What is the most likely cause of a high-amplitude, low-frequency artifact in an EEG channel?

A high-amplitude, low-frequency artifact in an EEG channel is most commonly associated with a sweat artifact. This type of artifact occurs when changes in skin conductance affect the electrical signals recorded by the EEG. When an individual sweats, especially during a sleep study or neurological examination, the sweat can create conductive pathways on the scalp that lead to prolonged low-frequency signals due to the impedance changes, resulting in a noticeable increase in amplitude.

Sweat artifacts often appear as slow waves on the EEG, which can easily be mistaken for neurological activity if not properly identified. Recognizing sweat artifacts is important for accurate interpretation of EEG data, as they can significantly distort the underlying brain activity, leading to incorrect clinical conclusions.

In contrast, EMG artifacts typically present as high-frequency, high-amplitude bursts due to muscle activity, while ECG artifacts would be characterized by distinct patterns corresponding to heartbeats, and 60-Hz artifacts are related to electrical interference, usually appearing as sinusoidal waves at a frequency of 60 Hz. Each type of artifact has distinct characteristics that assist in their identification, making it crucial for technicians to accurately differentiate between them during analysis.