Paradoxical compliances in otosclerosis.

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.