ABG, dips and notches evaluation of cochlear reserve in otosclerosis.

This study of a possible relationship between the ABG and the remodeling of the niche in otosclerosis in a significant number of patients operated on by stapedectomy allows the authors to define six types of ABG shape, corresponding to various types of stapedial fixation and remodeling of the niche. But the difficulties in finding the real bone conduction threshold levels, which ABG shapes depend on, lead us first to explain the mechanism of the various dips and notches altering bone conduction curves; and second, to try to find a safe and sure method for precise evaluation of the real cochlear reserve in otospongiosis/otosclerosis. We conclude that the best method is the bone conduction speech audiometry, mainly the bone conduction speech Weber tes, which automatically shows the true cochlear reserve of the ear to be operated on.