Patent Grant
11689866
The present invention pertains to hearing devices capable of performing a self-test as well as to a method for automatically testing a hearing device. This is especially important in conjunction with self-fitting and remote fitting of a hearing device as well as more generally providing remote support, i.e. in situations where no hearing device specialist, such as an audiologist, is present to test the hearing device locally before adjusting the hearing device settings to the needs and preferences of the user or to consult the user when experiencing problems with the hearing device.
In the context of the present invention the term “hearing device” refers to hearing aids (alternatively called hearing instruments or hearing prostheses) used to compensate hearing impairments of hard of hearing persons, as well as to audio and communication devices used to provide sound signals to persons with normal hearing capability, e.g. in order to improve hearing in harsh acoustic surroundings, and also to hearing protection devices employed to prevent damaging of the sense of hearing of a person when exposed to very loud noises such as gunshots. Such hearing devices are typically worn at or at least party within the ear, e.g. within the ear canal of the user.
Typically, hearing device settings, such as audio processing settings, need to be adjusted to the individual needs and preferences of a user, e.g. to compensate the specific hearing loss of the user. This process is commonly referred to as hearing device “fitting” and is usually performed by a hearing device specialist such as an audiologist, then often referred to as a hearing device “fitter”.
To avoid having to visit the fitter for instance to improve previous settings it is becoming increasingly popular to perform “remote fitting” or for the fitter to provide “remote support”, e.g. by allowing the fitter to adjust hearing device settings via a communication network to which the hearing device can be connected for instance with the aid of a smartphone. Alternatively, it has also become commonplace for the user himself to adjust the hearing device settings, a process referred to as “self-fitting”.
It is important to ensure that the hearing device is working properly (i.e. not malfunctioning) and being worn correctly by the user before commencing with remote fitting or self-fitting. This requires that the hearing device itself is capable of determining whether it is operating correctly or not, which can be achieved by means of an automatic “self-test”. Likewise, the outcome of such a self-test is instrumental for any kind of remote support, where the audiologist does not have direct access to the hearing device.
Hence, with the proliferation of hearing device self-fitting and remote fitting as well as generally providing remote support for hearing device users there in an increased need for effective and reliable automatic self-test/-diagnosing schemes.
It is an object of the present invention to provide a hearing device with a built-in automatic self-test mechanism. This object is achieved by the hearing device according to claim 1.
It is a further object of the present invention to provide a method for automatically self-testing a hearing device. Such a method is specified in claim 13.
Specific embodiments of the present invention are provided in the dependent claims.
In a first aspect, the present invention is directed to a hearing device, comprising:
In an embodiment of the hearing device the measurement bridge circuit is adapted to controllably supply a direct current (DC) or an alternating current (AC) to the receiver and to measure a voltage at the receiver.
In a further embodiment of the hearing device the direct current (DC) or the alternating current (AC) is provided by a respective current steering digital-to-analogue converter (DAC).
In a further embodiment of the hearing device the measurement bridge circuit, more particularly the respective current steering digital-to-analogue converter (DAC), is controllable by an output of the signal processor, or more particularly by an output of an audio delta-sigma(-type digital-to-analogue) converter.
In a further embodiment of the hearing device a first current steering digital-to-analogue converter (DAC) is controlled by a first output of the signal processor, or more particularly by a first code output by an audio delta-sigma(-type digital-to-analogue) converter to provide the direct current (DC), and wherein a second current steering digital-to-analogue converter (DAC) is controlled by a second output of the signal processor, or more particularly by a second code output by the audio delta-sigma(-type digital-to-analogue) converter to provide the alternating current (AC).
In a further embodiment the hearing device is operable in a normal mode and in a measurement (or test) mode, wherein in the normal mode the amplifier is enabled and provides an amplified output signal to the receiver, and wherein in the measurement mode the amplifier is disabled, in particular switched to a high impedance state, and the measurement bridge circuit supplies a direct current (DC) or an alternating current (AC) to the receiver and measures a voltage at the receiver.
In a further embodiment the hearing device is adapted to detect a presence of a fault condition if at least one of the following is determined to be incorrect based on at least one measurement of the voltage at the receiver:
In a further embodiment the hearing device further comprises a non-volatile memory storing reference data, wherein the reference data in particular pertain to one or more peaks of an impedance of the receiver, for instance in terms of a peak's amplitude and frequency, and wherein the one or more peaks are in particular determined by measuring the impedance of the receiver when the hearing device is being properly, in particular sealingly, worn in an ear canal of the user and/or when the hearing device is not being worn, and wherein the one or more peaks are in particular determined during fitting of the hearing device to needs and preferences of the user.
In a further embodiment the hearing device is adapted to detect a presence or absence of a fault condition based at least partly on the reference data, in particular based on a comparison of a quantity related to the at least one measurement of the voltage at the receiver with at least part of the reference data.
In a further embodiment the hearing device is adapted to detect the presence or absence of a fault condition based on one or more of the following:
The reference values are determined previously, for example during a fitting session.
In a further embodiment the hearing device is adapted to perform at least one of the following based on the presence or absence of a fault condition:
In a further embodiment of the hearing device the measurement bridge circuit comprises a resistor as a minimal load when no receiver is connected to the hearing device or when the receiver is incorrectly connected to the hearing device.
In a second aspect, the present invention is directed to a method for self-testing a hearing device, in particular the hearing device specified above, based on employing a measurement bridge circuit connected to a receiver of the hearing device in parallel with an amplifier of the hearing device, the method comprising the steps of:
In an embodiment of the method the measured voltage is indicative of the direct current (DC) or the alternating current (AC) impedance of the receiver, based upon which the presence of a fault condition is detected if at least one of the following is determined to be incorrect:
In a further embodiment the method further comprises at least one of the following based upon detecting the presence or absence of a fault condition:
In a further embodiment of the method a frequency of the alternating current (AC) applied to the receiver is varied, in particular to provide a frequency sweep or a polyphonic signal to the receiver as a test signal.
