Eye Movement Desensitisation and Reprocessing is now over 25 years old and is considered an evidenced based treatment. The question “Does it work?” has now been replaced by the bigger question “How does it work?”. Bear in mind we don’t know how Cognitive Behavioral Therapy works.
There are a number of theories but the one that makes sense to me is in the following article https://www.frontiersin.org/articles/10.3389/fpsyg.2017.01935/full#B46 which I will try and summarise as I understand it (all errors of interpretation are mine, email your corrections).
Essentially, as I understand it…
When we experience something overwhelming and relive the traumatic event there is reduced control of the pre-frontal cortex over the activated amygdala and hippocampus. It is posited that traumatic memories are “stuck” in the amygdala-hippocampal complex. Thus the traumatic memory, when triggered, seems to occur in the present.
We also know that during sleep we process and consolidate memories from the hippocampus to the neocortex.
During EMDR, therapists perform bilateral movements in front of the eyes whilst getting the client to focus on a fragmented traumatic memory or emotion.
EEG tracings show that the eye movements (much like in REM sleep) elicit a synchronisation of all cortical activity at a frequency in the delta range like slow-wave sleep.
This suggests that during EMDR therapy the traumatic memories are continuously “reactivated, replayed and encoded into existing memory networks”.
To quote the article:
“In fact, we posit that bilateral stimulation mimics the low-frequency stimulation typical of SWS (slow wave sleep), inducing a depotentiation of the AMPA receptors of amygdalar synapses, which in turn lead to a weakening of the traumatic memory. This reduction of the over-potentiation of amygdalar synapses makes traumatic memory more accessible, and facilitates the connection between emotional memory and episodic memory, thus promoting a shift of memory to associative and neocortical areas.”
Essentially, the bilateral movements used in EMDR rapidly allows us to process stuck traumatic memories as we would normally do with less traumatic memories during sleep.
They have a great picture an EEG tracing that show of how the bilateral movements mimic slow wave sleep Click on image to see it in the original article.
FIGURE 1. EEG tracing upon eye movements during an eye movement desensitization and reprocessing (EMDR) session. Note the slow wave sleep (SWS)-like frequency from the beginning to the end of bilateral stimulation.
I probably have not done the article justice so if you enjoy knowing how stuff works like me, have a look at the article.
Remember research regularly overturns previous evidence, perhaps a better explanation will emerge soon. Stay curious.
I look forward to hearing from you.
Clinical Psychologist MAPS
EMDR Accredited Practitioner.
Keywords: EMDR, mechanism of action, eye movements, sleep, slow wave sleep, REM, orienting response, working memory
Pagani M, Amann BL, Landin-Romero R and Carletto S (2017) Eye Movement Desensitization and Reprocessing and Slow Wave Sleep: A Putative Mechanism of Action. Front. Psychol. 8:1935. doi: 10.3389/fpsyg.2017.01935
Pagani, M., Di Lorenzo, G., Verardo, A. R., Nicolais, G., Monaco, L., Lauretti, G., et al. (2012). Neurobiological correlates of EMDR monitoring – An EEG study. PLOS ONE 7:e45753. doi: 10.1371/journal.pone.0045753