# US 11,076,780 B2 · Wideband acoustic immittance measurement apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,076,780 B2
- Document ID: US11076780B2
- Status: Granted
- Kind: B2
- Application number: 16/045,981
- Filed: 2018-07-26
- Published: 2019-02-07
- Granted: 2021-08-03
- Earliest claimed: 2017-08-03
- Assignees: Natus Medical Incorporated
- Applicants: Natus Medical Incorporated
- Inventors: Camilla MacGregor Magnussen; Ask Bojesen
- Web page: https://patentgrep.com/patent/US11076780B2

## CPC

- A61B 5/126: {measuring compliance or mechanical impedance of the tympanic membrane}
- A61B 5/7235: {Details of waveform analysis (detecting specific parameters of the electrocardiograph cycle A61B5/349)}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A new wideband acoustic immittance measurement apparatus is provided for determination of wideband acoustic immittance in the ear of the human, the apparatus comprising an ear probe for insertion in an ear canal of the human and having an acoustic output port for emission of sound into the ear canal of the human, and an acoustic input port for reception of sound from the ear canal of the human, and a loudspeaker that is arranged for acoustical connection with the acoustic output port of the ear probe for emission of the sound, and a microphone that is arranged for acoustical connection with the acoustic input port of the ear probe for generation of an audio signal as a function of sound received at the acoustic input port, and a processor that is adapted for controlling the loudspeaker to emit sound spanning a frequency range, and receiving the audio signal of the microphone, determining a complex acoustic admittance Y(f)=G(f)+jB(f) as a function of frequency f based on the emitted sound and the received audio signal, and identifying at least one middle ear resonance based on both the real and imaginary part of the determined acoustic admittance as a function of frequency f.

## Claims

### Claim 1

A wideband acoustic immittance measurement apparatus for determination of wideband acoustic immittance in an ear of a human, comprising
an ear probe configured to be inserted in the ear of the human and having an acoustic output port configured to emit sound into the ear of the human, and
an acoustic input port configured to receive sound in the ear of the human, and a loudspeaker that is acoustically connected with the acoustic output port of the ear probe for emission of the sound, and
a microphone that is acoustically connected with the acoustic input port of the ear probe for generation of an input audio signal as a function of sound pressure at the acoustic input port, and
a processor that is adapted for
providing an output audio signal to the loudspeaker for conversion into sound spanning a frequency range, and
receiving the input audio signal generated by the microphone,
determining wideband acoustic immittance F(f) as a function of frequency f based on the output audio signal and the input audio signal,
identifying a middle ear resonance based on the determined wideband acoustic immittance F(f) at a resonance frequency fres at which an acoustic admittance Y(f)=G(f)+jB(f) corresponding to the determined wideband acoustic immittance F(f) fulfils that a conductance G(fres) is a maximum of a conductance G(f) and that a gradient B′(fres) of a susceptance B(f) is a minimum of a gradient B′(f), where j is √{square root over (−1)}.

### Claim 2 (depends on 1)

A wideband acoustic immittance measurement apparatus according to claim 1, wherein the determined wideband acoustic immittance F(f) is selected from the group consisting of:
i) Acoustic admittance Y(f)=G(f)+jB(f)=|Y(f)|ejϕ(f) as a function of frequency f,
j) acoustic impedance Z(f)=R(f)+j*X(f)=|Z(f)|ejθ(f) as a function of frequency f, wherein R(f) is a resistance of Z(f) and X(f) is a reactance of Z(f),
k) acoustic reflectance
Γ
⁡
(
f
)
=
Z
⁡
(
f
)
-
Z
c
⁡
(
f
)
Z
⁡
(
f
)
+
Z
c
⁡
(
f
)
as a function of frequency f, wherein Zc is a characteristic impedance of an ear canal of the ear, and
l) acoustic absorbance A(f)=1−|Γ(f)|0 as a function of frequency f.

### Claim 3 (depends on 2)

The wideband acoustic immittance measurement apparatus according to claim 2, wherein the processor is adapted for identifying a plurality of middle ear resonances of the determined wideband acoustic immittance F(f) at a corresponding plurality of resonance frequencies fres,l, wherein at each resonance frequency fres,l the acoustic admittance Y(f)=G(f)+jB(f) corresponding to the determined wideband acoustic immittance F(f) fulfils that a conductance G(fres,i) is a maximum of the conductance G(f) and a gradient B′(fres,i) of the susceptance B(f) is a minimum of the gradient B′(f).

