Theory & Research
Visual vs. Auditory vs. Tactile Bilateral Stimulation: What Does the Evidence Say?
An evidence summary comparing visual, auditory and tactile bilateral stimulation in EMDR: what studies show, where evidence is limited, and why no modality is universally superior.
BilateralSync · Updated · 8 min read
Overview
EMDR began with eye movements, and clinicians now also use alternating tones and alternating taps. This article summarises what the research says about the three modalities. In short: eye movements have the largest evidence base; auditory and tactile stimulation are widely used and supported by some research but less studied; no modality has been shown to be universally superior for every client.
What the evidence says
Visual (eye movements). A meta-analysis by Lee and Cuijpers (2013) concluded that eye movements contribute to the effect of processing emotional memories in both clinical and laboratory studies.
Auditory (alternating tones). In a laboratory study, van den Hout and colleagues (2012) found that eye movements reduced memory vividness and emotionality more than alternating tones, and that tones taxed working memory less. Tones were not without effect, but the effect was smaller in that experiment.
Tactile (alternating taps). Tactile stimulation is the least studied. A small pilot study by Servan-Schreiber and colleagues (2006) compared different forms of tactile stimulation in PTSD patients and found improvements across conditions; it was not designed to show that taps are equivalent to eye movements.
What is uncertain. Head-to-head clinical trials comparing all three modalities in PTSD treatment are scarce, and laboratory findings on vividness may not translate directly into treatment outcomes.
In practice
Modality choice is a clinical decision. Clinicians commonly consider the client's comfort and sensory profile (for example light sensitivity, hearing, or touch-related trauma), whether eyes-closed processing is preferred, and practical constraints. For remote work, visual and auditory stimulation can be delivered on the client's own device; tactile stimulation needs hardware at the client's end.
Comparison at a glance
| Visual | Auditory | Tactile | |
|---|---|---|---|
| Research base | Largest | Moderate | Smallest |
| Working-memory load (lab) | Higher | Lower (van den Hout et al., 2012) | Less studied |
| Eyes closed possible | No | Yes | Yes |
| Remote delivery | Client's screen | Client's headphones | Requires device at client's end |
| Common reasons to choose | Default, most studied | Light sensitivity, eyes closed | Visual or auditory limits |
Combining modalities
Many tools allow visual and auditory stimulation at the same time. Some clinicians combine them to increase engagement, which fits the working-memory account, but there is limited direct evidence on combined stimulation in clinical outcomes. See BLS speed and set length for the related evidence on load.
Where to read more
Frequently asked questions
- Is auditory BLS as effective as eye movements?
- In at least one laboratory study, tones produced smaller effects than eye movements. Auditory BLS is widely used clinically, but it has a smaller evidence base.
- Which BLS modality is best?
- No modality is universally best. Eye movements have the most evidence; the choice for an individual client is a clinical decision.
- Can tactile BLS be used online?
- Only if the client has a tactile device at home. Visual and auditory BLS can be delivered through a browser on the client's own device.
References
- Lee, C. W., & Cuijpers, P. (2013). A meta-analysis of the contribution of eye movements in processing emotional memories. Journal of Behavior Therapy and Experimental Psychiatry, 44(2), 231–239.
- van den Hout, M. A., Rijkeboer, M. M., Engelhard, I. M., Klugkist, I., Hornsveld, H., Toffolo, M. J. B., & Cath, D. C. (2012). Tones inferior to eye movements in the EMDR treatment of PTSD. Behaviour Research and Therapy, 50(5), 275–279.
- Servan-Schreiber, D., Schooler, J., Dew, M. A., Carter, C., & Bartone, P. (2006). Eye movement desensitization and reprocessing for posttraumatic stress disorder: A pilot blinded, randomized study of stimulation type. Psychotherapy and Psychosomatics, 75(5), 290–297.
- Landin-Romero, R., Moreno-Alcázar, A., Pagani, M., & Amann, B. L. (2018). How does eye movement desensitization and reprocessing therapy work? A systematic review on suggested mechanisms of action. Frontiers in Psychology, 9, 1395.
This article is general professional information for clinicians. It is not clinical advice and does not replace EMDR training, consultation or individual clinical judgment. BilateralSync is a tool for delivering bilateral stimulation; it is not a treatment or a medical device.