AIR-PUMP ARRANGEMENT FOR AN ACOUSTIC MEASUREMENT DEVICE

Abstract

Disclosed herein are embodiments of an acoustic measurement device configured to provide acoustic property values for objective ear-condition evaluation of a patient's ear, in particular a human's ear. Said acoustic measurement device can be configured to be positioned within an ear canal of said patient and configured to take a resting position within said ear canal. Embodiments of the acoustic measurement device can include an air-pump arrangement, said air-pump arrangement, at least in said resting position, being in fluid connection with said ear canal through at least one tube running via said ear probe.

Claims

1. An acoustic measurement device configured to provide acoustic property values for objective ear-condition evaluation of a patient's ear, wherein: at least part of said acoustic measurement device being configured to be positioned within an ear canal of said patient and configured to take a resting position within said ear canal, said acoustic measurement device comprising an ear probe, said acoustic measurement device comprising an air-pump arrangement, said air-pump arrangement, at least in said resting position, being in fluid connection with said ear canal through at least one tube running via said ear probe, said air-pump arrangement, in said resting position, being configured to apply an air-pressure control procedure, consisting of at least one air-pressure level, across said patient's tympanic membrane of said ear, wherein: said acoustic measurement device, in said resting position, being configured to provide acoustic property values in reaction to said air pressure control procedure applied by said air-pump arrangement across said patient's tympanic membrane of said ear, characterized in that, said air-pump arrangement comprising at least two pumps, wherein said at least two pumps comprising a movable element in the form of a membrane.

2. Acoustic measurement device according to claim 1, wherein said at least two pumps are configured to act as membrane pumps for applying said air-pressure control procedure.

3. Acoustic measurement device according to claim 1, comprising: an acoustic input unit configured to capture acoustic signals representative for said air-pressure levels within said ear canal, a control device configured to control said air-pump arrangement, and a processing device configured to further process said captured acoustic signals.

4. Acoustic measurement device according to claim 1, wherein: said at least two pumps are formed as piezo-electric membrane pumps and are each arranged fluidically in series with at least one flow-regulating component, wherein the two piezo-electric membrane pumps are arranged parallel to each other, wherein: said at least one flow regulating component being configured and arranged within said air-pump arrangement such that said two piezo-electric membrane pumps is capable of working bidirectional when applying said air-pressure control procedure.

5. Acoustic measurement device according to claim 1, wherein: said at least two pumps comprising a first pump and a second pump, wherein said first pump and said second pump being poled in opposing directions to each other, or said at least two pumps are formed as piezo-electric membrane pumps, or said air-pump arrangement being configured such that said at least two pumps, preferably piezo-electric membrane pumps, can work simultaneously to control said air pressure level within said air pressure control procedure in said ear canal.

6. Acoustic measurement device according to claim 5, wherein said at least two pumps are formed as piezo-electric membrane pumps which are each fluidically arranged in series with at least one flow regulating component, in particular in the form of a flow resistor, wherein the two piezo-electric membrane pumps are arranged parallel to each other.

7. Acoustic measurement device according to claim 6, wherein: said air-pump arrangement providing a first piezo-electric membrane pump fluidically in series with a first flow resistor and a second piezo-electric membrane pump fluidically in series with a second flow resistor, wherein said first piezo-electric membrane pump and said second piezo-electric membrane pump are arranged parallel to each other, wherein: said air-pump arrangement being configured and arranged such that pressure between said first flow resistor and said second flow resistor can be controlled in said ear-canal of said ear, said air-pump arrangement thereby in particular essentially acting in a manner analogous to a voltage divider, by maintaining and adjusting an inlet pressure and an outlet pressure at said first and said second piezo-electric membrane pump.

8. Acoustic measurement device according to claim 3, wherein: an acoustic muffler is provided and arranged at said ear probe, said acoustic muffler being configured to constitute said flow regulating components, in particular in the form of a flow resistor, and configured to attenuate noise from said air-pump arrangement, said acoustic muffler in particular consisting of a network of narrow tubes and cavities, configured to attenuate acoustic noise and acting in a manner of a flow resistor.

