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Hearing loss is known to impair sound perception at low levels. Clinical practice places considerable emphasis on evaluating and compensating for hearing deficits at low levels [1], even though higher levels are common in everyday listening [2] and sound perception at higher levels may also be affected. Some individuals with a hearing loss perceive loud sounds similarly to normal-hearing listeners, whereas others are more or less sensitive to them [3]. Therefore, the cooperative project “LoudSounds” focuses on sound perception at moderate to high levels in individuals with and without hearing loss and on hearing aid compensation strategies in this level range.

In an initial study, reference data from 20 normal-hearing listeners were collected at two sites, Lübeck and Odense, using a closely aligned test battery. Speech intelligibility (SI) in noise was measured at 65 and 80 dB SPL speech level using adaptive and fixed-SNR procedures. Spectro-temporal modulation detection (STMD) was assessed at the same levels to examine its suitability as a proxy for speech processing abilities at high levels. Loudness perception (MCL, UCL) was assessed using adaptive categorical loudness scaling complemented by speech and speech-in-noise MCL/UCL measurements analogous to routine clinical measurements. Furthermore, discomfort ratings for various impulsive sounds that increased in level were collected, aiming to verify whether a previously developed free-field impulse procedure yields comparable outcomes when applied via headphones. Testing was performed under monaural and binaural conditions.

Preliminary analyses show expected level-dependent effects across the various measures. The SI results show declines with increasing level (“rollover”) in most participants, with binaural presentation leading to more rollover. The STMD results show similar effects at group level, but no clear correlation at the individual level. The loudness assessments performed with ACALOS and the clinically oriented MCL/UCL measurements show good test-retest reliability. The results of the two methods do not correlate strongly, indicating that they capture different aspects of loudness perception. The impulse discomfort data confirm that the previously established procedure can be applied successfully with headphones, producing outcomes comparable to loudspeaker presentation.

Overall, this study will provide a comprehensive dataset on sound perception at moderate to high levels for normal-hearing and hearing-impaired listeners. The initial results underscore the relevance of supra-threshold hearing assessment and form the basis for follow-up measurements with hearing-impaired listeners.

References

[1] Gelfand SA. Essentials of Audiology. 4. Aufl. Thieme; 2016.
[2] Christensen JH, Saunders GH, Porsbo M, Pontoppidan NH. The everyday acoustic environment and its association with human heart rate: evidence from real-world data logging with hearing aids and wearables. R Soc Open Sci. 2021 Feb 17;8(2):201345. DOI: 10.1098/rsos.201345
[3] Fereczkowski M, Neher T. Predicting Aided Outcome With Aided Word Recognition Scores Measured With Linear Amplification at Above-conversational Levels. Ear Hear. 2023 Jan-Feb 01;44(1):155-166. DOI: 10.1097/AUD.0000000000001263