US 2025/0082233 A1Published application

Apparatus and method for measuring clinical-audiometric parameters

AssigneeNeuranix S.R.L.

InventorsCarlos Esteban Graffigna, Domenico Stanzial

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Abstract

Apparatus and method for determining the immittance of a middle ear for clinical-audiometric investigations in a wide range of frequencies at ambient pressure, based on MEMS microphone technology and on measuring the acoustic pressure wave and the corresponding acoustic velocity wave by means of a pressure-pressure probe.

Claims15

Dependent claims

Method for determining the admittance of an auditory canal (6) for clinical-audiometric investigations, the method comprising at least one or more iterations of a procedure, in which each iteration is associated with a respective coupling configuration (Q, Q1, Q2) between an impedance probe (1) and the auditory canal (6), in which said procedure includes the following steps:

A. coupling the calibrated sealed impedance probe (1) having a known air volume Vprobe, through a first end (3) thereof, with the auditory canal (6) so that:
the air volume Vprobe sealed inside the impedance probe (1) and the air volume Vcanal inside the auditory canal (6) form an overall air volume Voverall, and
a longitudinal axis of the impedance probe (1) is substantially coincident to a longitudinal axis of the auditory canal (6);
B. sending a broadband exciting sound signal s(t) to the auditory canal (6) through a speaker (4) of the impedance probe (1), such speaker (4) being located at a second end (5) of the impedance probe (1) opposed to the first end (3);
C. directly detecting (220) an acoustic pressure p1(t), p2(t) back from the auditory canal (6) in at least two points x1 and x2,respectively, located along the longitudinal axis of the impedance probe (1) at distance Δx12 between them, by means of a microphone array (8) that is included in the impendence probe (1) and outputs electric signals r1(t) and r2(t);
D. acquiring and discretizing (230) the output electric signals r1(t) and r2(t) from the microphone array (8), obtaining discretized signals r1(n) and r2(n) respectively, with n∈[1;
N], N∈;
E. calculating (240) a first impulse response δ1au(n) and a second impulse response δ2au(n) by the following equations:
δ
1
a
⁢
u
(
n
)
=
IFFT
⁢
{
FFT
⁢
{
s
′
(
n
)
}
FFT
⁢
{
r
1
(
n
)
}
}
δ
2
a
⁢
u
(
n
)
=
IFFT
⁢
{
FFT
⁢
{
s
′
(
n
)
}
FFT
⁢
{
r
2
(
n
)
}
}
where s′(t) is the time reversed broadband sound signal s(t), FFT is a Fast Fourier Transfom and IFFT is an inverse FFT;
F. calculating (250) an impulse response δpau(n) of the acoustic pressures p1(t) and p2(t) and an impulse response δvau(n) of velocity of an air particle at measurement point x0 along the longitudinal axis of the impedance probe (1):
δ
v
a
⁢
u
(
n
)
=
δ
1
a
⁢
u
(
n
)
-
δ
2
a
⁢
u
(
n
)
(
ρ
·
Δ
⁢
x
1
⁢
2
)
+
δ
v
a
⁢
u
(
n
-
1
)
δ
p
a
⁢
u
(
n
)
=
δ
1
a
⁢
u
(
n
)
+
δ
2
a
⁢
u
(
n
)
2
such a measurement point x0 being a centre point between points x1 and x2;
G. converting (260) the impulse responses δpau(n), δvau(n) of pressure and velocity to pressure and velocity physical units by multiplying each one by a calibration constant α and β known a priori, respectively, as follows:
δ
p
(
n
)
[
Pascal
]
=
α
·
δ
p
a
⁢
u
(
n
)
δ
v
(
n
)
[
Pascal
⁢
meter
/
second
]
=
β
·
δ
v
a
⁢
u
(
n
)
H. calculating (270) frequency spectra {circumflex over (P)}*(ωm), {circumflex over (V)}*(ωm) of the impulse responses of pressure and velocity respectively, through Fast Fourier Transform, as follows:
{
V
^
*
(
ω
m
)
=
F
⁢
F
⁢
T
⁢
{
δ
v
⁢
(
n
)
}
P
^
*
(
ω
m
)
=
F
⁢
F
⁢
T
⁢
{
δ
p
⁢
(
n
)
}
where ωm is a discretized frequency with m∈[1;
N/2];
I. calculating (280) an admittance Ŷ*(ωm) as a ratio between a cross spectrum Ĝpv(ωm) of the spectrum of the acoustic pressure impulse response and of the spectrum of the acoustic velocity impulse response, and an auto spectrum Ĝpp(ωm) of the spectrum of the acoustic pressure impulse response:
Y
^
*
(
ω
m
)
=
G
^
pv
(
ω
m
)
G
^
pp
(
ω
m
)
=
V
^
*
(
ω
m
)
·
P
^
*
(
ω
m
)
P
^
*
(
ω
m
)
·
P
^
*
(
ω
m
)
L. obtaining (290) a calibrated frequency spectrum Ŷ(ωm) of the admittance through a calibration function Γ(ωm) known a priori, according to the equation:
Y
^
(
ω
m
)
=
Γ
⁡
(
ω
m
)
·
Y
^
*
(
ω
m
)
,
said steps D to L being performed by a control and processing device (11).

