With more than a quarter-century of credibility, Eye Movement Desensitisation and Reprocessing (EMDR) stands as an evidence-based treatment. The query “Does EMDR work?” has evolved into a grander question: “How does EMDR work?”
There are a number of theories but the one that makes sense to me is in the article Eye Movement Desensitization and Reprocessing and Slow Wave Sleep which I will try and summarise as I understand it (all errors of interpretation are mine, email your corrections).
The Overwhelm Loop: Emotional vs. Rational
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 (the amygdala and hippocampus become overstimulated). In other words, when you are triggered, the rational thinking part of your brain can’t control the emotional part of your brain. This is why when you get triggered, you can’t think and you feel overwhelmed.
Unprocessed Stuck Memories
Traumatic memories are “stuck” in the amygdala-hippocampal complex and when triggered, they seem to occur in the present. “Stuck” memories are thought to be unprocessed memories.
The Sleep Connection: EMDR and Dream Sleep
During sleep, we process and consolidate memories from the hippocampus to the neocortex. Normal, less traumatic memories, don’t become “stuck”, because at night when we dream (Rapid Eye Movement or REM phase), these are moved out of the amygdala-hippocampal complex and processed by the rest of the brain. This is one of the reasons we feel so much better after a good night’s sleep.
Neuroscientists propose that what happens during REM (dream) sleep happens during EMDR.
During EMDR, therapists move your eyes from side to side whilst getting you to focus on a fragmented traumatic memory or emotion. Much like when your eyes move side to side when you dream.
EMDR’s Brain Synchrony
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. EMDR temporarily slows your over-stimulated amygdala down and synchronises your brain waves helping you process the traumatic memory.
Trauma Unraveled
This suggests that during EMDR therapy the traumatic memories are continuously “reactivated, replayed and encoded into existing memory networks”. In other words, EMDR helps traumatic memories become “unstuck” and processed like normal, less traumatic memories.
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 of an EEG tracing that show how the bilateral movements mimic slow-wave sleep. Click to see it in the original article.
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.
A Glimpse at the Future
EMDR bilateral stimulation (moving your eyes side to side) mimics slow-wave sleep, calming the amygdala and allowing it to synchronise with the rest of the brain. Thus allowing your brain to process a traumatic memory. What we do in therapy (move your eyes side to side), is what you do every night when you dream.
Remember, curiosity keeps us learning, so delve into the original article if you’re intrigued. Stay open to new revelations.
Stay curious, always.
I look forward to hearing from you.
Kind regards,
Desne Doman
Clinical Psychologist MAPS
EMDR Accredited Practitioner.
References:
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
GREAT EXPLANATION OF EMDR. I FEEL MORE CONFIDENT ABOUT TALKING TO MY PSYCHIATRIST AND THERAPIST ABOUT IT. THANK YOU SO MUCH FOR THE VERY LUCID AND UNDERSTANDABLE COMMENTARY, AND THE LINKS TO SO MUCH ELSE BY OTHER PRACTITIONERS AND JOURNALS.
Phenominal explaination. I understand the fact that other evidence may prove parts of this to be incorrect. However, I’ve been practicing EMDR with my therapist since last August, and almost every time I ask her how the change i felt immediately happened? I am completely enthralled with EMDR now. I enrolled back in college and and am going to be a therapist so I too can share this with others.
I have PTSD and have had EMDR treatment for recurring nightmares. After 2 sessions my nightmares stopped! So I can and do support this treatment as certainly for me,it worked. If you are considering this treatment do not procrastinate as that will only keep the trauma going. Have EMDR as soon as it is offered.
I had EMDR for PTSD. The PTSD was to do with my suffering a brain injury. The EMDR was fantastic, but it uncovered that I have Complex PTSD from my childhood. I want to get EMDR for that in the future and hope to try it for Prolonged Grief that I have had for over thirteen years. Great article.
I was told I would need 4 to 6 months of EMDR once a week. That seems like a very long time. Is that outside what is normal or expected? Please speak about the expected time it takes to go through all 8phases of EMDR. I really appreciated your explanation of the therapy itself!
Hi Anne, On the face of it, 4 to 6 months of EMDR once a week would be outside normal expectations. EMDR is not talk therapy, it involves rapid processing
EMDR and particularly EMDR 2.0 is very effective and efficient, here at EMDR Therapy Sydney we average 8-10 sessions. It would take longer if you had several severe traumas.
Warmly,
Desne
Thank you so much for sharing this accessible explanation!
I am a psychologist and an EMDRIA Approved Consultant in Los Angeles. Echoing what Des wrote, this rapid treatment can also take longer . . . for very valid reasons.
EMDR can be quite short-term for single incident trauma, such as a car accident or witnessing a crime. However, for complex trauma that was ongoing, or occurred in childhood, or multiple traumas which compounded one another, it is often necessary to spend more time up front doing what we call “resourcing” so it is easier to be present in your body – and feel confident even noticing the disturbing material.
It is also frequently necessary to process multiple targets of disturbance which may or may not be related, although each target might represent a cluster of events.
4- 6 months of weekly EMDR therapy can often. accomplish more than years of talk therapy. You will know that it is working. I often have people who came in for one thing get so much relief that they say, “Well, there’s this other thing that has been bothering me, can we do that, too?”
Wishing all the best to you in your healing journey!
Thanks for this explanation! I am confused about the REM and SLS points in the paper and this article, as my understanding is that REM is associated with beta-like waves that more or less mirror your alert brain waves. The slow delta waves are happening when we are in deeper non-REM sleep. Wouldn’t it make more sense that EMDR is harnessing the work of REM in-session and that we are essentially doing the ground work for the reprocessing during our natural non-REM sleep later in the night and that this is where the reconsolidating is mainly happening from the A-H complex to the neocortex? This makes much more sense to me. I had two sessions of EDMR and was unsure about how it worked, but it did, even in such a short time.
Hi Emma, Thanks so much for your comment—it’s awesome to see you diving into the science behind EMDR! You’ve raised a really interesting point about REM and slow-wave sleep (SWS), so let me break it down in a simple way.
You’re right: REM sleep is linked to beta-like brainwaves, which are similar to when we’re awake, and it’s when a lot of emotional memory processing happens. Slow-wave sleep (SWS), on the other hand, is all about those deep delta waves and helps consolidate memories, moving them from the hippocampus to the neocortex for long-term storage.
Here’s how EMDR might tie into this:
During EMDR: The eye movements or other bilateral stimulation might mimic REM sleep, helping your brain start processing emotional memories and reducing their intensity. It’s like giving your brain a little nudge to start healing.
After EMDR: Your brain keeps working on those memories during SWS, especially at night. This is when the real “cleanup” happens—memories get filed away properly, and their emotional charge fades even more.
So, you’re spot on! EMDR could be doing the groundwork during the session (like REM), and your brain finishes the job during deep sleep (SWS). That’s probably why you felt better so quickly—your brain was already doing its thing!
Thanks again for sharing your thoughts and your experience. It’s amazing how just a couple of sessions can make such a difference, right? Keep asking great questions—it’s how we all learn!