9. Acoustic measurement device according to claim 1, wherein: said air-pump arrangement, in said resting position, being configured to apply said air pressure control procedure in the form of maintaining essentially a single air pressure level during said procedure, wherein: said air pressure level lying in the range of 600 to +400 daPa, or said air-pump arrangement, in said resting position, being configured to apply said air pressure control procedure in the form of performing varying air pressure levels during said procedure, wherein said varying air pressure levels during said procedure range between around 600 daPa to +400 daPa, wherein: in particular, said air-pump arrangement, in said resting position, being configured to perform said varying air-pressure levels with an adjustable air-pressure sweep rate.

10. Acoustic measurement device according to claim 1, wherein: said air-pump arrangement, in said resting position, being configured to apply said air pressure control procedure in the form of maintaining essentially a single air pressure level during said procedure, wherein: said air pressure level lying in the range of 600 to +400 daPa, and said air-pump arrangement, in said resting position, being configured to apply said air pressure control procedure in the form of performing varying air pressure levels during said procedure, wherein said varying air pressure levels during said procedure range between around 600 daPa to +400 daPa, wherein: in particular, said air-pump arrangement, in said resting position, being configured to perform said varying air-pressure levels with an adjustable air-pressure sweep rate.

11. Acoustic measurement device according to claim 1, wherein: said acoustic measurement device being configured to provide acoustic property values representative for said patient's middle-ear in reaction to a first pressure control procedure of said air pressure control procedure, applied by said at least two pumps of said air-pump arrangement across said patient's tympanic membrane of said ear, wherein: said first pressure control procedure in particular contains performing varying air pressure levels during said procedure, wherein said varying air pressure levels during said first pressure control procedure range between around 600 daPa to +400 daPa, wherein: in particular, said air-pump arrangement, in said resting position, being configured to perform said varying air-pressure levels with an adjustable air pressure sweep rate. said acoustic measurement device in particular being configured to act as a tympanometer.

12. Acoustic measurement device according to claim 1, wherein: said acoustic measurement device being configured to provide acoustic property values representative for said patient's inner ear in reaction to a second pressure control procedure of said air pressure control procedure, applied by said at least two pumps of said air-pump arrangement across said patient's tympanic membrane of said ear, wherein: said second pressure control procedure in particular contains performing and maintaining essentially a single air pressure level during said procedure, wherein: said essentially single air pressure level performed in particular lying in the range of 600 to +400 daPa, said acoustic measurement device in particular being configured to act as a hearing diagnostic instrument for pressurized acoustic-reflex measurement.

13. Acoustic measurement device according to claim 1, wherein: said acoustic measurement device being configured to provide acoustic property values representative for said patient's inner-ear in reaction to a third pressure control procedure of said air-pressure control procedure, applied by said at least two pumps of said air-pump arrangement across said patient's tympanic membrane of said ear, wherein: said third pressure control procedure in particular contains performing and maintaining essentially a single air pressure level during said procedure, wherein: said essentially single air pressure level performed in particular lying in the range of 600 to +400 daPa, said acoustic measurement device in particular being configured to act as a hearing diagnostic instrument for otoacoustic-emission measurement.

14. Acoustic measurement device according to claim 1, wherein: said at least two pumps comprising a first pump and a second pump, wherein said first pump and said second pump being poled in opposing directions to each other, and said at least two pumps are formed as piezo-electric membrane pumps, and said air-pump arrangement being configured such that said at least two pumps, preferably piezo-electric membrane pumps, can work simultaneously to control said air pressure level within said air pressure control procedure in said ear canal.

15. Acoustic measurement device according to claim 1, wherein the acoustic measurement device comprises a control device configured to control said air-pump arrangement.

16. A diagnostic instrumental arrangement configured to provide at least one objective ear-condition parameter of a patient's ear, in particular of a human's ear, comprising: an acoustic measurement device according to claim 1, a processing device configured to further process said captured acoustic signals to an evaluation device, said evaluation device being configured to execute an evaluation process to said processed acoustic signals associated to said air-pressure control procedure to obtain said at least one objective ear-condition parameter for said patient's ear.

