Psychogenic nonepileptic seizures: EEG and investigation

Principles for delivering improved care of people with functional seizures: Closing the treatment gap

Patients diagnosed with functional (psychogenic nonepileptic) seizures have similar or greater levels of disability, morbidity and mortality than people with epilepsy, but there are far fewer treatment services. In contrast to epilepsy, the current understanding of pathophysiological mechanisms and the development of evidence-based treatments for functional seizures is rudimentary. This leads to high direct healthcare costs and high indirect costs to the patient, family and wider society. There are many patient, clinician and system-level barriers to improving outcomes for functional seizures. At a patient level, these include the heterogeneity of symptoms, diagnostic uncertainty, family factors and difficulty in perceiving psychological aspects of illness and potential benefits of treatment. Clinician-level barriers include sub-specialism, poor knowledge, skills and attitudes and stigma. System-level barriers include the siloed nature of healthcare, the high prevalence of functional seizures and funding models relying on individual medical practitioners. Through the examination of international examples and expert recommendations, several themes emerge that may address some of these barriers. These include (1) stepped care with low-level, brief generalised interventions, proceeding to higher level, extended and individualised treatments; (2) active triage of complexity, acuity and treatment readiness; (3) integrated interdisciplinary teams that individualise formulation, triage, and treatment planning and (4) shared care with primary, emergency and community providers and secondary consultation. Consideration of the application of these principles to the Australian and New Zealand context is proposed as a significant opportunity to meet an urgent need.

The neurobiology of functional neurological disorders characterised by impaired awareness

We review the neurobiology of Functional Neurological Disorders (FND), i.e., neurological disorders not explained by currently identifiable histopathological processes, in order to focus on those characterised by impaired awareness (functionally impaired awareness disorders, FIAD), and especially, on the paradigmatic case of Resignation Syndrome (RS). We thus provide an improved more integrated theory of FIAD, able to guide both research priorities and the diagnostic formulation of FIAD. We systematically address the diverse spectrum of clinical presentations of FND with impaired awareness, and offer a new framework for understanding FIAD. We find that unraveling the historical development of neurobiological theory of FIAD is of paramount importance for its current understanding. Then, we integrate contemporary clinical material in order to contextualise the neurobiology of FIAD within social, cultural, and psychological perspectives. We thus review neuro-computational insights in FND in general, to arrive at a more coherent account of FIAD. FIAD may be based on maladaptive predictive coding, shaped by stress, attention, uncertainty, and, ultimately, neurally encoded beliefs and their updates. We also critically appraise arguments in support of and against such Bayesian models. Finally, we discuss implications of our theoretical account and provide pointers towards an improved clinical diagnostic formulation of FIAD. We suggest directions for future research towards a more unified theory on which future interventions and management strategies could be based, as effective treatments and clinical trial evidence remain limited.

Differentiating psychogenic nonepileptic seizures from epileptic seizures: An observational study of patients undergoing video-electroencephalography (VEEG) in Australia

Video-electroencephalography (VEEG) is an invaluable tool for the differentiation of psychogenic nonepileptic seizures (PNES) from epileptic seizures (ES). This paper (i) evaluates the demographics of patients undergoing VEEGs at the Princess Alexandra Hospital from July 1 2017 to July 1 2019 and identifies those subsequently diagnosed with PNES, (ii) determines the delay in PNES diagnosis and proportion of PNES patients on antiepileptic drugs (AEDs) prior to a VEEG, and (iii) determines the proportion of PNES patients who subsequently ceased their AEDs. Of the 94 patients in the study group, 51 were female and 43 were male. In total, 22 (23%) of VEEGs were consistent with epilepsy (ES), 25 (26%), with PNES, 5 (5%) mixed (PNES and ES), 5 (5%) with other types of events, and 37 were nondiagnostic. Two patients with non-diagnostic VEEGs were subsequently treated as PNES at the treating clinician's discretion. Regarding AEDs, 62 of the patients were on at least one agent at the time of VEEG recording. The mean durations of AED therapy and diagnostic delay for patients subsequently diagnosed with PNES were six years and seven years, respectively. Of these, the majority had their AEDs subsequently weaned/ceased. This study highlights the value of VEEG in diagnostic differentiation of epileptic from nonepileptic events, thereby preventing unnecessary AED therapy for patients with PNES. The results are consistent with previous studies in the literature evaluating VEEG clinical outcomes.

Plasma-lactate levels in simulated seizures - An observational study

PURPOSE

Differentiating between epileptic seizures, convulsive syncope or non-epileptic seizures is a common diagnostic challenge in the acute setting. Plasma-lactate levels have previously been proposed as a tool to aid in differentiating between epileptic and non-epileptic seizures, with lower levels of lactate suggesting a non-epileptic origin. The aim of this study was to investigate levels of lactate in non-epileptic seizures.

METHODS

Healthy subjects were asked to perform a simulated seizure lasting no more than 5 min. Venous blood samples were taken before and immediately after the simulated seizure and analyzed using an ABL90 FLEX yielding information about lactate, pH, pO2,pCO2, electrolytes and plasma glucose.

RESULTS

8 people participated in the study: 6 men and 2 women aged 27-45. The average pre-simulation lactate was 1.1 mmol/L while the average pH was 7.39. The average post-simulation lactate was 10.2 mmol/L while the average pH was 7.25. This means an average increase in plasma-lactate of 9.1 mmol/L and an average drop of 0.15 in pH.

CONCLUSION

Our data indicate that high rises in lactate levels are not specific for an epileptic origin. Further study of lactate as a marker for epileptic seizures is warrented.