Bilateral Stimulation and EMDR: How It Works and Why It Helps
If you've read anything about EMDR, you've probably seen the phrase "bilateral stimulation" and wondered what it actually involves. Maybe you've pictured a therapist waving a finger back and forth and thought it sounded a little strange. It's a fair reaction. The method does look unusual from the outside.
This page explains what bilateral stimulation is, how it fits into EMDR therapy, what the research does and doesn't show, and what it feels like to sit in the chair (or on your own couch, if we work online). I aim to give you enough to make an informed decision about whether EMDR is worth exploring.
What is bilateral stimulation?
Bilateral stimulation means alternating left-right input to the body's senses. In EMDR, it usually takes one of three forms:
Eye movements. You follow my hand, a light bar, or a moving dot on a screen as it travels side to side.
Tactile stimulation. You hold two small pulsers that vibrate in alternating hands, or you tap your own knees or shoulders left and right.
Auditory stimulation. You hear tones or soft sounds that alternate between your left and right ear through headphones.
Each one does the same job. It gives part of your attention something steady and rhythmic to track while another part of your attention stays with a difficult memory. EMDR clinicians call this "dual attention." You're connected to the past while staying clearly anchored in the present room.
That second part matters. Trauma memories tend to pull people fully back into the original experience. Bilateral stimulation helps keep one foot in today, which is often what makes it possible to revisit something painful without being swept away by it.
Where EMDR came from
EMDR stands for Eye Movement Desensitization and Reprocessing. Psychologist Francine Shapiro developed it in the late 1980s, after noticing that her own distressing thoughts seemed to lose their charge when her eyes moved rapidly back and forth during a walk. She tested the idea, published her first controlled study in 1989, and spent the following decades refining it into a structured therapy.
Early on, the method relied only on eye movements. Over time, clinicians found that tapping and tones could work too, which made EMDR accessible to people who can't comfortably do eye movements and, later, to clients working by video.
Today EMDR is one of the most researched trauma treatments available. The World Health Organization recommends it for post-traumatic stress in adults and children, and it appears in the PTSD treatment guidelines of the U.S. Department of Veterans Affairs and Department of Defense, among others.
Why would moving your eyes help with trauma?
This is the most common question I get, and it deserves an honest answer: researchers are still working out exactly why bilateral stimulation helps. There are a few leading explanations, and they aren't mutually exclusive.
The working memory explanation. This one has the strongest experimental support. Your working memory, the mental "desk space" you use to hold things in mind, has limited capacity. When you hold a painful memory while also tracking eye movements, the two tasks compete for that space. The memory tends to become less vivid and less emotionally intense. When the memory is later stored again, it seems to be stored in that softer form. Dozens of laboratory studies have found this effect.
The orienting response. Rhythmic side-to-side movement may trigger a mild "what's that?" response in the nervous system, followed by a relaxation once the brain registers there's no threat. Some researchers believe this pairing of a hard memory with a calm body helps the memory lose its alarm.
The sleep connection. Others have noted a resemblance between EMDR eye movements and the rapid eye movements of REM sleep, a phase in which the brain consolidates and integrates memories. This idea is interesting but less established than the working memory research.
Shapiro's own framework, called the Adaptive Information Processing model, describes trauma as an experience that got "stuck" before the brain could fully process it. The memory stays stored with the images, sensations, and beliefs it had at the time, such as "I'm not safe" or "It was my fault." EMDR, in this view, helps the brain finish the job, linking the old memory to what you know now.
There's also a fair scientific debate worth knowing about. Some researchers have argued that EMDR works mainly because of the memory exposure, with the eye movements adding little. Several analyses have found that eye movements do contribute a meaningful additional effect, though the debate isn't completely closed. What isn't in much dispute is that EMDR as a whole is an effective treatment for PTSD.
How bilateral stimulation fits into an EMDR session
Bilateral stimulation isn't the whole of EMDR. It's one tool inside a structured, eight-phase approach. A lot of good work happens before any processing begins.
History and treatment planning. We talk about what brings you in, what you hope will change, and which memories or patterns seem to be driving current difficulties. We also look at your history with enough care to decide whether, and when, EMDR makes sense.
