Effect of Below-Damage-Risk Criteria Environmental Noise On Auditory Perception and Working Memory

Abstract

Background: The current research finding is the first in reporting impaired auditory and cognitive abilities consequent to chronic exposure to below-damage-risk criteria (DRC) environmental noise in humans. Objective: The objective of this study is to assess the chronic effects of occupational noise below DRC on auditory and cognitive abilities. Methods: A static-group comparison design was used, with three groups with varying levels of noise exposure below DRC. Shopkeepers working in busy areas exposed daily to environmental noise below DRC and shopkeepers working in quiet residential areas and college students in quiet environments. Speech perception in noise, acceptable noise levels, and concurrent vowel identification were used to assess auditory abilities, while Operation SPAN and Backward Digit Span were used to assess cognitive abilities. The data were analyzed using multivariate analysis of variance, Pearson's product-moment correlation, discriminant function analysis, and mediation analysis. Results: The results showed significantly poor auditory stream segregation abilities and working memory abilities in the shopkeepers exposed to environmental noise below DRC when compared to the other two groups with very low levels of occupational noise. The findings of the study are discussed in light of the deleterious effect of the supposedly safe (below DRC) levels of environmental noise on auditory and cognitive abilities. Conclusions: The novel results of affected auditory and cognitive abilities resulting from below-DRC occupational noise exposure as observed in the current study will have a great impact on the applicability to the general populace and also open up new avenues of research in ecological acoustics.