Accessory equipment such as a CPAP machine or radio placed near the headbox may cause:

Accessory equipment such as a CPAP machine or radio placed near the headbox may cause:

• A. Spurious electrode impedance measures
• B. A 60Hz artifact
• C. Electrode pops
• D. Gap junction with sparking

Answer: (B)

The main idea is that nearby powered devices can introduce electrical noise at the power-line frequency into EEG recordings. A CPAP machine or a nearby radio can emit electromagnetic interference and ground noise that couples into the headbox and the EEG leads, behaving like an antenna. Because mains electricity usually runs at 60 Hz, this interference appears as a clear 60 Hz artifact on the EEG (and often on other channels too), distorting the signal you’re trying to measure. This is especially problematic because it can mimic or mask real brain activity and affect sleep staging. To prevent it, keep such equipment away from the headbox and recording leads, use shielded and properly routed cables, and ensure good grounding. The other options describe issues that aren’t the typical result of nearby accessory devices: spurious impedance measures come from contact quality, electrode pops from movement or poor adhesion, and sparking related to gap junctions isn’t a scenario encountered in clinical polysomnography.

The main idea is that nearby powered devices can introduce electrical noise at the power-line frequency into EEG recordings. A CPAP machine or a nearby radio can emit electromagnetic interference and ground noise that couples into the headbox and the EEG leads, behaving like an antenna. Because mains electricity usually runs at 60 Hz, this interference appears as a clear 60 Hz artifact on the EEG (and often on other channels too), distorting the signal you’re trying to measure. This is especially problematic because it can mimic or mask real brain activity and affect sleep staging. To prevent it, keep such equipment away from the headbox and recording leads, use shielded and properly routed cables, and ensure good grounding. The other options describe issues that aren’t the typical result of nearby accessory devices: spurious impedance measures come from contact quality, electrode pops from movement or poor adhesion, and sparking related to gap junctions isn’t a scenario encountered in clinical polysomnography.