Psychophysiological biomarkers of dissociation in psychogenic non-epileptic seizures

Misdiagnosis of patients with psychogenic non-epileptic seizures (PNES) as having epilepsy is a clinical relevant problem. Considerable problems for the patients, such as unnecessary anticonvulsant medication use and delay of suitable therapy, as well as a considerable economic burden are involved. Furthermore, after the diagnosis of PNES is confirmed, there is a lack of scientific evidence about the most efficient treatment for PNES. Evaluation of contributing factors is necessary. These factors should be implemented in explanatory models for the occurrence of PNES, which should be employed in diagnosis and treatment. Recent evidence suggests a role of deficiencies in neuronal information processing in multiple mental conditions. Although the focus in PNES research over the last two decades primarily has been on differential diagnosis and psychological and environmental factors, abnormalities in psychophysiological characteristics might also be involved in PNES. This review focuses on neurobiological substrates of PNES and dissociation, a trait which is often associated with PNES, to explore whether deviant information processing is involved in the aetiology of PNES. All studies examining the relationship between psychophysiological parameters and PNES have an exploratory character. However, the results suggest that neurophysiological characteristics, such as brain activity as visualized by functional MRI, cardiovascular measurements and neuroendocrine functioning, may be abnormal in patients with PNES. Future investigations should therefore elucidate the exact role of neurophysiological abnormalities in the aetiology of PNES.