In which condition would a high-frequency filter of 70Hz typically be used?

Utilizing a high-frequency filter set to 70Hz serves the primary purpose of capturing fast brain activity, such as beta waves and gamma activity. These brain waves typically oscillate in the higher frequency ranges, and a filter at this setting allows for the amplification and clear visualization of such rapid fluctuations on an EEG. This is particularly important in situations where precise assessment of cognitive processes or tasks is necessary, as they may involve rapid bursts of electrical activity.

On the other hand, a lower frequency filter would be inadequate in this context because it could inadvertently attenuate those vital fast activities, leading to a misinterpretation of the EEG data or oversimplifying the analysis of a patient's brain function during moments when high-frequency activity is significant. The role of higher frequency filters underscores their importance in studying conditions that require a detailed understanding of rapid neural processes.