Objective: This dissertation begins with an introduction to the problem posed by psychogenic nonepileptic seizures (PNES), followed by a thorough empirical literature review summarizing and critically evaluating the history of PNES, etiology, diagnosis, theoretical models, neurophysiology, psychophysiology and treatment practices. The chapter concludes with a discussion of the potential role for clinical care models to enhance treatment outcomes in pediatric PNES. Two empirical papers are then presented, the first of which sought to prospectively validate a clinical care pathway for PNES at a child epilepsy center. The second paper sought to determine the psychophysiology and dissociation characteristics of children newly referred for PNES while also exploring the relationship between psychophysiology features and PNES severity, including duration of illness and frequency of events at time of diagnosis.
Methods: Following Health Research Ethics Board approval at University of Nicosia and University of Calgary (data collection site), a retrospective chart review was conducted that included 43 children sequentially referred, assessed and treated for suspected PNES within a specialized neurology clinic psychology service over a 5-year period. These patients were included as participants in the clinical care pathway validation study. A subset of 33 patients also underwent psychophysiology assessment as part of standardized care and were selected for inclusion in the psychophysiology and dissociation study.
Results: Age ranged from 6 to 18 years of age at time of diagnosis with the majority of patients being female (n=29, 67%) and adolescent (n=31, 72%) with high level of adherence to the care algorithm (n=34, 84%). Standardized care resulted in high rates of full (n=27, 63%) and partial (n=12, 28%) remission, with 2 patients (5%) continuing to experience less than 50% reduction in PNES events, as self-reported at discharge (2 patients were lost to follow-up). The entire sample reported an average 96% decrease in monthly frequency of PNES events at discharge and a significant reduction in healthcare utilization related to PNES (74% fewer ambulance calls and 85% fewer emergency department visits). Post hoc analyses demonstrated that duration of PNES illness longer than 12 months (at diagnosis) increased odds of not achieving full remission by discharge (OR=5.94, p=0.019). Among patients included in the psychophysiology and dissociation subset, the majority were found to have autonomic decompensation at baseline (82%), lack of autonomic recovery from a cognitive stressor (58%) and diagnosis of behavioral hypocapnia (85%). Inhibition of normal skin conductance response to laboratory stressor was also associated with longer duration of PNES illness (𝜒𝜒2=4.47, p=0.035) and elevated heart rate (>90%) at baseline was associated with higher frequency of PNES events in the month preceding diagnosis (𝜒𝜒2=4.24, p=0.039). Overall high levels of dissociation and hyperventilation symptoms were self-reported by adolescent patients (n=19) and were positively correlated (Kendall’s tau=0.35, p=0.04).
Conclusions: The dissertation findings demonstrate that childhood PNES is characterized by psychophysiology features including baseline autonomic decompensation, increased respiratory CO2 sensitivity, poor autonomic recovery from stressors and substantial co-morbidity with suppression of the normal stress response. The above studies also demonstrate that standardized care for PNES leads to improved clinical outcomes and reduced healthcare utilization, and that delayed diagnosis and treatment of PNES longer than 12 months is associated with less favorable outcomes in children.
Psychogenic nonepileptic seizures in children - Clinical outcomes, dissociative and psychophysiology characteristics
- PhD thesis
- Social science -- Psychology