Electroacoustics - Audiometric equipment - Part 6: Instruments for the measurement of otoacoustic emissions

IEC 60645-6:2022 is available as IEC 60645-6:2022 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 606045-6:2022 applies to instruments designed primarily for the measurement of otoacoustic emissions in the human external auditory meatus evoked by acoustic probe stimuli. This document defines the characteristics to be specified by the manufacturer, specifies minimum mandatory functions for two types of instruments and provides performance specifications applicable to both instrument types. This document describes methods to be used to demonstrate conformance with the specifications in this document and guidance on methods for periodic calibration. The purpose of this document is to ensure that measurements made under comparable test conditions with different instruments complying with this document will be consistent. Instruments can provide a measurement function not specifically within the scope of this document and still comply with the relevant requirements of this document for the functions that are within the scope. This document is not intended to restrict development or incorporation of new features, nor to discourage innovative approaches. IEC 606045-6:2022 cancels and replaces the first edition published in 2009. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the nominal test frequency used in DPOAE is now defined as the higher of the two frequencies, f2;
b) the permitted deviation of the stimulus signal for TEOAE has been specified;
c) the frequency range for DPOAE stimulus signals has been redefined,
d) the stimulus level requirements for TEOAE have been redefined;
e) the stimulus level requirements for DPOAE have been redefined;
f) the harmonic distortion requirements for DPOAE have been redefined;
g) a minimum measurement range for DPOAE has been added.

Électroacoustique - Équipements audiométriques - Partie 6: Instruments pour la mesure des émissions otoacoustiques

IEC 60645-6:2022 est disponible sous forme de IEC 60645-6:2022 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L'IEC 60645-6:2022 s’applique aux instruments conçus principalement pour le mesurage des émissions otoacoustiques dans le conduit auditif externe humain qui sont évoquées par des stimuli provenant d’une sonde acoustique. Le présent document définit les caractéristiques à spécifier par le fabricant, spécifie les fonctions obligatoires minimales pour deux types d’instruments et fournit des spécifications de performance applicables à ces deux types d’instruments. Le présent document décrit les méthodes à utiliser pour démontrer la conformité aux spécifications du présent document et des recommandations relatives aux méthodes d’étalonnage périodique.
Le présent document a pour objet d’assurer que des mesurages réalisés dans des conditions d’essai comparables avec différents instruments conformes au présent document sont cohérents. Il est possible que les instruments assurent une fonction de mesure qui ne relève pas spécifiquement du domaine d’application du présent document et soient cependant conformes aux exigences pertinentes du présent document concernant les fonctions qui relèvent du présent domaine d’application. Le présent document n’est pas destiné à limiter l'élaboration ou l’ajout de nouvelles caractéristiques ni à décourager les approches innovantes. L'IEC 60645-6:2022 annule et remplace la première édition parue en 2009. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) la fréquence d’essai nominale utilisée dans les émissions otoacoustiques de produit de distorsion (DPOAE – Distortion Product Otoacoustic Emissions) est désormais définie comme la plus élevée des deux fréquences, f2;
b) l’écart permis du signal de stimulus pour les émissions otoacoustiques évoquées transitoires (TEOAE – Transient-Evoked Otoacoustic Emissions) a été spécifié;
c) la plage de fréquences pour les signaux de stimulus des DPOAE a été redéfinie;
d) les exigences relatives au niveau de stimulus pour les TEOAE ont été redéfinies;
e) les exigences relatives au niveau de stimulus pour les DPOAE ont été redéfinies;
f) les exigences relatives à la distorsion harmonique pour les DPOAE ont été redéfinies;
g) une étendue de mesure minimale pour les DPOAE a été ajoutée.

General Information

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

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IEC 60645-6
Edition 2.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electroacoustics – Audiometric equipment –
Part 6: Instruments for the measurement of otoacoustic emissions
Électroacoustique – Appareils audiométriques –
Partie 6: Instruments pour la mesure des émissions otoacoustiques
IEC 60645-6:2022-03(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60645-6
Edition 2.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electroacoustics – Audiometric equipment –
Part 6: Instruments for the measurement of otoacoustic emissions
Électroacoustique – Appareils audiométriques –
Partie 6: Instruments pour la mesure des émissions otoacoustiques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50 ISBN 978-2-8322-1086-6

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

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60645-6:2022 © IEC 2022
CONTENTS

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

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 8

4 Requirements for specific instruments ............................................................................. 9

5 General specifications ..................................................................................................... 9

