Assessing the comfort of earplugs: development and validation of the French version of the COPROD questionnaire

Abstract

Earplugs are a common form of protection for workers exposed to hazardous noise levels. Their comfort directly impacts the effective protection by influencing their consistent and correct use. Nevertheless, comfort definition may vary according to the studies. Thus, a previous review of the literature has shown that to improve our understanding of perceived comfort and to reduce measurement variability, it is advisable to consider comfort through a multidimensional construct (physical, acoustical, functional and psychological). On this basis, the COPROD questionnaire was developed. It is intended for people working in noisy environments. Nine earplug models were evaluated by 118 participants over a six-week period. This paper presents the successive analyses that were used to validate the structure of the questionnaire and confirm the relevance of the proposed dimensions and of the addressed items. First results suggest a preference for custom molded earplugs.

A comfort evaluation method based on an intelligent car cockpit

“…This evaluation model still has many limitations; a reason is that there are too few indicators set to fully represent whether the passenger is really comfortable. To improve our understanding of comfort and reduce variability in measurements, more dimensions should be considered (Terroir et al, 2021). The vehicle price was used in the model to define the quality of human-computer interaction, which had great defects and is not well represented.…”

Towards a practical methodology for assessment of the objective occlusion effect induced by earplugs

“…In contrast with a bone transducer, using speech is more accessible as no specialized equipment is required other than a simple feedback system (e.g., screen of a sound level meter) if the vocal effort is to be monitored. Additionally, it is deemed relevant to use speech as a stimulation source since it is often associated with discomforts in real life situations (Dillon, 2012;Doutres et al, 2019;Kochkin, 2010;Terroir et al, 2021). Using one's own voice as a stimulation source is, however, associated with some limitations.…”

“…This can lead to dislike of one's own voice (Berger, 1986;Kiessling et al, 2005;Kuk et al, 2005;Suter, 2002) or even cause an inhibition to speak (Eriksson-Mangold and Erlandsson, 1984). For example, the experienced acoustical discomfort related to the OE strongly participates to the feeling of overall (dis)comfort induced by earplugs situations (Terroir et al, 2021) and thus should be reduced to avoid the in-ear device non-use or misuse, which can be critical for the wearers (Doutres et al, 2019(Doutres et al, , 2020. Historically, a baseline method to assess the OE has been done through bone conduction (BC) audiometry by measuring hearing thresholds with and without an occlusion device (Berger and Kerivan, 1983;Goldstein and Hayes, 1965;Huizing, 1960;Reinfeldt et al, 2013;Stenfelt and Reinfeldt, 2007).…”

“…This leads to a subjective measure of the OE (referred to as OE subj ), described as improved lowfrequency hearing thresholds below 2 kHz (Berger and Kerivan, 1983;Reinfeldt et al, 2013). Although the assessment of OE subj involves all BC pathways (through outer, middle, and inner ear), it does not necessarily correlate to the experienced discomforts associated with the OE (referred to as OE exp ), which are mostly assessed through questionnaires and interviews (Hansen, 1997;Kiessling et al, 2005;Kuk et al, 2005;Mueller, 2003;Terroir et al, 2021;Vasil-Dilaj and Cienkowski, 2011). An alternative method consists in measuring the sound pressure level (SPL) inside the earcanal with and without an in-ear device, which eliminates the need for a subjective response from a test subject.…”

Numerical investigation of the earplug contribution to the low-frequency objective occlusion effect induced by bone-conducted stimulation

“…2 The name "OE" encompasses several descriptions of the phenomenon: (i) objective OE defined as the sound pressure level (SPL) difference measured by placing a microphone at or near the eardrum between occluded and open configuration, [3][4][5][6][7] (ii) subjective OE defined as the difference between the open and occluded hearing thresholds, [4][5][6]8 and (iii) perceptive OE related to the discomfort induced by the phenomenon and commonly quantified using questionnaires. [9][10][11] The perceptive OE is certainly the most important phenomenon to reduce since it is directly related to the acoustical comfort dimension of EP wearers. Both subjective and perceptive OE involve all bone-conduction pathways, whereas the objective OE only involves the outer ear pathway.…”