### Claim 4 (depends on 2)

The wideband acoustic immittance measurement apparatus according claim 2, wherein the determined wideband acoustic immittance F(f) is the acoustic admittance Y(f)=G(f)+jB(f), and wherein
the processor is adapted for identifying the middle ear resonance at the resonance frequency fres at which the acoustic admittance Y(f)=G(f)+jB(f) fulfils that the conductance G(fres) is a maximum of the conductance G(f) and that the gradient B′(fres) of the susceptance B(f) is a minimum of the gradient B′(f).

### Claim 5 (depends on 1)

The wideband acoustic immittance measurement apparatus according to claim 1, wherein the processor is adapted for identifying a middle ear resonance of the determined wideband acoustic immittance F(f) at a resonance frequency f.sub.res at which the acoustic admittance Y(f)=G(f)+jB(f) corresponding to the determined wideband acoustic immittance F(f) fulfils that a magnitude |Y(f.sub.res)| of the acoustic admittance Y(f) is a maximum of a magnitude |Y(f)| and that a gradient .PHI.′(f.sub.res) of a phase .PHI.(f) is a minimum of a gradient .PHI.′(f).

### Claim 6 (depends on 5)

The wideband acoustic immittance measurement apparatus according to claim 5, wherein the determined wideband acoustic immittance F(f) is selected from the group consisting of:
e) Acoustic admittance Y(f)=G(f)+jB(f)=|Y(f)|ejϕ(f) as a function of frequency f, wherein ϕ(f) is a phase of Y(f),
f) acoustic impedance Z(f)=R(f)+j*X(f)=|Z(f)|ejθ(f)as a function of frequency f, wherein R(f) is a resistance of Z(f), X(f) is a reactance of Z(f), and θ(f) is a phase of Z(f),
g) acoustic reflectance
Γ
⁡
(
f
)
=
Z
⁡
(
f
)
-
Z
c
⁡
(
f
)
Z
⁡
(
f
)
+
Z
c
⁡
(
f
)
as a function of frequency f, wherein Zc is a characteristic impedance of an ear canal of the ear, and
h) acoustic absorbance A(f)=1−|Γ(f)|0 as a function of frequency f.

### Claim 7 (depends on 6)

The wideband acoustic immittance measurement apparatus according to claim 6, wherein the processor is adapted for identifying a plurality of middle ear resonances of the determined wideband acoustic immittance F(f) at a corresponding plurality of resonance frequencies fres,1, wherein at each resonance frequency fres,l the acoustic admittance Y(f)=G(f)+jB(f) corresponding to the determined wideband acoustic immittance F(f) fulfils that a conductance G(fres,i) is a maximum of the conductance G(f) and a gradient B′(fres,i) of the susceptance B(f) is a minimum of the gradient B′(f).

### Claim 8 (depends on 6)

The wideband acoustic immittance measurement apparatus according claim 6, wherein the determined wideband acoustic immittance F(f) is the acoustic admittance Y(f)=G(f)+jB(f), and wherein
the processor is adapted for identifying the middle ear resonance at the resonance frequency fres at which the acoustic admittance Y(f)=G(f)+jB(f) fulfils that the conductance G(fres) is the maximum of the conductance G(f) and that the gradient B′(fres) of the susceptance B(f) is a minimum of the gradient B′(f).

### Claim 9 (depends on 1)

The wideband acoustic immittance measurement apparatus according to claim 1, wherein the processor is adapted for determining a parameter of the wideband acoustic immittance F(f) at the middle ear resonance of the determined wideband acoustic immittance F (f).

### Claim 10 (depends on 9)

The wideband acoustic immittance measurement apparatus according to claim 9, wherein the determined wideband acoustic immittance F(f) is selected from the group consisting of:
m) Acoustic admittance Y(f)=G(f)+jB(f)=|Y(f)|ejϕ(f) as a function of frequency f,
n) acoustic impedance Z(f)=R(f)+j*X(f)=|Z(f)|ejθ(f) as a function of frequency f,
o) acoustic reflectance
Γ
⁡
(
f
)
=
Z
⁡
(
f
)
-
Z
c
⁡
(
f
)
Z
⁡
(
f
)
+
Z
c
⁡
(
f
)
as a function of frequency f, wherein Zc is a characteristic impedance of an ear canal of the ear, and
p) acoustic absorbance A(f)=1−|Γ(f)|0 as a function of frequency f.