17. A diagnostic instrumental arrangement according to claim 16, wherein said diagnostic instrumental arrangement being mechanically connectable to a stand-alone device or being operated via a mobile end device, in particular a tablet or a smartphone.

18. Objective ear-condition evaluation method using an acoustic measurement device according to claim 1.

19. A diagnostic instrumental arrangement according to claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 shows an exemplary acoustic measurement device according to the application.

[0043] FIG. 2 shows a typical pressure-flow relationship of a typical membrane pump operated at its maximum power.

[0044] FIG. 3 shows a schematic illustration of an example according to the application of an electrical-analog circuit of two membrane pumps, represented by sources, connected to the volume of the ear-canal, represented by a capacitor, each in series with a flow resistor. Ground represents ambient pressure.

[0045] FIG. 4 shows a schematic illustration of an example according to the application of producing a tympanometric air-pressure procedure using two membrane pumps in terms of the ear-canal pressure (top), the pressure rate (middle), and the relative pump power of the two pumps (bottom).

DETAILED DESCRIPTION OF THE APPLICATION

[0046] In the following, an example of an acoustic measurement device 1 is shown and described, which comprises an exemplary air pump arrangement 2 according to the application. The air pump arrangement 2 may comprise a first and a second pump. The first and/or the second pump may be a membrane pump. For example, the first and/or the second pump may be a piezo-electric membrane pump. For example, the first and/or the second pump may be a miniature piezo-electric membrane pump. The acoustic measurement device 1 may be used in a diagnostic instrumental arrangement (not further shown here).

[0047] In FIG. 1, it is shown that the air-pump arrangement 2 of the acoustic measurement device 1 provides a first pump 3a (e.g. a miniature piezo-electric membrane pump) fluidically in series with a first flow resistor 4a and a second pump 3b (e.g. a miniature piezo-electric membrane pump) fluidically in series with a second flow resistor 4b. The air-pump arrangement 2 is configured and arranged such that pressure between the first flow resistor 4a and said second flow resistor 4b can be controlled in the ear-canal of the respective ear. Thereby, the air pump arrangement 2 essentially acts in the manner analogous to a voltage divider, by maintaining and adjusting an inlet pressure and an outlet pressure at the first and the second pump 3a, 3b.

[0048] Further, in FIG. 1, it is shown that at least part of said acoustic measurement device 1 may be positioned within an ear canal 5 of a patient 6 and be configured to take a resting position within said ear canal 5. The acoustic measurement device 1 may comprise an ear probe 7 positioned at least partly within said ear canal 5.

[0049] The ear probe 7 may comprise an ear tip 8, which may be releasably attached to an ear-probe body 9. When the ear probe 7 has been inserted into the ear canal 5 (and take a resting position), the ear tip 8 may provide a barometric seal toward the ear-canal walls 10 of the ear canal 5. The ear probe 7 may provide a stimulus into the ear of the patient 6 in a direction towards the eardrum 11 and receive a reflected part of said stimulus (i.e. capture acoustic signals), as indicated by the two arrows located in the ear canal 5.

[0050] The acoustic measurement device 1 may further comprise a control device 12 configured to control said pump arrangement 2.

[0051] The acoustic measurement device 1 may further comprise a processing device 13 configured to process said captured acoustic signals. An evaluation device of said processing device 13 may be configured to execute an evaluation process to said processed acoustic signals associated to an air-pressure control procedure to obtain at least one objective ear-condition parameter for said patient's 6 ear.

[0052] Preferably, the acoustic measurement device 1 is used for tympanometry, hence acts in the form of a tympanometer. However, in addition, the acoustic measurement device 1 may also be configured to perform diagnostic methods for pressurized acoustic-reflex measurement or diagnostic methods for otoacoustic-emission measurement.

[0053] The air pump arrangement 2 may be configured to apply an air pressure control procedure in the form of maintaining essentially a single air pressure level during the procedure. For example, the air pressure level then lies in the range of 600 to +400 daPa.

