EMDR Therapy: What’s Happening in the Brain? — BrainPost | Easy-to-read summaries of the latest neuroscience publications

Eye movements to treat traumatic disorders

In 1989, Francine Shapiro published a technique for treating trauma using eye movements. In the technique, a client will bring a traumatic incident to mind, and recall it while simultaneously following the therapist’s finger as it moves back and forth across their field of vision. A session also includes repeated evaluations of thoughts, emotions, and body sensations surrounding the event. This therapeutic approach came to be known as Eye Movement Desensitization and Reprocessing, or EMDR. Shapiro observed its effectiveness in treating severe post-traumatic stress disorder (PTSD). However, both scientists and the public viewed the technique with skepticism. For starters, it seemed “too easy,” (the words of one patient in Shapiro’s 1989 paper). It didn’t help that it was unclear how the technique worked and that it seemed similar to less scientifically reputable techniques such as hypnosis.

Despite its detractors, EMDR has slowly grown to become one of the preferred treatments for PTSD. Scientists and clinicians have teamed up to run randomized controlled trials, where people are assigned randomly to either EMDR or another treatment condition. These experiments are considered the gold standard for determining a treatment’s efficacy in the medical field, and enough of them have been done that we can now perform meta-analyses, which synthesize all the results from different experiments into one big analysis. The results? EMDR is at least as effective as other well-established treatments like cognitive-behavioral therapy or exposure therapy.

What does EMDR do in the brain?

The main hypothesis developed by Shapiro and colleagues to explain EMDR is called the Adaptive Information Processing model. According to this model, traumatic memories are not fully processed in the brain and create their own maladaptive networks that can be triggered, leading to flashbacks and other unwanted phenomena. EMDR encourages the traumatic memory to be brought up, fully processed, and reconsolidated in a more adaptive manner, integrating it with the rest of an individual’s life experience and diminishing its power to cause fear. Shapiro emphasizes the difference between memory reconsolidation (the hypothesized mechanism for EMDR), and memory extinction (the basis for exposure therapy).

EMDR responsiveness has indeed been linked with memory structures, such as the parahippocampal gyrus, deep in the brain. One study showed that at the start of EMDR therapy, there was greater activation in the frontal cortex (responsible for executive control) and the occipital cortex (responsible for visual stimuli). By the end of therapy, activity had shifted towards the parahippocampal gyrus and parietal lobe. Thus, the idea that eye movements promote memory reprocessing does not seem too far-fetched, but the exact mechanisms of EMDR are still being worked out.

One idea is that eye movements may take space in working memory, giving less “bandwidth” to the traumatic memory and therefore making it less vivid. Another is that they mimic the eye movements of REM sleep (the period of the sleep cycle where memories are consolidated) and thus promote reconsolidation of the traumatic memory. It's important to note here that EMDR can be done with methods other than eye movement, including tapping one’s shoulders on the right and left side or holding buzzers in the hands that vibrate in a right/left pattern. These methods are collectively called bilateral stimulation.

Some research shows that the bilateral stimulation used in EMDR can be effective even in animals who cannot be told the goal of the “therapy.” A recent study showed that when rodents were exposed to lights moving back and forth, their response to a previously fearful stimulus decreased (See a previous BrainPost).

What’s new?

Shapiro never intended EMDR to be applied solely to PTSD, and lately, there have been studies looking at its efficacy for other conditions, such as obsessive-compulsive disorder, psychosis, substance use disorders, and depression. While some results may look promising, there is not yet enough information to run the kind of meta-analyses that have established EMDR’s efficacy for PTSD.

Finally, Otgaar and colleagues have cautioned that undergoing EMDR therapy may change the validity of witness testimony in court, since it is, after all, a form of memory reprocessing, and could affect details of an event as the victim remembers it.

What's the bottom line?

EMDR therapy is a validated, non-pharmaceutical technique for the treatment of PTSD, and perhaps other mental health issues. While we don’t fully understand how it works, it involves memory processing and reconsolidation of previously acquired memories. As with any mental health treatment, make sure you ask a licensed therapist about this technique regarding your own situation.

