Psychogenic non-epileptic seizures—Diagnostic issues: A critical review

Autonomic nervous system functioning associated with psychogenic nonepileptic seizures: Analysis of heart rate variability

OBJECTIVE

Psychogenic nonepileptic seizures (PNESs) resemble epileptic seizures but originate from psychogenic rather than organic causes. Patients with PNESs are often unable or unwilling to reflect on underlying emotions. To gain more insight into the internal states of patients during PNES episodes, this study explored the time course of heart rate variability (HRV) measures, which provide information about autonomic nervous system functioning and arousal.

METHODS

Heart rate variability measures were extracted from double-lead electrocardiography data collected during 1-7days of video-electroencephalography monitoring of 20 patients with PNESs, in whom a total number of 118 PNESs was recorded. Heart rate (HR) and HRV measures in time and frequency domains (standard deviation of average beat-to-beat intervals (SDANN), root mean square of successive differences (RMSSD), high-frequency (HF) power, low-frequency (LF) power, and very low-frequency (VLF) power) were averaged over consecutive five-minute intervals. Additionally, quantitative analyses of Poincaré plot parameters (SD1, SD2, and SD1/SD2 ratio) were performed.

RESULTS

In the five-minute interval before PNES, HR significantly (p<0.05) increased (d=2.5), whereas SDANN (d=-0.03) and VLF power (d=-0.05) significantly decreased. During PNES, significant increases in HF power (d=0.0006), SD1 (d=0.031), and SD2 (d=0.016) were observed. In the five-minute interval immediately following PNES, SDANN (d=0.046) and VLF power (d=0.073) significantly increased, and HR (d=-5.1) and SD1/SD2 ratio (d=-0.14) decreased, compared to the interval preceding PNES.

CONCLUSION

The results suggest that PNES episodes are preceded by increased sympathetic functioning, which is followed by an increase in parasympathetic functioning during and after PNES. Future research needs to identify the exact nature of the increased arousal that precedes PNES.

Interval analysis of interictal EEG: pathology of the alpha rhythm in focal epilepsy

The contemporary use of interictal scalp electroencephalography (EEG) in the context of focal epilepsy workup relies on the visual identification of interictal epileptiform discharges. The high-specificity performance of this marker comes, however, at a cost of only moderate sensitivity. Zero-crossing interval analysis is an alternative to Fourier analysis for the assessment of the rhythmic component of EEG signals. We applied this method to standard EEG recordings of 78 patients divided into 4 subgroups: temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE), psychogenic nonepileptic seizures (PNES) and nonepileptic patients with headache. Interval-analysis based markers were capable of effectively discriminating patients with epilepsy from those in control subgroups (AUC~0.8) with diagnostic sensitivity potentially exceeding that of visual analysis. The identified putative epilepsy-specific markers were sensitive to the properties of the alpha rhythm and displayed weak or non-significant dependences on the number of antiepileptic drugs (AEDs) taken by the patients. Significant AED-related effects were concentrated in the theta interval range and an associated marker allowed for identification of patients on AED polytherapy (AUC~0.9). Interval analysis may thus, in perspective, increase the diagnostic yield of interictal scalp EEG. Our findings point to the possible existence of alpha rhythm abnormalities in patients with epilepsy.

Automatic Detection and Classification of Convulsive Psychogenic Nonepileptic Seizures Using a Wearable Device

Epilepsy is one of the most common neurological disorders and patients suffer from unprovoked seizures. In contrast, psychogenic nonepileptic seizures (PNES) are another class of seizures that are involuntary events not caused by abnormal electrical discharges but are a manifestation of psychological distress. The similarity of these two types of seizures poses diagnostic challenges that often leads in delayed diagnosis of PNES. Further, the diagnosis of PNES involves high-cost hospital admission and monitoring using video-electroencephalogram machines. A wearable device that can monitor the patient in natural setting is a desired solution for diagnosis of convulsive PNES. A wearable device with an accelerometer sensor is proposed as a new solution in the detection and diagnosis of PNES. The seizure detection algorithm and PNES classification algorithm are developed. The developed algorithms are tested on data collected from convulsive epileptic patients. A very high seizure detection rate is achieved with 100% sensitivity and few false alarms. A leave-one-out error of 6.67% is achieved in PNES classification, demonstrating the usefulness of wearable device in the diagnosis of PNES.

