What is Bilateral Stimulation in EMDR? A Deep Dive into Eye Movements and Techniques
Introduction
Eye Movement Desensitisation and Reprocessing (EMDR) therapy stands as a widely recognised, evidence-based approach for treating trauma, post-traumatic stress disorder (PTSD), and various other psychological conditions. At the heart of EMDR lies bilateral stimulation—a unique therapeutic component that distinguishes it from other therapeutic interventions. But what is bilateral stimulation in EMDR? This fundamental element involves alternating sensory stimuli that target both hemispheres of the brain, potentially facilitating the processing and integration of distressing memories. This blog post explores the mechanics of bilateral stimulation, particularly through eye movements, and examines its role in mental health treatment.
Key points:
EMDR is an evidence-based therapy primarily used for trauma treatment
Bilateral stimulation forms the core mechanism of EMDR therapy
Understanding bilateral stimulation helps explain how EMDR works to process traumatic memories
Different types of bilateral stimulation can be used during EMDR therapy sessions
Overview of EMDR Therapy
EMDR Eye Movements Explained
EMDR therapy represents a comprehensive psychotherapeutic approach aimed at alleviating distress associated with traumatic memories. Unlike traditional talk therapies, EMDR incorporates a structured eight-phase protocol that includes history-taking, preparation, assessment, desensitisation, installation, body scan, closure, and reevaluation. Central to several of these phases are rhythmic eye movements that clients perform while simultaneously focusing on traumatic memories.
Francine Shapiro developed EMDR therapy in 1987 after noticing that her own distressing thoughts diminished in intensity when she moved her eyes from side to side while walking through a park. This serendipitous discovery led to rigorous development and research, transforming an initial observation into a comprehensive therapeutic protocol. Originally focused solely on eye movements, the approach has evolved to include additional forms of bilateral stimulation while maintaining its core principles.
EMDR has gained significant recognition for its efficacy in treating PTSD, with organisations including the World Health Organisation, the American Psychological Association, and the Australian Psychological Society acknowledging it as an evidence-based intervention for trauma. Research demonstrates that EMDR can produce significant improvement in trauma symptoms, often in a relatively brief treatment period compared to some traditional approaches. Its applications have expanded beyond PTSD to include anxiety disorders, depression, phobias, and other conditions with traumatic components. For more details on its applications, you can visit organisations such as the Australian Psychological Society.
Key points:
EMDR follows a structured eight-phase approach to trauma resolution
Developed by Francine Shapiro in 1987 after a chance observation about eye movements
Recognised by major health organisations as evidence-based trauma treatment
Applications extend beyond PTSD to various trauma-related conditions
Source: Wikipedia on EMDR
Source: Trauma Therapy Overview
What is Bilateral Stimulation in EMDR?
What is Bilateral Stimulation in EMDR
Bilateral stimulation (BLS) refers to rhythmic, alternating sensory input that stimulates both the left and right hemispheres of the brain in a back-and-forth pattern. In EMDR therapy, this stimulation typically occurs through guided eye movements, alternating sounds, or tactile sensations like tapping. This bilateral component serves as the distinctive mechanism that differentiates EMDR from other therapeutic approaches, allowing for the unique processing of traumatic material.
BLS functions by engaging neural networks across both hemispheres of the brain, potentially enhancing communication between these regions. This cross-hemisphere activity bears striking similarities to what occurs naturally during Rapid Eye Movement (REM) sleep—a state in which emotional processing and memory consolidation naturally occur. By mimicking these natural processes in a controlled therapeutic environment, BLS may activate the brain's innate healing mechanisms.
The therapeutic role of bilateral stimulation appears to facilitate the "unsticking" of traumatic memories from the emotional centres of the brain, particularly the amygdala-hippocampus complex, where distressing memories often remain stored in fragmented, emotionally charged forms. During BLS, clients can access these memories while simultaneously engaging in a dual-attention task (the bilateral stimulation), which seems to reduce the emotional intensity of the memory. This dual-attention state allows the traumatic material to be processed and integrated into more adaptive memory networks. For more about BLS, you can refer to the resources provided by Phoenix Australia.
