ASTM F2504-05(2022)植入式中耳助听设备系统输出的描述

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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the

Development of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.

Designation:F2504-05(Reapproved 2022)

Standard Practice for

Describing System Output of Implantable Middle Ear

Hearing Devices¹

This standard is issued under the fixed designation F2504;the number immediately following the designation indicates the year of

original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A

superscript epsilon(ε)indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice defines means for describing system per-

formance(ex vivo)and,in particular,system output of an

implantable middle ear hearing device (IMEHD)by measuring

a physical quantity that is relevant to the insertion gain and

output level of the IMEHD when implanted in the patient.

1.2 This practice is similar to headphone calibration on an

artificial ear in which the sound pressure level (in decibel

sound pressure level (SPL))measured in the artificial ear can

be converted to patient hearing level (in decibel hearing level

(HL)using a known transfer function,as defined by ANSI 3.7.

These measurements can then be used to predict system

parameters relevant for patient benefit such as functional gain,

maximum output,and variability.Measurements defined in this

practice should be useful for patients,clinicians,

manufacturers,investigators,and regulatory agencies in mak-

ing comparative evaluations of IMEHDs.

1.3 The values given in SI units are to be considered the

standard.

1.4 This standard does not purport to address all of the

safety concerns,if any,associated with its use.It is the

responsibility of the user of this standard to establish appro-

priate safety,health,and environmental practices and deter-

mine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accor-

dance with internationally recognized principles on standard-

ization established in the Decision on Principles for the

Development of International Standards,Guides and Recom-

mendations issued by the World Trade Organization Technical

Barriers to Trade(TBT)Committee.

¹This practice is under the jurisdiction of ASTM Committee F04 on Medical and

Surgical Materials and Devices and is the direct responsibility of Subcommittee

F04.37 on Implantable Hearing Devices(IHDs).

Current edition approved Oct.1,2022.Published October 2022.Originally

approved in 2005.Last previous edition approved in 2014 as F2504-05(2014).

DOI:10.1520/F2504-05R22.

2.Referenced Documents

2.1 ANSI Standards:²

ANSI 3.6 Specification for Audiometers

ANSI 3.7 Method for Coupler Calibration of Earphones

ANSI 3.22 Specification of Hearing Aid Characteristics

3.Terminology

3.1 Refer to the block diagram of Fig.1 for a clarification of

the mathematical notations used in this section.

3.2 In the following definitions,these symbols are used for

physical quantities:

3.2.1 E=electrical drive signal(voltage or current)

3.2.2 p=sound pressure

3.2.3 v=vibration velocity

3.3 All transfer functions are denoted by the symbol H,with

the following subscripts indicative of the type of transfer

function:

3.3.1 A=IMEHD-aided

3.3.2 E=electrical

3.3.3 H=hearing level

3.3.4 S=sound field sound pressure

3.3.5 T=tympanic membrane (ear drum)sound pressure

3.3.6 U=unimplanted

3.3.7 V=vibration of stapes

3.4 Definitions:

3.4.1 coupling,n— points and methods of attachment.

3.4.2 displacement,n—integral of velocity measured in

nanometres.

3.4.3 ear-canal sound pressure,pr n—sound pressure pro-

duced in the ear canal,at the tympanic membrane,by a sound

field stimulus,specified in units of pascals.

3.4.4 equivalent hearing level, LH,n—ratio of an equivalent

sound pressure,Po,relative to the sound field pressure,

2 Available from American National Standards Institute(ANSI),25 W.43rd St.,

4th Floor,New York,NY 10036,http://www.ansi.org.

F2504-05(2022)

UNIMPLANTED MIDDLE EAR

SOUND

FIELD p

EXTERNAL

EAR PT

TM &

OSSICLES

STAPES&

INNER

EAR

IMEHDAIDED MIDDLE EAR

INPUT

TRANSDUCER

&PROCESSOR

OUTPUT

TRANSDUCER

SOUND

FIELD

STAPES&

INNER

EAR

FIG.1 Signal Flow in the Unimplanted and IMEHD-Aided Middle Ear

PRETSPL,at 0°incidence that is just detectable monaurally by a

normally hearing individual,as defined in ANSI S3.6,Table 9,

expressed in decibels:LH=20-l1og10PoPRETSPL).

3.4.5 equivalent sound pressure,Pon— unimplanted input

sound field pressure needed to produce a stapes velocity equal

to that produced by a specified IMEHD input in the IMEHD-

aided condition:Po=E·HEs ·

3.4.5.1 Discussion—The equivalent sound pressure is the

product of the equivalent sound pressure transfer function,HES,

and the IMEHD output transducer electrical input E:Po=E ·

HEs. The equivalent sound pressure can be expressed as

equivalent sound pressure level in units of decibels, SPLeq

calculated as 20-1og10po/2·10-⁵Pa).

