If a patient’s threshold is 25 dB and the stimulator is set to 85 dB, what is the intensity in dB SL?

To determine the intensity in dB SL (Sensation Level), you take the absolute intensity of the stimulus and subtract the patient’s threshold from it. The patient’s threshold is given as 25 dB. The intensity of the stimulator is set at 85 dB.

Calculating the dB SL involves this formula:

dB SL = Stimulus Intensity (in dB) - Patient's Threshold (in dB)

Using the provided values:

dB SL = 85 dB - 25 dB

dB SL = 60 dB

This means that the intensity of the stimulus that the patient perceives is 60 dB above their threshold. The reasoning behind this is to understand how the stimulus intensity compares to a patient's auditory threshold, and making this calculation is critical in neurophysiologic monitoring as it helps determine the efficacy and safety of auditory stimuli during procedures.