EMDR – Part III: Theoretical Causes of PTSD
Theorists have attempted to explain the brain mechanisms behind Post Traumatic Stress Disorder. One theory, the Adaptive Information Processing Theory postulates that traumatic memories are a problem with the mind’s information processing system (EMDR, Shapiro, xiv).
Under ordinary circumstances, when a negative event occurs, we think about it, dream about it, obsess over it, discuss it until it no longer bothers us. That information is then “filed away” and used as a resource to inform our future actions. Much of this processing and filing away, it is believed, occurs during REM phase of sleep.
However, a severe trauma appears to imbalance this process in the brain making usual processing become “stuck” leaving and individual to re-experience images, sounds, smells, nightmares, etc. from the negative event.
It is believed that the procedural elements of Eye Movement Desensitization and Reprocessing trigger the information processing necessary to file away the traumatic memory and release the individual from re-experiencing the event (Shapiro, EMDR Basic Principles pp 30-31).
The Amygdala and the Hippocampus
Here’s what we think is happening: Brain imaging indicates two brain structures – the amygdala and hippocampus play active parts in PTSD. The amygdala, it is believed, is involved with how we process fear. studies indicate this structure is hyperactive in people with PTSD.
The hippocampus plays an important role in the formation of memory. Some refer to it as the “narrative” part of the brain where memories are stored after the emotion has been extracted. There is some evidence that in people with PTSD there is a loss of volume in this structure. In addition, some studies have shown changes in size of hippocampus and amygdala before and after EMDR.
Brain Imaging Before and After
An Italian Neuroimaging Study used PET Scans, MRI’s, SPECT and EEG technologies to study the efficacy of EMDR. They studied the brain structures implicated in PTSD including:
Pre-frontal cortex – important for problem solving, learning is less activated when patients are exposed to reminders of trauma
Amygdala – evaluates incoming information of emotional nature
Hippocampus – Categorizes experiences. Decreases in size in traumatized populations
Neuroimaging of brain of female with Post Traumatic Stress Disorder. The red areas indicate overactivity in the brain.
Same patient after four ninety-minute EMDR sessions. (From Brain SPECT Imaging in PTSD and EMDR, Daniel G. Amen, MD)
In total, we don’t know HOW EMDR works for sure, we just know through exhaustive studies, that it does work for many clients.
What Does EMDR Look Like?
Unlike some therapeutic methods to treat trauma, EMDR does not require a detailed talking about the traumatic experience or an immersing of reliving of the event (EMDR, Shapiro, xiv). EMDR is not like hypnosis, in that the person is required to be fully present and aware of the process.
EMDR occurs in 8 different phases or steps. The client guides the content and depth of the interaction and the therapist serves as a facilitator. After taking a thorough history, the client choses what they would like to work on. The process is explained. In phase four, the therapist guides the client in “bilateral stimulation” of the brain. This is done by either eye movements (back and forth), or tapping or other means.
In summary, EMDR is a very effective method of treating clients with PTSD. Speak with your therapist about it if you feel it could be beneficial to you.