Method for producing a constant sound pressure level in hearing aids and corresponding hearing aid

2003 ◽  
Vol 114 (4) ◽  
pp. 1716
Author(s):  
Ulrich Sigwanz ◽  
Frank Wagner
Keyword(s):  
Sound Pressure Level ◽  
Hearing Aids ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Pressure Level

Hearing Aid Saturation and Aided Loudness Discomfort

1992 ◽  
Vol 35 (1) ◽  
pp. 175-185 ◽  
Author(s):  
Todd W. Fortune ◽  
David A. Preves
Keyword(s):  
Sound Pressure Level ◽  
Hearing Aids ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Significant Negative Correlation ◽  
Sound Quality ◽  
Pressure Level ◽  
The Subject ◽  
Clinical Measurements

Clinical measurements of the loudness discomfort level (LDL) are generally performed while the subject listens to a particular stimulus presented from an audiometer through headphones (AUD-HP). The assumption in clinical practice has been that the sound pressure level (SPL) corresponding to the sensation of loudness discomfort under AUD-HP conditions will be the same as that corresponding to LDL with the hearing aid. This assumption ignores the fact that the distortion produced by a saturating hearing aid could have an influence on the sensation of loudness. To examine these issues, 5 hearing-impaired subjects were each fit with four linear hearing aids, each having a different saturation sound pressure level (SSPL90). Probe-tube microphone measurements of ear canal SPL at LDL were made while the subjects listened to continuous discourse in quiet under aided and AUD-HP conditions. Also using continuous discourse, real-ear coherence measures were made at various output sound pressure levels near LDL. All four hearing aid types produced mean LDLs that were lower than those obtained under AUD-HP conditions. Those hearing aids with higher SSPL90 produced significantly higher LDLs than hearing aids with lower SSPL90. A significant negative correlation was found between real-ear SPL and real-ear coherence. Quality judgments made at LDL indicated that sound quality of hearing aids with higher SSPL90 was preferred to that of hearing aids with lower SSPL90. Possible fitting implications regarding the setting of SSPL90 from AUD-HP LDL measures are discussed.

A comparison of two methods for estimating sound pressure level at the tympanic membrane at high frequencies for hearing aids.

2010 ◽  
Vol 127 (3) ◽  
pp. 1868-1868
Author(s):  
Tao Zhang ◽  
Karrie Recker ◽  
Janice LoPresti ◽  
Matt Kleffner ◽  
William Ryan
Keyword(s):  
Tympanic Membrane ◽  
Sound Pressure Level ◽  
Hearing Aids ◽  
Sound Pressure ◽  
Pressure Level ◽  
High Frequencies

Using Average Correction Factors to Improve the Estimated Sound Pressure Level Near the Tympanic Membrane

2012 ◽  
Vol 23 (09) ◽  
pp. 733-750
Author(s):  
Karrie LaRae Recker ◽  
Tao Zhang ◽  
Weili Lin
Keyword(s):  
Tympanic Membrane ◽  
Sound Pressure Level ◽  
Hearing Aids ◽  
Best Practice ◽  
Sound Pressure ◽  
Pressure Level ◽  
Correction Factors ◽  
Ear Canal ◽  
Frequency Components ◽  
Ear Canals

Background: Sound pressure-based real ear measurements are considered best practice for ensuring audibility among individuals fitting hearing aids. The accuracy of current methods is generally considered clinically acceptable for frequencies up to about 4 kHz. Recent interest in the potential benefits of higher frequencies has brought about a need for an improved, and clinically feasible, method of ensuring audibility for higher frequencies. Purpose: To determine whether (and the extent to which) average correction factors could be used to improve the estimated high-frequency sound pressure level (SPL) near the tympanic membrane (TM). Research Design: For each participant, real ear measurements were made along the ear canal, at 2–16 mm from the TM, in 2-mm increments. Custom in-ear monitors were used to present a stimulus with frequency components up to 16 kHz. Study Sample: Twenty adults with normal middle-ear function participated in this study. Intervention: Two methods of creating and implementing correction factors were tested. Data Collection and Analysis: For Method 1, correction factors were generated by normalizing all of the measured responses along the ear canal to the 2-mm response. From each normalized response, the frequency of the pressure minimum was determined. This frequency was used to estimate the distance to the TM, based on the ¼ wavelength of that frequency. All of the normalized responses with similar estimated distances to the TM were grouped and averaged. The inverse of these responses served as correction factors. To apply the correction factors, the only required information was the frequency of the pressure minimum. Method 2 attempted to, at least partially, account for individual differences in TM impedance, by taking into consideration the frequency and the width of the pressure minimum. Because of the strong correlation between a pressure minimum's width and depth, this method effectively resulted in a group of average normalized responses with different pressure-minimum depths. The inverse of these responses served as correction factors. To apply the correction factors, it was necessary to know both the frequency and the width of the pressure minimum. For both methods, the correction factors were generated using measurements from one group of ten individuals and verified using measurements from a second group of ten individuals. Results: Applying the correction factors resulted in significant improvements in the estimated SPL near the TM for both methods. Method 2 had the best accuracy. For frequencies up to 10 kHz, 95% of measurements had <8 dB of error, which is comparable to the accuracy of real ear measurement methods that are currently used clinically below 4 kHz. Conclusions: Average correction factors can be successfully applied to measurements made along the ear canals of otologically healthy adults, to improve the accuracy of the estimated SPL near the TM in the high frequencies. Further testing is necessary to determine whether these correction factors are appropriate for pediatrics or individuals with conductive hearing losses.