5.1 Acoustic stimulus system ........................................................................................ 9

5.1.1 General requirements ...................................................................................... 9

5.1.2 Stimulus types ................................................................................................. 9

5.1.3 Stimulus frequency range .............................................................................. 10

5.1.4 Stimulus level ................................................................................................ 10

5.1.5 Intermodulation distortion .............................................................................. 11

5.2 Test quality assuring system ................................................................................. 11

5.2.1 Stability of acoustic response in the external auditory meatus ....................... 11

5.2.2 Test quality assurance ................................................................................... 11

5.2.3 Individual stimulus recordings ........................................................................ 11

5.3 Measuring system ................................................................................................. 12

5.3.1 Units of measurement .................................................................................... 12

5.3.2 Measurement range ....................................................................................... 12

5.3.3 Accuracy of measurement ............................................................................. 12

5.3.4 Frequency range ........................................................................................... 12

5.3.5 Noise reduction ............................................................................................. 12

5.3.6 Response detection ....................................................................................... 12

5.3.7 Response quality estimates ........................................................................... 12

5.3.8 Normative values ........................................................................................... 12

5.4 Presentation of results .......................................................................................... 12

6 Demonstration of conformity with specifications ............................................................. 13

6.1 General ................................................................................................................. 13

6.2 Probe signal .......................................................................................................... 13

6.2.1 Probe signal frequency spectrum ................................................................... 13

6.2.2 Probe signal level and harmonic distortion ..................................................... 13

6.2.3 Probe measurement accuracy ........................................................................ 13

6.3 Complete system .................................................................................................. 14

6.4 Maximum permitted expanded uncertainty of measurements U ....................... 14

max

7 General requirements .................................................................................................... 15

7.1 Marking ................................................................................................................. 15

7.2 Instruction manual ................................................................................................ 15

7.3 Safety requirements .............................................................................................. 15

7.4 Immunity to power and radiofrequency fields......................................................... 15

7.5 Warm-up time ....................................................................................................... 15

7.6 Voltage supply variation and environmental conditions.......................................... 15

7.6.1 Mains operation ............................................................................................. 15

7.6.2 Battery operation ........................................................................................... 15

7.6.3 Environmental conditions ............................................................................... 15

---------------------- Page: 4 ----------------------
IEC 60645-6:2022 © IEC 2022 – 3 –

8 Additional characteristics to be specified by the manufacturer ....................................... 16

9 Periodic calibration ........................................................................................................ 16

Bibliography .......................................................................................................................... 17

Table 1 – Mandatory functions for otoacoustic emission instruments....................................... 9

Table 2 – Documentation of test conditions, parameters and results ..................................... 13

Table 3 – Values of U for conformance and periodic calibration measurements .............. 14

max
---------------------- Page: 5 ----------------------
– 4 – IEC 60645-6:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS –
AUDIOMETRIC EQUIPMENT –
Part 6: Instruments for the measurement of otoacoustic emissions
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

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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 60645-6 has been prepared by IEC technical committee 29: Electroacoustics. It is an

International Standard.

This second edition cancels and replaces the first edition published in 2009. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) the nominal test frequency used in DPOAE is now defined as the higher of the two

frequencies, f ;
b) the permitted deviation of the stimulus signal for TEOAE has been specified;
c) the frequency range for DPOAE stimulus signals has been redefined,
d) the stimulus level requirements for TEOAE have been redefined;
e) the stimulus level requirements for DPOAE have been redefined;
---------------------- Page: 6 ----------------------
IEC 60645-6:2022 © IEC 2022 – 5 –
f) the harmonic distortion requirements for DPOAE have been redefined;
g) a minimum measurement range for DPOAE has been added.
The text of this International Standard is based on the following documents:
Draft Report on voting
29/1109/FDIS 29/1114/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.

A list of all parts in the IEC 60645 series, published under the general title Electroacoustics –

Audiometric equipment, 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.
---------------------- Page: 7 ----------------------
– 6 – IEC 60645-6:2022 © IEC 2022
INTRODUCTION

Developments in the field of diagnostic hearing measurement have resulted in a number of

instruments designed to evaluate the otoacoustic emissions of the human ear. Such emissions

may be evoked by acoustic test signals having different spectral and temporal characteristics.

The practical use of such instruments concerns the measurement of sound energy emitted by

the inner ear and its separation from sounds emerging from physiological or other sources.

The spontaneous otoacoustic emissions (SOAE) and stimulus frequency otoacoustic emissions

(SFOAE), which comprise part of the otoacoustic emissions, are not covered by this document.

Conformance to the performance specification in this document is demonstrated when a

measured deviation from a design goal equals or does not exceed the corresponding

acceptance limit(s), and the laboratory has demonstrated that the associated uncertainty of

measurement equals or does not exceed the maximum permitted uncertainty specified in this

document.
---------------------- Page: 8 ----------------------
IEC 60645-6:2022 © IEC 2022 – 7 –
ELECTROACOUSTICS –
AUDIOMETRIC EQUIPMENT –
Part 6: Instruments for the measurement of otoacoustic emissions
1 Scope

This part of IEC 60645 applies to instruments designed primarily for the measurement of

otoacoustic emissions in the human external auditory meatus evoked by acoustic probe stimuli.

