Speech intelligibility assessment of protective facemasks and air-purifying respirators

Abstract

Speech Intelligibility (SI) is the perceived quality of sound transmission. In healthcare settings, the ability to communicate clearly with coworkers, patients, etc. is crucial to quality patient care and safety. The objectives of this study were to 1) assess the suitability of the Speech Transmission Index (STI) methods for testing reusable and disposable facial and respiratory personal protective equipment (protective facemasks [PF], N95 filtering facepiece respirators [N95 FFR], and elastomeric half-mask air-purifying respirators [EAPR]) commonly worn by healthcare workers, 2) quantify STI levels of these devices, and 3) contribute to the scientific body of knowledge in the area of SI. SI was assessed using the STI under two experimental conditions: 1) a modified version of the National Fire Protection Association 1981 Supplementary Voice Communications System Performance Test at a Signal to Noise Ratio (SNR) of −15 (66 dBA) and 2) STI measurements utilizing a range of modified pink noise levels (52.5 dBA (−2 SNR) − 72.5 dBA (+7 SNR)) in 5.0 dBA increments. The PF models (Kimberly Clark 49214 and 3M 1818) had the least effect on SI interference, typically deviating from the STI baseline (no-mask condition) by 3% and 4% STI, respectively. The N95FFR (3M 1870, 3M 1860) had more effect on SI interference, typically differing from baseline by 13% and 17%, respectively for models tested. The EAPR models (Scott Xcel and North 5500) had the most significant impact on SI, differing from baseline by 42% for models tested. This data offers insight into the performance of these apparatus with respect to STI and may serve as a reference point for future respirator design considerations, standards development, testing and certification activities.

Efficacy of masks and face coverings in controlling outward aerosol particle emission from expiratory activities

“…www.nature.com/scientificreports/ This finding corroborates the interpretation that some proportion of the particulates observed during expiration were particulates aerosolized from the masks themselves. Another factor to consider is that masks can reduce the intelligibility of the speech signal 58 , and can reduce the intensity of sounds passed through them by a significant amount (e.g., > 10 dB in Saedi et al 59 ). Likely as a response to this, people will speak louder and otherwise adjust their speech when wearing masks.…”

Impact of enhanced personal protective equipment on colonoscopy performance during the COVID-19 pandemic

“…FFP respirators result in an array of physiological and psychological effects, with prolonged usage interfering with respiration, thermal equilibrium, and vision [11]. FFP respirators also interfere with inter-professional communication between health care workers [12]. Vision is of paramount importance during colonoscopy, as aspects including visual acuity, peripheral vision, and color detection are crucial for detection of lesions.…”

Speech intelligibility in respiratory protective equipment - Implications for verbal communication in critical care

“… Palmiero et al. (2016) [ 34 ] J Occup Environ Hyg n/a [laboratory] FRSM, FFP & half-mask elastomeric STI f calculated from test tones. RPE type FRSM: mean STI 0.78–0.79 (excellent).…”

“…When RPE has been evaluated in a laboratory setting (using test tones played through a specialist manikin wearing a variety of masks), FRSM were found to have excellent STI, FFR/FFP good STI, and elastomeric half-mask respirators poor/fair STI [ 34 ]. By cross-referencing their measured STI of a particular FFR at 0.71 with the findings of Radonovich et al.…”