Review-of-systems questionnaire as a predictive tool for psychogenic nonepileptic seizures

Patients with refractory epilepsy undergo video-electroencephalography for seizure characterization, among whom approximately 10-30% will be discharged with the diagnosis of psychogenic nonepileptic seizures (PNESs). Clinical PNES predictors have been described but in general are not sensitive or specific. We evaluated whether multiple complaints in a routine review-of-system (ROS) questionnaire could serve as a sensitive and specific marker of PNESs. We performed a retrospective analysis of a standardized ROS questionnaire completed by patients with definite PNESs and epileptic seizures (ESs) diagnosed in our adult epilepsy monitoring unit. A multivariate analysis of covariance (MANCOVA) was used to determine whether groups with PNES and ES differed with respect to the percentage of complaints in the ROS questionnaire. Tenfold cross-validation was used to evaluate the predictive error of a logistic regression classifier for PNES status based on the percentage of positive complaints in the ROS questionnaire. A total of 44 patients were included for analysis. Patients with PNESs had a significantly higher number of complaints in the ROS questionnaire compared to patients with epilepsy. A threshold of 17% positive complaints achieved a 78% specificity and 85% sensitivity for discriminating between PNESs and ESs. We conclude that the routine ROS questionnaire may be a sensitive and specific predictive tool for discriminating between PNESs and ESs.

Psychological problems and clinical outcomes of children with psychogenic non-epileptic seizures

PURPOSE

Our purpose was to investigate psychological problems and clinical outcomes in children with psychogenic non-epileptic seizures (PNES).

MATERIALS AND METHODS

We retrospectively reviewed the data of 25 patients who were diagnosed with PNES between 2006 and 2012.

RESULTS

Twenty-five children with PNES, aged 8 to 19 years (mean 13.82), were referred to psychiatrists for psychiatric assessment. On their initial visit, 72% of patients had comorbid psychological problems, including depression, anxiety, conduct disorder, adjustment disorder, Attention Deficit Hyperactivity Disorder, schizophrenia, and bipolar disorder. Among these, depression was the most frequent (36%). Predisposing and triggering factors included familial distress (40%), social distress (24%), and specific events (20%). The following treatment was advised based on the results of the initial psychological assessment: 3 patients regularly visited psychiatric clinic to assess their clinical status without treatment, nine underwent psychotherapy, and 13 received a combination of psychotherapy and psychopharmacological therapy. At the mean follow-up of 31.5 months after diagnosis, 20 patients (80%) were event-free at follow-up, three (12%) showed reduced frequency, and two (8%) experienced persistent symptoms.

CONCLUSION

The outcomes of PNES in children are much better than those in adults, despite a high rate of psychological comorbidities.

Ethical dilemmas in pediatric and adolescent psychogenic nonepileptic seizures

To date, only a very narrow window of ethical dilemmas in psychogenic nonepileptic seizures (PNES) has been explored. Numerous distinct ethical dilemmas arise in diagnosing and treating pediatric and adolescent patients with PNESs. Important ethical values at stake include trust, transparency, confidentiality, professionalism, autonomy of all stakeholders, and justice. In order to further elucidate the ethical challenges in caring for this population, an ethical analysis of the special challenges faced in four specific domains is undertaken: (1) conducting and communicating a diagnosis of PNESs, (2) advising patients about full transparency and disclosure to community including patients' peers, (3) responding to requests to continue antiepileptic drugs, and (4) managing challenges arising from school policy and procedure. An analysis of these ethical issues is essential for the advancement of best care practices that promote the overall well-being of patients and their families.

Resting-state networks and dissociation in psychogenic non-epileptic seizures

OBJECTIVE

Psychogenic non-epileptic seizures (PNES) are epilepsy-like episodes which have an emotional rather than organic origin. Although PNES have often been related to the process of dissociation, the psychopathology is still poorly understood. To elucidate underlying mechanisms, the current study applied independent component analysis (ICA) on resting-state fMRI to investigate alterations within four relevant networks, associated with executive, fronto-parietal, sensorimotor, and default mode activation, and within a visual network to examine specificity of between-group differences.

METHODS

Twenty-one patients with PNES without psychiatric or neurologic comorbidities and twenty-seven healthy controls underwent resting-state functional MR imaging at 3.0T (Philips Achieva). Additional neuropsychological testing included Raven's Matrices test and dissociation questionnaires. ICA with dual regression was used to identify resting-state networks in all participants, and spatial maps of the networks of interest were compared between patients and healthy controls.

