Results of impedancemetry have been compared with operative findings in 1 867 cases of otosclerosis, 1 583 of which were pure otosclerosis. This comparison indicated that: (1) with present techniques, the results of impedancemetry are only of a relative value in otosclerosis; it is thus necessary to asses the various connected anatomical elements in the middle ear with extreme rigor; (2) impedancemetry data have an absolute value in all disorders of the middle ear with closed eardrum associated with otosclerosis; (3) relative impedancemetry often gives informative results when it concurs with the other elements of clinical and audiometrical diagnosis; (4) impedancemetry data are a valuable element of early diagnosis of otosclerosis before the first audiometric expression, either by a lowering of compliance or, most of all, by appearance of an on-off effect (diphasic impedance change) or by disappearance of the stapedius reflex; (5) parallel or crossed paradoxical compliances are only apparently paradoxical and are usually the sign of either an early stapedo-vestibular fixation (before its audiometric expression) or an associated factor in the middle ear, both of which may have been unnoticed; (6) the problem of compliance value in otosclerosis will be solved only when the proper stapes frequency is found and when it is possible to test this frequency. This problem is the subject of our current research.

Adolescent↗

PubMedDate not supplied

Multifrequency impedance testing in relation to otospongiotic stapedial fixation and other factors.

After reviewing COLLETTI'S research, the authors describe their own experimental work on multifrequency impedance testing in relation to stapedial fixation in otospongiosis, and other factors. Their findings, based on 266 tested ears, lead the authors to the conclusion that : (1) the most useful frequencies, from the clinical point of view, are the low ones (220, 660 and 800 Hz); (2) the research frequencies, range beyond (900 to 2 000 Hz), for a finer diagnosis, but are confused by numerous artefacts and are not always reliable; (3) COLLETTI'S conclusions on the inversion of the peak and on the shifting of M and W, are valuable, but not always reliable in some cases.

Acoustic Stimulation↗