Eye Movement Desensitization and Reprocessing
Eye Movement Desensitization and Reprocessing (EMDR) is a psychotherapeutic approach developed by Francine Shapiro to resolve symptoms resulting from exposure to a traumatic or distressing event, such as rape. Clinical trials have demonstrated EMDR's efficacy in the treatment of post-traumatic stress disorder (PTSD).  It has shown to be more effective than some alternative treatments and equivalent to cognitive behavioral and exposure therapies (see effectiveness sections below). Although some clinicians may use EMDR for various problems, its research support is primarily for disorders stemming from distressing life experiences.
The theoretical model underlying EMDR treatment hypothesizes that EMDR works by processing distressing memories. EMDR is based on a theoretical information processing model which posits that symptoms arise when events are inadequately processed, and can be eradicated when the memory is fully processed. It is an integrative therapy, synthesizing elements of many traditional psychological orientations, such as psychodynamic, cognitive behavioural, experiential, physiological, and interpersonal therapies.
EMDR's most controversial aspect is an unusual component of dual attention stimulation, such as eye movements, bilateral sound, or bilateral tactile stimulation.  The contention is the effective elements of cognitive behavioral therapy, desensitization and reprocessing, have been rebranded with eye movements as a novel therapy.  As such some individuals have criticized EMDR and consider the use of eye movements to be completely unnecessary.. However, more recent studies have found that the eye movement in EMDR correlate with decreases in heart rate, skin conductance, and an increased finger temperature .  This is consistent with earlier research on physiological changes associated with EMDR .  Also recent studies that have removed eye movement from the method have found the procedure less effective .

# Description of therapy
According to Shapiro's theory, when a traumatic or distressing experience occurs, it may overwhelm usual ways of coping and be inadequately processed; it is then dysfunctionally stored in an isolated memory network.  When this memory network is activated, the individual may re-experience aspects of the original event, often resulting in inappropriate overreactions. This explains why people who have experienced or witnessed a traumatic incident may have recurring sensory flashbacks, thoughts, beliefs, or dreams.  An unprocessed incident can retain high levels of intensity, even though many years may have passed.
EMDR uses a structured eight-phase approach and addresses the past, present, and future aspects of the dysfunctionally stored memory. During the processing phases of EMDR, the client attends to the disturbing memory in multiple brief sets of about 15-30 seconds, while simultaneously focusing on the dual attention stimulus (e.g., therapist-directed lateral eye movements, alternate hand-tapping, or bilateral auditory tones).  Following each set of such dual attention, the client is asked what associative information was elicited during the procedure.  This new material usually becomes the focus of the next set.  This process of alternating dual attention and personal association is repeated many times during the session.
EMDR works directly with memory networks and enhances information processing by forging associations between the distressing memory and more adaptive information contained in other memory networks.  It is thought that the distressing memory is transformed when new connections are forged with more positive and realistic information.  This results in a transformation of the emotional, sensory, and cognitive components of the memory so that, when it is accessed, the individual is no longer distressed.  Instead he/she recalls the incident with a new perspective, new insight, resolution of the cognitive distortions, elimination of emotional distress, and relief of related physiological arousal.
When the distressing or traumatic event is an isolated incident, the symptoms can often be cleared with one to three EMDR sessions.  But when multiple traumatic events contribute to a health problem - such as physical, sexual, or emotional abuse, parental neglect, severe illness, accident, injury, or health-related trauma that result in chronic impairment to health and well-being - the time to heal may be longer.