Key points:
Bilateral stimulation involves rhythmic sensory input targeting both hemispheres of the brain
The mechanism parallels natural processes that occur during REM sleep
BLS helps "unstick" traumatic memories from emotional brain centres
The dual-attention task reduces emotional intensity while processing memories
Source: Aspire Counseling on BLS
Source: Relationship Store Blog
Understanding EMDR Eye Movements
EMDR Eye Movements Explained
The most recognised form of bilateral stimulation in EMDR involves rhythmic eye movements. During a typical session, a therapist guides the client to follow a visual stimulus—often the therapist's fingers or a light bar—that moves horizontally from side to side. While maintaining this visual tracking, the client simultaneously focuses on a targeted traumatic memory, including associated thoughts, emotions, and bodily sensations. These sets of eye movements typically last 20-30 seconds, after which the therapist checks in with the client about any changes in the memory's intensity or associated distress.
While eye movements remain the original and most widely recognised form of bilateral stimulation, EMDR practitioners frequently incorporate alternative modalities to accommodate client preferences and needs. These alternatives include:
Tactile stimulation: The therapist may tap alternately on the client's hands, knees, or shoulders, or the client may hold small vibrating devices called "tappers" or "pulsers"
Auditory stimulation: Alternating tones delivered through headphones, with sounds moving from left to right ear
Combined approaches: Some therapists use devices that simultaneously provide visual, auditory, and/or tactile stimulation
These eye movements and other forms of bilateral stimulation appear effective because they activate similar neural mechanisms to those naturally engaged during REM sleep. During REM sleep, the brain processes emotional experiences and integrates new information into existing memory networks—a process quite similar to what EMDR aims to accomplish. The alternating stimulation may also tax working memory, reducing the vividness and emotional charge of traumatic memories while creating a state of heightened adaptive information processing. For a deeper understanding of how BLS functions, check out insights from Nicole Franco Counseling.
Key points:
Eye movements involve following a stimulus horizontally while focusing on traumatic material
A typical set lasts 20-30 seconds, followed by therapist check-ins
Alternative modalities include tactile tapping and alternating auditory tones
These techniques mimic natural neural processes similar to REM sleep
Source: Nicole Franco Counseling
Source: Choosing Therapy on BLS
Does EMDR Use Tapping or Audio?
Does EMDR Use Tapping or Audio
While EMDR was originally developed using eye movements, the therapy has evolved to include various forms of bilateral stimulation, including tapping and audio. EMDR therapists regularly utilise these alternative modalities based on client preferences, specific therapeutic goals, and practical considerations during treatment sessions.
Tactile stimulation, commonly known as "tapping," can be administered in several ways:
Therapist-directed taps alternating between the client's knees, hands, or shoulders
Self-administered tapping by the client following the therapist's guidance
Hand-held devices ("tappers" or "pulsers") that vibrate alternately in each hand
Audio bilateral stimulation typically involves:
Headphones delivering alternating tones between the left and right ears
Specially designed EMDR audio recordings with rhythmic, alternating sounds
Apps or devices that provide customisable bilateral audio patterns
The selection of a particular modality often depends on specific therapeutic considerations. For example, tapping may be preferred during grounding or resource installation phases of therapy, particularly when clients need additional sensory input to maintain present-moment awareness. Audio stimulation might be chosen for clients who find visual tracking difficult or tiring, or for those with visual impairments. Some therapists find that certain modalities work better for specific types of traumatic material or during different phases of the EMDR protocol.
Research indicates that all forms of bilateral stimulation—visual, tactile, and auditory—appear effective in facilitating therapeutic processing. Most importantly, client comfort and preference play significant roles in modality selection, as the client's engagement with the process is essential for therapeutic success. Many EMDR therapists become adept at combining modalities or switching between them as needed throughout the treatment process.
