HIGH-FREQUENCY EAR PROBE WITH A HOLLOW TIP

Abstract

An instrument configured to test the middle-ear function of a test subject, such as in tympanometry and impedance audiometry is provided. The instrument comprises an ear probe for insertion in an ear of test subject, the ear probe comprises an acoustic output unit comprising a receiver, the acoustic output unit being configured to provide a stimulus into the ear of the test subject via said receiver, an acoustic input unit comprising a microphone, the acoustic input unit being configured to receive a reflected part of said stimulus via said microphone and provide an electrical input signal, an ear-probe body for accommodating said microphone and said receiver, and an ear-probe tip comprising a tip opening for outputting said stimulus and receiving said reflected part of the stimulus, wherein the ear-probe tip comprises a sound tube with a longitudinal axis (A), where said sound tube provides access between a receiver opening and a microphone opening, respectively, and said tip opening, which receiver opening and microphone opening are arranged at a distance (L) from said tip opening along said longitudinal axis (A), and wherein the instrument is configured to provide said stimulus comprising one or more frequencies above 226 Hz into the ear of the test subject via said receiver.

Claims

1. Instrument configured to test the middle-ear function of a test subject, such as in tympanometry and impedance audiometry, where the instrument comprises an ear probe for insertion in an ear of test subject, the ear probe comprising: an acoustic output unit comprising a receiver, the acoustic output unit being configured to provide a stimulus into the ear of the test subject via said receiver, an acoustic input unit comprising a microphone, the acoustic input unit being configured receive a reflected part of said stimulus via said microphone and provide an electrical input signal, an ear-probe body for accommodating said microphone and said receiver, and an ear-probe tip comprising a tip opening for outputting said stimulus and receiving said reflected part of the stimulus, wherein the ear-probe tip comprises a sound tube with a longitudinal axis (A), where said sound tube provides access between a receiver opening and a microphone opening, respectively, and said tip opening, and where said receiver opening and microphone opening are arranged at a distance (L) from said tip opening along said longitudinal axis (A), and wherein the instrument is configured to provide said stimulus comprising one or more frequencies above 226 Hz into the ear of the test subject via said receiver.

2. Instrument according to claim 1, wherein the instrument is configured to provide said stimulus comprising one or more frequencies up to at least 4 kHz.

3. Instrument according to claim 1, wherein the instrument is configured to determine one or more middle-ear-function parameters of the ear canal of the test subject based on one or more middle-ear-function parameters measured and/or calculated at said receiver opening and microphone opening.

4. Instrument according to claim 3, wherein determining one or more middle-ear-function parameters of the ear canal of the test subject is at least partly based on source parameters of the ear probe, as determined from a calibration procedure of the ear probe, such as acoustic Thévenin-equivalent source parameters, Norton-equivalent source parameters, or reflectance source parameters.

5. Instrument according to claim 3, wherein the one or more middle-ear-function parameters measured and/or calculated at said receiver opening and microphone opening comprises a measured sound pressure, a calculated impedance, a calculated acoustic admittance, and a calculated reflectance.

6. Instrument according to claim 3, wherein, determining one or more middle-ear-function parameters of the ear canal of the test subject, comprises propagating a transmission line from said calculated impedance at said receiver opening and microphone opening.

7. Instrument according to claim 1, wherein the middle-ear-function parameters of the ear canal of the test subject comprises one or more of an ear-canal impedance (Z.sub.ec), a complex ear-canal volume (V.sub.ec), an ear-canal admittance (Y.sub.ec), an ear-canal reflectance (R.sub.ec), and/or an ear-canal power absorbance (A.sub.ec).

8. Instrument according to claim 1, wherein the receiver opening and the microphone opening are arranged at equal distance (L) from said tip opening along said longitudinal axis (A).

