The effects of mastoid aeration on autophony in patients with patulous eustachian tube.

The effect of the mastoid pneumatization on sound transmission from the nasopharyngeal cavity to the inner ear, which is one of the important factors to indicate the severity of the patulous eustachian tube (ET), are investigated in patients with patulous ET. Twenty ears of 13 subjects with patulous ET were retrospectively analyzed. Sound transmission from the nasopharyngeal cavity to the inner ear was evaluated by observing the masking effects of noise presented in the nasopharyngeal cavity on the auditory threshold (nasal noise masking audiometry). The relationship between this masking effect and mastoid pneumatization were examined among the patients with similar conditions of ET patency. The masking effect of nasally presented noise was greater with less developed mastoid pneumatization. The present results indicate that the symptoms associated with patulous ET may be more distressful in patients with poorly developed mastoid cavity than in those with well-aerated mastoid under similar conditions of ET patency.