, low seizure frequency.

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.

Weakened functional connectivity in patients with psychogenic non-epileptic seizures (PNES) converges on basal ganglia

BACKGROUND

Psychogenic non-epileptic seizures (PNES) are involuntary paroxysmal events that are unaccompanied by epileptiform EEG discharges. We hypothesised that PNES are a disorder of distributed brain networks resulting from their functional disconnection.The disconnection may underlie a dissociation mechanism that weakens the influence of unconsciously presented traumatising information but exerts maladaptive effects leading to episodic failures of behavioural control manifested by psychogenic 'seizures'.

METHODS

To test this hypothesis, we compared functional connectivity (FC) derived from resting state high-density EEGs of 18 patients with PNES and 18 age-matched and gender-matched controls. To this end, the EEGs were transformed into source space using the local autoregressive average inverse solution. FC was estimated with a multivariate measure of lagged synchronisation in the θ, α and β frequency bands for 66 brain sites clustered into 18 regions. A multiple comparison permutation test was applied to deduce significant between-group differences in inter-regional and intraregional FC.

RESULTS

The significant effect of PNES-a decrease in lagged FC between the basal ganglia and limbic, prefrontal, temporal, parietal and occipital regions-was found in the α band.

CONCLUSION

We believe that this finding reveals a possible neurobiological substrate of PNES, which explains both attenuation of the effect of potentially disturbing mental representations and the occurrence of PNES episodes. By improving understanding of the aetiology of this condition, our results suggest a potential refinement of diagnostic criteria and management principles.

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.

Seizure occurrence during pediatric short-term EEG

AIM

To identify the patients who are more likely to experience a seizure during short-term EEG recording.

METHODS

We retrospectively reviewed the EEG recordings and medical records of 294 patients, who were admitted to the Pediatric Departments in Assaf Harofeh Medical Center, and referred for a short-term EEG during a 5-years period following a seizure.

RESULTS

Fifteen (5.1%) patients had seizures during short-term EEG. The likelihood of seizure occurrence was increased by history of seizures (odds ratio 11.86, 95% confidence interval 2.54-55.37), abnormal neurological examination (odds ratio 3.33, 95% confidence interval 1.05-10.55), and the presence of interictal epileptiform discharges (odds ratio 10.07, 95% confidence interval 1.26-80.42). Treatment with antiepileptic drugs and mental retardation were significantly more common among patients with seizures.

CONCLUSIONS

Children with a higher likelihood of a seizure during short-term EEG can be identified using data mainly obtained by history and neurological examination.

[French guidelines on electroencephalogram]

Electroencephalography allows the functional analysis of electrical brain cortical activity and is the gold standard for analyzing electrophysiological processes involved in epilepsy but also in several other dysfunctions of the central nervous system. Morphological imaging yields complementary data, yet it cannot replace the essential functional analysis tool that is EEG. Furthermore, EEG has the great advantage of being non-invasive, easy to perform and allows control tests when follow-up is necessary, even at the patient's bedside. Faced with the advances in knowledge, techniques and indications, the Société de Neurophysiologie Clinique de Langue Française (SNCLF) and the Ligue Française Contre l'Épilepsie (LFCE) found it necessary to provide an update on EEG recommendations. This article will review the methodology applied to this work, refine the various topics detailed in the following chapters. It will go over the summary of recommendations for each of these chapters and underline proposals for writing an EEG report. Some questions could not be answered by the review of the literature; in those cases, an expert advice was given by the working and reading groups in addition to the guidelines.

Diagnostic yield of short-term video-EEG monitoring for epilepsy and PNESs: a European assessment

INTRODUCTION

Although long-term video-EEG monitoring (LVEM) is routinely used to investigate paroxysmal events, short-term video-EEG monitoring (SVEM) lasting <24 h is increasingly recognized as a cost-effective tool. Since, however, relatively few studies addressed the yield of SVEM among different diagnostic groups, we undertook the present study to investigate this aspect.

METHODS

We retrospectively analyzed 226 consecutive SVEM recordings over 6 years. All patients were referred because routine EEGs were inconclusive. Patients were classified into 3 suspected diagnostic groups: (1) group with epileptic seizures, (2) group with psychogenic nonepileptic seizures (PNESs), and (3) group with other or undetermined diagnoses. We assessed recording lengths, interictal epileptiform discharges, epileptic seizures, PNESs, and the definitive diagnoses obtained after SVEM.

