What is the maximum frequency for the low filter during ECI recordings?

The maximum frequency for the low filter during electroencephalography (EEG) recordings, specifically in the context of the Electroencephalogram International (ECI) recordings, is established at 1.0 Hz. This specification helps to maintain high-quality signal integrity by preventing the overwhelming of low-frequency components that may distort the final EEG interpretation.

In EEG practice, a low cutoff frequency of 1.0 Hz effectively eliminates slow drift artifacts while still allowing for the recording of clinically significant lower frequency brain waves such as delta activity, which typically ranges from 0.5 Hz to 4 Hz. This setting strikes a balance—permitting the presence of crucial slow waves while reducing the potential confounding factors that could arise from very low-frequency noise or physiological artifacts.

Choosing a higher cutoff, such as 10 Hz or 30 Hz, would inadvertently filter out necessary low-frequency information that is vital for proper analysis and diagnosis. Therefore, setting the low filter at 1.0 Hz is optimal for accurate EEG data collection and interpretation.