Understanding the technique

The left–right rhythm used in EMDR

Bilateral stimulation (BLS) means alternating sensory cues between the left and right sides. It may involve following a moving light, listening to alternating tones, or feeling gentle taps. It’s a component of EMDR therapy, not a therapy on its own.

Three common forms

01 / Visual

Following a therapist’s hand, a light bar, or a moving dot across a screen.

02 / Auditory

Tones move between the left and right ears, typically using stereo headphones.

03 / Tactile

Gentle taps or vibrations alternate between hands, knees, or shoulders.

Why might it affect memories?

One leading explanation is the working-memory hypothesis: recalling a memory while tracking a moving stimulus divides limited attention. This can make a recalled image feel less vivid or emotionally intense. Other mechanisms have been proposed, and researchers have not established one complete explanation. BLS has not been shown to work simply by “balancing” the brain’s hemispheres.2, 3

What does the evidence say?

What we know

Therapist-delivered EMDR is an evidence-based treatment for PTSD. Studies also suggest that eye movements can reduce the rated vividness and emotionality of recalled memories.1, 3

What remains uncertain

Those findings do not establish that BLS alone treats trauma or PTSD. Evidence differs across visual, auditory, and tactile methods, and no form guarantees a calming response.2, 4

See bilateral stimulation on DIYEMDR

Our free browser-based exercise uses a moving orb and optional left–right guiding sounds, alongside memory cues and stabilizing words. Read the user guide before trying it.

Explore the tool →