Hearing conservation programs have long relied on lagging indicators. Audiograms and Significant Threshold Shifts (STS) confirm hearing damage after it has already occurred. They do not identify risk before permanent change sets in.
New research published in the International Journal of Audiology shows that the Personal Attenuation Rating (PAR) can fill that gap. The study demonstrates that PAR serves as a leading indicator of hearing risk, helping large-scale hearing conservation programs identify individuals most likely to experience hearing shifts before damage becomes permanent.
The study, led by Devon Kulinski, AuD, with Benjamin Sheffield and Douglas Brungart, analyzed real-world hearing protector fit testing and audiometric data from nearly 1,900 service members during routine hearing conservation appointments. The findings have direct implications for how modern programs approach prevention, fit testing, and operational efficiency.
Why Personal Attenuation Rating matters
PAR measures the actual attenuation an individual achieves with their hearing protection, not the assumed protection based on device labeling or population averages. Unlike metrics such as the Noise Reduction Rating (NRR), PAR reflects real-world fit and use.
This distinction is critical. Research has repeatedly shown that hearing protector attenuation varies widely among users, even when the same device is worn. As hearing conservation programs move toward individualized protection strategies, PAR provides visibility that audiograms alone cannot.
The study focused on two practical questions. Is there a relationship between PAR and the likelihood of experiencing an STS? Can existing pure-tone audiometric thresholds be used to streamline fit testing without sacrificing accuracy? The answers to both point to PAR as both a risk signal and a program efficiency lever.
Zero attenuation signals elevated risk
The strongest finding emerged at the lowest end of the PAR scale.
Participants with 0 dB PAR, meaning they received essentially no effective attenuation from their hearing protection, had an STS rate of 17.3%. That is more than double the overall sample average of 7.7%.
This reframes poor fit as more than a compliance issue or training gap. Inadequate attenuation is directly associated with measurable auditory injury over a one-year period.
Equally important, the study found no meaningful relationship between current hearing thresholds and PAR performance. Individuals with normal audiograms were just as likely to show poor attenuation. Audiometry alone cannot reveal this risk, underscoring the value of fit testing as a complementary tool.
A practical attenuation threshold emerges
Beyond identifying high-risk individuals, the researchers examined whether a minimum acceptable PAR could be defined.
Using both discrete and cumulative analyses, 15 dB PAR emerged as a meaningful inflection point. Below this level, STS rates increased steadily as attenuation decreased. Above it, further attenuation yielded diminishing returns in reducing hearing shift prevalence.
For program managers, this supports a targeted, risk-based approach. Focusing intervention on individuals below 15 dB PAR captures those most likely to benefit while avoiding unnecessary retesting and retraining for the broader population. Better outcomes do not require pushing everyone to extreme attenuation. They require identifying and correcting the lowest performers.
Cutting fit testing time nearly in half
The study also addressed a persistent operational challenge: time.
Many hearing conservation programs perform both pure-tone audiometry and hearing protector fit testing during the same appointment, often duplicating unoccluded threshold measurements.
The researchers demonstrated a strong correlation (R² = 0.85) between standard PAR calculations and PAR estimates derived by substituting existing pure-tone audiometric thresholds for the unoccluded portion of fit testing. Agreement between methods was high, with minimal systematic bias.
One of the study’s data collection sites used the Wireless Automated Hearing Test System (WAHTS), a wearable, boothless audiometric system that conducts both audiometry and hearing protector fit testing within the same clinical workflow. This integrated approach shows how modern hearing conservation programs can improve efficiency while maintaining high-quality, defensible data collection.
Practically speaking, this approach could reduce fit testing time by approximately 50% without compromising accuracy. For enterprise-scale programs managing thousands of annual tests, that time savings can be redirected toward training, retesting high-risk individuals, or expanding program access.
What this means for modern hearing conservation
Taken together, the findings position PAR as more than a documentation metric. PAR becomes a proactive tool that enables programs to identify individuals at highest risk before hearing damage occurs, focus training and intervention where it matters most, improve efficiency without sacrificing data quality, and shift from reactive monitoring to preventive risk management.
Audiograms remain essential. They document hearing status and track changes over time, but they tell us what has already happened.
PAR tells us what is likely to happen next.
For organizations responsible for protecting hearing at scale, this shift from lagging indicators to early warning signals is not incremental. It is foundational.
Ready to move from reaction to prevention?
If your hearing conservation program is looking to identify risk earlier, reduce testing inefficiencies, and make better use of fit-testing data, WAHTS helps integrate audiometry and hearing protector fit testing into a single, scalable workflow. Learn how WAHTS supports modern hearing conservation programs focused on prevention, efficiency and defensible data.