9. Instrument according to claim 1, wherein the instrument is configured to provide said stimulus as a wideband click.

10. Instrument according to claim 1, wherein the instrument further comprises an ear tip for releasable attachment to the ear-probe tip, where the ear tip is configured to provide a barometric seal toward the ear-canal walls in the ear of the test subject.

11. Instrument according to claim 1, wherein the ear-probe tip is releasably connected to said ear-probe body.

12. Instrument according to claim 1, wherein the instrument further comprises a pump and a pressure sensor, where the instrument is configured to control the pressure in the ear canal of the test subject by the pump and the pressure sensor.

13. Instrument according to claim 1, wherein the instrument further comprises one or more wax guards arranged at said receiver opening and/or at said microphone opening.

14. Instrument according to claim 1, wherein the instrument further comprises one or more wax guards arranged at said tip opening.

15. Instrument according to claim 1, wherein the instrument further comprises a signal generator for providing said stimulus, and a processor configured to carry out the determination of said one or more middle-ear-function parameters of the ear canal of the test subject.

16. Method of testing the middle-ear function of a test subject, such as in tympanometry and impedance audiometry, the method comprising: providing a stimulus at one or more frequencies above 226 Hz into the ear of the test subject by an acoustic output unit comprising a receiver, receiving a reflected part of said stimulus by an acoustic input unit comprising a microphone, providing an electrical input signal based on said reflected part of said stimulus by the acoustic input unit, providing an ear-probe tip comprising a tip opening for outputting said stimulus and receiving said reflected part of said stimulus, where the ear-probe tip comprises a sound tube with a longitudinal axis, and where said sound tube provides access between a receiver opening and a microphone opening, respectively, and said tip opening, and where the receiver opening and the microphone opening are arranged at a distance from said tip opening along said longitudinal axis.

17. Method according to claim 16, the method comprises determining an ear-canal impedance Z.sub.ec by propagating an ear-probe tip transmission line from an impedance calculated at said receiver opening and said microphone opening.

18. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to claim 16.

19. Instrument according to claim 2, wherein the instrument is configured to determine one or more middle-ear-function parameters of the ear canal of the test subject based on one or more middle-ear-function parameters measured and/or calculated at said receiver opening and microphone opening.

20. Instrument according to claim 4, wherein the one or more middle-ear-function parameters measured and/or calculated at said receiver opening and microphone opening comprises a measured sound pressure, a calculated impedance, a calculated acoustic admittance, and a calculated reflectance.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0163] The aspects of the disclosure may be best understood from the following detailed description taken in conjunction with the accompanying figures. The figures are schematic and simplified for clarity, and they just show details to improve the understanding of the claims, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts. The individual features of each aspect may each be combined with any or all features of the other aspects. These and other aspects, features and/or technical effect will be apparent from and elucidated with reference to the illustrations described hereinafter in which:

[0164] FIG. 1 shows an exemplary instrument according to the present application.

[0165] FIGS. 2A and 2B show cross sections of exemplary ear probes.

[0166] FIG. 3 shows a cross-section of an exemplary ear probe according to the present application.

[0167] FIGS. 4A-4C show exemplary measurements of complex ear-canal volume V.sub.ec and absorbance in an occluded-ear simulator using a hollow ear-probe tip, with and without compensation, and a standard ear-probe tip with individual tubing.

[0168] The figures are schematic and simplified for clarity, and they just show details which are essential to the understanding of the disclosure, while other details are left out. Throughout, the same reference signs are used for identical or corresponding parts.

[0169] Further scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only. Other embodiments may become apparent to those skilled in the art from the following detailed description.

DETAILED DESCRIPTION OF EMBODIMENTS

[0170] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. Several aspects of the instrument and methods are described by various blocks, functional units, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). Depending upon particular application, design constraints or other reasons, these elements may be implemented using electronic hardware, computer program, or any combination thereof.

[0171] FIG. 1 shows an exemplary instrument according to the present application.

[0172] In FIG. 1, the instrument 16 is shown to be located at and in connection with the head 12 of a test subject. A test subject may refer to a human, but animals may also be considered.

