Conductive Type Of Hearing Loss Research Articles

Repair of traumatic interruption of ossicular chain.

A unilateral, conductive-type hearing loss, with a marked air-bone gap of up to 60 db., and with the tympanic membrane intact, should arouse one's suspicion that there has been an interruption of the ossicular chain. 6 This suspicion would be fortified by a history of surgical intervention in the mastoid or middle ear. Besides the now frequently performed tympanotomies for stapes surgery with injury to the ossicular chain, a long-forgotten simple mastoidectomy may have to be blamed for such an interruption of the ossicular continuity. Displacement of the incus in an anterior-inferior direction easily occurs if the antrum and the epitympanic space is not approached with the necessary care when the simple mastoidectomy is performed. Utmost care should be exercised when the curet in this area is used. In the absence of a history of surgical intervention, the differential diagnosis includes congenital abnormalities of the ossicles, subluxation of the incudostapedial

Ototoxicity of quinine in experimental animals.

Quinine is a protoplasmotic poison which, in cases of cinchonism, produces tinnitus, hearing loss, dizziness, blurring of vision, photophobia, and hypotension. Administration of a large dose may produce delirium, unconsciousness, respiratory failure, and death. Ototoxicity of quinine seems to be the result of administration of a large dose or prolonged treatment, or it may be a matter of idiosyncrasy. Hearing loss of conductive type is said to occur, by Falbe-Hansen, 1 after several clinical and experimental observations, while Forbes 2 and Ruedi et al. 3 believed it is of perceptive type. The opinions concerning the location and nature of cochlear lesions as observed in experimental animals may be divided in two groups. The first group claims that quinine produced changes in the primary cochlear neurons and hypotonic degeneration in the cochlear receptor. The features and explanation of this phenomenon were put forward by Wittmaack, 4 and have been supported by