Occlusion and coupling effects with different earmold designs – all a matter of opening the ear canal?

Denk, Florian; Hieke, Thomas; Roberz, Malte; Husstedt, Hendrik

doi:10.1080/14992027.2022.2039966

Cited by 5 publications

(4 citation statements)

References 21 publications

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“…For the other half of the hearing aid users, a custom earmold was available and could be used for the study. An important feature of the coupling is the venting, which affects various important properties such as the maximum sound pressure level at lower frequencies, the amount of leakage (direct) sounds, the feedback path, the occlusion effect, or own voice perception [34]. Due to the nature of impulse sounds, most of the energy is at higher frequencies.…”

Section: Couplingmentioning

confidence: 99%

Evaluation of impulse noise reduction in hearing aids with technical measurements and ratings of discomfort

Husstedt,

Hilgerdenaar,

Frenz

et al. 2023

Acta Acust.

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Short, impulse-like sounds such as slamming of a door or rattle of dishes can be uncomfortable for hearing aid users. Therefore, many hearing aids provide impulse (or transient) noise reduction (INR) that should reduce loud and short sounds without impairing desired signals. In this work, we want to address the question whether hearing aid users require this type of signal processing to experience impulse sounds similarly as normal-hearing listeners. For this purpose, we evaluated INR in six commercially available hearing aids with technical measurements and with test subjects. During the technical evaluation, we presented seven different impulse signals to the hearing aids attached to a head and torso simulator (HATS) and determined the C-weighted peak sound pressure levels (LC,peak) at the output in different configurations. For the evaluation with test subjects, the discomfort of the same impulse sounds was rated by 24 hearing-impaired and 20 normal-hearing subjects. All subjects rated the discomfort unaided, and the hearing-impaired subjects also while successively wearing all six hearing aids with and without activated INR. As a main conclusion, hearing aid users without INR did not experience more discomfort compared to normal-hearing listeners for most of the impulse signals tested including the most uncomfortable ones, but INR further reduced experienced discomfort. Moreover, the technical measurements were correlated with the subjective ratings on discomfort.

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Section: Couplingmentioning

confidence: 99%

Evaluation of impulse noise reduction in hearing aids with technical measurements and ratings of discomfort

Husstedt,

Hilgerdenaar,

Frenz

et al. 2023

Acta Acust.

Self Cite

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“…In particular, we wished to investigate the potential contribution of occlusion and microphone position . Hearing-aid earmolds can be more or less occluding ( Cubick et al, 2022 ), and this has well-known effects on the perception of one's own voice ( Denk et al, 2023 ; Dillon, 2012 ; Winkler et al, 2016 ). It has been speculated previously that occluding earmolds may also disrupt the perception of external sounds ( Byrne et al, 1998 ; Byrne & Noble, 1998 ) but this idea has never been formally investigated.…”

Section: Introductionmentioning

confidence: 99%

Externalization of Speech When Listening With Hearing Aids

Best,

Roverud

2024

Trends in Hearing

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Subjective reports indicate that hearing aids can disrupt sound externalization and/or reduce the perceived distance of sounds. Here we conducted an experiment to explore this phenomenon and to quantify how frequently it occurs for different hearing-aid styles. Of particular interest were the effects of microphone position (behind the ear vs. in the ear) and dome type (closed vs. open). Participants were young adults with normal hearing or with bilateral hearing loss, who were fitted with hearing aids that allowed variations in the microphone position and the dome type. They were seated in a large sound-treated booth and presented with monosyllabic words from loudspeakers at a distance of 1.5 m. Their task was to rate the perceived externalization of each word using a rating scale that ranged from 10 (at the loudspeaker in front) to 0 (in the head) to −10 (behind the listener). On average, compared to unaided listening, hearing aids tended to reduce perceived distance and lead to more in-the-head responses. This was especially true for closed domes in combination with behind-the-ear microphones. The behavioral data along with acoustical recordings made in the ear canals of a manikin suggest that increased low-frequency ear-canal levels (with closed domes) and ambiguous spatial cues (with behind-the-ear microphones) may both contribute to breakdowns of externalization.

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“…However, the deep insertion can be responsible for mechanical discomfort due to the sensitivity of the earcanal bony part. For hearing aids, the use of vents 10 – 12 or open fittings 13 , 14 can drastically reduce the occlusion effect. These solutions are based on the reduction of the acoustic impedance of the occluded earcanal compared to an acoustically rigid occlusion 15 but come at the cost of decreasing the hearing aid performance due to acoustic feedback, limited amplification gain and near zero suppression of ambient noise 12 , 16 .…”

Section: Introductionmentioning

confidence: 99%

“…For hearing aids, the use of vents 10 – 12 or open fittings 13 , 14 can drastically reduce the occlusion effect. These solutions are based on the reduction of the acoustic impedance of the occluded earcanal compared to an acoustically rigid occlusion 15 but come at the cost of decreasing the hearing aid performance due to acoustic feedback, limited amplification gain and near zero suppression of ambient noise 12 , 16 . Furthermore, these solutions are not suitable for earplugs to ensure sufficient sound attenuation required for hearing protection purpose.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the occlusion effect induced by earplugs using quasi perfect broadband absorption

Carillo

Sgard

Dazel

et al. 2022

Sci Rep

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Passive earplugs are used to prevent workers from noise-induced hearing loss. However, earplugs often induce an acoustic discomfort known as the occlusion effect. This phenomenon corresponds to an increased auditory perception of the bone-conducted part of physiological noises at low-frequency and is associated with the augmentation of the acoustic pressure in the occluded earcanal. In this work, we report a new concept of passive earplugs for mitigating the occlusion effect between 100 Hz and 1 kHz. The strategy consists in reducing the input impedance of the earplug seen from the earcanal by using quasi-perfect broadband absorbers derived from the field of meta-materials. The proposed “meta-earplug” is made of 4 critically coupled Helmholtz resonators arranged in parallel. Their geometry is optimized using an evolutionary algorithm associated with a theoretical model of the meta-earplug input impedance. The latter is validated against a finite-element approach and impedance sensor measurements. The meta-earplug is manufactured by 3D printing. Artificial test fixtures are used to assess the occlusion effect and the insertion loss. Results show that the meta-earplug induces an occlusion effect approximately 10 dB lower than foam and silicone earplugs while it provides an insertion loss similar to the silicone earplug up to 5 kHz.

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Occlusion and coupling effects with different earmold designs – all a matter of opening the ear canal?

Cited by 5 publications

References 21 publications

Evaluation of impulse noise reduction in hearing aids with technical measurements and ratings of discomfort

Evaluation of impulse noise reduction in hearing aids with technical measurements and ratings of discomfort

Externalization of Speech When Listening With Hearing Aids

Reduction of the occlusion effect induced by earplugs using quasi perfect broadband absorption

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