Preparation. This phase gets less attention online than it deserves. We build your capacity to calm yourself and to come back to the present. This might include a calm-place exercise, breathing practices, or bringing to mind people and qualities that make you feel steady. Here, bilateral stimulation is used slowly and gently to strengthen those positive states. We also agree on a stop signal, so you can pause anything at any moment.
Assessment. We choose a specific memory and identify its parts: the image that stands out, the negative belief attached to it ("I'm powerless"), the belief you'd rather hold ("I can protect myself now"), the emotions, and where you feel it in your body. You rate how distressing it feels on a scale of 0 to 10, and how true the positive belief feels on a scale of 1 to 7.
Desensitization. This is where most of the bilateral stimulation happens. You bring up the memory and follow the movements, taps, or tones for a set time, often somewhere between 20 seconds and a minute or so. Then we stop, you take a breath, and you simply notice what came up. It might be an image, a feeling, a body sensation, a different memory, or nothing much. We go again from there. You don't need to analyze or explain. Your mind tends to lead the way.
Installation. Once the memory feels much less charged, we pair the positive belief with the memory and use bilateral stimulation to strengthen it.
Body scan. You notice whether any tension or discomfort remains in your body while holding the memory in mind. Anything left over becomes the next focus.
Closure. Every session ends with you feeling settled, whether or not the memory is fully processed. We use the calming skills from preparation and talk about what you might notice in the days ahead.
Reevaluation. At the next session, we check how the memory feels now and what shifted between sessions, then decide what comes next.
Speed and style aren't one-size-fits-all
How bilateral stimulation is delivered changes depending on what we're doing.
When we're building calm and inner resources, the stimulation is slow, and the sets are short. The goal is to deepen a good feeling without stirring up other material. When we're processing a hard memory, the stimulation is usually faster, and the sets are longer.
The type of stimulation is also your choice. Some people find eye movements the most effective. Others feel more grounded with tapping, especially if eye movements are uncomfortable, if they have certain eye conditions, or if they tend to drift away from the present. Some prefer tones. We may try more than one before settling on what works for you, and we can switch mid-session if something isn't helping.
What bilateral stimulation feels like
People describe it in very different ways. Some notice their thoughts moving quickly from one image to another, as if flipping through a photo album. Others feel strong emotions rise and then pass, like a wave. Some feel physical sensations shift, a tight chest loosening or warmth spreading through the hands. And sometimes not much seems to happen for a few sets before things begin to move.
A few things are worth knowing:
You stay awake and in control. EMDR is not hypnosis. You remain aware of where you are; you can talk at any time, and you can stop whenever you choose.
You don't need to describe everything. Unlike some talk therapies, EMDR doesn't require you to narrate every detail of a trauma. Many clients find this a relief.
Feelings can get stronger before they ease. That's a normal part of processing, and it's one reason the preparation phase matters.
Processing can continue between sessions. Some people notice vivid dreams, new memories, or shifts in mood for a day or two. This is usually a sign the brain is still integrating, and we talk about how to handle it.
The butterfly hug and self-administered bilateral stimulation
You may come across the "butterfly hug," a simple self-tapping technique. You cross your arms over your chest, rest your hands near your collarbones, and alternate gentle taps left and right, like a butterfly's wings. It was developed by EMDR therapists Lucina Artigas and Ignacio Jarero while working with survivors of Hurricane Pauline in Mexico in the late 1990s, and it's now used around the world, including with children and in group settings after disasters.
I often teach clients the butterfly hug or simple knee tapping as a self-soothing tool, used slowly while bringing to mind something calming. It can help with everyday stress or with settling after a hard day.
One caution, though. Using bilateral stimulation to calm yourself is very different from using it to work through traumatic memories on your own. Trauma processing is best done with a trained EMDR clinician who can help pace the work and keep you safe if difficult material surfaces. Apps and videos that promise DIY trauma processing tend to skip the preparation that makes EMDR safe.
Can bilateral stimulation work online?
Yes. In online EMDR, I can use an on-screen moving dot that you follow with your eyes, guide you through self-tapping, or use alternating tones through your headphones. Studies of virtual EMDR have found outcomes broadly similar to in-person treatment, and many clients find it easier to settle into the work from a familiar, private space.
