Neurophysiological correlates of dissociative symptoms.

METHODS: Studies reporting HRV, EEG and neuroimaging data related to hypnosis, dissociation and FNSS were identified by searching the electronic databases Pubmed and ScienceDirect.

RESULTS: The majority of the identified studies concerned the physiological characteristics of hypnosis; relatively few investigations on dissociation related FNSS were identified. General findings were increased parasympathetic functioning during hypnosis (as measured by HRV), and lower HRV in patients with FNSS. The large variety of EEG and functional MRI investigations with diverse results challenges definite conclusions, but evidence suggests that subcortical as well as (pre)frontal regions serve emotion regulation in dissociative conditions. Functional connectivity analyses suggest the presence of altered brain networks in patients with FNSS, in which limbic areas have an increased influence on motor preparatory regions.

CONCLUSIONS: HRV, EEG and (functional) MRI are sensitive methods to detect physiological changes related to dissociation and dissociative disorders such as FNSS, and can possibly provide more information about their aetiology. The use of such measures could eventually provide biomarkers for earlier identification of patients at risk and appropriate treatment of dissociative conditions.

J Neurol Neurosurg Psychiatry. 2012 Nov 22. van der Kruijs SJ, Bodde NM, Carrette E, Lazeron RH, Vonck KE, Boon PA, Langereis GR, Cluitmans PJ, Feijs LM, Hofman PA, Backes WH, Jansen JF, Aldenkamp AP. Epilepsy Centre Kempenhaeghe, , Heeze, The Netherlands.