Which filter settings are most appropriate for EEG, EOG, EKG, and EMG channels respectively?

Which filter settings are most appropriate for EEG, EOG, EKG, and EMG channels respectively?

• A. EEG 0.3/35, EOG 0.1/35, EKG 1.0/35, EMG 10/70
• B. EEG 1.0/70, EOG 1.0/70, EKG 0.3/35, EMG 1.0/35
• C. EEG 0.1/15, EOG 0.1/15, EKG 0.3/15, EMG 1.0/100
• D. EEG 0.5/40, EOG 0.5/40, EKG 0.5/40, EMG 3.0/50

Answer: (A)

Filtering is about keeping the signal parts you need for scoring while removing the noise and drift that can obscure those features. For sleep staging, you want EEG and EOG to retain the slower brain and eye movements but suppress slower drift and high-frequency noise. A practical choice is a bandpass that passes roughly 0.3 Hz up to 35 Hz for both EEG and EOG, which preserves the essential rhythms without introducing too much drift or noise. Some guidelines allow a very small adjustment for eye movements, such as a slightly lower high-pass (around 0.1 Hz), to avoid losing extremely slow ocular activity. The ECG needs to keep the essential waveform features like the QRS complex while removing baseline wander; a modest high-pass around 1 Hz with a low-pass of about 35 Hz achieves that balance, preserving diagnostic morphology without letting slow drift dominate. The chin EMG used for sleep staging requires a broader bandwidth to capture muscle tone and phasic activity but still avoid picking up excessive high-frequency noise. A high-pass near 10 Hz and a low-pass near 70 Hz provide that range, giving a clear view of muscle activity relevant for scoring without letting low-frequency drift or very high-frequency noise distort the signal. This combination reflects common practice and best supports accurate scoring across EEG, EOG, ECG, and EMG channels, making it the most appropriate set.

Filtering is about keeping the signal parts you need for scoring while removing the noise and drift that can obscure those features. For sleep staging, you want EEG and EOG to retain the slower brain and eye movements but suppress slower drift and high-frequency noise. A practical choice is a bandpass that passes roughly 0.3 Hz up to 35 Hz for both EEG and EOG, which preserves the essential rhythms without introducing too much drift or noise. Some guidelines allow a very small adjustment for eye movements, such as a slightly lower high-pass (around 0.1 Hz), to avoid losing extremely slow ocular activity.

The ECG needs to keep the essential waveform features like the QRS complex while removing baseline wander; a modest high-pass around 1 Hz with a low-pass of about 35 Hz achieves that balance, preserving diagnostic morphology without letting slow drift dominate.

The chin EMG used for sleep staging requires a broader bandwidth to capture muscle tone and phasic activity but still avoid picking up excessive high-frequency noise. A high-pass near 10 Hz and a low-pass near 70 Hz provide that range, giving a clear view of muscle activity relevant for scoring without letting low-frequency drift or very high-frequency noise distort the signal.

This combination reflects common practice and best supports accurate scoring across EEG, EOG, ECG, and EMG channels, making it the most appropriate set.