A bilateral stimulation device doesn't have to be a dedicated piece of hardware. TheraJoy delivers all three BLS modalities — visual, auditory, tactile — on iPhone.
Bilateral stimulation (BLS) is the alternating left-right sensory input used in EMDR therapy to support dual-attention processing. Research suggests that rhythmic bilateral stimulation while holding a distressing memory in mind facilitates the reprocessing of traumatic material — though the exact mechanism is still studied.
BLS is delivered in three modalities:
A moving light or therapist's finger guides left-right eye movements. Historically the original EMDR method.
Stereo audio tones alternate left-right through headphones. Useful when tactile isn't possible or preferred.
Handheld devices vibrate alternately. Preferred by many clients for its grounded, physical quality.
The dedicated BLS device market is dominated by a few hardware makers:
These devices do one thing well. But they require per-unit purchase, don't work for teletherapy without the client owning the same hardware, and can't be updated as EMDR protocols evolve.
TheraJoy delivers visual, auditory, and tactile bilateral stimulation from a single iPhone app. For tactile BLS, it uses Joy-Con controllers over Bluetooth — precision linear resonance actuators that produce clean, distinct alternating taps.
For therapists, the model changes entirely. One Pro subscription ($79/yr) covers your entire caseload — each client downloads the app free and joins your session via a shared code. No per-client hardware cost, no lending equipment, no tracking devices between sessions. See how it works for therapists.
| Feature | Dedicated BLS device | TheraJoy |
|---|---|---|
| Modalities | Usually tactile only | Visual + auditory + tactile |
| Cost | $100–$600+ per unit | Free download / $49–79/yr |
| Teletherapy | Client must own same hardware | Client joins free by code |
| Client hardware needed | Yes — per device | Joy-Cons optional; visual/audio work without |
| Speed adjustment | Limited range | 0.25–3 Hz, mid-session |
| Software updates | Firmware only, if ever | Regular app updates |
| Free trial | No | 7-day trial |
Some clinicians prefer a dedicated BLS device for the physical weight and "clinical instrument" feel — some clients respond better to something that feels purpose-built. Clients without smartphones or Joy-Cons also need a hardware option. These are real advantages worth acknowledging.
For the majority of practices — especially those doing teletherapy, equipping multiple clients, or building a new practice without legacy hardware — the app model is materially better on cost and access.
Download TheraJoy and run your first bilateral stimulation session today. No hardware required to start.
Download on the App Store