How EMDR
Therapy Works
EMDR therapy works at the level of memory storage itself, activating the brain’s own processing system to resolve experiences that have become stuck. Understanding the mechanism explains why the results are lasting.
Adaptive Information
Processing
EMDR therapy is grounded in the Adaptive Information Processing (AIP) model, developed by Dr Francine Shapiro. The model proposes that the brain has an innate system designed to digest experiences and integrate them into existing memory networks — extracting what is useful, resolving what is distressing, and filing the material away in a form that no longer generates emotional interference.
When an experience overwhelms this system — through intensity, perceived threat, shame, or the absence of adequate support at the time — the memory becomes stored in an unintegrated form. It retains the original emotions, physical sensations, and beliefs from the moment of encoding. The processing system froze rather than completed its work.
These frozen memories do not stay dormant. They activate in response to current triggers that resemble the original experience, flooding the nervous system with material from the past as if it were happening now. EMDR therapy activates the brain’s information processing system to complete the work it left unfinished.
“It is not the event itself that causes lasting distress, but the way the memory was stored. Resolve the storage, and the distress resolves with it.”
Adaptive Information Processing Model (Shapiro, 1995)An event exceeds the brain’s capacity to process it in the moment. Trauma, loss, humiliation, threat, or repeated adverse experience.
The memory is frozen with its original emotional charge, physical sensations, and negative beliefs intact. “I am not safe.” “I am not good enough.” “It was my fault.”
Current situations activate the frozen memory. The nervous system responds as if the original event is recurring, generating distress disproportionate to the present.
The memory is fully digested, placed in the past, and stripped of its emotional charge. A more adaptive belief takes its place. The past no longer floods the present.
The eight phases
of EMDR therapy
EMDR therapy follows a structured eight-phase protocol developed by Dr Francine Shapiro and now used worldwide. The phases are not rigid sequential boxes but an integrated clinical framework that ensures thorough assessment, adequate preparation, and complete processing before treatment concludes.
A thorough clinical history is taken. The therapist identifies the presenting difficulties, the experiences that may underlie them, and develops a treatment plan. This includes mapping the target memories that will be processed in subsequent sessions.
The client is introduced to the EMDR therapy process, bilateral stimulation, and what to expect. Stabilisation and resourcing work is done to ensure the client has adequate psychological capacity to engage with processing. No trauma material is accessed in this phase.
The target memory is identified and its components are structured: the image, the negative belief it reinforces, the desired positive belief, the associated emotions and body sensations, and its current level of disturbance (SUD) and positive belief strength (VOC).
The core processing phase. The client holds the activated target memory in awareness while bilateral stimulation is applied. Associations emerge naturally and are followed until the memory’s disturbance reduces to zero. The therapist facilitates without directing the process.
Once disturbance has reduced, the positive belief identified in Phase Three is paired with the target memory and strengthened using bilateral stimulation until it feels fully true. This replaces the old negative belief at the level of the memory itself.
The client scans their body for any residual physical tension or discomfort connected to the target memory. If any disturbance is found, it is processed further using bilateral stimulation. Complete processing includes the resolution of somatic as well as cognitive and emotional material.
Each session is closed carefully, regardless of whether processing has been completed. The client is stabilised, briefed on what to expect between sessions, and given resources to use if disturbance arises. Processing sometimes continues naturally between appointments.
At the start of subsequent sessions, previously processed targets are reviewed to confirm integration and identify any material that has since emerged. The treatment plan is updated accordingly, and new targets may be identified as earlier processing clears the way.
Bilateral stimulation:
why it works
Bilateral stimulation is the element of EMDR therapy that distinguishes it from all other psychological treatments. It refers to any form of alternating left-right sensory input applied rhythmically while the client holds a target memory in mind.
The most compelling scientific hypothesis for why bilateral stimulation produces change concerns its relationship to REM (Rapid Eye Movement) sleep — the phase during which the brain naturally processes the emotional residue of daily experience. During REM, the eyes move rapidly from side to side while the hippocampus replays recent experiences and the amygdala’s emotional charge gradually diminishes. Memory traces become labile, and emotional learning is consolidated.
