Cervical VEMP - Protocol & Parameter Selection

This video guides clinicians on the selection of parameters to record the cervical VEMP. You can read the full transcript below.

Stimulus type

Amanda Goodhew: With the Eclipse software open, we can take a look at our cVEMP protocol.

So there is a default cVEMP protocol, and if we click on temporary test setup, we can look at the parameters within this.

The cVEMP protocol defaults to using a tone burst stimulus, but a recent paper published in 2023 did a comparison between different stimulus types and found that the narrowband CE-Chirp stimulus family actually provided larger response amplitudes.

So today I'm going to select the narrowband CE-Chirp 500 Hz stimulus.

Transducer type

The other thing that's important to check is that we're using the correct transducer.

Now for this test, we are using air conduction, but it's important to check that we've selected either inserts or headphones, depending on which one we're using.

We are using insert phones, so we'll make sure that that is selected there.

EMG-controlled stimulus recording

Towards the bottom of the screen, we can see some VEMP-specific settings.

The top line is the EMG-controlled stimulus recording.

If this is selected, it means that the stimulus will only be presented, and the Eclipse will only record when the patient's EMG contraction is within the range that has been set.

So if they do not provide sufficient muscle contraction, the stimulus won't present, and they should hear that through the transducer that's delivering the stimulus.

EMG monitor

The patient's EMG monitor option provides an additional visual indication of whether the patient has achieved the appropriate EMG contraction.

So this is displayed as a visual bar on the screen, and the range of this can be set specifically for each patient if need be.

EMG scaling

EMG scaling is a further option at the bottom of the screen here.

I am going to leave this off, because I prefer to record my waveforms not-scaled and then apply scaling afterwards.

You can have this on for the recording.

I find it easier to visualize the raw recordings first and then apply scaling afterwards.

And I'll demonstrate how we can do this later.

EMG monitor tone

On the right-hand side here, we also have a monitor tone.

So this is a sound that is delivered for the patient to listen to, in the same way as the EMG monitor bar, but this provides an auditory indication as to whether they are providing sufficient muscle contraction.

So I'm happy with all of the settings in this instance here so we can press OK.

And then we are ready to start the test.