After treatment, individuals with PTSD show a reduction in avoidant behaviours and cognitive distortions and report that the targeted traumatic memory has become less vivid and emotional.
A review of 26 randomized controlled trials of EMDR concluded that EMDR significantly reduced the experience of depression, anxiety, and subjective distress in individuals with PTSD. The outcome reported that compared to psychotropic medication, EMDR has been shown to be more successful and efficient in achieving symptom reduction.
A variety of long-lasting cognitive benefits have been reported by clients following EMDR therapy. These benefits of EMDR therapy include improved cognitions, enhanced episodic memory retrieval and increased accuracy of the recalled memory. Other benefits include better attentional orienting, somatic awareness, mindfulness, and free association.
There are four main theories as to why EMDR works so effectively:
Theory 1: EMDR taxes working memory
The first explanation for why EMDR works is that it interacts with working memory processes. EMDR is a dual-attention procedure that requires a client to divide their attention between the bilateral stimulation and an aversive memory. The aversive memory is held in your Working Memory., and evidence supports that performance deteriorates when two tasks make demands there at the same time.
Theory 2: EMDR increases interhemispheric connectivity
A second leading theory describing EMDR’s benefit is that Eye Movements toward repetitive Bilateral Stimulation either auditory, tactile, or visual, boost interhemispheric communication between the right and left cerebral hemispheres as they do in your Repeated Eye Movement (REM) sleep. Your REM Sleeps acts as a filtering system in the same way as you would clean up data on a hard drive.
Theory 3: EMDR adjusts the storage of traumatic memories
Memory consolidation research shows that cognitive aspects of memories are processed through the hippocampus, whereas emotional components of memories are mostly stored in the amygdala. During deep state sleep, memory traces from the hippocampus and amygdala combine to form one memory with both cognitive and emotional components. Animal studies show the integration of this memory reduces the negative emotional charge of the recalled event.
Theory 4: EMDR produces an orienting response and de-arousal
An orienting response is a physiological reflex that occurs in response to a a real or perceived adverse event. Eye Movement induces physiological de-arousal to the stimulus and induces relaxation due to decreased electro- dermal responses and heart rate. Studies show a decrease in oxygenated hemoglobin concentration in the lateral prefrontal complex that correlates with symptom reduction
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