Why is a low-frequency filter (LFF) setting of 100 Hz preferred for recording spinal cord evoked potentials (SC EPs)?

The preference for a low-frequency filter (LFF) setting of 100 Hz when recording spinal cord evoked potentials (SC EPs) is primarily due to the nature of these potentials, which are generally of relatively short duration.

SC EPs are responses generated by the spinal cord to stimulation, and they manifest as quick, transient waveforms on the recording. A low-frequency cutoff, such as 100 Hz, allows for the preservation of these rapid and brief signals while effectively filtering out lower frequency noise that could obscure the shorter duration potentials.

This filtering helps ensure that the recorded waveform accurately reflects the evoked potential being measured without distortion that might be introduced by slower signals. In contrast, setting the LFF too low could lead to the loss of critical high-frequency components essential for accurately interpreting the SC EPs. Thus, the choice of a 100 Hz LFF is ideal for capturing the relevant temporal characteristics of these electrical signals while maintaining clarity in the recorded data.