This is done to understand the middle ear condition. Probe tone of 225Hz frequency is presented to the ear canal by varying the pressure condition in the ear canal from -200 to 200 dapa. The result is displayed on the screen as different patterns . each pattern reveals different middle ear pathology. Audiologist make diagnosis based on the pattern. This evaluation helps us understanding the conditions such as middle ear fluid, ETdysfunction, ossicular discontinuity, otoscelosis etc