RESULTS

The mean age was 34 (±18.7) years, and the median recording length was 18.6 h. Among the 226 patients, 127 referred for suspected epilepsy - 73 had a diagnosis of epilepsy, none had a diagnosis of PNESs, and 54 had other or undetermined diagnoses post-SVEM. Of the 24 patients with pre-SVEM suspected PNESs, 1 had epilepsy, 12 had PNESs, and 11 had other or undetermined diagnoses. Of the 75 patients with other diagnoses pre-SVEM, 17 had epilepsy, 11 had PNESs, and 47 had other or undetermined diagnoses. After SVEM, 15 patients had definite diagnoses other than epilepsy or PNESs, while in 96 patients, diagnosis remained unclear. Overall, a definitive diagnosis could be reached in 129/226 (57%) patients.

CONCLUSIONS

This study demonstrates that in nearly 3/5 patients without a definitive diagnosis after routine EEG, SVEM allowed us to reach a diagnosis. This procedure should be encouraged in this setting, given its time-effectiveness compared with LVEM.

Reexamining the added value of intermittent photic stimulation and hyperventilation in routine EEG practice

OBJECTIVE

Investigate the added value of hyperventilation (HV) and intermittent photic stimulation (IPS) to the routine electroencephalogram (EEG).

METHOD

This is a retrospective review of 1,172 successive EEGs. The records with evidence of epileptogenic activity were identified and further analyzed to identify if the activation techniques could trigger the expression of epileptic activity not seen otherwise in the nonactivated tracing.

RESULTS

Activation procedures provided additional information in 9.5% of the abnormal EEG files. They helped establish the diagnosis of an epileptic disorder or further characterize the epileptic syndrome. This occurred exclusively in the younger age group (age <36 years), and predominantly in women.

CONCLUSION

IPS and HV are easy to perform and remain important adjuncts to routine EEG. They may trigger the expression of epileptogenic activity in an otherwise uneventful EEG. Whereas their diagnostic value was obvious in the younger age group, we found no evidence to support their usefulness in the middle-age and elderly groups.

The yield and clinical utility of outpatient short-term video-electroencephalographic monitoring: a five-year retrospective study

Outpatient short-term video-electroencephalographic monitoring (OVEM) is recognized as a useful tool in the diagnosis of epilepsy and other paroxysmal disorders. The aim of this retrospective study was to determine the diagnostic yield of OVEM. We analyzed 175 OVEM records of adults (111 females and 64 males) referred over a period of 5 years. The mean length of recording was 3.8 h. The highest yield was found in psychogenic nonepileptic seizures (PNES) (37.1%), followed by interictal epileptiform discharges (17.2%), and epileptic seizures (6.9%). The provisional diagnosis was epilepsy in 77.7% and PNES in 22.3% before the test. Outpatient short-term video-electroencephalographic monitoring changed the pre-test diagnosis in 30.9% of patients. Outpatient short-term video-electroencephalographic monitoring is a useful diagnostic test for PNES. It has a higher yield for PNES than epilepsy.

Catastrophising and normalising in patient's accounts of their seizure experiences

PURPOSE

To extend our previous research demonstrating that linguistic/interactional features in patients' talk can assist the challenging differential diagnosis of epilepsy and psychogenic nonepileptic seizures (PNES) by exploring the differential diagnostic potential of references to non co-present persons (third parties).

METHOD

Initial encounters were recorded between 20 seizure patients (13 with PNES, seven with epilepsy) who were subsequently diagnosed by the recording of typical seizures with video-EEG. An analyst blinded to the medical diagnoses coded and analysed transcripts.

RESULTS

There were no significant differences between the two diagnostic groups in terms of the total number of third party references or references made spontaneously by patients without prompting from the doctor. However, patients with PNES made significantly more prompted references to third parties (p=0.022). 'Castrophising' third party references were made in 12/13 (92.3%) of encounters with PNES patients and 1/7 (14.3%) of encounters with epilepsy patients (p=0.001, OR 72, 95% CI=3.8-1361.9). Normalising references were identified in 2/13 (15.4%) of encounters in the PNES and 6/7 (85.7%) of encounters in the epilepsy groups (p=0.004, OR 33, 95% CI=2.5-443.6).

