Which action is NOT helpful in identifying a 60-Hz artifact?

Which action is NOT helpful in identifying a 60-Hz artifact?

• A. Applying and removing the AC (line) filter
• B. Decreasing time base to count the frequency
• C. Decreasing the HFF from 70 Hz to 35 Hz
• D. Increasing the LFF from 0.3 Hz to 1.0 Hz

Answer: (D)

The ability to identify a 60-Hz artifact hinges on how mains-line noise behaves under frequency-related adjustments. A true 60-Hz artifact is tied to the electrical mains, so actions that reveal or influence that specific frequency help you confirm its presence. Toggling the AC line filter is directly informative: if the artifact diminishes when the filter is engaged, that suggests the pattern is linked to line noise rather than brain activity. So this is helpful for identification. Using a shorter time base to view a longer segment of the trace allows you to count cycles and estimate the frequency more accurately. Being able to measure roughly a 60-Hz rate on the screen supports recognizing the artifact as mains-related. Adjusting the high-frequency filter changes how much high-frequency energy remains on the trace. Since 60 Hz sits in the higher end of the spectrum, listening to how the signal changes as you alter the high-frequency cut-off can help confirm whether a pattern is due to high-frequency line noise, aiding identification. Increasing the low-frequency filter cutoff, which mainly affects very slow drifts, does not influence the 60-Hz content and thus provides little to no information about whether the pattern is a line-noise artifact. This is why it’s not helpful for identifying a 60-Hz artifact.

The ability to identify a 60-Hz artifact hinges on how mains-line noise behaves under frequency-related adjustments. A true 60-Hz artifact is tied to the electrical mains, so actions that reveal or influence that specific frequency help you confirm its presence.

Toggling the AC line filter is directly informative: if the artifact diminishes when the filter is engaged, that suggests the pattern is linked to line noise rather than brain activity. So this is helpful for identification.

Using a shorter time base to view a longer segment of the trace allows you to count cycles and estimate the frequency more accurately. Being able to measure roughly a 60-Hz rate on the screen supports recognizing the artifact as mains-related.

Adjusting the high-frequency filter changes how much high-frequency energy remains on the trace. Since 60 Hz sits in the higher end of the spectrum, listening to how the signal changes as you alter the high-frequency cut-off can help confirm whether a pattern is due to high-frequency line noise, aiding identification.

Increasing the low-frequency filter cutoff, which mainly affects very slow drifts, does not influence the 60-Hz content and thus provides little to no information about whether the pattern is a line-noise artifact. This is why it’s not helpful for identifying a 60-Hz artifact.