Limitations of the Envelope Difference Index as a Metric for Nonlinear Distortion in Hearing Aids

To investigate the relationship of nonlinear distortion to gain control position, 35 hearing aids of differing makes and models were examined. Distortion levels were observed at eight gain settings, each of which represented 12.5% of the total available rotation of the gain control. Distortion was measured at 500, 700, 900 Hz, and at the frequency of maximum distortion. The results support previous findings of high nonlinear distortion at or near maximum acoustic gain in some hearing aids. In order to obtain reductions in the distortion levels observed at full-on gain, extensive counter rotations of the gain control dial frequently were necessary.

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Nonlinear Distortion in Modern Hearing Aids

Journal of Speech and Hearing Research ◽

10.1044/jshr.1003.586 ◽

1967 ◽

Vol 10 (3) ◽

pp. 586-592 ◽

Cited By ~ 1

Author(s):

Stephen H. Lotterman ◽

Roger N. Kasten

Keyword(s):

Hearing Aids ◽

Nonlinear Distortion ◽

Harmonic Distortion ◽

Frequency Range ◽

Distortion Products ◽

Input Signals ◽

Total Distortion

Nonlinear distortion was investigated in 367 new hearing aids. Among the first group of instruments examined, the level of harmonic distortion present at 500, 700, and 900 Hz was studied, together with the frequency and extent of maximum distortion. Ear-level instruments generally yielded lower distortion values than did body types. The frequency of maximum distortion tended to fall below 1000 Hz for body-worn instruments, while the frequencies at which maximum distortion occurred for the ear-level hearing aids were predominandy above 1000 Hz. The variability in total distortion exhibited within groups of fifteen instruments each of identical make and model was examined among a second group of instruments. Results for this procedure, which employed 60 dB SPL input signals and full-on acoustic gain settings, indicated that, although most of the instruments exhibited distortion products of less than 10% throughout their frequency range, total nonlinear distortion in excess of 20% was not uncommon among these hearing aids.

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Howling Detection and Suppression Based on Segmented Notch Filtering

Sensors ◽

10.3390/s21238062 ◽

2021 ◽

Vol 21 (23) ◽

pp. 8062

Author(s):

Yanping Li ◽

Xiangdong Huang ◽

Yi Zheng ◽

Zhongke Gao ◽

Lei Kou ◽

...

Keyword(s):

Closed Form ◽

Hearing Aids ◽

Nonlinear Distortion ◽

Transfer Characteristic ◽

Fast Response ◽

Echo Cancellation ◽

High Quality ◽

Impulsive Response ◽

Notch Filtering ◽

Closed Form Formula

The existing adaptive echo cancellation based howling (typically in hearing aids) removal methods have several drawbacks such as insufficient attenuation of the howling component, slow response and nonlinear distortion. To solve these problems, we propose a segmented notch filtering based scheme. Specifically, firstly, it is proved that the attenuation value can reach −330 dB at any detected howling frequency; secondly, the filter coefficients can be readily calculated by a closed-form formula, yielding a fast response to the sudden howling accident; thirdly, the closed-form formula of this filter is theoretically an even function, indicating that this filter possesses a linear transfer characteristic. In combination with proper segmentation and precisely removing these transient samples arising from FIR (Finite Impulsive Response) filtering, nonlinear distortion can be entirely avoided. Experimental results show that our proposed scheme can not only accurately estimate the howling frequency, but can also completely remove it, which yields a high-quality output waveform with a recovery SNR of about 22 dB. Therefore, the proposed segmented notching based scheme possesses vast potential for hearing aid development and other relevant applications.

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Teachers' Stereotypes of Children Who Wear Hearing Aids

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.1203.139 ◽

1981 ◽

Vol 12 (3) ◽

pp. 139-144 ◽

Cited By ~ 3

Author(s):

Cletus G. Fisher ◽

Kenneth Brooks

Keyword(s):

Elementary School ◽

School Child ◽

Hearing Aids ◽

Hearing Aid ◽

Social Implications ◽

Elementary School Child ◽

Classroom Teachers ◽

Frequency Of Occurrence ◽

Service Training

Classroom teachers were asked to list the traits they felt were characteristic of the elementary school child who wears a hearing aid. These listings were evaluated according to the desirability of the traits and were studied regarding frequency of occurrence, desirability, and educational, emotional, and social implications. The results of the groupings are discussed in terms of pre-service and in-service training.