A few practical things help: a private room, a laptop or larger screen rather than a phone for eye movements, a reliable internet connection, and headphones. We also make a plan for what happens if the connection drops, so you're never left mid-process without support.
What EMDR can help with
EMDR was developed for post-traumatic stress, and that remains where the evidence is strongest. Many clients come to EMDR for:
single traumatic events such as accidents, assaults, medical emergencies, or sudden losses
the long shadow of childhood experiences, including neglect, emotional abuse, or growing up in chaos
relationship betrayal and its aftermath
performance anxiety and fear that seems out of proportion to the present situation
painful beliefs about yourself that don't budge with insight alone, such as "I'm not enough" or "I'm always on my own"
Research on EMDR for conditions like anxiety, depression, and chronic pain is growing, though it's less established than for PTSD. I'll always be straightforward with you about what the evidence suggests for your situation.
When EMDR needs a slower or adapted approach
EMDR is safe for most people when done well, but some situations call for extra care, more preparation, or a different starting point. These include:
significant dissociation, such as frequently losing time or feeling detached from yourself
active crisis, self-harm, or safety concerns
substance use that's currently out of control
major life instability that leaves little room for intensive emotional work
certain medical considerations, including seizure history or some eye conditions, which may mean choosing tapping or tones instead of eye movements
None of these automatically rule out EMDR. They mean we'd build stability first and move at a pace that protects you.
How long does EMDR take?
It varies widely. A single, clearly defined traumatic event in someone with good support can sometimes be processed in a handful of sessions. Long-standing patterns rooted in childhood or many layered experiences generally take longer, often with more time spent in preparation. In our first conversations, I can give you a realistic sense of what to expect.
Choosing an EMDR therapist
If you're considering EMDR, it's reasonable to ask a therapist:
whether they've completed an EMDRIA-approved EMDR training
whether they're an EMDRIA Certified Therapist or working toward certification
how much of their practice involves EMDR and trauma work
how they handle preparation and what they do if a session becomes overwhelming
whether they offer EMDR online and how they adapt it
A good EMDR therapist will welcome these questions.
Frequently asked questions
What is bilateral stimulation in EMDR?
It's rhythmic left-right input, delivered through eye movements, tapping, or alternating tones, used while you focus on a memory. It helps keep you grounded in the present while the memory is processed.
Is bilateral stimulation the same as EMDR?
No. Bilateral stimulation is one component of EMDR, which is a structured eight-phase therapy that includes history-taking, preparation, processing, and closure.
Do eye movements work better than tapping?
Some lab research suggests eye movements may tax working memory more strongly, but in practice the best method is the one that keeps you comfortable and engaged. Many clients do excellent work with tapping or tones.
Will I lose control or relive the trauma?
You stay fully aware throughout, and you can stop anytime. Emotions may rise during processing, but preparation ensures you have ways to steady yourself, and sessions end with you feeling settled.
Can I do bilateral stimulation on my own?
Gentle self-tapping, like the butterfly hug, can be a helpful calming tool. Processing traumatic memories should be done with a trained EMDR therapist.
Does EMDR work online?
Yes. Eye movements can follow an on-screen dot, and tapping and tones translate easily to video. Research and clinical experience suggest results comparable to in-person EMDR for many clients.
Curious whether EMDR is right for you?
If you're burdened with something that hasn't shifted with talking alone, EMDR may be worth a closer look. I offer EMDR in person and online for adults, professionals, and midlife women throughout New York State.
Working With Kimberly Christopher, LCSW
Integrative Psychotherapy New York offers depth-oriented psychotherapy, EMDR therapy, and couples therapy for high-functioning adults, couples, and midlife women throughout New York City and New York State via secure telehealth. This is an intentionally small private practice built around individualized, sophisticated clinical care — not a platform, not a rotating roster of providers. If you've been thinking about starting therapy, returning to therapy, or moving beyond the work that hasn't been enough, a consultation is the place to begin.
Schedule a Consultation | Text: 212-529-8292
Kimberly Christopher, LCSW, is a New York City-based psychotherapist, EMDR specialist, and founder of Integrative Psychotherapy New York. Licensed in New York State (License #079234) and Massachusetts (# 1141334). Serving individuals and couples throughout Manhattan and New York State via secure telehealth.