RESULTS

Patients displayed higher dissociation scores, lower cognitive performance and increased contribution of the orbitofrontal, insular and subcallosal cortex in the fronto-parietal network; the cingulate and insular cortex in the executive control network; the cingulate gyrus, superior parietal lobe, pre- and postcentral gyri and supplemental motor cortex in the sensorimotor network; and the precuneus and (para-) cingulate gyri in the default-mode network. The connectivity strengths within these regions of interest significantly correlated with dissociation scores. No between-group differences were found within the visual network, which was examined to determine specificity of between-group differences.

CONCLUSIONS

PNES patients displayed abnormalities in several resting-state networks that provide neuronal correlates for an underlying dissociation mechanism.

The economic cost of nonepileptic attack disorder in Ireland

The present study endeavored to calculate a conservative estimate of both incidence- and prevalence-based costs of nonepileptic attack disorder (NEAD) in Ireland by applying previously identified prevalence figures to Irish population figures. Variables related to the economic cost of NEAD were identified based on a retrospective chart review of patients diagnosed with NEAD at Beaumont Hospital, Dublin. The annual cost per patient of undiagnosed NEAD was calculated as €20,995.30. The combined cost of diagnosis and psychological treatment of NEAD was estimated at €8728. Although it is difficult to determine precise economic costings, early diagnosis and intervention would result in a significant economic saving to the exchequer, a reduction in hospital waiting-list times, and a better prognosis for patients.

Clinical events in psychogenic non-epileptic seizures based on semiological seizure classification

OBJECTIVES

None of the classifications of psychogenic non-epileptic seizures (PNES) have been widely accepted and used by physicians so far. In this study we aimed at classifying PNES on the basis of a modified version of semiological seizure classification (SSC). We also sought to assess the interrater reliability (IRR) of the PNES diagnosis based on SSC.

METHODS

We classified PNES into four types on the basis of our modification of SSC: pseudoaura, dialeptic, motor, and special (atonic, astatic, hypotonic) spells. Pseudoauras were not included in the statistical analysis. Ninety-one PNES attacks were observed during the 55 video-EEG sessions recorded for all patients. The interrater agreement was assessed by the kappa coefficient.

RESULTS

Twenty-nine women (78·3%) and eight men (21·6%) were surveyed, with a mean age of 28·4 ± 9·6 (range 16-54). The final diagnosis of PNES was established after a mean of 4·5 ± 2·3 years following the onset of PNES attacks in the patients. The mean seizure duration in the PNES was 241 seconds and 40·5% of our patients had PNES longer than 300 seconds. Motor and special PNES were the most common types observed by all the raters. The kappa values for each pair were as follows: Observers I-II 0·51 (p = 0·000), Observers I-III 0·47 (p = 0·000), and Observers II-III 0·73 (p = 0·000).

CONCLUSIONS

Interobserver agreement was moderate and substantial for three observers who classified PNES according to our modified SSC. The modified version of SSC could be used without difficulty in classifying PNES. Using SSC for PNES both shortens the period before diagnosis and eliminates the need to learn another new and acceptable classification for PNES.

Semiological characteristics of adults with psychogenic nonepileptic seizures (PNESs): an attempt towards a new classification

This study was carried out to analyze the semiological characteristics of adults with psychogenic nonepileptic seizures (PNESs) and to propose a modified new classification of PNESs. This retrospective analysis included 82 patients (M:F=38:44; mean age: 33.4 ± 12.0 years) diagnosed to have PNESs based on video-EEG recording. Detailed semiological characteristics including pattern of limb movements, body movements, psychological/emotional manifestations, "aura", level of consciousness, age at onset of PNESs, age at diagnosis, and history of AED intake were recorded. We classified our cohort of patients as per available classifications and proposed a modified new classification. Age at onset of PNESs was 21.8 ± 14.1 years (range: 2-64; median: 18.5 years), age at diagnosis was 29.3 ± 12.7 years (range: 2-67; median: 26.0 years), and delay in diagnosis was 7.4 ± 7.3 years (range: 0-28; median: 5.0 years). There were 369 recorded attacks (range: 1-10; median: 4). Prior to VEEG, 47 (57.3%) patients were incorrectly diagnosed as having true epileptic seizures initially and were on antiepileptic drugs (AEDs), 15 (18.3%) patients had an initial diagnosis of PNESs which remained unchanged after VEEG analysis, and 20 (24.4%) patients had both PNESs and epileptic seizures. We could not classify 40-66% of our patients into any of the available classification proposed by previous authors. We categorized all our patients into the following categories of a modified new classification: abnormal hypermotor response: 23 (28%), abnormal partial motor response: 18 (22%), affective/emotional behavior phenomena: 4 (4.9%), dialeptic type: 5 (6.1%), nonepileptic aura: 5 (6.1%), and mixed pattern: 27 (32.9%). Incorrect diagnosis of PNESs leads to unnecessary prescription of AEDs, with side effects and cost implications. A modified systematic classification of PNESs is proposed which would help in the better characterization of PNESs.

