In the case of a constant artifact in multiple channels, what is the most advisable action?

When dealing with a constant artifact that appears in multiple channels during a sleep study, assessing common connections and re-referencing channels is the most advisable course of action. This approach helps identify whether the artifact is being caused by a shared source, such as a grounding issue or interference from other equipment, which could impact multiple recordings simultaneously.

By re-referencing, you can adjust the electrical connections of the channels to see if this mitigates the artifact. This step is essential because the problem likely arises due to the setup or connections, rather than an isolated issue with individual channels or their specific filters.

Switching to a different patient ground connection or implementing a 60-Hz filter may address the symptoms but may not resolve the underlying issue causing the artifact. Similarly, recalibrating all equipment might not be necessary if the problem is related to common connections rather than the functioning of the individual tools. Therefore, evaluating and re-referencing the channels is the best initial step to diagnose and resolve the persistent artifact effectively.