What is the minimum common-mode rejection ratio (CMRR) for amplifiers used in EP recording?

The minimum common-mode rejection ratio (CMRR) for amplifiers used in electrophysiological (EP) recording is typically set at a standard of 10,000:1. This level of CMRR is crucial because it ensures that the amplifier effectively rejects common-mode signals, such as electrical noise or interference that can be picked up equally by both input channels.

A CMRR of 10,000:1 indicates that the amplifier can reduce these unwanted signals significantly, allowing for a clearer recording of the actual physiological signals of interest. This high ratio is particularly important in intraoperative monitoring and EP studies due to the high levels of electrical interference present in operating rooms and other clinical environments.

Lower CMRR values, such as 1,000:1 or even 5,000:1, may not provide sufficient noise reduction, potentially compromising the quality and integrity of the recordings. Therefore, 10,000:1 serves as the standard threshold to guarantee reliable and accurate electrophysiological data collection.