3.4.6 equivalent sound pressure level,Lo,n—logarithmic

representation of equivalent sound pressure,Lo=20-1og10PQ).

3.4.7 hearing level(HL),L,n—ratio of the input sound field

pressure,ps,relative to the sound field pressure PRETSPLat 0°

incidence that is just detectable monaurally by a normally

hearing individual,as defined in ANSI S3.6,Table 9,expressed

in decibels as:L=20·log10(Ps/PRETSPL).

3.4.8 IMEHD electrical input at threshold Erhreshold

n—electrical input to the IMEHD output transducer at thresh-

old of audibility.

3.4.9 IMEHD harmonic distortion, n—harmonic distortion

of the stapes velocity IMEHD-aided analogous to ANSI S3.22,

Section 6.11S,from sinusoidal inputs ofthe frequencies 500,

800,and 1600 Hz;input levels shall be Emax- 20 dB.

3.4.10 IMEHD output transducer; n—electromechanical

output transducer of the IMEHD.

3.4.11 IMEHD output transducerfrequency range,n—using

the equivalent sound pressure transfer function,HEs,draw a

horizontal line at the average for 1000,1600,and 2500 Hz,

then subtract 20 dB,or divide by 10;the lower and the upper

bounds ofthe frequency response range are where the average

line crosses the transfer function curve.

3.4.12 IMEHD output transducer input,E,n—electrical

input to the IMEHD output transducer,specified in volts or

amperes,as appropriate for the particular device.

3.4.13 IMEHD system frequency range,n—using the inser-

tion gain transfer function(velocity),Hv,draw a horizontal

line at the average for 1000,1600,and 2500 Hz,then subtract

20 dB,or divide by 10;the lower and the upper bounds ofthe

frequency response range are where the average line crosses

the transfer function curve.

3.4.14 input sound field pressure, Ps,n—sound stimulus

measured in the free field and presented to the listener in either

the IMEHD-aided or unimplanted condition,specified in units

of pascals.

3.4.15 maximum electrical transducer input,Emax

n—maximum electrical output of the sound signal processor,

specified as peak-to-peak or root mean square value,specified

in volts or amperes,as appropriate for the particular device.

3.4.16 maximum equivalent sound pressure,PE,max

n—equivalent sound pressure that corresponds to the maximum

electrical output Emax ofthe implant electronics,PEmax=Emax'

HES·

3.4.17 maximum equivalent sound pressure level,LE,max

n—logarithmic representation of the maximum equivalent

sound pressure LE,max=20-log10(PEmax/2·10-⁵Pa).

3.4.18 soundpressure at threshold,Pthreshold n—stimulus

sound field pressure at the threshold of audibility.

3.4.19 stapes velocity(IMEHD-aided),VA, n—translational

velocity of the stapes when driven by the IMEHD output

transducer,specified in units of mm/s.

3.4.20 stapes velocity(unimplanted) ,Vu,n—translational

velocity of the stapes when driven by sound input to the middle

ear specified in units of mm/s.

Transfer Function

3.4.21 acousto-electric transfer function,HsE, n—electrical

input to the IMEHD output transducer E produced by a sound

field,divided by the input sound field pressure ps:HsE=E/ps.

3.4.21.1 Discussion—HsE will depend on the particular gain

settings used,for example,full-on gain or minimal gain.The

gain should be reported whenever that transfer function is used.

3.4.22 acousto-vibrational transfer function(IMEHD

aided),HsvA—stapes velocity(IMEHD aided)divided by the

input sound field pressure:HsvA=VAps.

3.4.22.1 Discussion—This quantity can be measured di-

rectly or computed from the product ofthe electro-vibrational

F2504-05(2022)

transfer function,HEv,and the acousto-electric transfer

function,HsE,measured in the IMEHD-aided condition:HsvA

=VA/ps.

3.4.23 acousto-vibrational transfer function(unimplanted),

Hsvu, n—stapes velocity(unimplanted)when driven by the

input sound field,divided by the input sound field pressure:

Hsvu =Vu/ps.

3.4.23.1 Discussion—This quantity can be measured di-

rectly or computed from the product of the middle-ear transfer

function,HTv,and the ear-canal transfer function,Hsr,mea-

sured in the unimplanted condition:Hsvu=vU/Ps=HsrHTv.

3.4.24 ear-canal pressure transfer function,Hsz, n—ear

canal sound pressure,Pr,produced by the input sound field

pressure,ps,in the unimplanted case,divided by that input

sound field pressure:Hsr=Prps;this quantity is unitless(1,

2)³

．

3.4.25 electro-vibrational transferfunction,HEv ,n—stapes

velocity(IMEHD-aided)when driven by the IMEHD output

transducer,divided by the transducer input: HEv=vA/E.

