Middle ear pressure equilibration ability and spontaneous pressure changes in healthy ears with ventilation tubes.

CONCLUSION

The results of this study give support to the theory that opening the middle ear (ME) to the atmosphere leads to a deterioration in its pressure regulation capacity. However, this is probably not the reason why a perforation of the tympanic membrane becomes chronic.

OBJECTIVE

Direct, continuous measurement is a method of studying ME pressure regulation. We found previously that subjects with chronic central perforation (CCP) had a negative ME pressure in the daytime, in contrast to subjects with healthy ears. In this study, in order to elucidate the cause of this negative pressure, measurements were performed in healthy ears with ventilation tubes (VTs).

MATERIAL AND

METHODS

A VT was inserted 1 week prior to the measurements in 18 subjects. A hearing protector was tightly fitted deep into the external ear canal and connected to a portable system consisting of a pressure transducer and a memory.

RESULTS

The measurements revealed a mean ME pressure during the first 3 h of -27 daPa. Ten subjects showed an initial decrease in pressure leading to a considerable negative mean ME pressure and a poor ability to equilibrate pressure differences through the Eustachian tube, like the subjects with CCP.