This document defines the characteristics to be specified by the manufacturer, specifies

minimum mandatory functions for two types of instruments and provides performance

specifications applicable to both instrument types. This document describes methods to be used

to demonstrate conformance with the specifications in this document and guidance on methods

for periodic calibration.

The purpose of this document is to ensure that measurements made under comparable test

conditions with different instruments complying with this document will be consistent.

Instruments can provide a measurement function not specifically within the scope of this

document and still comply with the relevant requirements of this document for the functions that

are within the scope. This document is not intended to restrict development or incorporation of

new features, nor to discourage innovative approaches.
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 60318-4, Electroacoustics – Simulators of human head and ear – Part 4: Occluded-ear

simulator for the measurement of earphones coupled to the ear by means of ear inserts

IEC 60318-5, Electroacoustics – Simulators of human head and ear – Part 5: 2 cm coupler for

the measurement of hearing aids and earphones coupled to the ear by means of ear inserts

IEC 60601-1, Medical electrical equipment – Part 1: General requirements for basic safety and

essential performance

IEC 60601-1-2, Medical electrical equipment – Part 1-2: General requirements for basic safety

and essential performance – Collateral standard: Electromagnetic disturbances – Requirements

and tests

IEC 60645-1:2017, Electroacoustics – Audiometric equipment – Part 1: Equipment for pure-

tone and speech audiometry

IEC 60645-3:2020, Electroacoustics – Audiometric equipment – Part 3: Test signals of short

duration

ISO/IEC Guide 98-3, Uncertainty of measurement – Part 3: Guide to the expression of

uncertainty in measurement (GUM:1995)
---------------------- Page: 9 ----------------------
– 8 – IEC 60645-6:2022 © IEC 2022
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
3.1
otoacoustic emissions
OAE

acoustic signals generated in the inner ear which can be recorded in the external auditory

meatus
3.2
transient-evoked otoacoustic emissions
TEOAE

acoustic signals emitted by the inner ear after stimulation with a stimulus of short duration

3.3
distortion product otoacoustic emissions
DPOAE

acoustic signals generated in the inner ear during stimulation with two pure tones

Note 1 to entry: The pure tones are frequencies f and f , f being the lower frequency.

1 2 1

Note 2 to entry: The frequencies of the DPOAE are given by the formulas for intermodulation distortions (IMD), i.e.

2f – f , 2f – f , etc.
1 2 2 1
3.4
nominal test frequency
frequency for which a DPOAE measurement is reported
3.5
primary tones
pure-tone stimuli used to evoke DPOAE
3.6
probe

part of the instrument, usually containing acoustic transducers, interfacing the instrument to the

ear
3.7
ear tip

device used to assist acoustic coupling, to reduce acoustic leakage, to reduce the influence of

environmental noise on measurements and to aid retention of the probe in the external auditory

meatus
3.8
probe signal

acoustic stimulus signal that is emitted into the external auditory meatus by means of a probe

---------------------- Page: 10 ----------------------
IEC 60645-6:2022 © IEC 2022 – 9 –
3.9
peak-to-peak equivalent sound pressure level
peSPL

root mean squared (RMS) value of a long-duration sinusoidal sound signal which, when

compared under the same test conditions with a short-duration output signal from the transducer

under test, has the same peak-to-peak value (i.e., difference between the extreme positive and

the extreme negative values) as the short-duration signal
Note 1 to entry: See IEC 60645-3:2020, Figure 2.
4 Requirements for specific instruments

Two different types of otoacoustic emission instruments are specified by the requirements for

minimum mandatory functions (see Table 1). Additional functions are not precluded. The two

types relate to their presumed primary application (diagnostic/clinical or screening); however,

a device of one type is not required to comply with the additional specifications of the other

type.
Table 1 – Mandatory functions for otoacoustic emission instruments
Type
1 2
Diagnostic/clinical Screening
Automatic test x x
Manual test x
Display of PASS/REFER x
Display of detailed result in graphical and/or tabular x
format
Display of stability of acoustic response in the x
external auditory meatus (see 5.2.1)
Display of response quality estimate (see 5.3.7) x
Digital storage of detailed result x
Export of full test report x

Type 1. This type of devices shall include the ability to manually start the test and to adjust the parameters of the

test.

Type 2. This type of device shall include the ability to automatically start the test.