313 more elements

Method according to previous claim, wherein the distance Δx12 is equal to 12 mm.

Method according to any one of the preceding claims, wherein the calibrated frequency spectrum Ŷ(ωm) of the admittance is further input to a display (16) to be displayed (295).

Method according to any one of the preceding claims, wherein the impedance probe (1) and the auditory canal (6) are coupled into a first coupling configuration (Q1), the exciting sound signal s(t) is a fast sweep signal sfast(t) varying in frequency over a time Tsweepfast less than one second, to obtain a first calibrated admittance Ŷ1(ωm) and said procedure comprises further the additional step:

M. checking whether a resonance condition in the calibrated admittance Ŷ1(ωm) is satisfied, thereby a peak of the module of the first calibrated admittance Ŷ1(ωm) corresponds to zero-crossing of its phase, and wherein:
if a resonance condition does not occur, another iteration of said procedure comprising steps A to M is implemented, wherein the impedance probe (1) and the auditory canal (6) are coupled in another coupling configuration (Q2) that is different from the previous coupling configuration (Q1) and the exciting sound signal s(t) is the fast sweep signal sfast(t);
if a resonance condition occurs, steps B to L of such procedure are implemented, wherein the coupling configuration is the one for which the resonance condition occurs and the exciting sound signal s(t) is a sweep signal varying in frequency over a time greater than the time Tsweepfast of the fast sweep signal sfast(t), and said one or more iterations of said procedure end.

Dependencies are inferred from the claim text.

Facts

Application: 18/958,947Filed 25 Nov 2024
Priority: IT 10202000002485621 Oct 2020
Published: 13 Mar 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

A61B 5/126
Objective methods: measuring compliance or mechanical impedance of the tympanic membrane
A61B 5/6817
Ear: ear canal
A61B 5/7228
Signal processing specially adapted for physiological signals or for diagnostic purposes: signal modulation applied to the input signal sent to…
A61B 5/7257
Characterised by using transforms: using Fourier transforms

Family

Application18/017,990Continuation · filed 25 Jan 2023
Application18/958,947Continuation
US 12,150,757 B2Related patent
US 2023/0284935 A1Published application
US 2025/0082233 A1This patent