Clinical profile of psychogenic non-epileptic seizures in adults: A study of 63 cases

AIMS

To evaluate clinical profile and short-term outcome of psychogenic non-epileptic seizures (PNES) in Indian adult population.

SETTING AND DESIGN

A prospective observational study, conducted at tertiary teaching institute at New Delhi.

MATERIALS AND METHODS

Sixty-three patients with confirmed PNES were enrolled. The diagnosis was based on witnessing the event during video-electroencephalography (Video-EEG) monitoring. A detailed clinical evaluation was done including evaluation for coexistent anxiety or depressive disorders. Patients were divided into two groups on the basis of excessive or paucity of movements during PNES attacks. Patients were followed-up to 12 months for their PNES frequency.

STATISTICAL ANALYSIS

Means and standard deviations were calculated for continuous variables. Chi-square and Students t-test were used to compare categorical and continuous variables respectively.

RESULTS

The mean age at onset of PNES was 25.44 years; with F:M ratio of 9.5:1. Coexistent epilepsy was present in 13 (20.63%) cases. Twenty-two patients (44%) with only PNES (n = 50) had received antiepileptic drugs. Out of 63 patients of PNES 24 (38.1%) had predominant motor phenomenon, whereas 39 (61.9%) had limp attacks. The common features observed were pre-ictal headache, ictal eye closure, jaw clenching, resistant behavior, ictal weeping, ictal vocalization, and unresponsiveness during episodes. Comorbid anxiety and depressive disorders was seen in 62.3% and 90.16% patients, respectively. Short-term (6-12 months) outcome of 45 patients was good (seizure freedom in 46.66% and >50% improvement in 24.44% cases).

CONCLUSION

PNES is common, but frequently misdiagnosed and treated as epileptic seizures. A high index of suspicion is required for an early diagnosis. Proper disclosure of diagnosis and management of the psychiatric comorbidities can improve their outcome.

LIMITATION

Limited sample size and change in seizures frequency as the only parameter for the assessment of the outcome are the two major limitations of our study.

Use of postictal respiratory pattern to discriminate between convulsive psychogenic nonepileptic seizures and generalized tonic-clonic seizures

Distinguishing between generalized tonic-clonic seizures (GTCSs) and convulsive psychogenic nonepileptic seizures (PNESs) can be difficult at the bedside, and this distinction has important implications for patient care. This study used a fully blinded method to examine postictal breathing parameters to identify features distinguishing between generalized tonic-clonic seizures (GTCSs) and convulsive psychogenic nonepileptic seizures (PNESs). Three blinded readers examined edited video recordings of the postictal phase of 72 convulsive seizure episodes recorded from 56 patients. There were 59 GTCS episodes and 13 PNES episodes. Postictal breathing after a PNES episode was more rapid than after a GTCS episode and, thereafter, normalized more rapidly. Postictal breathing after a GTCS episode was more likely to be characterized by stertorous respirations. Postictal breathing after a PNES episode was very unlikely to be characterized by stertorous respirations. Postictal respiratory pattern can assist in discriminating between GTCS and convulsive PNES.

Subgroup classification in patients with psychogenic non-epileptic seizures

INTRODUCTION

In this open non-controlled clinical cohort study, the applicability of a theoretical model for the diagnosis of psychogenic non-epileptic seizures (PNES) was studied in order to define a general psychological profile and to specify possible subgroups.

METHODS

Forty PNES patients were assessed with a PNES "test battery" consisting of eleven psychological instruments, e.g., a trauma checklist, the global cognitive level, mental flexibility, speed of information processing, personality factors, dissociation, daily hassles and stress and coping factors.

RESULTS

The total PNES group was characterized by multiple trauma, personality vulnerability (in a lesser extent, neuropsychological vulnerabilities), no increased dissociation, many complaints about daily hassles that may trigger seizures and negative coping strategies that may contribute to prolongation of the seizures. Using factor analysis, specific subgroups were revealed: a 'psychotrauma subgroup', a 'high vulnerability somatizing subgroup' (with high and low cognitive levels) and a 'high vulnerability sensitive personality problem subgroup'.