CONCLUSION

There are significant differences in how patients with epilepsy or patients with PNES refer to third parties. Patients with PNES are more likely to be prompted to tell doctors what others have told them about their seizures. Patients using third party references to catastrophise their seizure experiences are more likely to have PNES, whilst patients who use third party references to normalise their life with seizures are more likely to have epilepsy.

State of consciousness and interictal epileptiform discharges predict seizure occurrence during routine EEG

OBJECTIVES

To identify the patients who are more likely to experience a seizure during routine electroencephalography (EEG) recording.

METHODS

We retrospectively reviewed the EEG recordings and medical records of 262 patients, who were admitted in the Neurology Department in Assaf Harofeh Medical Center and referred to the EEG laboratory between October 2006 and 2008 after a seizure.

RESULTS

Eighteen (6.8%) patients had seizures during routine EEG [patients with seizures (PWS)]. The likelihood of seizure occurrence during routine EEG was increased by the presence of interictal epileptiform discharges (odds ratio, 29.85; 95% confidence interval, 6.54-136.21; P=0.001) and abnormal state of consciousness (odds ratio, 9.04; 95% confidence interval, 1.02-80.33; P=0.037). Increased seizure frequency before admission, localization-related epilepsy, and EEG background slowing were significantly more common among PWS compared with patients without seizures on routine EEG (P=0.009, 0.042, and 0.036, respectively).

CONCLUSIONS

The presence of interictal epileptiform discharges and decreased state of consciousness increase significantly the likelihood of seizure occurrence during routine EEG. Localization-related epilepsy, increased seizure frequency before admission, and EEG background slowing are more common among PWS.

When do psychogenic nonepileptic seizures occur on a video/EEG telemetry unit?

To maximize the efficiency of diagnostic video/EEG telemetry, we retrospectively studied the occurrence of clinical events during admission in 254 patients. One hundred fifty-nine patients had psychogenic nonepileptic seizures (PNES) and 95 had epileptic seizures (ES). Twenty-five with PNES and none with ES had an event before or during electrode placement (P<0.0001). In the remaining 229, the initial event occurred within 48 hours of electrode placement in 98.5% patients with PNES and 100.0% of patients with ES. Time to occurrence of initial event did not differ between groups (P=0.69). 17.1% patients with PNES and 51.6% with ES had events between 12 AM and 6 AM (P=0.001). In conclusion, during diagnostic video/EEG telemetry, most patients who experience PNES or ES have diagnostic, typical events within 2 days. Although time to initial event after electrode placement does not differ between diagnoses, events prior to or during placement are most likely PNES and events at night are most likely ES.

Using interactional and linguistic analysis to distinguish between epileptic and psychogenic nonepileptic seizures: a prospective, blinded multirater study

This study was carried out to test the suggestion that close interactional and linguistic examination of the communication between neurologists and patients during a first encounter can contribute to the differential diagnosis of epilepsy or psychogenic nonepileptic seizures. Twenty unselected patients admitted for video/EEG telemetry because of diagnostic uncertainty were included. Two linguists blinded to all medical data independently studied video recordings and transcripts of 25- to 35-minute interactions. They attempted to predict the medical diagnosis on the basis of qualitative assessments addressing 17 separate observations. They also used a diagnostic scoring aid (DSA) to convert their qualitative assessments into a simple numeric score. Using qualitative assessment, both linguists predicted 17 of 20 (85%) diagnoses (kappa=0.59). With the DSA, diagnoses were predicted with a sensitivity of 85.7% (71.4%) and a specificity of 84.6% (92.3%). This blinded, prospective multirater study confirms the diagnostic value of linguistic and interactional observations in the seizure clinic setting.

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.

Psychogenic nonepileptic seizures in patients with learning disability: comparison with patients with no learning disability

Among a consecutive series of patients with psychogenic nonepileptic seizures (PNES), we compared patients with learning disability (LD) (n=25) with patients with no LD (n=263), with respect to demographic and clinical variables. A higher proportion of the LD group had epilepsy as well as PNES (P<0.001) (uncorrected P values are quoted), and a higher proportion were taking antiepileptic drugs at the time of diagnosis of PNES (P=0.007). Fewer patients with LD had a history of antecedent sexual abuse (P=0.036). A higher proportion of the LD group had previous pseudostatus (P<0.001), and a higher proportion had immediate situational or emotional triggers for their attacks (P<0.001). There were trends toward a higher proportion of men in the LD group (P=0.056) and a longer delay between onset of PNES and diagnosis (P=0.072). Our data suggest potentially important clinical differences between PNES populations with and without LD, as well as possible differences in mechanism.

