Low-Cost Earmuff Shown to Significantly Reduce Cast-Saw Noise.

Hearing protection devices reduce cast-saw noise. It would be helpful to identify the devices that are both effective and economical. Prior studies have shown that expensive noise-reduction headphones significantly reduced the anxiety associated with cast removal with a powered oscillating saw. The cost of such headphones, however, is a drawback for some practices and hospitals. It would be helpful to determine whether lower cost ear protection can provide effective cast-saw noise reduction. In addition, it is unclear whether the noise reduction ratings (NRRs), the average sound-level reduction provided by a hearing protection device in a laboratory test, provided by manufacturers accurately characterize the effectiveness for reducing cast-saw noise. Note that noise-cancelling devices do not carry an NRR because they are not designed as hearing protectors. Five ear protection devices with different NNRs were tested. The devices varied greatly in cost and included earplugs, low-cost earmuffs, and noise-cancelling headphones. To standardize the evaluation, each device was fitted to an acoustic mannequin with high-fidelity ear microphones while a fiberglass spica cast was cut. An additional test was run without hearing protection as a control. The low-cost devices significantly reduced the saw noise, with the exception of earplugs, which had highly variable performance. The noise reduction was similar between low-cost earmuffs and the high-cost earphones when the noise-cancelling feature was not active. Active noise cancelling provided further reductions in the noise level. Patients can experience high anxiety during cast removal. The current study shows that low-cost earmuffs significantly reduce cast-saw noise. Patient care settings may be more likely to offer hearing protection that is one twenty-fifth the cost of noise-cancelling headphones. An NRR appears to be a reliable guide for selecting hearing protection that reduces cast-saw noise.

A simple, cost-effective, and novel method for determining the efficiency of industrial and commercial noise-canceling earmuffs.

CONTEXT: There are several ways to assess the noise reducing efficiency of earmuffs, but they usually involve using human participants and/or specialized equipment. OBJECTIVE: The current study was designed to develop a less labor-intensive, cost-effective, participant-free first-pass method for measuring the efficiency of earmuffs. METHODS: We evaluated the noise-cancelling ability of five different types of earmuffs (3M: Optime 98, Optime 105; iDEA USA V201; Tronsmart Encore S6; Bose QuietComfort 35) under laboratory and field conditions. We compared our results to the microphone-in-real-ear (MIRE) method. Lastly, a survey of college-aged students was also conducted to determine which earmuffs were the most comfortable and provided the best fit. RESULTS: Of the five earmuffs studied, the Optime 98 and Bose earmuffs were most effective at reducing noise levels in both the laboratory and field. These earmuffs also received the highest scores for comfort, fit, and perceived ability to reduce noise, with Bose being slightly more preferred than Optime 98. The MIRE method provided the same overall results as the laboratory and field tests. CONCLUSION: Our method for evaluating the noise-canceling ability of earmuffs could be used to supplement more complicated testing procedures as a first-pass method.

Costs and effectiveness of hearing conservation programs at 14 US metal manufacturing facilities.

OBJECTIVE: This study characterised overall and specific costs associated with hearing conservation programmes (HCPs) at US metal manufacturing sites, and examined the association between these costs and several noise-induced hearing loss (NIHL) outcomes. DESIGN: We interviewed personnel and reviewed records at participating facilities. We also measured noise for comparison to the ten-year average of measurements made by each facility. NIHL outcomes assessed included rates of standard threshold shifts (STS) and high-frequency hearing loss, as well as prevalence of hearing impairment, for each participating facility. We used linear regression to identify per-person HCP costs that best predicted the NIHL outcomes. STUDY SAMPLE: We evaluated 14 US metal manufacturing facilities operated by a single company. RESULTS: Annual HCP costs ranged from roughly $67,000 to $397,000 (average $308 ± 80 per worker). Our full-shift noise measurements (mean 83.1 dBA) showed good agreement with the facilities' measurements (mean 82.6 dBA). Hearing impairment prevalence was about 15% overall. Higher expenditures for training and hearing protector fit-testing were significantly associated with reduced STS prevalence. Higher training expenditures were also related to lower hearing impairment prevalence and high-frequency hearing loss rates. CONCLUSIONS: HCP costs were substantial and variable. Increased workplace spending on training and fit-testing may help minimise NIHL.

Cost-Effective Hearing Conservation: Regulatory and Research Priorities.

