Electroacoustics - Hearing aids - Part 16: Definition and verification of hearing aid features

IEC 60118-16:2022 gives definitions for common hearing aid features such as noise reduction or feedback reduction, etc. Only acoustical inputs are considered. Binaural features are currently not covered in this document. In addition, measurement procedures are described to verify hearing aid features. The objective is not to evaluate the performance of features but to verify their existence and functionality.
Furthermore, definitions and procedures are kept as general as possible so that this document can be applied to various types of hearing aids, for example, air-conduction hearing aids or bone conduction hearing aids. To this end, the general definition for the term "hearing aid" given in IEC 60118-0 is adopted, and this document does not refer to any specific ear simulator or acoustic coupler but uses a general definition of a coupler. However, if a general view is not applicable or leads to unclear or complex wording, the situation for an air-conduction hearing aid only is considered. Nevertheless, an explanation is given on how this document can be applied to hearing aids which do not use air conduction.

Électroacoustique - Appareils de correction auditive - Partie 16: Définition et vérification des caractéristiques des appareils de correction auditive

L'IEC 60118-16:2022 définit les caractéristiques communes des appareils de correction auditive telles que la réduction du bruit ou la réduction des retours, etc. Seules les entrées acoustiques sont prises en considération. Les caractéristiques binaurales ne sont actuellement pas couvertes par le présent document. En outre, des procédures de mesure destinées à vérifier les caractéristiques des appareils de correction auditive sont décrites. L’objectif n’est pas d’évaluer les performances des caractéristiques, mais de vérifier leur existence et leur fonctionnalité.
Par ailleurs, les définitions et les procédures sont maintenues aussi générales que possible de telle sorte que le présent document peut être appliqué à différents types d'appareils de correction auditive, par exemple, appareils de correction auditive à conduction aérienne ou à conduction osseuse. À cette fin, la définition générale du terme "appareil de correction auditive" donnée dans l’IEC 60118-0 est adoptée, et le présent document ne fait référence à aucun simulateur d'oreille ou aucun coupleur acoustique spécifiques, mais utilise une définition générale du terme "coupleur". Toutefois, lorsqu’une vue générale n’est pas applicable ou entraîne une formulation peu claire ou complexe, seule la situation d’un appareil de correction auditive à conduction aérienne est prise en considération. Néanmoins, une explication est donnée sur la manière dont le présent document peut être appliqué à des appareils de correction auditive qui n’utilisent pas la conduction aérienne.

General Information

Status
Published
Publication Date
15-Mar-2022
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
16-Mar-2022
Ref Project

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IEC 60118-16
Edition 1.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electroacoustics – Hearing aids –
Part 16: Definition and verification of hearing aid features
Électroacoustique – Appareils de correction auditive –
Partie 16: Définition et vérification des caractéristiques des appareils de
correction auditive
IEC 60118-16:2022-03(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60118-16
Edition 1.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electroacoustics – Hearing aids –
Part 16: Definition and verification of hearing aid features
Électroacoustique – Appareils de correction auditive –
Partie 16: Définition et vérification des caractéristiques des appareils de
correction auditive
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50 ISBN 978-2-8322-1088-7

Warning! Make sure that you obtained this publication from an authorized distributor.

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® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60118-16:2022 © IEC 2022
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 6

4 Application to non-air-conduction hearing aids ............................................................... 10

5 Test equipment .............................................................................................................. 10

5.1 Acoustical requirements ........................................................................................ 10

5.2 Examples of test signals for common listening situations ...................................... 11

6 Verification of noise reduction........................................................................................ 11

6.1 Noise reduction for speech enhancement .............................................................. 11

6.2 Gain reduction for noise ........................................................................................ 12

7 Strategies of hearing aid programs and their verification................................................ 13

7.1 General ................................................................................................................. 13

7.2 User-selected hearing aid programs ...................................................................... 13

7.2.1 Description .................................................................................................... 13

7.2.2 Verification .................................................................................................... 13

7.3 Automatically-selected hearing aid programs depending on listening

situation ................................................................................................................ 14