[0054] In addition, the air pump arrangement 2 may be configured to apply the air pressure control procedure in the form of performing varying air pressure levels during the respective procedure with varying air pressure levels during the procedure in the range of around 600 daPa to +400 daPa. The air pump arrangement 2 may be capable of performing the standardized procedures of varying air pressure for different instrumental types according to IEC 60645-5 (2005), which will be described by way of an example in the context with FIGS. 2 to 4 below.

[0055] In FIG. 2, a typical relationship between maximum pressure P(max) and maximum flow U max of a single membrane pump (herein 3a or 3b), as known in the art operated at maximum power is illustrated. Decreasing the power delivered to the pump results in an offset parallel to this linear relationship.

[0056] FIG. 3 illustrates the operating principle of the air pump arrangement 2 of the acoustic measurement device 1 by an electrical-analog circuit of the two membrane pumps 3a, 3b, represented by sources, connected to the volume of the ear-canal, represented by a capacitor C ec, each in series with a flow regulating component in the form of the flow resistor 4a, 4b. The ground 14 represents ambient pressure.

[0057] Unlike a regular membrane-pump arrangement where two membrane pumps, each one being fluidically in series with one check valve, never operate simultaneously, the air pump arrangement 2, as given in FIG. 3, is based on simultaneous operation of the two membrane pumps formed as membrane pumps 3a, 3b.

[0058] While this configuration of air-pump arrangement 2 restricts the total flow through the system (compared to the case of no flow resistors), it allows accurately controlling the pressure between the two flow resistors 4a, 4b, i.e., in the ear canal, in a manner analogous to a voltage divider, by maintaining and adjusting the pressure at the outlet and inlet of the membrane pumps 3a and 3b, respectively and, thus, the flow through the resistors 4a, 4b. That is, maintaining a constant air pressure in the ear canal requires continuous operation of one membrane pump (3a or 3b).

[0059] This is opposed to the prior art pumps used in acoustic measurement devices, as piston pumps, peristaltic pumps, and gear pumps, where maintaining a constant ear-canal pressure simply requires stopping the pump.

[0060] In particular, the air pump arrangement 2 solves the issue associated with regular membrane pumps of not being able to control the flow through the membrane pump 3a, 3b due to a negative pressure drop in the flow direction because the pressure drops in the system occur across the two flow resistors 4a, 4b. That is, each membrane pump 3a, 3b can generate a change in pressure between the membrane pump 3a, 3b and flow resistor 4a, 4b, regardless of the pressure in the ear canal, and force a larger flow through the resistor than dictated by the ear-canal-to-ambient pressure difference.

[0061] Depending on the flow resistances R.sub.1 (associated with flow resistor 4a) and R.sub.2 (associated with flow resistor 4b), operating membrane pumps 3a and 3b at some constant power results in a given point of operation on the pressure-flow relationship in FIG. 2 and the pressures P.sub.1 and P.sub.2. Disregarding non-linear effects by assuming that the flow resistances R.sub.1 and R.sub.2 of each flow resistor 4a and 4b does not depend on the flow, the pressure in the ear canal P.sub.ec when the system is in a steady state can be calculated based on the voltage-divider equation,

[00001]$P_{ec}=\frac{\left(P_1-P_2\right)R_2}{R_1+R_2}.$

[0062] Thus, manipulating P.sub.1 and P.sub.2 by controlling the drive power to each membrane pump 3a, 3b any pressure can be achieved in the ear canal Pee and this pressure can be altered in any direction.

[0063] Deriving the pump drive powers that yield a constant-rate ear-canal pressure P.sub.ec(t) is more complicated because the pressure-flow operational point of each pump changes temporarily in response to sudden changes in power until a steady state has been reattained. Assuming that the pressure-flow operational point remains constant and that a change in pump powers result in proportional changes in P.sub.1(t) or P.sub.2(t), the ear-canal pressure response P.sub.ec(t) resulting from step changes in pump drive powers takes the form of an exponential decay,

P.sub.ec(t)=e.sup.bt+c.

