Hearing sensitivity in rural Michigan.

In a survey of the hearing sensitivity of a rural mid-Michigan population, 1,325 adults over 15 years of age received pure tone air conduction tests in a "mini" IAC room housed in a small trailer. In addition, a detailed questionnaire was administered to each person to obtain information about his exposure to noise vocationally and avocationally, family history of hearing loss, etc. Results indicated that, on the average, individuals displayed hearing losses considerably greater than was predicted on the basis of presbycusis alone. Also, people who had never had any industrial noise exposure had thresholds almost as poor as those who had worked in factories. These findings are discussed in view of the subject's exposure to various types of nonoccupational noise such as snowmobiles and motorcycles.