Enhancement of right hemisphere eeg functional connectivity after emdr therapy

Introduction Brain connectivity changes have been recently demonstrated in victims of psychological traumas treated with the eye movement desensitization and reprocessing (EMDR). Objectives Forty victims of psychological traumas were investigated at the first \{EMDR\} session (t0) and at the last one performed after processing the index trauma (t1). Aims To investigate differences in \{EEG\} functional source connectivity during bilateral ocular stimulation (BS) during \{EMDR\} therapy at t0 and t1. Methods Brain electrical activity during whole \{EMDR\} sessions was record with a 37-channel EEG. \{EEG\} functional connectivity analysis was based on the lagged phase synchronization (LPS), derived by a two-step eLoreta procedure: dimensionality reduction of inverse matrix from 6239 voxels to 28 regions of interest (ROIs); \{LPS\} index computation, for each spectrum band, in all possible \{ROI\} pairs. Results Significant differences were detected between t0 and t1 in alpha band \{LPS\} indexes. A prevalent enhancement in right intrahemispheric functional connectivity was found in t1 respect to t0, particularly among \{ROI\} pairs of (a) frontal regions (anterior frontal, orbital frontal, lateral frontal cortices) and limbic structures (anterior cingulate cortex, ACC), (b) frontal regions and associative areas (insula cortex, parietal lobe), (c) \{ACC\} and primary visual cortex and (d) \{ACC\} and associative areas. Conclusions These findings suggest that \{EMDR\} efficacy is associated to electrical brain connectivity changes during BS. An enhancement in the right hemisphere alpha band functional connectivity of areas involved in cognitive control, emotional processing and visual associative functions may play a key role in the elaboration of psychological traumas.