5 General specifications
5.1 Acoustic stimulus system
5.1.1 General requirements

Specifications for the acoustic stimulus system are as given in the relevant parts of Clause 6,

Clause 8 and Clause 10 of IEC 60645-1:2017 and Clause 5 of IEC 60645-3:2020 with the

exceptions specified below.

NOTE If the instrument is designed to also allow the measurement of hearing thresholds, the full text of the relevant

clauses of IEC 60645-1:2017 applies.
5.1.2 Stimulus types
5.1.2.1 General

The general properties and temporal characteristics of the acoustic stimulus signals are

specified within 5.1.2.2 and 5.1.2.3 depending on the type of OAE being measured.

---------------------- Page: 11 ----------------------
– 10 – IEC 60645-6:2022 © IEC 2022
5.1.2.2 TEOAE

The full characteristics of the short-duration signal used for the measurements of TEOAE shall

be specified by the manufacturer (i.e., as specified in IEC 60645-3:2020).

NOTE A series of clicks with different polarity and levels is often used and this is usually referred to as a "non-

linear click series". The specifications found in IEC 60645-3 are applicable to each single click in the series.

5.1.2.3 DPOAE

The stimulus signal used for the measurement of DPOAE shall be composed of two primary

tones with frequencies f and f . Although the DPOAE of principal interest is at a frequency of

1 2

2f – f , the nominal test frequency of the measurement normally refers to f . If f is used as

1 2 2 1

the nominal test frequency, this shall be stated by the manufacturer. If additional test signals

are used (such as those used for masking), their full characteristics shall be specified by the

manufacturer.
5.1.3 Stimulus frequency range
5.1.3.1 General

The frequency content of the stimulus signal shall, as a minimum, meet the requirements

specified in 5.1.3.2 and 5.1.3.3 depending on the type of OAEs being measured.
5.1.3.2 TEOAE

The frequency spectrum of the transient stimulus signal shall at least cover the range from

0,5 kHz to 4 kHz for Type 1 instruments and the range from 1,5 kHz to 3 kHz for Type 2

instruments. The stimulus level frequency spectrum shall be flat within a limit of ±5 dB as

measured in an occluded-ear simulator according to IEC 60318-4 or a 2 cm coupler according

to IEC 60318-5, using the ear simulator or 2 cm coupler microphone, over the frequency range.

5.1.3.3 DPOAE

For the measurement of DPOAE, nominal stimulus frequencies between 0,75 kHz and 8 kHz in

at least three steps per octave shall be provided in instruments of Type 1 and at least two

frequencies between 1 kHz and 4 kHz for Type 2. The frequency ratio of the two primary tones

shall be stated by the manufacturer and shall normally be from 1:1,15 to 1:1,25.
The acceptance limit of the actual frequencies is ±1 %.
5.1.4 Stimulus level
5.1.4.1 General

The sound pressure level of the stimulus signals shall be variable within the ranges specified

in 5.1.4.2 and 5.1.4.3 depending on the type of OAEs. Its actual value within the residual

ear-canal volume shall be measured prior to each recording with the probe microphone.

5.1.4.2 TEOAE

For Type 1 instruments, the stimulus level shall be adjustable with a step size no greater than

5 dB and include a range of at least 60 dB peSPL to 85 dB peSPL. For Type 2 instruments, a

single fixed level of stimulus is acceptable, and this level shall be stated clearly in the

documentation since it impacts on the specificity of screening for a certain level of hearing loss.

The stimulus levels stated shall be measured in an occluded-ear simulator according to

IEC 60318-4 or a 2 cm coupler according to IEC 60318-5, using the occluded-ear simulator or

2 cm coupler microphone.
---------------------- Page: 12 ----------------------
IEC 60645-6:2022 © IEC 2022 – 11 –

To combat possible probe placement movement during the test, it is recommended that the

stimulus level be confirmed regularly during data acquisition for both Type 1 and Type 2

instruments.
The acceptance limit of the stimulus signal given above is ±1,5 dB.

NOTE Type 2 instruments are expected to provide a stimulus level between 80 dB peSPL and 86 dB peSPL to

maintain compatibility with established neonatal hearing screening programs.
5.1.4.3 DPOAE

For Type 1 instruments, the stimulus levels of the primary tones shall be adjustable with a step

size no greater than 5 dB and include a range from 30 dB SPL to 70 dB SPL. For Type 2

instruments, a single fixed level for each of the two stimuli is acceptable but shall be stated

clearly in the documentation since it impacts on the specificity of screening for a certain level

of hearing loss. This measurement shall be performed in an occluded-ear simulator according

to IEC 60318-4 or in a 2 cm coupler according to IEC 60318-5 using the occluded-ear simulator

or 2 cm coupler microphone. The level L of the primary tone with the lower fr
...

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