EMDR via Zoom and Telehealth: Bilateral Stimulation Setup

Written by Murat Yön, clinical psychologist, EMDR Europe accredited therapist

Updated 2026-10-14 · For EMDR-trained clinicians

Delivering EMDR over Zoom, Teams, Meet or Doxy.me is routine for many clinicians. The part that goes wrong is often not the clinical protocol; it is bilateral stimulation (BLS) that reaches the client mixed down, delayed or uneven. This guide covers the technical side of telehealth EMDR: how to keep auditory BLS in stereo, what to check on each video platform, and when to generate the stimulation on the client's own device instead. If you only need a quick stereo check, the free browser BLS tool has a left / right test you can run with a client before the first set.

Why stereo and alternation matter for auditory BLS

Auditory BLS is defined by alternation: a tone is heard in the left ear, then the right, at a steady rhythm. If both ears receive the same signal, what remains is a repeated sound, not a bilateral one. Clinicians who work remotely therefore need three things to be true at the same moment: the signal is stereo, it is routed to headphones, and its timing is regular.

Video platforms are built for speech. By default they tend to apply noise suppression, echo cancellation, automatic gain control and speech-oriented compression, and many send audio as a single mono channel. Each of these is sensible for conversation and each can interfere with a short tone alternating between channels. A tone can be clipped by noise suppression, softened by gain control, or collapsed into mono. Because the client simply hears "a sound", you may not notice the alternation is gone unless you test.

Video is more fragile still: a shared light bar depends on a frame rate that adapts to bandwidth, and a dropped frame breaks the rhythm. This is one reason many remote clinicians prefer auditory BLS (see the guide to bilateral stimulation modalities).

How the main video platforms handle audio

Setting names differ between desktop, web and mobile clients and change often. Confirm them against each vendor's current help page, and verify the result with your client rather than trusting a setting.

Zoom

In the Zoom desktop app, the audio settings include an Audio Profile option called Original sound for musicians, with a Stereo audio checkbox beneath it. Zoom's help page describes stereo as an option for sending a stereo microphone signal, and lists limits: it applies to the Windows and macOS desktop apps (not the mobile app), needs a paid plan and a stereo-capable microphone or audio interface, increases CPU use and bandwidth, and recordings are saved in mono. Zoom's help pages are written around microphones, so they do not promise that your shared computer sound reaches the client as alternating stereo. Treat the setting as a possible aid and test it with your client.

Microsoft Teams

Teams lets you include computer sound when you share your screen: an Include sound toggle in the desktop app, or Also share tab audio and Also share system audio options in the web version. Microsoft's help page notes that all computer audio, notifications included, is shared, that Windows needs Teams and the computer on the same speaker, that Mac needs the Teams audio driver, and that running many apps can cause lagging or dropped audio. It does not mention stereo, so treat stereo as unverified until you have tested it with a real client on their usual device.

Google Meet

Meet can share audio when you present a tab, a window or the whole screen. In December 2025 Google announced that presenters can send stereo sound when the shared content is stereo, with limits: only users on the web can send stereo, and only attendees on Chrome or Firefox can receive it. A client joining from a phone app or another browser may therefore receive something different from what you send.

Doxy.me

Doxy.me offers screen sharing with an option to include tab or computer audio; the exact labels, browser support and plan requirements change between versions, so check its current help pages. It does not promise stereo alternation, so a left / right check is still the deciding step.

Platforms can pass stereo in some configurations, but you cannot assume it. The reliable check follows.

Headphones and the left / right check

Ask the client to wear stereo headphones or earbuds in both ears. Speakers, a single earbud, and some Bluetooth modes that switch to a call profile can all collapse the channels. Then, before any target is brought up, run a short check:

1. Play a tone on the left only and ask which ear hears it. Repeat for the right.
2. Start slow alternation and ask the client to describe it back ("left, right, left, right") rather than answering yes or no.
3. Ask about volume and pitch. A tone that feels sharp at first can be much harder to tolerate after ten minutes.
4. Agree a stop signal and confirm you both know it.

Asking the client to report what they hear is more informative than any setting you toggle on your side, because the client's device, headphones and operating system are all part of the chain. Repeat the check whenever the client changes device, headphones or location.

Screen-share stimulus or stimulus on the client's device

There are two broad ways to deliver BLS in a remote session.