CONCLUSION

Using a theoretical model in PNES diagnosis, PNES seem to be a symptom of distinct underlying etiological factors with different accents in the model. Hence, describing a general profile seems to conceal specific subgroups with subsequent treatment implications. This study identified three factors, representing two dimensions of the model, that are essential for subgroup classification: psychological etiology (psychotrauma or not), vulnerability, e.g., the somatization tendency, and sensitive personality problems/characteristics ('novelty seeking'). For treatment, this means that interventions could be tailored to the main underlying etiological problem. Also, further research could focus on differentiating subgroups with subsequent treatment indications and possible different prognoses.

The influence of impression management scales on the Personality Assessment Inventory in the epilepsy monitoring unit

The Somatic Complaints scale (SOM) and Conversion subscale (SOM-C) of the Personality Assessment Inventory perform best in classifying psychogenic non-epileptic seizures (PNES) from epileptic seizures (ES); however, the impact of positive impression management (PIM) and negative impression management (NIM) scales on SOM and SOM-C classification has not been examined. We studied 187 patients from an epilepsy monitoring unit with confirmed PNES or ES. On SOM, the best cut score was 72.5 T when PIM was elevated and 69.5 T when there was no bias. On SOM-C, when PIM was elevated, the best cut score was 67.5 T and 76.5 T when there was no bias. Negative impression management elevations (n=9) were too infrequent to analyze separately. Despite similarities in classification accuracy, there were differences in sensitivity and specificity with and without PIM, impacting positive and negative predictive values. The presence of PIM bias generally increases positive predictive power of SOM and SOM-C but decreases negative predictive power.

Comparing standard medical care for nonepileptic seizures in Chile and the United States

OBJECTIVE

We sought to compare the diagnostic and treatment practices for psychogenic nonepileptic seizures (PNES) in the United States (US) to Chile.

METHODS

A survey on the diagnostic and treatment practices for PNES was administered to practicing clinicians in Chile. Results from 96 Chilean respondents were compared to results from 307 US clinicians. Type I error (alpha) was set to 0.005 for multiple comparisons.

DIAGNOSIS

The diagnosis of PNES is made by inpatient video-EEG/LTM in 89% of the US respondents compared to 25% of the Chilean respondents (p<0.0001). The diagnosis of PNES is made by history and exam alone at twice the rate in Chile (38%) than in the US (16%; p<0.0001).

TREATMENT

A higher proportion of the Chilean respondents (65%) endorsed psychopharmacotherapy as potentially beneficial compared to the US respondents (31%; p<0.0001).

DISCUSSION

This cross-cultural multi-site survey reveals some differences in PNES evaluation and management between neurologists and other clinicians in the US and in Chile. Access to video EEG may improve PNES diagnosis and treatment.

Automated diagnosis of epilepsy using EEG power spectrum

Interictal electroencephalography (EEG) has clinically meaningful limitations in its sensitivity and specificity in the diagnosis of epilepsy because of its dependence on the occurrence of epileptiform discharges. We have developed a computer-aided diagnostic (CAD) tool that operates on the absolute spectral energy of the routine EEG and has both substantially higher sensitivity and negative predictive value than the identification of interictal epileptiform discharges. Our approach used a multilayer perceptron to classify 156 patients admitted for video-EEG monitoring. The patient population was diagnostically diverse; 87 were diagnosed with either generalized or focal seizures. The remainder of the patients were diagnosed with nonepileptic seizures. The sensitivity was 92% (95% confidence interval [CI] 85-97%) and the negative predictive value was 82% (95% CI 67-92%). We discuss how these findings suggest that this CAD can be used to supplement event-based analysis by trained epileptologists.

Diagnostic utility of the Structured Inventory of Malingered Symptomatology for identifying psychogenic non-epileptic events

The Structured Interview of Malingered Symptomatology (SIMS) is a self-report instrument that asks patients whether they experience atypical or implausible symptoms. The instrument has not been evaluated in an epilepsy population, and the potential for it to accurately distinguish between patients with psychogenic non-epileptic events (PNEE) and epileptic event groups has not been established. The SIMS was administered to patients in long-term video-EEG monitoring of these patients, 91 with PNEE and 29 with epilepsy were included in this study. Structured Interview of Malingered Symptomatology total scores as well as neurological and affective subscales were found to be predictors of group membership. Sensitivity and specificity across several different base rates of PNEE as well as maximum level likelihood ratios are presented. The findings not only demonstrate the utility of marked score elevations in differentiating PNEE from epilepsy but also point to considerable caution in interpreting mild elevations. Implications for the utility of this instrument in epilepsy evaluations are discussed.