### Claim 11 (depends on 9)

The wideband acoustic immittance measurement apparatus according to claim 9, wherein the processor is adapted for identifying a plurality of middle ear resonances of the determined wideband acoustic immittance F(f) at a corresponding plurality of resonance frequencies fres,l, wherein at each resonance frequency fres,l the acoustic admittance Y(f)=G(f)+jB(f) corresponding to the determined wideband acoustic immittance F(f) fulfils that a conductance G(fres,i) is a maximum of the conductance G(f) and a gradient B′(fres,i) of the susceptance B(f) is a minimum of the gradient B′(f).

### Claim 12 (depends on 9)

The wideband acoustic immittance measurement apparatus according claim 9, wherein the determined wideband acoustic immittance F(f) is the acoustic admittance Y(f)=G(f)+jB(f), and wherein
the processor is adapted for identifying the middle ear resonance at the resonance frequency fres at which the acoustic admittance Y(f)=G(f)+jB(f) fulfils that the conductance G(fres) is the maximum of the conductance G(f) and that the gradient B′(fres) of the susceptance B(f) is a minimum of the gradient B′(f).

### Claim 13 (depends on 9)

A wideband acoustic immittance measurement apparatus according to claim 9, wherein the parameter of the wideband acoustic immittance F(f) at the middle ear resonance is selected from the group consisting of the magnitude of the conductance G(f.sub.res), the magnitude of the minimum of the gradient of the susceptance B′(f.sub.res).

### Claim 14 (depends on 1)

The wideband acoustic immittance measurement apparatus according claim 1, wherein the determined wideband acoustic immittance F(f) is the acoustic admittance Y(f)=G(f)+jB(f), and wherein the processor is adapted for identifying the middle ear resonance at the resonance frequency f.sub.res at which the acoustic admittance Y(f)=G(f)+jB(f) fulfils that a magnitude |Y(f.sub.res)| of the acoustic admittance Y(f) is a maximum of a magnitude |Y(f)| and that a gradient .PHI.′(f.sub.res) of a phase .PHI.(f) is a minimum of a gradient .PHI.′(f).

### Claim 15 (depends on 1)

The wideband acoustic immittance measurement apparatus according to claim 1, the apparatus further comprising:
a housing for accommodation of an air pump, and wherein the ear probe comprises
an ear probe air conduit for connection with the air pump and having an air output for applying a static pressure to an ear canal through an ear tip air conduit of an ear tip configured to be inserted into the ear canal of the human and for sealing the ear canal with an air tight seal, and wherein
the processor is adapted for
controlling the air pump to provide static pressures p spanning a pressure range, and
determine a wideband acoustic immittance F (f, p) as a function of frequency f and static pressure p based on the output audio signal and the input audio signal and the provided static pressure p.

### Claim 16 (depends on 1)

The wideband acoustic immittance measurement apparatus according to claim 1, wherein
the processor is adapted for
determining a baseline compensated admittance YBC(f, p1, p2)=Y1(f, p1)−Y2(f, p2) between a determined acoustic admittance Y1(f, p1) as a function of frequency f at a first static pressure p1 and a determined acoustic admittance Y2(f, p2) as a function of frequency f at a second static pressure p2, and
identifying a middle ear resonance based on the baseline compensated acoustic admittance YBC(f, p1, p2) by determining a first frequency fres,1 and a second frequency fres,2 at which the baseline compensated acoustic admittance YBC(f, p1, p2)=Y1(f, p1)−Y2(f, p2) fulfils that the baseline compensated conductance GBC(fres,1, p1, p2)=G1(fres,1, p1)−G2(fres,1, p2) of the baseline compensated acoustic admittance YBC(f, p1, p2) is a local or global maximum and that a gradient B′(fres,2, p1, p2) of a baseline compensated acoustic susceptance BBC(f, p1, p2)=B1(f, p1)−B2(f, p2) is a local or global minimum and identifying a middle ear resonance when an value of a difference between fres,1 and fres,2 is less than a threshold value.

### Claim 17 (depends on 1)

The wideband acoustic immittance measurement apparatus according claim 1 wherein a frequency range of the output audio signal includes the range from 200 Hz-3 kHz.

### Claim 18 (depends on 1)

The wideband acoustic immittance measurement apparatus according claim 1 wherein a frequency range of the output audio signal includes the range from 200 Hz-4 kHz.

### Claim 19 (depends on 1)

The wideband acoustic immittance measurement apparatus according claim 1 wherein the processor is adapted for controlling a display to show a plot of the determined wideband acoustic immittance F(f) with an indication of the identified middle ear resonance.

### Claim 20 (depends on 19)

The wideband acoustic immittance measurement apparatus according claim 19 wherein a frequency range of the output audio signal includes the range from 200 Hz-3 kHz.