[0173] The instrument 16 may be configured to test the middle-ear function of the test subject, such as in tympanometry and impedance audiometry.

[0174] The instrument 16 is shown to comprise two parts, but may of course be combined to only one part, or alternatively be divided into several parts.

[0175] In FIG. 1, a first part may be arranged inside the ear canal 15 of the test subject. Alternatively, or additionally, the first part may be arranged at least partly outside the ear canal 15. The first part is shown to be an ear probe 1 suitable for insertion in the ear.

[0176] The ear probe 1 may comprise an ear tip 9, which may be releasably attached to an ear-probe body 4. When the ear probe 1 has been inserted into the ear canal 15, the ear tip 9 may provide a barometric seal toward the ear-canal walls 13 of the ear canal 15. The ear probe 1 may provide a stimulus into the ear of the test subject in a direction towards the eardrum 14 and receive a reflected part of said stimulus, as indicated by the two arrows located in the ear canal 15.

[0177] A second part 23 of the instrument is shown to be arranged outside the ear canal 15 of the test subject. Alternatively, or additionally, the second part 23 (or at least some elements of the second part 23) could be combined with the ear probe 1.

[0178] The second part 23 may comprise a pump 17 and a pressure sensor 18 by which the instrument 1 can control the pressure in the ear canal 15 in the space between the ear probe 1 and the eardrum 14. Therefore, the pump 17 and a pressure sensor 18 may be in fluid communication with the ear canal 15. The pump 17 and a pressure sensor 18 may provide a pressure equal to, above, or below ambient pressure.

[0179] The second part 23 may comprise a signal generator 19 for generating said stimulus to be introduced into the ear canal 15 of the test subject.

[0180] The second part 23 may comprise an acoustic output unit 20. The acoustic output unit 20 may be connected to the signal generator 19 and may comprise a receiver (not shown) located in the ear probe 1. The acoustic output unit 20 may be configured to introduce said stimulus which is generated by the signal generator 19 into the ear of the test subject, via said receiver.

[0181] The second part 23 may comprise a processor 21 configured to carry out a determination of one or more middle-ear-function parameters of the ear canal of the test subject.

[0182] The second part 23 may comprise an acoustic input unit 22. The acoustic input unit 22 may be connected to the processor 21 and may comprise a microphone (not shown) located in the ear probe 1. The acoustic input unit 22 may be configured to receive a reflected part of said stimulus via said microphone 3 and provide an electrical input signal to said processor 21, based on which the processor 21 may carry out said determination.

[0183] As indicated in FIG. 1, the second part 23 may be connected to the first part (the ear probe 1). The first and second part 23 may be connected by a wired or a wireless connection 30.

[0184] FIGS. 2A and 2B show cross-sections of exemplary ear probes.

[0185] Each of the two ear probes are shown to comprise an ear-probe body 24, an ear-probe tip 25, and an ear tip 26.

[0186] Inside the ear-probe body 24, a receiver 27 for providing a stimulus into the ear of a test subject and a microphone 28 for receiving a reflected part of said stimulus are arranged.

[0187] In FIG. 2A, an opening of the receiver 27 and an opening of the microphone 28 are located at equal distance from the tip opening 29 of the ear probe, as is indicated by the dotted vertical line. Thereby, the receiver provides the stimulus to (and the microphone receives the reflected part from) the hollow ear-probe tip 25 at a distance from the tip opening 29. One or more middle-ear-function parameters are then determined at the location indicated by the dotted vertical line inside the ear-probe tip 25.

[0188] In FIG. 2B, separate stimulus-delivery tubes 34,35 lead from the receiver 27 and the microphone 28, respectively, to the tip opening 29 of the ear probe (indicated by the dotted vertical line), and do not combine/merge inside the ear-probe tip 25. Thereby, the stimulus is provided directly to (and received directly from) the ear canal of the test subject. One or more middle-ear-function parameters are then determined at the location indicated by the dotted vertical line at the tip opening 29.