Key challenges in the current management of syncope

Patients commonly present with syncope at emergency departments and other facilities for urgent care. Syncope is understood by physicians to be a transient, self-terminating period of cerebral hypoperfusion that usually results from systemic hypotension, and clinical guidelines for the care of patients with presumed syncope are available. However, the diagnosis and management of such patients continue to pose important diagnostic, therapeutic, and economic challenges, which are the focus of this Review. First, we discuss how to improve symptom characterization to distinguish syncope from other forms of transient loss of consciousness and syncope mimics. Second, we compare methods of risk stratification in patients with suspected syncope, and recommend the introduction of syncope clinics with enhanced interdisciplinary collaboration to optimize patient care at reduced expense. Third, we highlight the importance of the appropriate selection of diagnostic tools and treatment strategies in these syncope clinics. Finally, we address the difficulties associated with therapy for the most-common form of syncope--vasovagal or reflex syncope.

Resetting of brain dynamics: epileptic versus psychogenic nonepileptic seizures

We investigated the possibility of differential diagnosis of patients with epileptic seizures (ES) and patients with psychogenic nonepileptic seizures (PNES) through an advanced analysis of the dynamics of the patients' scalp EEGs. The underlying principle was the presence of resetting of brain's preictal spatiotemporal entrainment following onset of ES and the absence of resetting following PNES. Long-term (days) scalp EEGs recorded from five patients with ES and six patients with PNES were analyzed. It was found that: (1) Preictal entrainment of brain sites was reset at ES (P<0.05) in four of the five patients with ES, and not reset (P=0.28) in the fifth patient. (2) Resetting did not occur (p>0.1) in any of the six patients with PNES. These preliminary results in patients with ES are in agreement with our previous findings from intracranial EEG recordings on resetting of brain dynamics by ES and are expected to constitute the basis for the development of a reliable and supporting tool in the differential diagnosis between ES and PNES. Finally, we believe that these results shed light on the electrophysiology of PNES by showing that occurrence of PNES does not assist patients in overcoming a pathological entrainment of brain dynamics. This article is part of a Supplemental Special Issue entitled The Future of Automated Seizure Detection and Prediction.

Patients with psychogenic non-epileptic seizures referred to a tertiary epilepsy centre: patient characteristics in relation to diagnostic delay

OBJECTIVE

This clinical study examines patient and seizure characteristics of patients with psychogenic non-epileptic seizures (PNES) in a tertiary epilepsy centre. The main focus was whether a new subgroup of PNES patients emerged with a relatively short referral time and possible specific characteristics.

METHODS

All PNES patients referred to a specialist program in our centre between mid 2007 and mid 2009 were consecutively included. This yielded a study cohort of 90 patients.

RESULTS

The majority of the patients have a patient history with many medical symptoms and they were or had been in treatment by a medical specialist. Furthermore diffuse psychological/psychiatric symptoms and subsequent treatments are also remarkably common, in general without a clear psychological diagnosis. The average time between seizure onset and referral to an epilepsy centre is remarkably low (4.29 years). About 50% of the patients were referred within 2 years of seizure onset. This 'active high speed referral group' had significantly more previous psychological complaints, significantly more previous psychological/psychiatric treatments and a trend towards more previous medical investigations.

CONCLUSION

There seems to be a new subgroup of PNES patients with a short referral time, characterized by a more active attitude towards examination of the symptoms in combination with an active attitude to apply for treatment. However, the PNES cohort as a whole is characterized by having somatoform symptoms based on a process of somatization.

MMPI-II personality profiles of patients with psychogenic nonepileptic seizures

This comparative study explored whether psychogenic nonepileptic seizures (PNES) are a unique disorder with distinctive personality characteristics or (seen from the personality profile) PNES are allied with the domain of a general functional somatic symptom and syndrome (FSSS). We compared the Minnesota Multiphasic Personality Inventory 2 (MMPI-2) results for 41 patients with newly diagnosed PNES and 43 patients with newly diagnosed insomnia. There were no statistically significant quantitative scoring differences on the main clinical scales, indicating that there is no substantial difference in "personality makeup" between the two groups with a FSSS. Additional subscale analysis indicated that patients with PNES reported significantly more somatic complaints (Hysteria 4) and bizarre sensory experiences (Schizophrenia 6). Further profile analysis revealed that the personality pattern of patients with PNES was characterized by a strong tendency toward "conversion V, a lack of control pattern and less excessive worries" as compared with patients with insomnia. Patients with PNES are characterized by a stronger tendency toward somatization and externalization, which has treatment implications.

