[Middle ear affections with intact tympanic membrane and fluctuating hearing loss (author's transl)]

Typical cases of a fluctuating air-bone-gap (fixation and loose coupling) are reported. The possible causes are listed with those cases especially considered, whose anamnesis gives no clue to the causes. The fluctuations, normally evoked by the patient using tube function, were demonstrated by means of the tympano-audiometric method.