Autophony in patients with patulous eustachian tube: Experimental investigation using an artificial middle ear

OBJECTIVE: To investigate the contribution of anatomical factors, such as the caliber of the patent eustachian tube (ET) and the volume of the middle ear cavity, on vocalized sound transmission to the inner ear. METHODS: Model experiment using artificial middle ear. RESULTS: In the present model experiment, sound transmission from the pharynx to the inner ear under patulous conditions was affected by the caliber of the ET and by the mastoid volume, especially in the low-frequency region, that is, a larger caliber of the ET and smaller mastoid volume resulted in greater sound transmission from the pharyngeal space to the inner ear. CONCLUSION: Patulous symptoms may be more distressful in patients with poorly developed mastoid cavity than in those with well-aerated mastoid under similar conditions of patulous ET.