The preferred type of amplifier in polysomnography is:

The preferred type of amplifier in polysomnography is:

• A. Single ended
• B. Triple ended
• C. Differential
• D. Multifrequency

Answer: (C)

In polysomnography the signals you’re measuring are very small voltages, so rejecting noise is essential. A differential amplifier does just that by amplifying the difference between two input leads while largely canceling anything that is present equally on both (common-mode noise), such as mains interference or stray electrical pickup. This high common-mode rejection ratio keeps the true EEG, EOG, and EMG signals clear, which is crucial for accurately scoring sleep stages and identifying artifacts. It also helps tolerate small differences in electrode impedance without letting noise dominate the signal. Single-ended amplification, which references one input to ground, is more susceptible to noise because it can’t cancel common-mode signals as effectively. Triple-ended or multifrequency descriptions aren’t standard for this purpose, so they don’t provide the same reliable noise rejection. That’s why the differential amplifier is the preferred choice.

In polysomnography the signals you’re measuring are very small voltages, so rejecting noise is essential. A differential amplifier does just that by amplifying the difference between two input leads while largely canceling anything that is present equally on both (common-mode noise), such as mains interference or stray electrical pickup. This high common-mode rejection ratio keeps the true EEG, EOG, and EMG signals clear, which is crucial for accurately scoring sleep stages and identifying artifacts. It also helps tolerate small differences in electrode impedance without letting noise dominate the signal. Single-ended amplification, which references one input to ground, is more susceptible to noise because it can’t cancel common-mode signals as effectively. Triple-ended or multifrequency descriptions aren’t standard for this purpose, so they don’t provide the same reliable noise rejection. That’s why the differential amplifier is the preferred choice.