Stimulus streamed through the call

You run a browser tool or media file on your computer and share the tab or system audio. It needs nothing from the client but headphones and a working call. The cost is that the signal passes through the platform's audio pipeline, so timing and stereo depend on the platform, your upload, the client's download and the client's device. Any change to speed or tone is applied on your side, which is convenient, but it reaches the client with whatever delay the connection adds. The free BLS tool in your browser can be used this way; read the platform notes above and test first.

Stimulus generated on the client's device

Here the call carries your voice and face, while a separate app plays the stimulus on the client's own phone or computer, so the audio never passes through the video platform. In EMDR Mobile's online session, the client joins the free client app through a join link or with a username and password, the stimulus plays on the client's device, and the therapist controls start and stop, speed (1 to 15), volume (1 to 20), tone and automatic sets. The client chooses how the stimulus looks (shape, colour, background and size) in Customize Appearance. The therapist panel does not include a left / right test, so the check described above is still done by asking the client. For face-to-face sessions, the app plays auditory BLS through headphones without needing an internet connection.

Neither route is right for every clinic. Streaming through the call needs no installation for the client. Device-side generation removes the video platform from the timing path but asks the client to install the free app. EMDR Mobile delivers auditory and visual stimulus on the client's device; it has no tactile option. The criteria guide for choosing a BLS tool sets out the trade-offs, and light bar alternatives compares the delivery options more broadly.

Latency and frame rate

Two different delays matter. Audio sent through a call is buffered, compressed and re-timed by the platform, so the beat you hear on your side and the beat the client hears can drift apart, and the client's tones can arrive in uneven clumps when the connection is poor. Shared video is worse: platforms lower the frame rate to protect the call, which makes a moving light bar or dot stutter. Neither problem is visible to the person who is sending the stimulus.

Practical steps: use a wired connection or a strong Wi-Fi signal on your side; ask the client to close other apps and to stay near the router; avoid screen-sharing a moving visual if you can use auditory BLS instead; and ask the client to describe the rhythm back to you during the first slow set. If they report gaps or bunching, treat it as a delivery fault and change the route, for example by moving to a stimulus generated on the client's device, before starting reprocessing.

Plan for connection drops

Agree the plan before reprocessing begins, not after the call freezes. A workable plan has four parts:

• A fallback channel. A phone number, or a second device, that you can use immediately if the video fails.
• A rule for silence. Tell the client that if they lose your voice or the stimulus, they should stop, open their eyes, orient to the room and wait for your call.
• A grounding routine they can run alone. Whatever you have already rehearsed in preparation, such as the calm place or a container exercise.
• Their location and an emergency contact in your notes, as your jurisdiction and professional body require.

If the stimulus plays on the client's device and the call drops, check how your tool behaves in that case before you rely on it, and describe that behaviour to the client in advance. If the stimulus travels through the call, a drop stops both together, which is at least predictable.

Practical settings for the first remote session

• Start with lower volume and slower alternation than you would use in the room, then adjust with the client's feedback. See the guide to speed, set length, tone and volume.
• Keep early sets short while you learn how this client's device, headphones and connection behave.
• Turn off notifications and other audio on both devices. A message chime in the middle of a set is more disruptive than it sounds.
• Make the closure sequence deliberate. A client on a video call can go from reprocessing to their own living room in one click.

Pre-session checklist

• The client has stereo headphones or earbuds and knows which ear is which.
• Both of you have turned off notifications and other audio, and have a charged device or a power source.
• You have run the left / right check and a short slow alternation, and the client has described it back.
• If the stimulus plays on the client's device, the app is installed, they can join with the link or credentials you shared, and you have both seen it start and stop.
• You hold a fallback phone number, the client's location and an emergency contact, as required where you practise.
• The stop signal and the grounding routine have been agreed and rehearsed.

Where EMDR Mobile fits

EMDR Mobile is a therapist-controlled app: the therapist starts and stops, sets speed, volume and tone, and uses automatic sets, while the client's device plays the stimulus. It is one option among several, and the free browser tool at emdrmobile.com/bls is a reasonable starting point for clinicians who want to test stereo behaviour on their platform before choosing anything else. The eight-phase reference places BLS within the wider protocol, which remains the clinician's responsibility whatever tool is used.