What is a ground loop and what causes it?

A ground loop occurs when electrical signals loop from one ground lead to another through a patient's head or body, resulting in unwanted interference in the readings obtained during a polysomnography study. This phenomenon typically arises when there is a difference in voltage between two ground points, which can create a return path for electrical noise or interference.

In a clinical setting, ground loops can be particularly problematic because they may contribute to inaccurate data, affecting the overall quality of the polysomnographic recordings. They commonly result from improper grounding techniques or unbalanced ground connections in a multi-lead system where electrodes are placed at various locations on the body. A clear understanding of this concept is crucial for ensuring accurate assessment and diagnosis in sleep studies.