Electroencephalography coherence, memory vividness, and emotional valence effects of bilateral eye movements during unpleasant memory recall and subsequent free association: Implications for eye movement desensitization and reprocessing

This study examined the effects of bilateral stimulation during unpleasant memory recall followed by free association, similar to Phase 4 of EMDR therapy. Forty-six female nonpatients were randomly assigned to one of three conditions: bilateral eye movements (BEMs), eye fixation with background movements (BDM), or eye fixation (Dot) control, each while recalling a moderately unpleasant memory and each followed by free association to the memory. Electroencephalography recordings were conducted on these participants during the 1-minute free association of the original memory after each of five administrations of the conditions. Results revealed only trend increases in Beta interhemispheric coherence following BEMs. However, statistically significant increases in Right Frontal Theta and Beta intrahemispheric coherences were found following BEMs, with similar trend increases for Left Frontal Theta and Beta and for Right Frontal Gamma. Cortical electrode maps are presented for these Beta coherence effects. Ratings of imagery vividness and emotional valence were collected after each set of eye movements plus free associations and showed a significant decrease across all conditions. Results are discussed within the context of a proposed integrated 2-stage cortical coherence model. Suggestions are made for future research, including investigation of possible implications for treatment of traumatic brain injury.