Definition of hearing impairment and its effect on prevalence figures. A survey among senior citizens

In order to explain the variation found in the literature, this article describes how the definition of hearing impairment affects reported prevalence when applied to the same population. The study comprised 1041 persons (354 women, 687 men) aged 55 years or older (mean age 67 years, SD 7 years). Pure tone audiometry was performed on all subjects. They were asked about their hearing by means of a structured questionnaire. The prevalences of hearing impairment were calculated based on nine criteria including: participants' subjective impression, five Dutch and international audiometric definitions, consultation of a General Practitioner, referral to an ENT specialist and hearing aid possession. Results showed a variation in prevalence figures from 6 to 30% and 10 to 49%, for women and men, respectively. Definitions including 4 kHz emphasized sex differences more strongly. In conclusion, gross differences in prevalence figures on hearing impairment are found as a result of the definition used. The variation in prevalence figures found in the literature can, at least partly, be explained by the use of different definitions.