What should be checked first when 60Hz interference is seen on an EEG recording?

When 60Hz interference is observed on an EEG recording, checking the electrode impedance first is essential because it can directly impact the quality of the EEG signal. High electrode impedance can lead to poor signal quality, making the EEG more susceptible to noise and interference. If the electrode impedance is not within the acceptable range, it can allow external electrical noise, such as the 60Hz hum commonly associated with power sources, to contaminate the recording.

By ensuring that the electrode impedances are low and consistent across all channels, you can enhance the integrity of the data being collected. Properly applied electrodes with low impedance minimize the impact of external interference, leading to a clearer representation of the brain's electrical activity. Therefore, addressing electrode impedance as the first step is crucial in troubleshooting the 60Hz interference effectively.