7.3.1 Description .................................................................................................... 14

7.3.2 Verification by setting a marker ...................................................................... 15

7.3.3 Verification using a linear gain configuration .................................................. 15

8 Verification of feedback reduction .................................................................................. 16

8.1 General ................................................................................................................. 16

8.2 Coupling of the hearing aid ................................................................................... 16

8.3 Measurement procedure ....................................................................................... 16

8.4 Post processing .................................................................................................... 17

9 Verification of the number of hearing aid channels ......................................................... 18

9.1 Visualization of the effect of multichannel signal processing ................................. 18

9.2 Evaluation of the number of independent channels ............................................... 19

10 Verification of an output limiter ...................................................................................... 20

Annex A (informative) Coupling of the hearing aid to the measurement coupler in

order to provoke feedback .................................................................................................... 21

A.1 Simplified coupling of air-conduction hearing aids to the 2 cm acoustic

coupler ................................................................................................................. 21

A.2 Head and torso simulator with vented ear canal extension .................................... 22

Annex B (informative) Particular guidance ........................................................................... 24

B.1 Verification of user selected hearing aid programs ................................................ 24

B.2 Automatically-selected hearing aid programs depending on listening

situation ................................................................................................................ 25

B.2.1 Verification by setting a marker ...................................................................... 25

B.2.2 Verification by using a linear gain configuration ............................................. 27

Bibliography .......................................................................................................................... 29

Figure 1 – Visualization of user selected HAPs ..................................................................... 13

Figure 2 – Visualization of automatically-selected HAPs depending on listening

situation ................................................................................................................................ 14

---------------------- Page: 4 ----------------------
IEC 60118-16:2022 © IEC 2022 – 3 –

Figure 3 – Example of the plot of the results of the feedback reduction measurement ........... 18

Figure A.1 – Simplified coupling of air-conduction hearing aids with one microphone to

the 2 cm acoustic coupler to provoke feedback ................................................................... 21

Figure A.2 – Simplified coupling of air-conduction hearing aids with two microphones to

the 2 cm acoustic coupler to provoke feedback ................................................................... 22

Figure A.3 – Head and torso simulator for the measurement of air-conduction hearing

aids according to IEC/TS 60318-7 together with an ear simulator according to

IEC 60318-4 and a vented ear canal extension ..................................................................... 22

Figure A.4 – Example for a vented ear canal extension with medium flow (left) and high

flow (right) ............................................................................................................................ 23

Figure B.1 – Visualization of the verification of user-selected hearing aid programs .............. 24

Figure B.2 – Visualization of the measurement of the reference data for the verification

of automatically-selected hearing aid programs by setting a marker ...................................... 25

Figure B.3 – Visualization of the measurement for the verification of

automatically-selected hearing aid programs by setting a marker where a marker is set

to the hearing aid program 1 ................................................................................................. 26

Figure B.4 – Visualization of the measurement for the verification of

automatically-selected hearing aid programs by using a linear gain configuration ................. 28

Table 1 – Examples of test signals for different listening situations ....................................... 11

Table 2 – Symbols used for the evaluation and results of the feedback reduction

measurement ........................................................................................................................ 17

Table 3 – Example results of the procedure for the verification of multichannel signal

processing ............................................................................................................................ 19

Table B.1 – Example results for the verification of user selected hearing aid programs ......... 24

Table B.2 – Example results for the verification of automatically-selected hearing aid

programs by setting a marker ................................................................................................ 27

Table B.3 – Example for the evaluation of the results for the verification of

automatically-selected hearing aid programs by setting a marker .......................................... 27

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– 4 – IEC 60118-16:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS – HEARING AIDS –
Part 16: Definition and verification of hearing aid features
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

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with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

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6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 60118-16 has been prepared by technical committee 29: Electroacoustics. It is an

International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
29/1110/FDIS 29/1116/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at http://www.iec.ch/standardsdev/publications.
---------------------- Page: 6 ----------------------
IEC 60118-16:2022 © IEC 2022 – 5 –

A list of all parts in the IEC 60118 series, published under the general title Electroacoustics –

Hearing aids, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

---------------------- Page: 7 ----------------------
– 6 – IEC 60118-16:2022 © IEC 2022
ELECTROACOUSTICS – HEARING AIDS –
Part 16: Definition and verification of hearing aid features
1 Scope

This part of IEC 60118 gives definitions for common hearing aid features such as noise

reduction or feedback reduction, etc. Only acoustical inputs are considered. Binaural features

are currently not covered in this document. In addition, measurement procedures are described

to verify hearing aid features. The objective is not to evaluate the performance of features but

to verify their existence and functionality.

