Effect of life in industrialized societies on hearing in natives of Easter Island.

In an effort to determine whether life in industrialized societies can have an effect on hearing, 90 natives from Easter Island over 45 years old were evaluated. They underwent complete clinical and audiological assessment and were divided into groups according to those having lived only on the island or those having lived in modern civilization. With all factors being equal, except exposure to modern civilization, our results showed that living in civilized societies has a significant negative effect on hearing; the severity is directly proportional to the years of exposure. The median hearing thresholds of natives always living on the island (men and women combined) was found to be similar to those of female citizens of the United States; there was no significant difference in hearing thresholds between men and women among these natives. These results suggest that there are no significant inherent racial differences nor significant inherent differences between males and females in the sensitivity of hearing. A relationship between aging and hearing was noted and interpreted as true or intrinsic presbycusis. There were no cases of otosclerosis, Meniere's disease, or exostoses of the external ear canal among natives who had always lived on the island. Pure natives were found not to be prone to otitis media in spite of having an extremely high incidence of severe upper respiratory tract allergies.