## Therapy process
- Phase I: In the first sessions, the patient's history and an overall treatment plan are discussed. During this process the therapist identifies and clarifies potential targets for EMDR. Target refers to a disturbing issue, event, feeling, or memory for use as an initial focus for EMDR. Maladaptive beliefs are also identified.
- Phase II: Before beginning EMDR for the first time, it is recommended that the client identify a safe place, an image or memory that elicits comfortable feelings and a positive sense of self. This safe place can be used later to bring closure to an incomplete session or to help a client tolerate a particularly upsetting session.
- Phase III: In developing a target for EMDR, prior to beginning the eye movements, a snapshot image is identified that represents the target and the disturbance associated with it. Using that image is a way to help the client focus on the target, a negative cognition (NC) is identified - a negative statement about the self that feels especially true when the client focuses on the target image. A positive cognition (PC) is also identified - a positive self-statement that is preferable to the negative cognition.
- Phase IV: The therapist asks the patient to focus simultaneously on the image, the negative cognition, and the disturbing emotion or body sensation. Then the therapist usually asks the client to follow a moving object with his eyes; the object moves alternately from side to side so that the client's eyes also move back and forth. After a set of eye movements, the client is asked to report briefly on what has come up; this may be a thought, a feeling, a physical sensation, an image, a memory, or a change in any one of the above. In the initial instructions to the client, the therapist asks him to focus on this thought, and begins a new set of eye movements. Under certain conditions, however, the therapist directs the client to focus on the original target memory or on some other image, thought, feeling, fantasy, physical sensation, or memory. From time to time the therapist may query the client about his current level of distress. The desensitization phase ends when the SUDS (Subjective Units of Disturbance Scale) has reached 0 or 1.
EMDR also uses a three-pronged approach, to address past, present and future aspects of the targeted memory.

## Vocabulary of terms
The following basic terms are described in Shapiro's 2001 text
- Information Processing:  During information processing, a physiologically-based system sorts new (perceptual) information, makes connections between new information and other information already stored in associated memory networks, encodes the material, and stores it in memory.
- Adaptive Resolution:  When information processing is complete, learning takes place, and information is stored in memory with appropriate emotion.  The new information is therefore available to guide future action.
- Dysfunctionally Stored Information:  When information processing is incomplete, the information is not connected to more adaptive information, and it is stored in a memory network with a high negative emotional charge. It can cause reactivity and can be the cause of various symptoms.
- Reprocessing:  During reprocessing in EMDR, new associative links are forged between dysfunctionally stored information and adaptive information, resulting in complete information processing and adaptive resolution.
- Memory Networks:  Memory networks are neurobiological associations of related memories, sensations, images, thoughts, and emotions.
- Target Memory:  The target memory is the memory of a distressing or traumatic event, which still causes current distress, and which has been selected to be targeted during EMDR treatment.
- Memory Components: All components of the target memory are accessed during Phase Three to ensure that the memory network is fully activated.  These components include the image, cognitions, emotions, and body sensations.
- VOC (Validity of cognition) scale: VOC ratings are used in EMDR to measure baseline validity of the positive cognition during Phase Three, and to assess progress being made, where 1 = not true, and 7 = completely true.
- SUD (Subjective units of disturbance) scale:  SUD ratings are used in EMDR, exposure therapies, and other treatments to measure baseline emotional or physical pain and also to assess progress being made. This is a personal measurement of distress, where 0 = no distress, and 10 = worst distress possible.
- Interweave: The interweave is a specific strategy used by the clinician to assist processing if the client appears to be having difficulty accessing more adaptive information.  Ideally, the interweave contains needed information that would have been available except for blockage of inner pathways by trauma responses.