3.4.26 equivalent sound pressure transfer function,HES,

n—unimplanted sound field pressure needed to produce a

stapes velocity equivalent to that produced by an electrical

IMEHD input in the IMEHD-aided condition,divided by the

IMEHD input.

3.4.26.1 Discussion—If the electrical IMEHD input pro-

duces a linear change in stapes velocity with a change in input

electrical stimulus,the equivalent sound pressure transfer

function,HEs,can be computed as the quotient between the

vibro-electric transfer function (IMEHD-aided),HEv,and the

vibro-acoustic transfer function (unimplanted), Hsvu:HEs=

(v/E)/(v/ps)= HEVHsvu.

3.4.27 insertion gain transfer function(sound field),Hss,

n—ratio of the equivalent sound pressure produced in the

IMEHD-aided case with a given electrical input to the IMEHD

output transducer and the input sound field pressure used as

input in the IMEHD-aided case required to produce the same

IMEHD output transducer electrical input:Hss=Pe/ps; this

ratio is unitless.

3.4.27.1 Discussion—With a linear sound signal processor,

the insertion gain(sound field)can be computed from the

product of the equivalent sound pressure transfer function,HES,

and the electro-acoustic transfer function, HsE:Hss=Pe/Ps=

Hse·Hes.Hss willdepend on the particular gain settings used,

for example,full-on gain or minimal gain.The gain should be

reported whenever that transfer function is used.

3.4.28 insertion gain transfer function(velocity),HVv

n—ratio of the stapes velocity (IMEHD-aided)and the stapes

velocity(unimplanted)produced by a given input sound field:

Hvv =VAVu;the ratio is unitless and can be expressed in

decibels as 20-log10(HV).

3.4.28.1 Discussion—With a linear sound signal processor

and IMEHD,that is,a processor whose electrical output E is

proportional to the input sound field pressure,ps,and an

IMEHD whose vibrational output is proportional to its electri-

3The boldface numbers in parentheses refer to the list of references at the end of

this standard.

cal output,the insertion gain(sound field),Hss,willequal the

insertion gain transfer function (velocity),Hv.

3.4.29 maximum insertion gain transfer function(sound

field),Hss,maxn n—maximum insertion gain transfer function

(sound field)that can be achieved with the implant electronics.

3.4.30 middle-ear transferfunction, HT,n—stapes velocity

(unimplanted)produced by an ear-canal sound pressure,di-

vided by the ear-canal sound pressure,in units of mm/s/Pa:

HTv=vUPr ·

3.5 Acronyms:

3.5.1 IHD—implantable hearing device

3.5.2 IMEHD—implantable middle-ear hearing device

3.5.3 LDV—laser Doppler vibrometry

3.5.4 SPL—sound pressure level

4.Summary of Practice

4.1 This practice involves the use of human temporal bones

and laser Doppler interferometry measurements of middle ear

structures velocities,to test for the ex-vivo performances of

IMEHD.Once a procedure for measuring system output has

been defined,several characteristics of the IMEHD can be

specified.Detailed instructions for measuring and reporting

these characteristics are given below.The important character-

istics are:

4.1.1 For Transducers:

4.1.1.1 Equivalent sound pressure transfer function,

4.1.1.2 IMEHD output transducer frequency range,and

4.1.1.3 IMEHD harmonic distortion.

4.1.2 For the System:

4.1.2.1 Maximum insertion gain transfer function(sound

field)(see full-on gain in ANSI S3.22,paragraph 3.7),

4.1.2.2 Maximum equivalent sound pressure level(see

OSPL90 in ANSI S3.22,paragraph 3.5),and

4.1.2.3 IMEHD system frequency range.

5.Significance and Use

5.1 IMEHDs are alternatives to air conduction hearing aids.

They are similar to air conduction hearing aids in that they

process incoming sound by applying frequency shaping and

compression to create an analog,vibratory audio frequency

output.IMEHDs differ from hearing aids in that they do not

create an airborne acoustical output signal with an electroa-

coustical output transducer in the external ear canal,but rather

a mechanical stimulation that results in the vibration of the

cochlear fluid.Therefore,the IMEHD output signal is not

readily accessible after implantation in the way hearing aid

output is accessible with real-ear probe microphone measure-

ments.Different devices will use different methods of coupling

to the ossicular chain or cochlea.This makes it difficult to

design a uniform model of the middle ear in the way the 2-cm³

coupler is used as a model of the external ear canal with

conventional hearing aids.

5.2 This practice provides uniformity of data collection

practices,thus allowing IMEHD in vitro performances to be

evaluated and readily compared.Once clinical data are

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标签： #ASTM #AS #植入式中耳助听设备

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1ThisinternationalstandardwasdevelopedinaccordancewithinternationallyrecognizedprinciplesonstandardizationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecommendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.Designation:F2504-05...

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