Psychogenic nonepileptic seizures and suicidal behavior on a video/EEG telemetry unit: the need for psychiatric assessment and screening for suicide risk

Patients with epilepsy and psychogenic nonepileptic seizures (PNES) have an increased prevalence of psychiatric illness and risk for suicidal ideation/suicidal behavior/suicide compared with the general population. Recent literature suggests that antiepileptic drugs (AEDs) used to treat epilepsy, pain, and psychiatric disorders increase the risk of suicide and that this increased risk may be AED selective. This case analyzes a suicide attempt on a video/EEG telemetry unit. Specific risk factors associated with increased risk of suicidal behaviors pertinent to this case are reviewed: epilepsy, multiple psychiatric diagnoses including affective disorder, AEDs, PNES, prior medically serious suicide attempt, and suicide attempt within the past month. Specific psychometric rating scales to screen for both psychiatric illness and suicide risk and psychiatric assessment should be integral components of the evaluation and treatment of patients on video/EEG telemetry units.

Questioning the role of abuse in behavioral spells and epilepsy

Past sexual trauma is frequently linked to the development of behavioral spells, present among 30% of patients admitted for video/EEG monitoring. Current attempts to verify and explore mechanisms in this reported association revealed that patients with epilepsy (n=58) and those with behavioral spells (n=38) did not differ in their self-report of past sexual trauma (among approximately 38% in each group). Ninety percent (90%) of men with behavioral spells endorsed past physical abuse, however, compared with 45% of men with epilepsy, and 40% of men with spells likely met current criteria for posttraumatic stress disorder. Among all patients, the presence of past physical, but not sexual, abuse positively predicted the diagnosis of spells rather than epilepsy. Current findings do not support a preponderance of sexual trauma in behavioral spells, yet within the subset of men with spells, greater exposure to physical abuse and current symptoms of posttraumatic stress disorder may be important etiological and sustaining factors.

Do patients with psychogenic nonepileptic seizures have positive covert attitudes toward sickness?

Some individuals with psychogenic nonepileptic seizures (PNES) are seen as having adopted a "sick role" that relinquishes them of responsibility for meeting stressful life demands. Thus, patients with PNES may have positive, albeit unrecognized, attitudes toward seizures, or perhaps illness in general. Because such covert attitudes may not be amendable to self-report, the current study used the Implicit Association Test (IAT), a methodology by which attitudes toward illness and disability can be inferred from performance on an ostensibly neutral task. Individuals with PNES did not have a reduced interference effect when responding to sickness-related and pleasant words on the same response key. Exploratory analyses revealed that a pronounced somatic focus and higher extraversion were associated with more neutral attitudes toward illness among patients with PNES. This IAT methodology found little support for the notion that patients with PNES harbor positive attitudes toward illness. Limitations of the IAT methodology are reviewed and recommendations are provided.

Clinical features of psychogenic nonepileptic seizures: a study of 64 cases in southwest China

This article describes the clinical features of psychogenic nonepileptic seizures (PNES) in people in southwest China. Patients with a confirmed diagnosis of pure PNES by video/EEG monitoring were retrospectively reviewed. A total of 64 patients with PNES were included, 32 (50%) of whom were male. Twenty (31.3%) patients had previously been misdiagnosed and treated for epilepsy. Psychological trauma and head injuries were considered antecedent traumatic factors. A history of abuse was rare. The PNES cases were divided into three subtypes: psychogenic minor motor seizures, psychogenic major motor seizures, and unresponsive seizures. Age at onset was identified as a predictor of prognosis. The results of this study demonstrated a higher prevalence of PNES in males compared with previous studies. The semiology of PNES in China is similar to that in Western countries. Classification of semiology may be helpful in the differential diagnosis of PNES.

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.

Predictive factors for outcome of invasive video-EEG monitoring and subsequent resective surgery in patients with refractory epilepsy

OBJECTIVE

This is a descriptive study of patients who underwent invasive video-EEG monitoring (IVEM) at Ghent University Hospital. The aim of the study is to identify predictive factors for outcome of IVEM and resective surgery (RS). These factors may optimize the patient flow following the non-invasive presurgical evaluation towards IVEM and RS or other treatments.