The withdrawal of antiepileptic drugs in patients with non-epileptic seizures: safety considerations

The majority of patients with psychogenic non-epileptic seizures (PNES) do not have epilepsy. There are a number of compelling reasons to take these patients off antiepileptic drugs (AEDs), including drug toxicity and teratogenicity, as well as possibly poorer outcome of PNES and increased risk of iatrogenic harm when patients present to emergency rooms on AEDs as emergencies. However, many patients with PNES who do not have epilepsy remain on AEDs postdiagnosis. Some studies do report patients taken off medication as an outcome measure, but with no assessment of the safety of withdrawal, or specification of the criteria for 'excluding' epilepsy. One study has assessed the safety of taking patients satisfying some simple criteria for the absence of an underlying epilepsy off AEDs, and has found the procedure to be safe, given appropriate postwithdrawal follow-up. Patients with PNES who do not have evidence of epilepsy should be referred to a centre with appropriate expertise in epilepsy diagnosis so that AEDs can be withdrawn in safe conditions.

The safety of antiepileptic drug withdrawal in patients with non-epileptic seizures

BACKGROUND

To determine whether withdrawal of anticonvulsant drugs (AED) can be carried out safely in patients with non-epileptic seizures (NES).

METHODS

Prospective evaluation of safety and outcome in 78 patients with NES who satisfied a standardised set of criteria for excluding the diagnosis of coexisting or underlying epilepsy.

FINDINGS

The patients were taking from one to three AED. Sixty four patients were withdrawn as outpatients, 14 as inpatients. Five patients stopped their drugs abruptly, and two had AED restarted and had to be withdrawn again. Otherwise all patients adhered to withdrawal schedules. A new type of attack in addition to NES was seen in three patients (complex partial seizures in all three cases). NES frequency declined in the group as a whole over the period of the study (follow up 6-12 months) in all individuals except for eight patients in whom there was a transient increase. Fourteen patients reported new physical symptoms after withdrawal; however, no serious adverse events were reported.

CONCLUSIONS

With appropriate diagnostic investigation and surveillance during follow up withdrawal of AED can be achieved safely in patients with NES.

Adding Video Recording Increases the Diagnostic Yield of Routine Electroencephalograms in Children with Frequent Paroxysmal Events

PURPOSE

To report on the usefulness of adding video recording to routine EEG studies of infants and children with frequent paroxysmal events.

METHODS

We analyzed the efficacy of this diagnostic means during a 4-year period. The decision whether to add video recording was made by the pediatric EEG interpreter at the time of the study. Studies were planned to last between 20 and 30 min, and, if needed, were extended by the EEG interpreter. For most studies, video recording was added from the beginning of EEG recording. In a minority of cases, the addition of video was implemented during the first part of the EEG test, as clinical events became obvious. In these cases, a new study (file) was begun. The success rate was analyzed according to the indications for the EEG study: paroxysmal eye movements, tremor, suspected seizures, myoclonus, staring episodes, suspected stereotypias and tics, absence epilepsy follow-up, cyanotic episodes, and suspected psychogenic nonepileptic events.

RESULTS

Video recording was added to 137 of 666 routine studies. Mean patient age was 4.8 years. The nature of the event was determined in 61 (45%) of the EEG studies. Twenty-eight percent were hospitalized patients. The average study duration was 26 min. This diagnostic means was particularly useful for paroxysmal eye movements, staring spells, myoclonic jerks, stereotypias, and psychogenic nonepileptic events. About 46% of 116 patients for whom cognitive data were available were mentally retarded. EEG with added video recording was successfully performed in all 116 cases and provided useful information in 29 (55%) of these 53 patients.

CONCLUSIONS

Adding video recording to routine EEG was helpful in 45% of cases referred for frequent paroxysmal events. This technique proved useful for hospitalized children as well as for outpatients. Moreover, it was successfully applied in cognitively impaired patients. Infants and children with paroxysmal eye movements, staring spells, myoclonic jerks, stereotypias, and pseudoseizures especially benefited from this diagnostic means. Because of its low cost and the little discomfort imposed on the patient and his or her family, this technique should be considered as a first diagnostic step in children with frequent paroxysmal events.