[0189] FIG. 3 shows a cross-section of an exemplary ear probe according to the present application.

[0190] In FIG. 3, the ear probe 1 comprises an ear-probe body 4, an ear-probe tip 10, and an ear tip 9.

[0191] The ear-probe body 4 accommodates a microphone 3 and a receiver 2. The receiver 2 may form part of the acoustic output unit of the instrument. The microphone 3 may form part of the acoustic input unit of the instrument.

[0192] The ear-probe tip 10 may comprise a tip opening 5 (at one (distal) end of the ear-probe tip 10). The tip opening 5 opens up to the ear canal, when the ear probe 1 is inserted in the ear canal. The tip opening 5 facilitates the output of a stimulus generated in the signal generator to the ear canal and the receiving of a reflected part of the stimulus.

[0193] At an opposite (proximal) end 31 of the ear-probe tip 10, the ear-probe tip 10 is connected to the ear-probe body 4. The ear-probe tip 10 and the ear-probe body 4 may be connected in a releasable manner, so that the user (operator) operating the instrument, e.g., a hearing-care professional, may easily decouple/detach the ear-probe tip 10, when e.g., the ear-probe tip 10 needs cleaning or replacement. In FIG. 3, the ear-probe tip 10 (i.e., said opposite end 31) is shown to protrude into a recess 32 of the ear-probe body 4.

[0194] The ear-probe tip 10 may comprise a sound tube 6 with a longitudinal axis A. The sound tube 6 may provide access between a receiver opening 7 and a microphone opening 8, respectively, and said tip opening 5. The sound tube 6 may be at least partly hollow. In FIG. 3, it is illustrated that the sound tube 6 is hollow between the receiver opening 7 and microphone opening 8 and the tip opening 5. The receiver opening 7 and the microphone opening 8 may be arranged at a distance L from said tip opening 5 seen along said longitudinal axis A.

[0195] The ear probe 1 may further comprise an ear tip 9. The ear tip 9 may be formed from a flexible material and thereby provide a barometric seal toward the ear-canal walls in the ear. The ear tip 9 may be releasably attached/connected to the ear-probe tip 10. Thereby, the ear tip 9 may be removed from the ear-probe tip 10 and be replaced by a new ear tip 9 after use.

[0196] The ear probe 1 may further comprise one or more wax guards 11 (e.g., wax filters) to prevent, e.g., cerumen from entering the ear-probe tip 10, or at least from entering the microphone 3 and receiver 2. The one or more wax guards 11 may be arranged at any location between the receiver 2 or microphone 3 and the tip opening 5. In FIG. 3, wax guards are arranged in the tubing between the receiver 2/microphone 3 and their respective openings 7,8. However, it is also contemplated that the wax guards may be arranged at the ear-probe tip 5 to completely prevent cerumen from entering the ear probe 1.

[0197] The receiver opening 7 and the microphone opening 8 are shown to be located inside the sound tube 6. The location of said receiver opening 7 and microphone opening 8 are determined by a protrusion 33 of the ear-probe body 4, which extends into said sound tube 6, when the ear-probe tip 10 is attached to the ear-probe body 4.

[0198] During testing of middle-ear function of the test subject, the sound pressure P.sup.tip.sub.ec is measured at the location of the receiver opening 7 and the microphone opening 8 (indicated by the vertical dotted line). The corresponding impedance Z.sup.tip.sub.ec can be calculated by the following equation (equation 5), where P.sub.s and Z.sub.s are predetermined source parameters of the ear-probe tip 10.

