How is frequency expressed in a PSG recording?

Frequency in a polysomnography (PSG) recording is expressed in hertz (Hz), which denotes the number of cycles per second of a periodic waveform. This measurement is essential as it relates to the various brain wave patterns, muscle activity, and other physiological signals recorded during a sleep study. Each type of waveform, such as delta, theta, alpha, and beta waves, has a distinct frequency range that helps in identifying sleep stages and diagnosing sleep disorders.

Understanding frequency in hertz is crucial as it allows clinicians to analyze the timing and patterns of brain activity, which plays a significant role in assessing sleep architecture and any potential abnormalities. The use of hertz as a measurement unit is standard in many disciplines involving waveforms, including EEG and other signal processing fields.