Hearing thresholds of a non-noise-exposed population in Dundee.

In order to provide a control population for a previous investigation of noise-induced hearing loss in a population of female jute weavers (Taylor, Pearson, Mair, and Burns, I965) a survey was conducted on the hearing thresholds of 296 school teachers in Dundee, Scotland, by pure tone earphone listening. This population, although not exposed to industrial noise, is subjected to city noise and differs, therefore, from the rural population of Hinchciffe (I959), whose presbycusis data have been used in previous studies. The results show that Dundee female school teachers do not conform to British Standard in the age group I8-24 years. The presbycusis data (i8-65 years age group), however, show close agreement with those of Hinchciffe (i959) and Corso (I963). The distributions of hearing threshold observed were normal. In the assessment of hearing loss due to loom noise in a population of Dundee female jute weavers (Taylor et al., I965) it was necessary to estimate hearing threshold changes due to advancing years (presbycusis). This was done using the results available in the work of Hinchcliffe (I959) on a rural population in Scotland. It may be argued, however, that a rural population is not exposed to noise levels similar to those found within the City of Dundee and its suburbs, and that such a population may not be used as a control for the Dundee weavers. It was, therefore, necessary to find a predominantly female population not exposed to industrial noise and yet living in Dundee. Moreover, it was desirable to choose, as the control population, a large, stable occupational group with a single central administration. No industrial group satisfied these conditions. The population of female school teachers employed by the Local Authority was found to be suitable for this investigation.