# Empirical evidence regarding EMDR
Over the last 18 years evidence has accumulated that supports EMDR as an effective treatment for problems associated with distressing memories.   The evidence about whether it works will be first considered on the basis of what scientific committees from around the world have concluded, then EMDR will be compared to typical treatments, medication and traditional exposure based treatments.
Effectiveness: EMDR compared to typical treatments
EMDR has been demonstrated to have significant advantages over usual treatment for PTSD in an HMO setting, and improvement was maintained at a six month follow-up.  EMDR has been shown to be effective on measures of trauma, depression and anxiety in women who had been sexually abused as children.
Effectiveness: EMDR compared to medication
To date EMDR has only been compared directly to medication in one study. Van der Kolk et al. found EMDR to be more effective than fluoxetine, an SSRI in treating trauma, especially six months post-treatment. The study also suggests a role for SSRIs as a reliable first-line intervention.
Effectiveness: EMDR versus traditional exposure treatments (studies in the last 5 years)
EMDR proved significantly better than stress inoculation training with prolonged exposure in a study with 24 participants diagnosed with post traumatic stress disorder. Although reduction in symptom severity was equivalent post treatment, at follow-up, EMDR lead to greater gains on both self report and observer rated measures of PTSD and self report measures of depression.  In another study of 22 participants who had also been diagnosed with PTSD, both EMDR and prolonged exposure were found to be effective post treatment.  Participants receiving EMDR appeared to improve quicker in that 70% had reached a level of clinically significant improvement in PTSD after three EMDR sessions compared to only 17% in the prolonged exposure condition.  
EMDR was also found to work more quickly than exposure based treatments in a larger trial with 105 participants. At a fifteen-month follow-up, gains for both treatments were generally maintained. The only significant difference at follow-up was an improvement in depression according to an independent observer in favour of EMDR.
EMDR and Prolonged Exposure (PE) were found to be equivalently efficacious and both superior to a waitlist control in a controlled trial of 74 female rape victims.  Measures used by blind assessors included PTSD, depression, dissociation and state anxiety.  Unlike other studies noted above, there was no difference between the active treatments in rate of improvement.  The study met the highest criteria for methodological rigour proposed by Foa and Meadows.
The improvements in EMDR over CBT are not limited to English speaking cultures. In a study involving Iranian girls who had been sexually abused, EMDR was found to be significantly more efficient than CBT.  
Although most studies show EMDR and CBT to be about the same, one study reported an opposite effect. Analysis of changes in symptoms for the 15 participants who completed treatment indicated greater reductions on symptom measures of avoidance and re-experiencing for imaginal exposure treatment over EMDR but equivalent reductions on hyper arousal.  However there were no differences between the two treatments in the intent to treat analysis and no differences between the two treatments on percentage of people with PTSD diagnosis at follow-up.
Effectiveness: meta-analysis 
EMDR was found in the first ever meta-analysis of PTSD to be equally effective as exposure therapy and SSRIs. Two recent meta-analyses concluded that traditional exposure therapy and EMDR have equivalent effects both immediately after treatment and at follow-up.The most recent meta-analysis looked at 38 randomized controlled trials for PTSD treatment and concluded that the first-line psychological treatment for PTSD should be Trauma-Focused CBT or EMDR.

# Other applications of EMDR
Although controlled research has concentrated on the application of EMDR to PTSD, a number of studies have investigated EMDRs efficacy with other anxiety disorders as well as numerous reports of diverse clinical applications.
Case reports have been published on the application of EMDR to the treatment of (a) personality disorders ( Fensterheim, 1996a; Korn & Leeds, in press; Manfield, 1998), (b) dissociative disorders ( Fine & Berkowitz, 2001; Lazrove & Fine, 1996; Paulsen, 1995; Twombly, 2000), ( c ) a variety of anxiety disorders ( De Jongh & Ten Broeke, 1998; Goldstein & Feske, 1994; Lovett, 199; Nadler, 1996; Shapiro & Forrest, 1997) and (d) somatoform disorders ( Brown, Mcgoldrick, & Buchanan, 1997; Grant & Threlfo, 2002).  However, controlled research is needed to evaluate the efficacy of these applications.
In designing the research the entire EMDR protocol should be evaluated within the context of the potential special needs of the particular population.  For instance, Brown et al. (1997) evaluated the application of EMDR in seven consecutive cases of Body Dysmorphic Disorder (BDD), which has been reported to necessitate 8 to 20 sessions of cognitive behavior therapy with varying success rates ( Neziroglu, McKay, Todaro, & Yaryura-Tobias, 1996; Beale et al., 1996; Wilhelm, Otto, Lohr, & Deckersbach, 1999).  In contrast, Brown et al. reported the elimination of BDD in five of the seven consecutive cases in one to three sessions of EMDR through the processing of the etiological memory.  While this result indicates the EMDR holds promise for the treatment of this disorder, future controlled research should include a greater number of sessions in order to evaluate the more comprehensive clinical picture.
EMDR can work on a multitude of problems that are less complex than PTSD.  One of these is uncomplicated depression.  The EMDR Casebook by Philip Manfield, PH.D. has documented several case studies in which EMDR was used.  In the case about uncomplicated depression, Manfield was able to help his client, George, resolve several childhood issues that have plagued his adult life. Moreover, EMDR can work for diseases such as postpartum depression.  By having the client target a distinctive memory and work through it with a series of eye movements, the client is then able to achieve a positive cognition.
EMDR has been used on children to treat a variety of conditions. 
It has been used in the treatment of children who have experienced trauma and complex trauma. 
It is often cited as a component in the treatment of Complex Post Traumatic Stress Disorder, emotional dysregulation, and in the treatment of children exposed to chronic early maltreatment that is related to Attachment disorder.  It is recognised by the UK National Institute for Health & Clinical Excellence (NICE) Guidelines as a treatment for PTSD.
Full article: EMDR 12 Years after Its Introduction: Past and Future Research Francine Shapiro; Mental Research Institute, Palo Alto, CA Journal of Clinical Psychology, Vol. 58(1), 1-22 (2002) 2002 John Wiley & Sons, Inc.