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Abstract

A. coupling the calibrated sealed impedance probe (1) having a known air volume Vprobe, through a first end (3) thereof, with the auditory canal (6) so that:
the air volume Vprobe sealed inside the impedance probe (1) and the air volume Vcanal inside the auditory canal (6) form an overall air volume Voverall, and
a longitudinal axis of the impedance probe (1) is substantially coincident to a longitudinal axis of the auditory canal (6);
B. sending a broadband exciting sound signal s(t) to the auditory canal (6) through a speaker (4) of the impedance probe (1), such speaker (4) being located at a second end (5) of the impedance probe (1) opposed to the first end (3);
C. directly detecting (220) an acoustic pressure p1(t), p2(t) back from the auditory canal (6) in at least two points x1 and x2,respectively, located along the longitudinal axis of the impedance probe (1) at distance Δx12 between them, by means of a microphone array (8) that is included in the impendence probe (1) and outputs electric signals r1(t) and r2(t);
D. acquiring and discretizing (230) the output electric signals r1(t) and r2(t) from the microphone array (8), obtaining discretized signals r1(n) and r2(n) respectively, with n∈[1;
N], N∈;
E. calculating (240) a first impulse response δ1au(n) and a second impulse response δ2au(n) by the following equations:
δ
1
a
⁢
u
(
n
)
=
IFFT
⁢
{
FFT
⁢
{
s
′
(
n
)
}
FFT
⁢
{
r
1
(
n
)
}
}
δ
2
a
⁢
u
(
n
)
=
IFFT
⁢
{
FFT
⁢
{
s
′
(
n
)
}
FFT
⁢
{
r
2
(
n
)
}
}
where s′(t) is the time reversed broadband sound signal s(t), FFT is a Fast Fourier Transfom and IFFT is an inverse FFT;
F. calculating (250) an impulse response δpau(n) of the acoustic pressures p1(t) and p2(t) and an impulse response δvau(n) of velocity of an air particle at measurement point x0 along the longitudinal axis of the impedance probe (1):
δ
v
a
⁢
u
(
n
)
=
δ
1
a
⁢
u
(
n
)
-
δ
2
a
⁢
u
(
n
)
(
ρ
·
Δ
⁢
x
1
⁢
2
)
+
δ
v
a
⁢
u
(
n
-
1
)
δ
p
a
⁢
u
(
n
)
=
δ
1
a
⁢
u
(
n
)
+
δ
2
a
⁢
u
(
n
)
2
such a measurement point x0 being a centre point between points x1 and x2;
G. converting (260) the impulse responses δpau(n), δvau(n) of pressure and velocity to pressure and velocity physical units by multiplying each one by a calibration constant α and β known a priori, respectively, as follows:
δ
p
(
n
)
[
Pascal
]
=
α
·
δ
p
a
⁢
u
(
n
)
δ
v
(
n
)
[
Pascal
⁢
meter
/
second
]
=
β
·
δ
v
a
⁢
u
(
n
)
H. calculating (270) frequency spectra {circumflex over (P)}*(ωm), {circumflex over (V)}*(ωm) of the impulse responses of pressure and velocity respectively, through Fast Fourier Transform, as follows:
{
V
^
*
(
ω
m
)
=
F
⁢
F
⁢
T
⁢
{
δ
v
⁢
(
n
)
}
P
^
*
(
ω
m
)
=
F
⁢
F
⁢
T
⁢
{
δ
p
⁢
(
n
)
}
where ωm is a discretized frequency with m∈[1;
N/2];
I. calculating (280) an admittance Ŷ*(ωm) as a ratio between a cross spectrum Ĝpv(ωm) of the spectrum of the acoustic pressure impulse response and of the spectrum of the acoustic velocity impulse response, and an auto spectrum Ĝpp(ωm) of the spectrum of the acoustic pressure impulse response:
Y
^
*
(
ω
m
)
=
G
^
pv
(
ω
m
)
G
^
pp
(
ω
m
)
=
V
^
*
(
ω
m
)
·
P
^
*
(
ω
m
)
P
^
*
(
ω
m
)
·
P
^
*
(
ω
m
)
L. obtaining (290) a calibrated frequency spectrum Ŷ(ωm) of the admittance through a calibration function Γ(ωm) known a priori, according to the equation:
Y
^
(
ω
m
)
=
Γ
⁡
(
ω
m
)
·
Y
^
*
(
ω
m
)
,
said steps D to L being performed by a control and processing device (11).

313 more elements

Facts

Application

18/958,947Filed 25 Nov 2024

Priority

IT 10202000002485621 Oct 2020

Published

13 Mar 2025

Term ends

Not estimatedThe source records don’t support an estimate.

Classification13 codes

A61B 5/126
Objective methods: measuring compliance or mechanical impedance of the tympanic membrane
A61B 5/6817
Ear: ear canal
A61B 5/7228
Signal processing specially adapted for physiological signals or for diagnostic purposes: signal modulation applied to the input signal sent to…
A61B 5/7257
Characterised by using transforms: using Fourier transforms