[00010]$Z_{ec}^{tip}=Z_s\frac{P_{ec}^{tip}}{P_s-P_{ec}^{tip}}.$

[0199] From this, the ear-canal impedance Z.sub.ec can be calculated by propagating the ear-probe tip transmission line out of the impedance Z.sup.tip.sub.ec according to the following (equation 6):

[00011]$Z_{ec}=\frac{a_{12}-a_{22}{Z}_{ec}^{tip}}{a_{21}{Z}_{ec}^{tip}-a_{11}}.$

[0200] FIGS. 4A-4C show exemplary measurements of complex ear-canal volume V.sub.ec and absorbance in an occluded-ear simulator using a hollow ear-probe tip, with (see FIG. 3) and without compensation (see FIG. 2A), and a standard ear-probe tip (see FIG. 2B) with individual tubing.

[0201] Initial calibration of the ear probes and following measurements to test the middle-ear function using the ear probes were conducted with an ear-probe tip that had a hollow portion of 6 mm, i.e., with a hollow sound tube of a length (L) of 6 mm from the receiver opening and the microphone opening, respectively, to the tip opening.

[0202] The measurements were conducted using both the proposed compensation scheme (see equations 5 and 6 above for the determination of ear-canal impedance (Z.sub.ec)) accounting for the hollow ear-probe tip and using the conventional methods (with an ear probe in line with FIG. 2A).

[0203] Furthermore, comparison measurements were made using a standard tip with individual tubing (with an ear probe in line with FIG. 2B) and conventional calibration methods as described in [4].

[0204] Results are shown in FIG. 4A-4C in terms of (see also above for further detail) the complex ear-canal volume:

[00012]$V_{ec}=\frac{\rho c^2}{j\omega Z_{ec}},$

[0205] and power absorbance:

A.sub.ec=1−|R.sub.ec|.sup.2,

[0206] where the ear-canal reflectance:

[00013]$R_{ec}=\frac{Z_{ec}-Z_0}{Z_{ec}+Z_0},$

[0207] in a standardized occluded-ear simulator [5].

[0208] The results clearly demonstrate how using the hollow ear-probe tip and the proposed compensation methods are in line with those using a conventional method with the standard ear-probe tip (see FIG. 2B) up to 4 kHz. Conversely, results using the hollow ear-probe tip without compensation (see FIG. 2A) becomes increasingly unreliable above approximately 750 Hz.

[0209] It is intended that the structural features of the devices described above, either in the detailed description and/or in the claims, may be combined with steps of the method, when appropriately substituted by a corresponding process.

[0210] As used, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well (i.e., to have the meaning “at least one”), unless expressly stated otherwise. It will be further understood that the terms “includes,” “comprises,” “including,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, but an intervening element may also be present, unless expressly stated otherwise. Furthermore, “connected” or “coupled” as used herein may include wirelessly connected or coupled. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. The steps of any disclosed method are not limited to the exact order stated herein, unless expressly stated otherwise.

[0211] It should be appreciated that reference throughout this specification to “one embodiment” or “an embodiment” or “an aspect” or features included as “may” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Furthermore, 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 will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects.

[0212] The claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more.

REFERENCES

[0213] [1] IEC 60645-5 (2004). Instruments for the measurement of aural acoustic impedance/admittance (International Electrotechnical Commission, Geneva, Switzerland). [0214] [2] Allen, J. B. (1986). Measurement of eardrum acoustic impedance. In J. Allen, J. Hall, A. Hubbard, S. Neely, & A. Tubis (Eds.), Peripheral Auditory Mechanisms (pp. 44-51). Springer-Verlag. [0215] [3] Nørgaard et al. (2018). A coupler-based calibration method for ear-probe microphones. J. Acoust. Soc. Am., 144(4), 2294-2299. [0216] [4] Nørgaard, K. R., Fernandez-Grande, E., & Laugesen, S. (2017). Incorporating evanescent modes and flow losses into reference impedances in acoustic Thévenin calibration. J. Acoust. Soc. Am., 142(5), 3013-3024. [0217] [5] IEC 60318-4 (2010). Occluded-ear simulator for the measurement of earphones coupled to the ear by means of ear inserts (International Electrotechnical Commission, Geneva, Switzerland).