Key points:
EMDR utilises both tapping and audio as alternatives to eye movements
Tactile stimulation includes therapist tapping, self-tapping, or vibrating devices
Audio stimulation delivers alternating tones through headphones
All modalities show effectiveness, with selection based on client needs and preferences
Source: Aspire Counseling Blog
Source: Nicole Franco on BLS
How EMDR Rewires the Brain
How EMDR Rewires the Brain
EMDR's bilateral stimulation appears to influence brain function at both neurobiological and psychological levels. Neuroimaging studies have demonstrated that EMDR therapy produces measurable changes in brain activity, particularly in regions associated with emotional regulation and memory processing. During bilateral stimulation, researchers have observed decreased activity in the amygdala (the brain's alarm system) and increased activity in prefrontal cortical regions responsible for rational thinking and emotional regulation.
This modulation of brain activity may explain EMDR's effectiveness in treating traumatic memories. Typically, traumatic memories are stored in fragmented, emotionally charged forms that bypass normal memory processing. They remain "stuck" in the limbic system without proper integration into contextual memory networks. Bilateral stimulation appears to facilitate communication between these emotional brain regions and higher cortical areas, allowing for adaptive reprocessing of the traumatic material.
The scientific evidence supporting EMDR's neurobiological mechanisms continues to grow. Research indicates that EMDR therapy:
Helps shift traumatic memories from implicit (emotional, sensory) memory systems to explicit (narrative, contextual) memory systems
Reduces hyperarousal in the sympathetic nervous system, allowing for more effective emotional processing
Facilitates memory reconsolidation, a process in which memories become temporarily malleable and can be updated with new, less distressing information
Promotes hemispheric integration, potentially enhancing communication between brain regions that may have become disconnected due to trauma
Multiple randomised controlled trials demonstrate EMDR's effectiveness for trauma treatment, with symptom reduction often occurring more rapidly than in traditional talk therapies. A meta-analysis published in the Journal of Clinical Psychology found that 84-90% of single-trauma victims no longer met criteria for PTSD after only three 90-minute sessions. These findings point to EMDR's ability to efficiently reorganise neural networks associated with traumatic memories. For more insights, consider referencing the National Center for PTSD for additional context on EMDR’s applications.
Key points:
Bilateral stimulation modulates activity in the amygdala and prefrontal cortex
EMDR helps reprocess fragmented traumatic memories into integrated memory networks
The therapy promotes communication between emotional and rational brain regions
Scientific evidence demonstrates both neurobiological changes and clinical effectiveness
Source: PMC Article on EMDR
Source: Choosing Therapy on BLS
Frequently Asked Questions about EMDR
Is EMDR therapy safe?
EMDR is generally considered safe when administered by a properly trained therapist. As an evidence-based therapy, EMDR has been extensively researched and has demonstrated minimal adverse effects. However, the therapy does involve accessing potentially distressing memories, which can temporarily increase emotional discomfort during sessions. A qualified EMDR therapist creates safety protocols and employs stabilisation techniques to manage this discomfort. Individuals with certain conditions such as seizure disorders, severe dissociative disorders, or serious heart conditions should discuss potential contraindications with their healthcare providers before beginning EMDR.
How many sessions are typical?
The number of EMDR sessions varies based on individual factors, including the complexity of trauma history, co-occurring mental health conditions, and personal resilience factors. For single-incident traumas (such as a car accident), research indicates that 6-12 sessions may be sufficient for significant symptom reduction. More complex trauma histories, particularly those involving childhood trauma or multiple traumatic events, typically require longer treatment durations. The eight-phase EMDR protocol ensures thorough preparation and processing, with the therapist and client collaboratively determining when treatment goals have been met. To learn more about the therapy process, see the resource on What Happens in an EMDR Session.
