The Effectiveness of Hearing Protection Devices: A Systematic Review and Meta-Analysis

Abstract

Background: To prevent intensive noise exposure in advance and be safely controlled during such exposure, hearing protection devices (HPDs) have widely been used for workers. The present study evaluates the effectiveness of these HPDs, partitioned into three different outcomes, such as sound attenuation, sound localization, and speech perception. Methods: For thus systematic review and meta-analysis, standardized mean differences (SMDs) and effect size were calculated using a random-effect model. Seven electronic journal databases were used to search published articles from 2000 to 2020. Based on inclusion criteria, 20 articles were chosen and then analyzed. Results: Overall, the HPD function performed significantly well for their users (SMDs: 0.457, 95% confidence interval [CI]: 0.034-0.881, p< 0.05). Specifically, a subgroup analysis showed a meaningful difference in sound attenuation (SMDs: 1.080, 95% CI: 0.167-1.993, p< 0.05) when to wear and not to wear HPDs, but indicated no significance between the groups for sound localization (SMDs: 0.177, 95% CI: 0.540-0.894, p = 0.628) and speech perception (SMDs: 0.366, 95% CI: -0.100 -1.086, p = 0.103). Conclusions: The HPDs work well for their originally designated purposes without interfering to find the location of the sound sources and for talking between workers. In a further study, various factors, such as characteristics of the users, selection of appropriate types, and fitting methods for wearing in different circumstances should be differenciated in terms of offering the most useful infomation to the workers.