# How does EMDR work?
There is no definitive explanation as to how EMDR works.  There is some empirical support for three explanations regarding how an external stimulus such as eye movement can facilitate the processing of traumatic memories.   The first hypothesis views PTSD as a failure by the individual to process episodic memory; the bilateral eye movements involved in EMDR facilitate interaction between the brain's hemispheres, which then improves the processing of trauma-related memories.  This hypothesis is supported by a study that tested the effects of eye movement on the ability to retrieve episodic memory. The study found better recall following a horizontal eye movement task compared to that following no eye movement or a vertical eye movement task.
A second hypothesis suggests that eye movements facilitate processing of trauma memories by activating a neurobiological state similar to REM sleep wherein associative links to episodic memories are formed and these memories are then integrated into general semantic networks.  Stickgold proposed that PTSD occurs when an event is sufficiently arousing to prevent its transfer from encoding from an episodic memory to a semantic memory. As a result of high arousal levels, associations between the traumatic event and other related events fail to develop. He argues that the attentional redirecting in EMDR induces a neurobiological state similar to REM sleep.  He then reviews the research that suggests that REM sleep enhances processing of episodic memory through the preferential activation of weak associative and semantic links. Thus in EMDR trauma-related information that is closely associated with a target event is weakened and ancillary information loosely related to the event is strengthened, allowing the integration of trauma-related material with other loosely associated events in the persons life.  Support for this argument comes from a study that found that, compared to eye fixation, eye movement promoted attentional flexibility and increased preparedness to process metaphorical material.
A third hypothesis links the eye movements in EMDR with the orienting response.  MacCulloch and Feldman argued that eye movements trigger the investigation component of the orienting response, which can either produce avoidance behaviour or inhibit avoidance responses.  Inhibiting avoidance behaviour includes reducing both negative somatic responses and cognitive changes that would allow fresh investigatory behaviour to commence. MacCulloch and Feldman proposed that initially when danger is identified there is a negative affect response. However a second part of the orienting response is to scan for further danger, and this investigatory reflex seems to accompany a positive physical response. In the authors opinion, eye movement induces this investigatory reflex and produces a relaxation response. A relaxation response was, in fact, found in a study that investigated the autonomic responses of participants when they were engaged in an eye movement task as part of EMDR treatment and when participants focused on negative memories while engaging in eye movement .  However there is not a differential effect of eye movement on a relaxation response when participants focused on positive memories. This supports the hypothesis that eye movements are an orienting response mechanism rather than a simple relaxation mechanism.
Further data consistent with the orienting response hypothesis was the finding that EMDR treatment was associated with increased left pre-frontal hemisphere activation. Investigatory and approach behavior has been shown to be associated with the anterior left hemisphere regions.

# Controversy
EMDR has created a good deal of controversy since its inception. Many doubt that the eye movements have a central role, that the mechanisms of eye movements are speculative and the theory leading to the practice is non-falsifiable and not amenable to scientific enquiry 
Although one meta-analysis concluded that EMDR is not as effective, or as long lasting as specific exposure therapy .  Several other researchers using meta-analyses have found EMDR to be at least equivalent in effect size to specific exposure therapies .

## Are eye movements necessary?
Early studies looking at the contribution of eye movements to treatment effectiveness in EMDR found that eye movements are not necessary to the treatment effect . However recent evidence suggests that this may not be the case because when eye movement is removed from the method, the procedure is less effective.. MacCulloch (2006) argued that the eye movements make a unique contribution to EMDR, whereas Salkovskis (2002) believes that the eye movements are irrelevant and that the effectiveness of the procedure is solely due to it sharing similar properties to cognitive behavioral therapies, such as desensitization and exposure .

## Similarity to desensitization and exposure treatments
Several papers have highlighted key differences between EMDR and traditional exposure treatments.  A recent study has found key differences in the crucial processes of EMDR and traditional exposure.  Unlike traditional exposure where reliving responses in the treatment session was found to be associated with post session improvement reliving responses were not associated with any improvement in EMDR.  Rather greater improvement in PTSD symptoms was found to be associated with distancing responses given in session.