Why are there 3 different probe tones for the GSI TympStar Pro?
The first probe tone that GSI TympStar Pro uses is the 226 Hz probe tone. This is the most common probe tone for patients who are older than six months. This probe tone is very predictable and repeatable. The research shows this is the fastest way to diagnose a relatively normal middle ear system.
The second probe tone is the 1000 Hz probe tone, used primarily to diagnose infants who are younger than six months. The reason we use that probe tone is because the infant ear is mass dominated so you may get erratic responses if you use the 226 Hz probe tone on this patient population. An infant may also have effusion in the ear and get a completely normal tympanogram. The 1000 Hz moves that probe tone away from the resonance frequency of the infant ear so that you can test with confidence and interpret those predictable responses just like the 226 Hz probe tone.
The third probe tone that the TympStar Pro uses is the 678 Hz probe tone. This is a more diagnostic probe tone for when you need to get a critical look at the middle-ear components. If you have a patient with symptoms that don’t add up with audiometric results, you can move to the 678 Hz probe tone, look at the susceptance and the conductance separately, and really get a better idea of a disarticulation or fixation in the middle ear system.