The first atypical graph is called a Type B tympanogram. This type indicates little or no flexibility of the eardrum, which could be attributed to fluid/infection located behind the eardrum, or even a hole in the eardrum. The second atypical graph is a Type C tympanogram. This type has a peak, indicating flexibility of the eardrum, but the peak is shifted to the left (in the negative numbers), indicating an abnormal amount of negative pressure in the ear canal. This can be attributed to congestion of the sinuses, often due to colds or allergies. (All the picture graphs were taken from Wikipedia)
Tympanometers come in a few different varieties. I, personally, have used two different kinds. The first kind I used is a little more complicated and, although portable, is more of a hassle to move around, as it must be plugged into an outlet. A picture, taken from www.drkaneent.com, is shown below.This shows a person holding the probe, which is the part you stick into the ear canal. You can also see that it prints out a paper copy of the graph (described and shown above).
The second variety that I have used before is much smaller and is shaped more like a gun (It looks a lot like an otoscope) which sits on a charger when not in use. It is much easier to stick in the ear, and gives you a picture of the graph on a small screen. If you wanted to print it out, the charger has a printer built into it. A picture, from www.eardoc.info, is shown below.
This concludes my segment on gadgets used in hearing screenings--next I will be discussing some very interesting technologies used as alternatives to oral communication.