Imagine you are trying to put a traumatic event behind you. Your therapist asks you to recall the memory in detail while rapidly moving your eyes back and forth, as if you are watching a high-speed Ping-Pong match. The sensation is strange, but many therapists and patients swear by the technique, called eye movement desensitization and reprocessing (EMDR). Although skeptics continue to question EMDR's usefulness, recent research supports the idea that the eye movements indeed help to reduce symptoms of post-traumatic stress disorder (PTSD).
Much of the EMDR debate hinges on the issue of whether the eye movements have any benefit or whether other aspects of the therapeutic process account for patients' improvement. The first phase of EMDR resembles the start of most psychotherapeutic relationships: a therapist inquires about the patient's issues, early life events, and desired goals to achieve rapport and a level of comfort. The second phase is preparing the client to mentally revisit the traumatic event, which might involve helping the person learn ways to self-soothe, for example. Finally, the memory processing itself is similar to other exposure-based therapies, minus the eye movements. Some experts argue that these other components of EMDR have been shown to be beneficial as part of other therapy regimens, so the eye movements may not deserve any of the credit. New studies suggest, however, that they do.
In a January 2011 study in the Journal of Anxiety Disorders, for example, some patients with PTSD went through a session of EMDR while others completed all the components of a typical EMDR session but kept their eyes closed rather than moving them. The patients whose session included eye movements reported a more significant reduction in distress than did patients in the control group. Their level of physiological arousal, another common symptom of PTSD, also decreased during the eye movements, as measured by the amount of sweat on their skin.
One of the ways EMDR's eye movements are thought to reduce PTSD symptoms is by stripping troubling memories of their vividness and the distress they cause. A study in the May 2012 Behaviour Research and Therapy examined the effectiveness of using beep tones instead of eye movements during EMDR. The researchers found that eye movements outperformed tones in reducing the vividness and emotional intensity of memories.
Those studies relied on self-reports of symptom severity, however, so researchers at Utrecht University in the Netherlands sought more objective confirmation of a change in vividness by also measuring participants' reaction times to fragments of a previously viewed picture. The work, published online in July 2012 in Cognition and Emotion, compared two groups of participants who had committed one detailed picture to memory. When asked to recall the picture and focus on it mentally, one group was instructed to perform eye movements. That group had slower reaction times to the familiar picture fragments in a subsequent memory test, and subjects reported that the vividness of the recalled pictures had decreased.
These studies and others from the past several years have helped validate EMDR—so much so that the American Psychiatric Association, the International Society for Traumatic Stress Studies, and the Departments of Defense and of Veterans Affairs have deemed it an effective therapy.
Yet how it works remains unclear. Chris Lee, a psychologist at Murdoch University in Australia and co-author of the January 2011 study, says a common theory is that EMDR takes advantage of memory reconsolidation: every time we recall a memory, it is changed subtly when we file it away again. For instance, parts of the memory may be left out, or new ideas and feelings are stored alongside of it. Making eye movements during recall, Lee explains, may compete with the recollection for space in our working memory, which causes the trauma memory to be less intense when recalled again.
“Our experiments clearly show that negative autobiographical memories are very rich in sensory detail, and by pairing them with eye movements, they lose this sensory richness,” Lee says. “People describe that the memories become less vivid and more distant, that they seem further in the past and harder to focus on. What follows after this distancing is a reduction in the associated emotional levels.” In other words, the traumatic memory stays, but its power has been diminished.