Control of hearing-aid saturated sound pressure level by frequency-shaped output compression limiting

1999 ◽  
Vol 28 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Hugh J. McDermott ◽  
Michelle R. Dean ◽  
Harvey Dillon
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Pressure Level

Hearing Loss, Speech, and Hearing Aids

1993 ◽  
Vol 36 (2) ◽  
pp. 228-244 ◽  
Author(s):  
Dianne J. Van Tasell
Keyword(s):  
Hearing Loss ◽  
Sound Pressure Level ◽  
Hearing Aids ◽  
Speech Signal ◽  
Sound Pressure ◽  
Current Knowledge ◽  
Current Data ◽  
Pressure Level ◽  
Impaired Hearing ◽  
Moderate Hearing Loss

Modern hearing aids permit adjustment of a number of electroacoustic parameters, among them frequency response, saturation sound pressure level, and various aspects of compression. Relatively little is known, however, about how the electroacoustic characteristics of hearing aids affect the information-bearing properties of speech. Even less is known about how hearing aids might alleviate or exacerbate the effects of impaired hearing. This article reviews current knowledge in three areas: (a) characteristics of mild/moderate hearing loss, (b) informationbearing aspects of speech, and (c) the relation between electroacoustic characteristics of hearing aids and the speech signal. Concluding suggestions are made regarding the implications of the current data for selecting hearing-aid characteristics.

Probe-Tube Microphone Measures of Vent Effects With In-the-Canal Hearing Aid Shells

1992 ◽  
Vol 1 (2) ◽  
pp. 58-62 ◽  
Author(s):  
Andrew Stuart ◽  
Robert Stenstrom ◽  
Odilia MacDonald ◽  
Mark P. Schmidt ◽  
Gail MacLean
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Low Frequency ◽  
Pressure Level ◽  
Frequency Responses ◽  
Upward Shift

The acoustic effects of three different configurations of vented in-the-canal (ITC) hearing aid shells were investigated. Real-ear sound pressure level measures (200–2000 Hz) were obtained from unvented and vented ITC shells from 12 adult subjects. In general, with increasing vent size, an increase in the amount of low-frequency reduction and an upward shift in vent kneepoints and vent-associated resonance occurred. The use of venting may be considered clinically for low-frequency reduction in ITC hearing aid frequency responses.

Effect of Canal Depth on Sound Pressure Level Distribution in Human Bilateral Ears

2011 ◽  
Vol 145 ◽  
pp. 63-67
Author(s):  
Jen Fang Yu ◽  
Wei De Cheng
Keyword(s):  
Sound Pressure Level ◽  
Hearing Aids ◽  
Sound Pressure ◽  
Stimulus Frequency ◽  
Pressure Level ◽  
Ear Canal ◽  
Custom Made ◽  
Different Depths ◽  
Ear Canals ◽  
The Right

This study was to measure the sound pressure level distribution by ear canal resonance in the human left and right external auditory canals (EAC). The gain for different stimulus frequencies was analyzed at four different measuring depths (0.5 cm, 1.0 cm, 1.5 cm and 2.0 cm) from the entrance of the ear canal bilaterally. Comparative evaluation showed that the gain for different stimulus frequencies at a depth of 2.0 cm was consistent with the results of Dillon’s study. In addition, the gain for the right EAC at 4000 Hz was larger than that of the left EAC by 1.2 dB at 0.5 cm, 1.8 dB at 1.0 cm, and 0.8 dB at 1.5 cm. This seems to suggest that gain at 4000 Hz is more affected by depth in the right EAC than in the left EAC. This study further found that the gain at the stimulus frequency of 4000 Hz was more affected by the depth than at 2000 Hz for the bilateral ear canals respectively. These gain differences between the right and left ears were statistically significant (p<0.05) at any of four measuring depths. The findings of this study may have an understanding of gain distribution to have implications for microphone placement of custom-made bilateral hearing aids (i.e. ITC or CIC) as these are placed at different depths within the ear canal. Keywords: Sound pressure level; Canal depth; Ear canal resonance; Real ear measurement; External auditory canal

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