Furthermore, definitions and procedures are kept as general as possible so that this document

can be applied to various types of hearing aids, for example, air-conduction hearing aids or

bone conduction hearing aids. To this end, the general definition for the term "hearing aid" given

in IEC 60118-0 is adopted, and this document does not refer to any specific ear simulator or

acoustic coupler but uses a general definition of a coupler. However, if a general view is not

applicable or leads to unclear or complex wording, the situation for an air-conduction hearing

aid only is considered. Nevertheless, an explanation is given on how this document can be

applied to hearing aids which do not use air conduction.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.

IEC 60118-0:— , Electroacoustics – Hearing aids – Part 0: Measurement of the performance

characteristics of hearing aids

IEC 60118-15, Electroacoustics – Hearing aids – Part 15: Methods for characterising signal

processing in hearing aids with a speech-like signal

IEC 61260-1, Electroacoustics – Octave-band and fractional-octave-band filters – Part 1:

Specifications

ISO 21748, Guidance for the use of repeatability, reproducibility and trueness estimates in

measurement uncertainty evaluation
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
___________

Fourth edition under preparation. Stage at the time of publication: IEC FDIS 60118-0:2022

---------------------- Page: 8 ----------------------
IEC 60118-16:2022 © IEC 2022 – 7 –
3.1
sound pressure level
SPL

ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the

square of a reference value, p expressed in decibels, where the reference value, p , is 20 µPa

0 0

[SOURCE: ISO/TR 25417:2007, 2.2, modified – The abbreviated term has been added and the

symbol, formula and notes to entry have been omitted.]
3.2
1/f noise
pink noise

random noise having a continuous spectrum and such that the power spectral density is

proportional to the reciprocal of the frequency in the frequency range considered

3.3
signal-to-noise ratio
SNR

difference in sound pressure level between the target signal, usually speech, and the

interference signal, usually noise
3.4
hearing aid
wearable instrument intended to aid a person with impaired hearing
[SOURCE: IEC 60118-0:—, 3.2]
3.5
reference point

point related to the hearing aid sound inlet port(s) for the purpose of defining the position of the

hearing aid
3.6
hearing aid user
person wearing a hearing aid to alleviate hearing impairment
3.7
measurement coupler
device through which the output of a hearing aid can be measured

Note 1 to entry: For an air-conduction hearing aid, usually the acoustic coupler according to IEC 60318-5 or the

occluded-ear simulator according to IEC 60318-4 is used as a measurement coupler and for a bone conduction

hearing aid, the coupler according to IEC 60318-6 or a skull simulator is used.
3.8
hearing aid program
HAP

set of parameters, defining at least the frequency characteristic and possibly other parameters

of the signal processing of a hearing aid that can be selected by the hearing aid user or that

are automatically selected by the hearing aid to adapt the signal processing to specific listening

situations
---------------------- Page: 9 ----------------------
– 8 – IEC 60118-16:2022 © IEC 2022
3.9
configurable hearing aid program
configurable HAP

hearing aid program with an adjustable set of parameters, which can be configured and

reconfigured to meet the individual needs of the hearing aid user without influencing the

processing in other programs

Note 1 to entry: Usually fitting software provided by the hearing aid manufacturer, a computer and a programming

interface are used to configure the set of parameters.

Note 2 to entry: The fact that a hearing aid program is configurable has the benefit that the signal processing can

be optimized to the individual needs, for example, for a specific listening situation for this specific user.

