In polysomnography, what does the sensitivity setting refer to?

In polysomnography, the sensitivity setting is a crucial component in the accuracy and quality of sleep study recordings. It specifically refers to the ratio of input signal voltage to the amplitude of the pen deflection. This means that by adjusting the sensitivity, technicians can control how much the pen moves in response to the electrical signals from the patient being monitored.

When sensitivity is set correctly, it allows for proper visualization of the data on the recording strip or digital output. If the sensitivity is too low, small signals may not be evident, leading to potential misinterpretation of the patient's sleep patterns or disruptions. Conversely, if sensitivity is set too high, the pen may deflect excessively for small electrical signals, which can obscure important data. Thus, setting the correct sensitivity ensures that the oscillations reflecting brain waves, muscle activity, and other physiological signals are captured accurately and clearly on the polysomnograph. This is critical for accurate sleep staging and diagnosis.