Tympanometry in the evaluation of vascular lesions of the middle ear and tinnitus of vascular origin.

The occurrence of vascular perturbations in the tympanogram in association with glomus tumors has previously been noted in the literature. We have broadened the scope of this method of diagnosis in the study of 3 glomus tympanicum and 3 glomus jugulare tumors, 1 dehiscent high jugular bulb, 1 aberrant carotid artery in the middle ear and 2 cases of pulsatile tinnitus of vascular origin. Analysis of illustrative tympanograms at standard and at increased sensitivity (x 20) obtained in these cases are presented. The following factors as they relate to the mechanism of recording the vascular perturbations are presented: air pressure and/or presence of fluid in the middle ear; compliance of the tympanic membrane and ossicular chain as affected by the mass, size and degree of vascularity of the mass and presence of extraneous sounds. A new method of recording the vascular perturbations utilizing a time-base generator affixed to an X-Y plotter is described. It is the purpose of this study to demonstrate the utility of obtaining tympanograms at standard and at increased sensitivity in the evaluation of vascular middle ear lesions and tinnitus of vascular origin.