PATIENTS AND METHODS

Over the past 16 years, 68/710 refractory epilepsy patients included in the presurgical evaluation protocol (M/F 41/27, mean age 33 years) underwent IVEM at Ghent University Hospital. Patient features and follow-up data were collected from the patients' medical files and the electronic patient database at the neurology and neurosurgery department. Predictive factors for IVEM outcome were identified by comparing features of patients with a positive IVEM outcome (i.e. ictal onset zone identification) and patients with a negative IVEM outcome. Predictive factors for RS outcome were identified by comparing features of patients with Engel class I and patients with Engel class II-IV outcome.

RESULTS

In 56/68 patients (82%) IVEM outcome was positive. The occurrence of a seizure-free interval in the patient's history and a non-localizing ictal scalp EEG in patients with a structural abnormality on MRI (p<0.05) were predictive factors for a negative IVEM outcome. 32/68 patients underwent RS. In 22/32 (70%) patients RS resulted in an Engel class I outcome. A structural abnormality on MRI was a predictive factor for a positive RS outcome in patients in whom a focal or regional focus was resected (p<0.05).

CONCLUSION

This study shows that IVEM identifies one or more ictal onset zone(s) in up to 80% of patients. The potential of IVEM to identify the ictal onset zone is unlikely in patients with a seizure-free interval in their medical history and a non-localizing ictal scalp EEG during the non-invasive presurgical evaluation. Half of these patients underwent RS with long-term seizure freedom in 70%. Patients with structural MRI lesions have the highest chance of seizure freedom. These findings may contribute to the optimization of patient management during both the invasive and non-invasive presurgical work-up.

[Drug-resistant epilepsy]

BACKGROUND

Despite the introduction of many new antiepileptic drugs during recent years, about one third of the epilepsy population continue to have drug-resistant seizures. We present two hypotheses on mechanisms of drug-resistant epileptic seizures.

MATERIAL AND METHODS

The article is based on our own clinical experience and literature identified through a PubMed search using the words: refractory, intractable, pharmacoresistant, drug resistant epilepsy/seizures.

RESULTS

There is no international consensus on the definition of drug-resistant epilepsy. Some epilepsy types appear to respond to drug treatment, while others are more resistant. Animal models and refractory patients have been studied to find mechanisms that can explain the lack of drug response in some types of epilepsy. Currently, two main hypotheses prevail. The transporter hypothesis implies an over-expression of the proteins (e.g. P-glycoprotein) capable of transporting drugs out of the epileptic focus. The target hypothesis implies changes in receptors or ion channels in the epileptic cellular network, which render this area less susceptible to antiepileptic drugs.

INTERPRETATION

Both hypotheses have weaknesses, and alternative theories have been presented. Much remains before the causes of drug-resistant epilepsy are understood. If patients do not achieve seizure control after having tried 2-3 antiepileptic drugs, they should be referred to the national epilepsy centre for a renewed diagnostic evaluation and for consideration of non-pharmacological treatment.

Psychogenic non-epileptic seizures--definition, etiology, treatment and prognostic issues: a critical review

In this review we systematically assess our currently available knowledge about psychogenic non-epileptic seizures (PNES) with an emphasis on the psychological mechanisms that underlie PNES, possibilities for psychological treatment as well as prognosis. Relevant studies were identified by searching the electronic databases. Case reports were not considered. 93 papers were identified; 65 of which were studies. An open non-randomized design, comparing patients with PNES to patients with epilepsy is the dominant design. A working definition for PNES is proposed. With respect to psychological etiology, a heterogeneous set of factors have been identified. Not all factors have a similar impact, though. On the basis of this review we propose a model with several factors that may interact in both the development and prolongation of PNES. These factors involve psychological etiology, vulnerability, shaping, as well as triggering and prolongation factors. A necessary first step of intervention in patients with PNES seems to be explaining the diagnosis with care. Although the evidence for the efficacy of additional treatment strategies is limited, variants of cognitive (behavioural) therapy showed to be the preferred type of treatment for most patients. The exact choice of treatment should be based on individual differences in the underlying factors. Outcome can be measured in terms of seizure occurrence (frequency, severity), but other measures might be of greater importance for the patient. Prognosis is unclear but studies consistently report that 1/3rd to 1/4th of the patients become chronic.