Safety and research
Definition
Sham stimulation is a comparison condition designed to resemble active stimulation while withholding or altering the hypothesised active component.
Aliases and abbreviations
sham control · placebo-like stimulation · control stimulation
Editorial record
Published: August 25, 2026 · Reviewed: August 25, 2026
Expanded definition
In device trials, sham design may change the stimulation site, intensity, waveform, duration, or timing while trying to preserve a believable participant experience.
A useful sham should support blinding and should not create a systematic difference in expectations, sensation, contact, or study procedures. Researchers therefore need to assess whether participants can guess their assignment.
Sham is not automatically biologically inactive. Earlobe stimulation, low-intensity stimulation, brief ramping, or another active-feeling control may have physiological or sensory effects that complicate interpretation.
What the term does not establish
Why the distinction matters
The credibility and biological activity of the control condition can change the estimated treatment effect and the certainty of conclusions.
Main guide
A focused overview of ear anatomy, sham locations, blinding, and protocol-specific interpretation.
Explore sham designRelated terms
Safety and research
Measurement and interpretation
Anatomy
Protocol and stimulation parameters
Protocol and stimulation parameters
Measurement and interpretation
Editorial scope
This glossary entry supports general education. It does not diagnose, recommend treatment, or transfer findings from one VNS method, protocol, or device to another.