A typical sham protocol is designed to mimic the sensation of real stimulation without delivering an effective dose, making it ideal for placebo-controlled studies.
The stimulation begins as usual, typically with a brief ramp-up phase, as configured in the protocol.
Once the ramp-up is complete, there is a 5s plateau.
Then there is the ramp-down, with its duration defined in the Sham configuration settings.
For the remainder of the session, no meaningful stimulation is delivered, but the device continues to behave as if it were active — for example, maintaining indicator lights or recording EEG data.
This approach reproduces the initial/ending physical sensations associated with transcranial electrical stimulation (e.g., tingling, itching), helping to preserve blinding without causing any significant neurophysiological effects.
How to configure Sham protocol:
In a stimulation protocol, you can activate the Sham mode by enabling the Sham button. This allows you to simulate stimulation without delivering a full therapeutic dose, helping to maintain blinding in controlled studies.
Ramp-up: The time it takes for the device to gradually reach the target current amplitude.
Ramp-down: The time it takes for the device to gradually stop the stimulation.
Within the Sham configuration, you can define two additional parameters:
Up: Equivalent to Ramp-up; it controls the initial increase in current to simulate real stimulation.
Fade-out: The time over which the current is reduced.
Double Sham
We can create a double sham protocol, where the first part follows the standard sham procedure (as previously explained), and the second part mirrors it in reverse. This second stimulation is applied again to mimic the sensation of a final stimulation phase.
Fade-in refers to the time the device takes to gradually reach the target stimulation amplitude.
Fade-out is the symmetric ramp-down phase where the amplitude decreases gradually.
Down is equivalent to ramp-down.
The interval between the first ramp up and the second ramp down corresponds to the duration defined in the protocol step settings. In the following image
If the Step Total Duration (TD) is 5 mins and the first Up (FU) is 5s and the last Down (LD) is 11s, the Real Step Duration (RSD) will be 5mins + 5s + 11s = 5mins and 16s