[0064] The constants a, b, and c are mathematical expressions comprised by R.sub.1, R.sub.2, the compliance of the ear canal C.sub.ec (which is inversely proportional to its volume), and the initial and final values of the pressure step functions P.sub.1(t) and P.sub.2(t). Consequently, the pressures P.sub.1(t) or P.sub.2(t) required to produce linear changes to the ear-canal pressure P.sub.ec(t) when operating only one membrane pump 3a or 3b at a time can be immediately calculated.

[0065] While it is possible to predict how the membrane pumps 3a, 3b should be driven to achieve ear-canal pressure with constant pressure sweep rates with the given approximations and a given ear-canal volume, practical application in ear-canals of varying volumes require a regulation algorithm. In such a case, for example, a PID controller is used to achieve these constant pressure-sweep rates. For example, this regulation algorithm is based on the air pressure measured by a pressure sensor close to the ear probe.

[0066] Accordingly, the acoustic measurement device may comprise a pressure sensor.

[0067] A standard air-pressure procedure required to generate a tympanogram may usually consists of three principal steps.

[0068] First, the air pump arrangement is used to pump to a desired starting pressure. In terms of the pressure difference across the tympanic membrane, this starting pressure may be within at least the range of 600 to +200 daPa for type-1 instruments and 200 to +200 daPa for type-2 and type-3 instruments (IEC 60645-5 (2005)), although instruments often support wider pressure ranges, e.g., 600 to +400 daPa (see FIG. 4).

[0069] The second step involves a pressure sweep, specified by a constant pressure sweep rate in units of daPa/s (positive or negative depending on the direction of the sweep), from the starting pressure to the stopping pressure of opposite operational sign. Type-1 instruments must be capable of maintaining a constant sweep rate of 50 daPa/s with a tolerance of 10 daPa/s for the duration of the sweep (IEC 60645-5 (2005)), passing the 0-daPa pressure-difference point. The acoustic measurements of the middle ear may be acquired during this pressure sweep of the second step.

[0070] Finally, as the third step, the ear-canal pressure is returned to ambient pressure in a controlled manner to minimize patient discomfort, concluding the pressurization procedure.

[0071] Other air-pressure procedures used in tympanometry may include a manual tympanogram, where the operator adjusts the pressure in the ear canal using, e.g., a slider, while observing the acoustic changes to the middle ear.

[0072] FIG. 4 now exemplifies the application of the acoustic measurement device 1 with two membrane pumps 3a, 3b and the two (precision-orifice) flow resistors 4a, 4b to produce the above described standardized 3 step sequence of air pressure procedure of a tympanogram in a small cavity in terms of the pressure measured by the pressure sensor (top), the pressure rate (middle), and the relative pump drive power of the two membrane pumps 3a, 3b (bottom).

[0073] The sequence shown in FIG. 4 is not based on a regulation algorithm; instead, pump drive-power curves were predefined with trial-and-error adjustments to produce approximately linear pressure changes in the given cavity volume. It is evident how only membrane pump 3a is required for the initial linear pressurization of the ear canal, and only membrane pump 3b is required for the concluding linear depressurization. Notice also the simultaneous operation of the two membrane pumps 3a, 3b during the pressure sweep, crossing the 0-daPa point. For the pressure sweep in this example, the power of pump 3a was set to linearly decrease over some specified time while the power of pump 3b was adjusted to create a linear pressure sweep.

[0074] It is intended that the structural features of the devices, arrangements and instruments described above, either in the detailed description and/or in the claims, may also account for the corresponding process as it is claimed by the objective ear-condition evaluation method using such devices, arrangements and instruments.

[0075] The particular features, structures or characteristics may be combined as suitable in one or more embodiments of the disclosure. The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects, variants and configurations will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects.

[0076] Accordingly, the scope should be judged in terms of the claims that follow.

REFERENCES

[0077] IEC 60645-5, 2005 Instruments for the measurement of aural acoustic impedance/admittance. (International Electrotechnical Commission, Geneva, Switzerland)