Measurement of hearing aid internal noise

Lewis, James D.; Goodman, Shawn S.; Bentler, Ruth A.

doi:10.1121/1.3327808

Cited by 14 publications

(16 citation statements)

References 8 publications

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“…While SNR has been shown to remain similar across gain settings in some hearing aids [4], SNR can also vary significantly from one device and recording condition to another [28]. These considerations are important when using a physiological discrimination approach; while one hearing aid may show a physiological amplification affect, another device may not because of the specific acoustic features that are modified.…”

Section: Discussionmentioning

confidence: 99%

Clinical Use of Aided Cortical Auditory Evoked Potentials as a Measure of Physiological Detection or Physiological Discrimination

Billings

Papesh

Penman

et al. 2012

International Journal of Otolaryngology

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The clinical usefulness of aided cortical auditory evoked potentials (CAEPs) remains unclear despite several decades of research. One major contributor to this ambiguity is the wide range of variability across published studies and across individuals within a given study; some results demonstrate expected amplification effects, while others demonstrate limited or no amplification effects. Recent evidence indicates that some of the variability in amplification effects may be explained by distinguishing between experiments that focused on physiological detection of a stimulus versus those that differentiate responses to two audible signals, or physiological discrimination. Herein, we ask if either of these approaches is clinically feasible given the inherent challenges with aided CAEPs. N1 and P2 waves were elicited from 12 noise-masked normal-hearing individuals using hearing-aid-processed 1000-Hz pure tones. Stimulus levels were varied to study the effect of hearing-aid-signal/hearing-aid-noise audibility relative to the noise-masked thresholds. Results demonstrate that clinical use of aided CAEPs may be justified when determining whether audible stimuli are physiologically detectable relative to inaudible signals. However, differentiating aided CAEPs elicited from two suprathreshold stimuli (i.e., physiological discrimination) is problematic and should not be used for clinical decision making until a better understanding of the interaction between hearing-aid-processed stimuli and CAEPs can be established.

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Section: Discussionmentioning

confidence: 99%

Clinical Use of Aided Cortical Auditory Evoked Potentials as a Measure of Physiological Detection or Physiological Discrimination

Billings

Papesh

Penman

et al. 2012

International Journal of Otolaryngology

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“…A measure of magnitude squared coherence (Lewis et al 2010) was used to compare the spectral distortion of stimuli at the input and output of the HA for the DNR-on and DNR-off conditions. This comparison was made in attempts to quantify any spectral distortion resulting from DNR processing or from the inversion method.…”

Section: Methodsmentioning

confidence: 99%

“…Another method that can be used to quantify the changes caused by signal processing is magnitude squared coherence which has been used to quantify internal HA noise (Lewis et al 2010) and the impact of HA signal processing on signal integrity, including amplitude compression (Kates and Arehart 2005) and DNR (Ma and Loizou 2011). Coherence represents the comparison of the signal power at the input of the HA to the total power at the output of the HA as a function of frequency.…”

Section: Introductionmentioning

confidence: 99%

Listening Effort and Perceived Clarity for Normal-Hearing Children With the Use of Digital Noise Reduction

et al. 2014

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Objectives The goal of this study was to evaluate how digital noise reduction (DNR) impacts listening effort and judgment of sound clarity in children with normal hearing. It was hypothesized that, when two DNR algorithms differing in signal-to-noise ratio (SNR) output are compared, the algorithm which provides the greatest improvement in overall output SNR will reduce listening effort and receive a better clarity rating from child listeners. A secondary goal was to evaluate the relation between the inversion method measurements and listening effort with DNR processing. Design Twenty-four children with normal hearing (ages 7-12 years) participated in a speech recognition task in which consonant-vowel-consonant nonwords were presented in broadband background noise. Test stimuli were recorded through two hearing aids with DNR-off and DNR-on at 0 dB and +5 dB input SNR. Stimuli were presented to listeners and verbal response time (VRT) and phoneme recognition scores were measured. The underlying assumption was that an increase in VRT reflects an in increase in listening effort. Children rated the sound clarity for each condition. The two commercially available HAs were chosen based on: 1) an inversion technique which was used to quantify the magnitude of change in SNR with the activation of DNR, and 2) a measure of magnitude-squared coherence which was used to ensure that DNR in both devices preserved the spectrum. Results One device provided a greater improvement in overall output SNR than the other. Both DNR algorithms resulted in minimal spectral distortion as measured using coherence. For both devices, VRT decreased for the DNR-on condition suggesting that listening effort decreased with DNR in both devices. Clarity ratings were also better in the DNR-on condition for both devices. The device showing the greatest improvement in output SNR with DNR engaged improved phoneme recognition scores. The magnitude of this improved phoneme recognition was not accurately predicted with measurements of output SNR. Measured output SNR varied in the ability to predict other outcomes. Conclusions Overall, results suggest that DNR effectively reduces listening effort and improves subjective clarity ratings in children with normal hearing but that these improvements are not necessarily related to the output SNR improvements or preserved speech spectra provided by the DNR.

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“…3, across the audio range 125 Hz-8 kHz, is about 50 pm rms. This value corresponds to about 31 dB SPL (A) @ 1 kHz [3], which can be considered as the equivalent input noise, close to the values of commercially available hearing aids [13].…”

Section: Resultsmentioning

confidence: 99%

Demodulation of quasi-quadrature interferometric signals for use in the totally implantable hearing aids

Tomić

Djinovic

Petričević

2017

Biomed. Opt. Express

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Abstract:We propose and experimentally prove an algorithm for demodulation of interferometric signals, modified for use in a totally implantable hearing aid device. A fiber optic configuration, which generates two quasi-quadrature signals by a passive 3x3 coupler, for a non-contact detection of the middle ear ossicle vibration is employed. We simulated the ossicle vibration and large movements and demonstrated the effectiveness of the algorithm to compensate changes of the signal DC values and the phase shift introduced by the coupler. Applying the proposed algorithm we obtained the output signal stability better than 0.5 dB, and the system equivalent input noise of about 31 dB (A) SPL @ 1 kHz.

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Measurement of hearing aid internal noise

Cited by 14 publications

References 8 publications

Clinical Use of Aided Cortical Auditory Evoked Potentials as a Measure of Physiological Detection or Physiological Discrimination

Clinical Use of Aided Cortical Auditory Evoked Potentials as a Measure of Physiological Detection or Physiological Discrimination

Listening Effort and Perceived Clarity for Normal-Hearing Children With the Use of Digital Noise Reduction

Demodulation of quasi-quadrature interferometric signals for use in the totally implantable hearing aids

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