This is a good introduction (1) into EMDR, the theory behind it and how it works in reprocessing the past!

“EMDR: A Chance Discovery
Eye Movement Desensitization and Reprocessing (EMDR) was developed by psychologist, Francine Shapiro, in 1987, following a chance observation she made while out walking. Shapiro noticed that the disturbing thoughts she was contemplating at the start of her walk had disappeared suddenly.

In addition, when Shapiro brought those thoughts back to mind,
they were not as disturbing as they were before. Specifically, Shapiro noticed the rapid and diagonal motion of her eyes as she walked and contemplated disturbing thoughts. Again, while walking, the original thoughts lost their disturbing effect.

Shapiro began making eye movements deliberately, while concentrating on disturbing thoughts and memories, with the same result. The disturbances disappeared. Shapiro branched out and experimented by intentionally combining disturbing thoughts with eye movements. Shapiro enlisted friends, colleagues, and
students in an effort to explore and standardize her approach to processing memories with eye movements.

Over the course of six months, with the help of seventy individuals, Shapiro developed a standard procedure of using eye movements that consistently alleviated her subjects’ complaints. In 1989, the first controlled treatment outcome study of EMDR for Post Traumatic Stress Disorder (PTSD) was published in the Journal of Traumatic Stress. Later, in 1990, Shapiro discovered that other forms of bi-lateral stimulation, tactile taps, auditory tones, and
visual lights, had the same affect on processing as eye movements (Shapiro, 2001).

EMDR is a well-studied therapeutic approach for treating individuals who are struggling in the aftermath of traumatic incidents (Solomon, Solomon, & Heide, 2009). EMDR has been
studied across fourteen different populations; thirty studies indicate positive treatment outcomes when utilizing EMDR treatment techniques (Shapiro 2001). In twenty controlled studies, EMDR
proved to be more effective in treating trauma than pharmaceuticals and other forms of psychotherapy (Van der Kolk, Spinazzola, Blaustein, Hopper, Hopper, & Korn, et al., 2007).

A dozen randomized studies testing the eye movements in isolation have found them to be associated with facilitated memory retrieval, reduced negative emotions, increased vividness of mental imagery, and attentional flexibility (Sack et al. 2008).

EMDR has been validated as an evidence-based approach and included in the Substance Abuse and Mental Health Services Administration’s National Registry of Evidence-based Programs and Practices (Gomez, 2013). The California Evidence-Based Clearing house for Child Welfare has accepted EMDR therapy as an evidence-based approach for children (Gomez, 2013). Also, EMDR has been recommended as a first line of treatment in numerous practice guidelines, including those of the American Psychiatric Association (2004).
EMDR is a comprehensive psychotherapy that is compatible with all contemporary theoretical orientations. According to Shapiro (2001), EMDR is an integration of a multitude of theories: psychodynamic, behavior, cognitive, experiential, hypnotic, and systems theory. EMDR is based on the notion that traumatic experiences affect all domains of thought, emotion, sensation, and physical parts of the self. EMDR is a front-line trauma treatment applicable to a broad range of clinical issues (Shapiro & Laliotis, 2011).

EMDR: The Mechanism of Change

The precise neurobiological basis of EMDR is unknown. One hypothesis is that the visual, tactile, or auditory bilateral stimulation alternately stimulates the right and left sides of the brain, forcing a shift of attention across the midline (Solomon, Solomon, & Heide, 2009).
Another hypothesis is that the repetitive redirecting of attention in EMDR induces a REM-like sleep state, which facilitates the activation of the episodic memories. The memories are then
processed and integrated into neural networks in the neo-cortex as semantic (narrative) memory (Stickgold, 2002).

Elofsson, von Scheele, Theorell, & Sondergaard (2008) explored the
physiological correlates of eye movements during EMDR and found that during EMDR, eye movements activate the parasympathetic system and inhibit the sympathetic system, a response similar to the brain’s physiological response during REM sleep.

