Alaric M Indranada1, Saul A Mullen2, Melanie J Wong3, Wendyl J D'Souza3, Richard A A Kanaan4. 1. The University of Melbourne, Department of Psychiatry, Austin Health, Heidelberg, VIC 3084, Australia. 2. The Florey Institute of Neuroscience and Mental Health, Heidelberg, VIC 3084, Australia. 3. The University of Melbourne, Department of Clinical Neurosciences, St Vincent's Health, VIC 3065, Australia. 4. The University of Melbourne, Department of Psychiatry, Austin Health, Heidelberg, VIC 3084, Australia; The Florey Institute of Neuroscience and Mental Health, Heidelberg, VIC 3084, Australia; King's College London, Department of Psychological Medicine, Institute of Psychiatry, Weston Education Centre, Denmark Hill, London SE5 9RJ, UK. Electronic address: richard.kanaan@unimelb.edu.au.
Abstract
OBJECTIVES: Psychogenic nonepileptic seizures (PNES) resemble seizures but are psychological in origin. The etiology of PNES remains poorly understood, yet several theories argue for the importance of autonomic dysregulation in its pathophysiology. We therefore conducted a retrospective study to investigate autonomic dynamics leading up to a seizure to inform their mechanistic relevance. METHODS: One hundred one patients with PNES and 45 patients with epileptic seizure (ES) were analyzed for preictal heart rate (HR) and respiratory rate (RR) at baseline and at minute intervals from 5 min to onset. RESULTS: Patients with PNES showed rising HR (p < 0.001, repeated-measures analysis of variance (ANOVA)) and rising RR (p = 0.012, repeated-measures ANOVA) from baseline to the onset of their seizures. Patients with ES did not exhibit significant preictal HR or RR increase. Patients with PNES had nonsignificantly higher preictal HR and RR than patients with ES. SIGNIFICANCE: Patients with PNES exhibit increasing autonomic arousal prior to seizure events unlike patients with epilepsy. This may reflect increasing levels of preictal anxiety, and future studies could study patients' subjective experiences of the preictal period, and more definitive measures of ventilation to see if this supported a model of PNES as "panic without panic".
OBJECTIVES:Psychogenic nonepileptic seizures (PNES) resemble seizures but are psychological in origin. The etiology of PNES remains poorly understood, yet several theories argue for the importance of autonomic dysregulation in its pathophysiology. We therefore conducted a retrospective study to investigate autonomic dynamics leading up to a seizure to inform their mechanistic relevance. METHODS: One hundred one patients with PNES and 45 patients with epilepticseizure (ES) were analyzed for preictal heart rate (HR) and respiratory rate (RR) at baseline and at minute intervals from 5 min to onset. RESULTS:Patients with PNES showed rising HR (p < 0.001, repeated-measures analysis of variance (ANOVA)) and rising RR (p = 0.012, repeated-measures ANOVA) from baseline to the onset of their seizures. Patients with ES did not exhibit significant preictal HR or RR increase. Patients with PNES had nonsignificantly higher preictal HR and RR than patients with ES. SIGNIFICANCE: Patients with PNES exhibit increasing autonomic arousal prior to seizure events unlike patients with epilepsy. This may reflect increasing levels of preictal anxiety, and future studies could study patients' subjective experiences of the preictal period, and more definitive measures of ventilation to see if this supported a model of PNES as "panic without panic".