Bilateral stimulation in EMDR therapy activates the same neural circuitry. Meta-analytic research has confirmed that eye movements play a specific and significant role in the changes EMDR therapy produces — they are not incidental to the treatment. The processing also engages the right hemisphere, which plays a dominant role in processing negative emotional experience, achieving integration that purely verbal, left-hemisphere approaches cannot reach.
“The nature and location of brain changes associated with EMDR, as well as the method’s modus operandi and results, suggest EMDR is consistent with the type of integrated bottom-up approach recommended by neuroscientists.”
Grant, M. (2015). Neuropsychology of Chronic Pain & EMDR. The Neuropsychotherapist.The original and most researched form of bilateral stimulation. The client follows a moving light bar or the therapist’s hand as their eyes track from side to side. The most extensively validated method in the research literature.
Small vibrating devices held in each hand pulse alternately, delivering tactile bilateral stimulation. Effective for clients who find eye movements uncomfortable, and well-suited to online delivery.
Alternating tones delivered through headphones stimulate each hemisphere in turn. Particularly useful for online EMDR therapy sessions where tactile or visual methods may be less accessible.
A self-administered form of tactile bilateral stimulation in which the client crosses their arms over their chest and taps alternately. Used in resourcing and between-session stabilisation work.
The neuroscience of
EMDR therapy
SPECT scan and neuroimaging research has mapped the brain changes that EMDR therapy produces. These changes are measurable, consistent, and explain the subjective experience of resolution that clients report.
The amygdala is the brain’s threat-detection centre. In individuals with unprocessed memories, it fires as if the original threatening situation is recurring whenever a reminder is encountered. SPECT scan evidence confirms reduced amygdala activation following EMDR therapy processing. Stimuli that previously triggered distress no longer do so.
The hippocampus encodes memories with temporal context — marking them as past. When hippocampal encoding is incomplete, the brain cannot clearly distinguish a past event from a present threat. EMDR therapy re-engages hippocampal processing, so the memory is filed as historical rather than continuing to activate as current danger.
The prefrontal cortex governs emotional regulation, rational appraisal, and executive function. Under threat, it is functionally inhibited by amygdala activation — the neurological basis of feeling overwhelmed and unable to think clearly. EMDR therapy restores prefrontal availability by resolving the amygdala’s threat response at its source.
Following EMDR therapy processing, the anterior cingulate cortex produces what clients consistently describe as the distancing effect: previously distressing material feels less charged, less immediate, less personally significant. The memory becomes accessible as information without remaining intrusive as experience.
Reduction in temporal lobe activation following EMDR therapy is associated with decreased intrusion of episodic memory — the involuntary replaying of distressing events. The memory that used to arrive unbidden is no longer intruding. It can be recalled deliberately without triggering the original distress response.
EMDR therapy and
the sleeping brain
One of the most compelling explanations for how EMDR therapy works is its parallel with REM sleep — the stage of sleep during which the brain naturally processes the emotional residue of the day’s experiences.
During REM, the eyes move rapidly from side to side. Simultaneously, the hippocampus replays recently encoded memories and the amygdala’s emotional response gradually reduces. Memories are consolidated, their emotional charge diminishes, and what is useful is integrated into existing memory networks. The brain is essentially digesting experience.
Bilateral stimulation in EMDR therapy appears to activate the same hippocampal-amygdala memory reconsolidation circuitry. When a frozen memory is held in awareness during bilateral stimulation, the same reduction in amygdala activation and hippocampal re-engagement occurs — but directed precisely at the specific unprocessed material generating distress, rather than whatever the sleeping brain selects to process spontaneously.
This is why the gains from EMDR therapy are lasting. Reprocessed memories do not return to their unprocessed state. The change is structural, not symptomatic.
During REM sleep, the eyes move laterally while the hippocampus replays experiences and amygdala activation gradually diminishes. Emotional memories lose their charge, adaptive learning consolidates, and experience is integrated into existing memory networks with its useful content retained and its emotional intensity resolved.
During EMDR therapy, bilateral stimulation activates analogous neural circuitry while the client holds a specific target memory in dual awareness. The same reduction in amygdala activation, hippocampal re-engagement, and memory reconsolidation occurs — but directed precisely at the unprocessed material generating psychological distress. The process is targeted rather than incidental.
Ready to begin
the process?
Dr JC Coetzee · PhD · Clinical Psychologist · Advanced EMDR Therapy Specialist