Another hypothesis was made following a neuro-imaging study of EMDR. Brain scans were administered before and after EMDR treatment of six PTSD subjects who each received three EMDR sessions. The investigators reported an increase in bilateral activity that modulates the limbic system and helps individuals perceive the difference between real and imagined threat.

The increase in brain activity suggests a decrease in hyper-vigilance. Results of this study also found an increase in prefrontal lobe metabolism that suggested a greater ability to make sense of incoming sensory stimulation (Levin, Lazrove, & Van der Kolk, 1990).

EMDR: Guided by the Adaptive Information Processing Model
EMDR is guided by the adaptive information processing (AIP) model. In the AIP model, disturbing memories are typically processed by thinking, talking, and dreaming about the experience. As the brain processes a memory, the memory is transferred from the limbic system to the left cerebral cortex and is stored with other memories. Stored memories can later be retrieved to understand new experiences (Solomon, Solomon, & Heide, 2009).

When an individual experiences a traumatic incident, the associated thoughts and feelings are highly charged and emotionally overwhelm the brain’s capacity to process information. Therefore, it is difficult for the brain to integrate traumatic incidents into memories, connect them with similar memories, and store them in the left cerebral cortex. Rather, the memory of the experience may not be fully processed and instead dysfunctionally stored in the limbic system indefinitely (Solomon, Solomon, & Heide, 2009).

Dysfunctionally stored traumatic memories can lead to maladaptive coping strategies. A dysfunctionally stored memory remains stored with all of the emotions, physical sensations, and beliefs that were part of the original event. When activated, the unprocessed memory is experienced as it was originally, with the emotions, physical sensations, and beliefs fundamentally unchanged. Regardless of how much time has elapsed or whether the person remembers it, the memory remains unaltered and provides the basis of current responses and behaviors (Shapiro& Laliotis, 2011).

For example, many children have experienced humiliation sometime in school. Some children are able to integrate the event with other events, both positive and negative, and the memory is largely forgotten. For other children, the experience of the humiliation is perceived as being overwhelming and traumatic. The memory of the humiliating event does not get processed; it is stored with all of the original emotions, sensations, and beliefs associated with the event. Stored dysfunctionally, activation of the memory becomes the foundation for inappropriate, or maladaptive, responses in the future.

When a similar experience occurs in the future, it triggers the dysfunctionally stored memory, which then automatically colors the child’s perception of the present experience (Shapiro & Laliotis, 2011).
Hence, the AIP model guides therapists to identify the child’s relevant past experiences that are perpetuating maladaptive patterns of response, as evidenced by the child’s symptoms,
and to process those memories to the level of adaptive resolution. In the process, the part of the memory that is useful is incorporated, that which is useless is discarded. Once resolved, the
memory of the event serves to guide the child appropriately in the future (Shapiro & Laliotis, 2011).

The unprocessed components of memory are accessed in a systematic way during EMDR processing. Shapiro & Laliotis (2011) describe the process stating: the targeted memory that is “frozen” in time becomes “unfrozen,” and new associations are made with the previously disconnected adaptive information related to survival,
positive experiences, and one’s sense of identity. As this assimilation occurs, new insights and emotions emerge and the earlier affect states and perceptions are generally discarded.

Clients are no longer subject to the same emotional volatility, distorted perceptions and intense somatic responses, and instead experience a new sense of self that is congruent with their current life situation. The overall goal of EMDR is to address the individual’s current problems of daily living by accessing the dysfunctionally stored memories that are being triggered by the client’s current life conditions, and engage the natural neural processes by which these memories are transmuted into appropriately stored memories. (p.193)

Since EMDR is an integrative psychotherapy approach, guided by the AIP model, therapists can incorporate techniques and interventions from other disciplines, as necessary, to meet the clinical needs of the child. According to Shapiro and Laliotis (2011):
the hallmark of EMDR therapy is the emphasis on physiologically stored memory as the primary foundation of pathology, and the application of specifically targeted information processing the primary agent of change. EMDR a distinct integrative
psychotherapy approach used to address both individual and systemic issues. (p.192)