EVIDENCE OF FUNCTIONAL RÔLE OF BASILAR MEMBRANE IN AUDITION

Abstract

A number of normal adults were given 2-4 gm. NaN02 to lower the blood pressure and the alterations in their audiograms were studied. It is considered that the alteration was due to vasodila-tation of the cochlear artery in its unbranched portions, the vasodilatation producing increased weight to the basilar membrane and interfering with its auditory function. Epinephrine (15-30 minims) was administered to these individuals and their audiograms studied. Reasons are given for assuming that vasoconstriction of the cochlear artery results, the vasoconstriction decreasing the weight of the basilar membrane and increasing its auditory function. It was found that marked depression and considerable increase of auditory acuity resulted in that portion of the organ of Corti directly over the unbranched cochlear artery which responded by vasodilatation and vasoconstriction. It is concluded that the basilar membrane is actively concerned in audition although it is not denied that the tectorial membrane may also be necessary.[long dash]Author''s summary and conclusions.