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The Hearing Aid Effect in African American and Caucasian Males as Perceived by Female Judges of the Same Race

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.3002.165 ◽

1999 ◽

Vol 30 (2) ◽

pp. 165-172 ◽

Cited By ~ 5

Author(s):

Mary Davis ◽

Rhonda Jackson ◽

Tina Smith ◽

William Cooper

Keyword(s):

African American ◽

Hearing Aids ◽

Undergraduate Education ◽

Hearing Aid ◽

Semantic Differential ◽

Semantic Differential Scale ◽

Education Majors ◽

Female Undergraduate ◽

Lay Persons ◽

Males And Females

Prior studies have proven the existence of the "hearing aid effect" when photographs of Caucasian males and females wearing a body aid, a post-auricular aid (behind-the-ear), or no hearing aid were judged by lay persons and professionals. This study was performed to determine if African American and Caucasian males, judged by female members of their own race, were likely to be judged in a similar manner on the basis of appearance, personality, assertiveness, and achievement. Sixty female undergraduate education majors (30 African American; 30 Caucasian) used a semantic differential scale to rate slides of preteen African American and Caucasian males, with and without hearing aids. The results of this study showed that female African American and Caucasian judges rated males of their respective races differently. The hearing aid effect was predominant among the Caucasian judges across the dimensions of appearance, personality, assertiveness, and achievement. In contrast, the African American judges only exhibited a hearing aid effect on the appearance dimension.

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A Support Program

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.2502.112 ◽

1994 ◽

Vol 25 (2) ◽

pp. 112-114 ◽

Cited By ~ 3

Author(s):

Henna Grunblatt ◽

Lisa Daar

Keyword(s):

Hearing Aids ◽

School Counselor ◽

Support Program ◽

Educational Audiology ◽

Part Program ◽

One To One

A program for providing information to children who are deaf about their deafness and addressing common concerns about deafness is detailed. Developed by a school audiologist and the school counselor, this two-part program is geared for children from 3 years to 15 years of age. The first part is an educational audiology program consisting of varied informational classes conducted by the audiologist. Five topics are addressed in this part of the program, including basic audiology, hearing aids, FM systems, audiograms, and student concerns. The second part of the program consists of individualized counseling. This involves both one-to-one counseling sessions between a student and the school counselor, as well as conjoint sessions conducted—with the student’s permission—by both the audiologist and the school counselor.

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Equivalent Noise Dose Obtained Through Hearing Aids in the Classrooms of Hearing-Impaired Children

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.2103.147 ◽

1990 ◽

Vol 21 (3) ◽

pp. 147-150

Author(s):

Ronald A. Wilde

Keyword(s):

Hearing Aids ◽

High Gain ◽

Hearing Impaired ◽

Deaf Children ◽

Impaired Children ◽

Very High ◽

Hearing Impaired Children

A commercial noise dose meter was used to estimate the equivalent noise dose received through high-gain hearing aids worn in a school for deaf children. There were no significant differences among nominal SSPL settings and all SSPL settings produced very high equivalent noise doses, although these are within the parameters of previous projections.

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Students as Active Participants in Hearing Aid Maintenance

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.2303.208 ◽

1992 ◽

Vol 23 (3) ◽

pp. 208-213 ◽

Cited By ~ 3

Author(s):

Marsha Lipscomb ◽

Peggy Von Almen ◽

James C. Blair

Keyword(s):

Inner City ◽

Hearing Aids ◽

School System ◽

Regular Education ◽

Hearing Aid ◽

Hearing Impairments ◽

City School

Twenty students between the ages of 6 and 19 years who were receiving services for students with hearing impairments in a metropolitan, inner-city school system were trained to monitor their own hearing aids. This study investigated the effect of this training on the percentage of students who wore functional hearing aids. Ten of the students received fewer than 3 hours of instruction per day in the regular education setting and generally had hearing losses in the severe to profound range. The remaining 10 students received greater than 3 hours of instruction per day in the regular education setting and had hearing losses in the moderate to severe range. The findings indicated improved hearing aid function when students were actively involved in hearing aid maintenance programs. Recommendations are made concerning hearing aid maintenance in the schools.

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