What is an expected outcome of a properly functioning notch filter during a PSG?

A properly functioning notch filter is designed to selectively eliminate specific frequencies from a signal, which is particularly important in polysomnography (PSG) recording. The primary function of a notch filter is to reduce electrical noise that can interfere with the signals being monitored, such as EEG, EOG, or EMG.

In the context of PSG, one common source of electrical noise is the 60 Hz power line interference that can obscure the true signals from brain activity. By applying a notch filter at this frequency, the unwanted noise is significantly reduced, allowing for clearer and more accurate recordings of the brain's electrical activity. This reduction in electrical noise helps improve the quality of the signals obtained during sleep studies, leading to a more accurate interpretation of the sleep data.

Therefore, the expected outcome of a properly functioning notch filter during a PSG is indeed a reduction in electrical noise, which is critical for ensuring high-quality data during sleep evaluations.