What can clients expect during an EMDR session?
A typical EMDR session begins with the therapist creating a safe therapeutic environment. Clients are first taught stabilisation techniques to manage potential distress. During the processing phases, the client focuses on a targeted memory while simultaneously engaging in bilateral stimulation. The therapist guides this process without interpreting or directing the client's experience. Throughout the session, the therapist conducts periodic "check-ins" to assess changes in the memory's emotional intensity, associated body sensations, and emerging insights. Sessions typically last 60-90 minutes and end with closure exercises to ensure the client feels grounded before leaving. Between sessions, clients may notice continued processing as the brain integrates the therapeutic work.
Does EMDR work for conditions other than PTSD?
While EMDR was initially developed for trauma treatment, research supports its effectiveness for various conditions that have traumatic or distressing memories as contributing factors. These include anxiety disorders, depression, grief, phobias, and pain disorders. The therapy appears particularly effective when present symptoms connect to earlier distressing life experiences. However, EMDR represents one of many evidence-based approaches, and its suitability depends on individual assessment and treatment planning by qualified mental health professionals.
Key points:
EMDR is considered safe when conducted by trained professionals
Treatment typically ranges from 6-12 sessions for single traumas, longer for complex trauma
Sessions involve memory processing with bilateral stimulation and periodic check-ins
EMDR may benefit various conditions beyond PTSD, particularly those with trauma components
Conclusion
What is Bilateral Stimulation in EMDR
Bilateral stimulation forms the cornerstone of EMDR therapy, providing a unique mechanism through which traumatic memories can be processed and integrated. Through rhythmic eye movements, alternating sounds, or tactile sensations, bilateral stimulation engages both hemispheres of the brain, facilitating communication between regions that may have become disconnected through trauma. This bilateral component appears to help the brain access its natural healing capacity, allowing traumatic memories to shift from their fragmented, emotionally charged state to a more integrated, contextualised form.
The journey through understanding bilateral stimulation reveals the sophisticated neurobiological underpinnings of EMDR therapy. By mimicking natural processes similar to REM sleep while simultaneously focusing on traumatic material, EMDR creates a unique dual-attention state that appears to facilitate adaptive information processing. This process can help reduce the emotional intensity of traumatic memories without erasing them, allowing individuals to recall difficult experiences without being overwhelmed by them.
For those experiencing the effects of trauma, understanding the role of bilateral stimulation in EMDR provides insight into how this therapeutic approach differs from traditional talk therapies. While many therapeutic approaches focus primarily on changing thoughts or behaviours, EMDR addresses the neurobiological foundations of trauma, potentially offering a path to healing that aligns with how the brain naturally processes emotional experiences.
Key points:
Bilateral stimulation is the distinctive mechanism in EMDR therapy
It facilitates communication between brain hemispheres and memory networks
The process helps transform emotionally charged memories into integrated, manageable forms
Understanding BLS provides insight into EMDR's unique approach to trauma healing
Further Resources
For those interested in learning more about EMDR therapy and bilateral stimulation, several reputable resources provide in-depth information:
EMDR International Association (EMDRIA) - Offers comprehensive information about EMDR therapy, research updates, and therapist directories. Visit their site here.
Phoenix Australia - Centre for Posttraumatic Mental Health - Provides evidence-based resources on trauma treatment, including EMDR. More details can be found here.
Australian Psychological Society - Features clinical guidelines and information about evidence-based trauma therapies. Check out their overview here.
Peer-reviewed journals such as the Journal of EMDR Practice and Research and the Journal of Traumatic Stress regularly publish new findings about EMDR's mechanisms and applications. These scientific resources can provide deeper insights into the neurobiological foundations of bilateral stimulation.
If you would like to know more about EMDR therapy or speak with a registered psychologist about whether it might be suitable for your circumstances, you can contact Salt & Earth Psychology for more information. Understanding the available treatment options is an important step in making informed decisions about mental health care.
