Hearing Difficulties Despite Normal Audiograms: A Case of Extended High-Frequency Loss

Many people experience difficulty hearing, especially in noisy environments, despite their audiograms showing normal hearing. This can be frustrating and confusing, leaving individuals wondering why they struggle to follow conversations in cocktail-party listening situations, ultimately affecting their quality of life. We examine a specific type of hearing loss that might explain some of these challenges: extended high-frequency (EHF) hearing loss.Figure 1: Audiogram with normal (blue) and elevated (red) hearing thresholds in the EHF.Figure 2: Scores on self-assessment of hearing ability significantly lower in individuals with EHF loss. Data adapted with modifications.1WHAT IS EHF HEARING LOSS? Ears can detect a wide range of sound frequencies, from low rumbles to high-pitched squeaks (0.2 to 20kHz). EHF refers to the higher end of this range, generally above 8kHz. EHF may contribute to several crucial aspects of hearing: Speech clarity: EHF sounds add detail and sharpness to speech, making it easier to distinguish between similar-sounding words and understand conversations in noisy environments. Spatial hearing: EHF cues help us localize sound sources, allowing us to identify where a speaker is positioned or navigate complex acoustic environments. Overall sound quality: EHF contributes to the richness and fullness of various sounds, from music and nature sounds to everyday noises. EHF loss can be present despite normal audiograms. Standard hearing tests typically assess frequencies up to 8kHz. This means someone with normal results could still have a significant loss in the EHF range, impacting their ability to hear and process sounds in this crucial region. Figure 1 depicts an audiogram with normal (blue) and elevated (red) hearing thresholds in the EHF. IMPACT OF EHF LOSS Our study examined the impact of EHF loss on the daily listening experiences of young adults.1 We compared two groups: individuals with normal EHF hearing and those with EHF loss, with both groups having normal results on standard audiometric tests. The study found that over half of the participants with EHF loss reported difficulty hearing in noisy environments. This suggests they struggle to follow conversations, understand speech clearly, and participate fully in social situations with background noise. Individuals with EHF loss scored significantly lower on a self-assessment of hearing ability2 compared to those with normal EHF hearing, as depicted in Figure 2, indicating that individuals with EHF loss experience more difficulty in various everyday listening situations, including understanding speech in noise, following conversations with multiple speakers, and locating sound sources. The differences in self-reported hearing difficulties were not explained by standard audiogram results, suggesting that EHF loss specifically contributes to these everyday listening challenges. Those with lower self-reported hearing abilities also had poorer speech-in-noise recognition based on the digit triplet in noise test. This suggests a link between EHF loss and difficulties understanding speech in noisy situations. EHF LOSS: A MISSING LINK? Our findings suggest that EHF hearing loss could be a missing link for some individuals who experience hearing difficulties despite normal results on a clinical audiogram. This could explain why they struggle to understand speech in noise or navigate their surroundings using sound, even though their hearing seems normal on paper. It is important to note, however, that not everyone with EHF loss experiences these difficulties. Some individuals may have other underlying factors contributing to their hearing challenges, or their EHF loss may be too subtle to affect their daily lives. Though EHF hearing loss can impact daily life, it is rarely measured due to perceived minimal effects or lack of treatment options with normal audiograms. This leaves many adults with undetected EHF loss, potentially hindering their ability to understand speech in noise and impacting their quality of life. It is important to consider EHF hearing loss when evaluating hearing ability, even in young adults with normal results on standard tests. Further research is needed to understand the individual variations in how EHF loss manifests and its impact on hearing in different people. Future research should also explore potential management strategies for individuals with EHF loss, including hearing aids or other interventions. By acknowledging the potential impact of EHF loss and continuing research in this area, we can help individuals with these challenges receive appropriate diagnosis and support, ultimately improving their quality of life and ability to fully engage with the world around them.