References +

Jeffries, F. W., & Davis, P. (2013). What is the Role of Eye Movements in Eye Movement Desensitization and Reprocessing (EMDR) for Post-Traumatic Stress Disorder (PTSD)? A Review. Behavioural and Cognitive Psychotherapy, 41(3), 290–300. https://doi.org/10.1017/S1352465812000793

Marsden, Z., Lovell, K., Blore, D., Ali, S., & Delgadillo, J. (2018a). A randomized controlled trial comparing EMDR and CBT for obsessive-compulsive disorder. Clinical Psychology & Psychotherapy, 25(1), e10–e18. https://doi.org/10.1002/cpp.2120

Nardo, D., Högberg, G., Looi, J. C. L., Larsson, S., Hällström, T., & Pagani, M. (2010). Gray matter density in limbic and paralimbic cortices is associated with trauma load and EMDR outcome in PTSD patients. Journal of Psychiatric Research, 44(7), 477–485. https://doi.org/10.1016/j.jpsychires.2009.10.014

Novo Navarro, P., Landin-Romero, R., Guardiola-Wanden-Berghe, R., Moreno-Alcázar, A., Valiente-Gómez, A., Lupo, W., García, F., Fernández, I., Pérez, V., & Amann, B. L. (2018). 25 years of Eye Movement Desensitization and Reprocessing (EMDR): The EMDR therapy protocol, hypotheses of its mechanism of action and a systematic review of its efficacy in the treatment of post-traumatic stress disorder. Revista de Psiquiatría y Salud Mental (English Edition), 11(2), 101–114. https://doi.org/10.1016/j.rpsmen.2015.12.002

Otgaar, H., Houben, S. T. L., Rassin, E., & Merckelbach, H. (2021). Memory and eye movement desensitization and reprocessing therapy: A potentially risky combination in the courtroom. Memory, 29(9), 1254–1262. https://doi.org/10.1080/09658211.2021.1966043

Pagani, M., Di Lorenzo, G., Monaco, L., Daverio, A., Giannoudas, I., La Porta, P., Verardo, A. R., Niolu, C., Fernandez, I., & Siracusano, A. (2015). Neurobiological response to EMDR therapy in clients with different psychological traumas. Frontiers in Psychology, 6. https://doi.org/10.3389/fpsyg.2015.01614

Roberts, B. R. T., Fernandes, M. A., & MacLeod, C. M. (2020). Re-evaluating whether bilateral eye movements influence memory retrieval. PLOS ONE, 15(1), e0227790. https://doi.org/10.1371/journal.pone.0227790

Santarnecchi, E., Bossini, L., Vatti, G., Fagiolini, A., La Porta, P., Di Lorenzo, G., Siracusano, A., Rossi, S., & Rossi, A. (2019). Psychological and Brain Connectivity Changes Following Trauma-Focused CBT and EMDR Treatment in Single-Episode PTSD Patients. Frontiers in Psychology, 10, 129. https://doi.org/10.3389/fpsyg.2019.00129

Shapiro, F. (1989). Efficacy of the eye movement desensitization procedure in the treatment of traumatic memories. Journal of Traumatic Stress, 2(2), 25.

Solomon, R. M., & Shapiro, F. (2008). EMDR and the Adaptive Information Processing Model: Potential Mechanisms of Change. Journal of EMDR Practice and Research, 2(4), 315–325. https://doi.org/10.1891/1933-3196.2.4.315

Talbot, D. (2021). Examination of Initial Evidence for EMDR as a Treatment for Obsessive-Compulsive Disorder. Journal of EMDR Practice and Research, 15(3), 167–173. https://doi.org/10.1891/EMDR-D-21-00004

Valiente-Gómez, A., Moreno-Alcázar, A., Treen, D., Cedrón, C., Colom, F., Pérez, V., & Amann, B. L. (2017). EMDR beyond PTSD: A Systematic Literature Review. Frontiers in Psychology, 8, 1668. https://doi.org/10.3389/fpsyg.2017.01668