Test-retest variability of eustachian tube responses in children with persistent middle ear effusion.

In our previous studies on eustachian tube function in children with middle ear effusion, we found that many ears were evacuated by the act of sniffing. When subjects were tested repeatedly, however, responses to sniffing were very variable. In order to study the spontaneous variability, a total of 51 subjects (81 ears) were retested. The results of the retest were very similar to those of the first test when all the ears were considered as a group. However, in individual ears pronounced variability was seen. In the sniff test, responses changed qualitatively in 30% of the ears, and in 27% of the ears there was a change in the ability to equalize pressure by swallowing. Thus, the results of the group were highly reproducible, while at the same time individual results were highly variable with time.