An extreme high frequency filter setting would likely cause which of the following effects in an EEG waveform?

An extreme high frequency filter setting in an EEG waveform primarily removes high-frequency components while allowing lower frequency signals to pass through. When applied, this filter can cause a distinctive alteration in the shape of the waveform. Specifically, it can produce a "peak" effect at the top of the waveform due to the attenuation of the high-frequency activity. As the high frequencies are filtered out, the remaining waveform may exhibit sharper, more pronounced peaks. This effect makes the predominant low-frequency activity more apparent, thus resulting in a more peaked appearance.

Understanding the impact of high-frequency filtering is key in EEG signal interpretation, as it can significantly affect the visual representation of brain activity, especially in different sleep stages or pathological conditions. Consequently, the correct identification of this filter's effects ensures accurate analysis and interpretation of EEG data.