Hearing conservation programs (HCPs) mandated by the US Occupational Safety and Health Administration (OSHA) cost about $350/worker/year. Are they cost-effective? A cross-sectional model of the US adult population with and without HCPs incorporates (1) the American Medical Association's method for estimating binaural hearing impairment and whole-person impairment; (2) the model of the International Organization for Standardization (ISO) for estimating both age-related and noise-induced hearing loss; and (3) an acceptable cost of $50,000 per quality-adjusted life year. The ISO model's outputs were audiometric thresholds for groups of people with different age, sex, and noise exposure history. These thresholds were used to estimate cost per quality-adjusted life year saved for people in HCPs with different noise exposure levels. Model simulations suggest that HCPs may be cost-effective only when time-weighted average (TWA) noise exposures are ≥ 90 dBA. Enforcing existing regulations, requiring engineering noise control at high exposure levels, and using new methods that can document hearing protection device performance could improve cost-effectiveness. If the OSHA action level remains at 85 dBA-TWA, reducing the permissible exposure limit to the same level would simplify management and slightly improve cost-effectiveness. Research should evaluate employer compliance across industries, determine whether workers currently excluded from HCP regulations are at risk of noise-induced hearing loss, and develop cost-effective HCPs for mobile workers in construction, agriculture, and oil and gas drilling and servicing. Research on HCP cost-effectiveness could be extended to incorporate sensitivity analyses of the effects of a wider range of assumptions.

Increase in use of protective earplugs by Rock and Roll concert attendees when provided for free at concert venues.

OBJECTIVE: To determine the prevalence of hearing protection use among attendees of Rock and Roll concerts at baseline and in concerts where earplugs are provided for free at concert venue entrances. DESIGN: Six concerts performed at two music venues in Toronto, Canada were evaluated. Study personnel observed and recorded the use of hearing protection at three concerts where no earplugs were distributed, and three concerts where earplugs were provided for free at the concert venue entrance. STUDY SAMPLE: A total of 955 individuals over the age of 18 were observed at six concerts. Six hundred and thirty-seven individuals (64% male) were observed at concerts where no earplugs were provided, and 318 individuals (68% male) were observed at concerts where free earplugs were provided. RESULTS: Multivariate logistic regression demonstrated a significant increase in hearing protection usage at concerts where earplugs were provided for free at the concert venue entrance, odds ratio 7.27 (95% CI: 3.24-16.30). CONCLUSION: The provision of free earplugs at concert venues may be a simple and inexpensive intervention that could be a component of a larger public health campaign to prevent non-occupational noise-induced hearing loss.

Hearing protection for clubbers is music to their ears.

ISSUE ADDRESSED: while it is difficult to promote the use of hearing protectors in noisy workplaces and leisure settings, some nightclub attendees choose to wear earplugs when exposed to loud music. This qualitative study investigated the perceptions of clubbers about the advantages and disadvantages of earplug use in nightclubs. Such first-hand information could potentially be used to educate non-wearers about the features of different earplug types, the experience of wearing earplugs and their relative merits. METHODS: structured telephone interviews were conducted with 20 regular clubbers who wear different types of earplugs at nightclubs. Participants were asked about their experience of wearing earplugs and, in particular, what they perceive to be the advantages and disadvantages of earplugs. RESULTS: participants' responses revealed that cheaper foam earplugs are considered less satisfactory than more expensive earplugs, which are relatively discreet and comfortable, facilitate communication with others, create minimal music distortion and, in some cases, improve music sound quality. In terms of effectiveness, all types of earplugs were considered beneficial in reducing the after-effects of loud music and providing hearing protection. CONCLUSIONS: the perceived advantages of earplugs, which are often not recognised by non-earplug wearers, should be communicated in order to encourage the use of earplugs among clubbers.

Earplugs and eye masks: do they improve critical care patients' sleep?

Disturbed sleep and sleep deprivation is common in patients in critical care settings. Noise and inappropriate use of light/dark cycles are two of the causes of sleep interruptions. The purpose of the study was to evaluate eye masks and earplugs to help control patients' exposure to noise and light within the critical care environment. An intervention study using a two group post-test quasi-experimental design of high dependency patients within a cardiothoracic critical care unit was undertaken by a group of critical care nurses. Sleep assessment rating scales and open-ended questions were used to obtain patients' reported experiences of their sleep. Patients self-selected into either an intervention or non-intervention group. Sixty-four patients consented to take part in the study, 34 patients tried the interventions earplugs and eye masks and many found they improved sleep. However, noise was still a factor preventing sleep for both groups of patients. Mixed reports were found with the interventions from very comfortable to very uncomfortable. At a cost of 2.50 pounds sterling/patient, earplugs and eye masks were a relatively cheap intervention with notable improvements for some critically ill patients. Further research is required with a larger sample size, plus an examination of both earplugs and eye masks separately. Offering patient's earplugs and eye masks to improve sleep should be considered as a matter of routine nursing practice, this should include time to show patients how to use and try them out for comfort.