Eustachian tube function in an American Indian population.

A comparatively high prevalence of acute and chronic otitis media (OM) has been reported for the native American Indian population. The present study reports data on the function of the eustachian tube (ET) in 25 White Mountain Apache Indians ranging in age from 3 to 36 years. All study subjects had a history of OM and reported to the reservation clinic with tympanic membrane perforations and a dry middle ear (ME). The results of inflation-deflation tests on these subjects indicated that the Indians had lower forced opening pressures than had been measured in a group of Caucasians with perforations secondary to chronic OM. Of the 23 subjects studied, 67% equilibrated applied positive ME pressures and 38% equilibrate negative pressures by swallowing. During forced response testing, the passive resistance of the ET was found to be lower and the active resistance equivalent to that of a group of Caucasians with traumatic perforations and otherwise negative otologic histories. While the ET was predilated in these subjects by constant airflow, active swallowing further dilated the tube in 67% of the subjects, constricted the tube in 25%, and had no effect in 8%. This study indicated that the ET of the American Indian was functionally different from that of Caucasians previously studied and was characterized by comparatively abnormal, low passive tubal resistance which may be considered to facilitate ventilatory function and to impair protective function. The difference may account for the high prevalence of OM with perforation and the low incidence of cholesteatoma in this population.