In polysomnography, sensitivity is generally measured in:

In polysomnography, sensitivity is generally measured in:

• A. uV/mm
• B. uV/cm
• C. uV/in
• D. Hz/mm

Answer: (A)

Sensitivity in polysomnography describes how much voltage is represented by a given vertical distance on the EEG trace. It is expressed as microvolts per millimeter, because the trace height is read in millimeters on the paper or display. This means that at a sensitivity of, say, 10 µV/mm, every millimeter of vertical deflection equals 10 microvolts of brain activity. This unit directly ties voltage to the physical height of the trace, making amplitude interpretation consistent across channels and studies. Other units like µV/cm or µV/in would distort the true height-per-voltage relationship, and Hz/mm would refer to frequency, not amplitude, so they aren’t used.

Sensitivity in polysomnography describes how much voltage is represented by a given vertical distance on the EEG trace. It is expressed as microvolts per millimeter, because the trace height is read in millimeters on the paper or display. This means that at a sensitivity of, say, 10 µV/mm, every millimeter of vertical deflection equals 10 microvolts of brain activity. This unit directly ties voltage to the physical height of the trace, making amplitude interpretation consistent across channels and studies. Other units like µV/cm or µV/in would distort the true height-per-voltage relationship, and Hz/mm would refer to frequency, not amplitude, so they aren’t used.