In Reply.—Mr Cox raises two points. One is that our article is misleading because, according to his experience, obtaining a hermetic seal in impedance testing is not infrequent. Experience varies, particularly in testing children. Often one does not have a second chance to tighten or change an ear tip with a young child. Sometimes one or two reflex levels are the only valid information obtained. Also, in routine testing with noise-induced hearing-loss population, a quick Metz recruitment test is often done in our clinic without tracing the tympanogram, ie, without verifying the seal. The main point, however, is not the number of cases or method employed, if valid, but how to use clinical information to its fullest value.
In answer to Mr Cox's assertion about reflex decay tracing, we did not recommend the use of the "no seal" test for that purpose. A hermetic seal and adjustment to the