3.10
non-configurable hearing aid program
non-configurable HAP

hearing aid program configured by the manufacturer or automatically by the hearing aid

depending on the listening situation, which cannot be reconfigured either by the hearing aid

user or by using the fitting software without influencing the processing in other programs

3.11
listening situation
situation in which a hearing aid user requires a specific signal processing

Note 1 to entry: This definition is intentionally different from the term "acoustic environment" in ISO 12913-1:2014,

2.2 and 3.4.
3.12
noise reduction

feature of the signal processing of a hearing aid intended to reduce noise with respect to the

absolute level or relative to the level of a target signal
3.13
noise reduction for speech enhancement

feature of the signal processing of a hearing aid intended to increase the signal-to-noise ratio

even if speech and noise are presented simultaneously from the same direction and have the

same long-term average spectrum

Note 1 to entry: It is possible that the increase in signal-to-noise ratio will not increase speech intelligibility.

3.14
gain reduction for noise

feature of the signal processing of a hearing aid intended to decrease the gain for noise

compared to the gain for speech even if speech and noise are presented successively from the

same direction and have the same long-term average spectrum
3.15
feedback

return of some of the energy of the output signal from the hearing aid to the input of the same

hearing aid
3.16
critical feedback condition

situation where feedback causes a whistling noise at the output of the hearing aid

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IEC 60118-16:2022 © IEC 2022 – 9 –
3.17
feedback reduction

feature of the signal processing of a hearing aid to reduce or completely avoid the occurrence

of the critical feedback condition without reducing gain

Note 1 to entry: Changing the feedback path, by, for example, increasing the sealing of the earmold, is not a part

of the signal processing and therefore not understood as feedback reduction.
3.18
hearing aid channel

feature of the signal processing of a hearing aid that enables individual adjustment of the gain

and the parameters of an automatic gain control for a certain frequency range

Note 1 to entry: A hearing aid channel can consist of multiple hearing aid bands.

3.19
hearing aid band

feature of the signal processing of a hearing aid that enables individual adjustment of the gain

for a certain frequency range
3.20
maximum power output
MPO

maximum level at the output of the hearing aid which is adjustable by the output limiter

3.21
output limiter

feature of a hearing aid that allows one to define and redefine a limit for maximum power output

(MPO)
3.22
fitted maximum output sound pressure level
fitted OSPL90

maximum output SPL of a hearing aid when measured after fitting with 90 dB input SPL

[SOURCE: IEC 60601-2-66:2019, 201.3.206, modified – Note to entry has been omitted.]

3.23
functional test setting
FTS

setting of the hearing aid where all accessible features in the fitting software are manually

disabled and a linear gain is applied equally to the reference test setting of the gain control

according to IEC 60118-0

Note 1 to entry: The difference between reference test setting (RTS) as defined in IEC 60118-0 and the functional

test setting (FTS) is due to the fact that not always all features are accessible in the fitting software and can be

disabled.
3.24
rank

number of singular values of a matrix A that are equal to or exceed 0,95 which is

written as rank(A)
3.25
singular values

number of positive real values in linear algebra which can be computed for a

matrix as a result of a singular value decomposition (SVD)
---------------------- Page: 11 ----------------------
– 10 – IEC 60118-16:2022 © IEC 2022
4 Application to non-air-conduction hearing aids

Definitions and procedures in this document are kept as general as possible so that this

document can be applied to various types of hearing aids, for example, air-conduction hearing

aids or bone conduction hearing aids. However, in some subclauses and definitions, a general

view is not applicable or leads to an unclear or complex wording so that only air-conduction

hearing aids are considered.

NOTE For example, a sound pressure level is considered for the output signal of the hearing aid. However, this

holds for air-conduction hearing aids only. For bone conduction, the output is a force, and for other devices the output

can be any other physical quantity.

To apply this document to devices other than air-conduction hearing aids, it is required that:

• the input signal is an acoustic sound pressure,
• the output signal can be quantified by another physical quantity,

• and a measurement coupler exists that enables the measurement of this physical quantity

at the output of the hearing aid.

For bone conduction hearing aids, the output sound pressure level shall be replaced by an

output force level. In additi
...

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