the accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based : ( a ) ear canal volume does not change when ear canal pressure is varied , and ( b ) an ear canal pressure of 200 dapa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 dapa can be attributed to the ear canal volume alone .
C0220825
evaluated
C0184661
procedure