In a further embodiment of the method detecting the presence or absence of a fault condition is based on determining an impedance of the receiver as a function of a frequency of the alternating current (AC) applied to the receiver and comparing the determined impedance with predetermined reference data.
In a further embodiment the method is started upon each powering-on of the hearing device, in particular the method is started with a time delay after powering-on the hearing device.
In a further embodiment the method is started when initiating fitting of the hearing device to needs and preferences of the user, for instance when initiating a self-fitting session or a remote fitting session.
In a further embodiment the method is started when initiating a remote support session.
In a further embodiment the method is started by the user, for instance by operating a control element at the hearing device or at a hearing device accessory, such as a remote control unit or a mobile phone, in particular a smartphone.
It is pointed out that combinations of the above-mentioned embodiments may give rise to even further, more specific embodiments of the hearing device and method according to the present invention.
The present invention is further described with reference to the accompanying drawings that pertain to an exemplary embodiment, and which are to be considered in connection with the following detailed description. What is shown in the drawings is:
Before fitting a hearing device it needs to be ensured that the hearing device or an otoplastic connected to a hearing device is correctly inserted into the ear canal and sufficiently sealing the ear canal such that no or only very little ambient sound directly reaches the eardrum (i.e. bypasses the hearing device or otoplastic), viz. that the acoustic coupling is in order. Furthermore, it must be ascertained that the correct receiver is being used in the hearing device, e.g. that the desired earphone is connected to the behind-the-ear (BTE) part of a receiver-in-the-canal (RIC) type hearing device (also referred to as canal receiver technology, CRT), and furthermore, it must be guaranteed in this case that the electrical connection between the receiver and the BTE part is intact. Finally, it must be made sure that the receiver and the sound port directed towards the eardrum is not clogged with cerumen, which would otherwise attenuate the sound output by the receiver into the ear canal. All these problems can be detected by measuring the receiver acoustic impedance as a function of frequency when the hearing device is being worn by the user. By measuring the impedance versus frequency the electrical and acoustical condition of the receiver/earphone as well as the acoustic coupling can be evaluated. Thereby, the direct current (DC) impedance helps to determine whether the receiver is of the correct type and whether the receiver is electrically correctly connected (e.g. detect an open connection as well as a short circuit). Each type of receiver/earphone has a specific characteristic frequency response. When a receiver is properly plugged/inserted into the ear canal the acoustical impedance curve (i.e. the alternating current (AC) impedance) will typically exhibit a shift of the resonance peaks towards lower frequencies compared to the case when the hearing device is not being worn. Similarly, when the receiver is clogged and the sound is being obstructed when being output into the ear canal, the resonance peaks are shifted even more towards lower frequencies than when the receiver is not correctly inserted into the ear canal.
According to the present invention DC and AC impedance measurement is done using a measurement bridge circuit, parallel to the main H-bridge (audio amplifier). A functional schematic of the proposed measurement circuit is shown in
In order to avoid the use of a resistor to determine the voltage and therewith the impedance in the audio path, thereby increasing the output impedance and impacting (i.e. reducing) the MPO during normal operation of the hearing device, the present invention proposes to provide a second, measurement bridge circuit 5 in parallel with the H-bridge of the class D audio amplifier 3, specifically for measuring the receiver's electrical and acoustical impedance. The measurement bridge circuit 5 is thus connected to the same two input ports of the receiver 4 as the H-bridge of the class D audio amplifier 3, and supplies an alternating current (AC) and/or direct current (DC) signal to the receiver 4, while measuring the voltage across the receiver 4. The DC current is provided by a first pair of current steering digital-to-analogue converters (DACs) 7. This first pair of current steering digital-to-analogue converters 7 is controlled by a first output A of the signal processor 2, in particular by an output of an audio delta-sigma converter, more particularly by a noise shaper output code of the audio delta-sigma converter. Likewise, the AC current is provided by a second pair of current steering digital-to-analogue converters (DACs) 7′. This second pair of current steering digital-to-analogue converters 7′ is controlled by a second output B of the signal processor 2, in particular by the output of the audio delta-sigma converter, more particularly by another portion of the noise shaper output code of the audio delta-sigma converter.
When performing a receiver impedance measurement the hearing device is set to a measurement/self-test mode in which the audio amplifier 3 is disabled, in particular switched to a high impedance state, and the measurement bridge circuit 5 supplies a DC or an AC current to the receiver 4 and measures a voltage at the receiver 4, which is amplified by the measurement amplifier 6 to provide an measurement voltage signal, which is then fed to an input C of the signal processor 2. All voltage signals may be analog or digital signals. Conversion between the analog and digital domain may be realised within the signal processor 2 or by a separated analog-to-digital converter (not shown). Based on the measurement voltage signal the signal processor 2 can determine the presence of a fault condition, e.g. when the receiver 4 is not correctly connected to the hearing device, or when the connected receiver 4 is not of a certain, desired receiver type, or when the hearing device is not correctly placed within the ear canal of the user of the hearing device, or when the receiver 4 or sound outlet of the hearing device is obstructed, for instance clogged by cerumen/earwax. When the self-test/measurement has been completed the hearing device is switched back to a normal mode of operation where the audio amplifier 3 is enabled and provides an amplified output signal to the receiver 4.
In order to determine certain fault conditions reference data for the frequency-dependent impedance is required. This reference data in particular includes the resonance frequency of one or more peaks of the impedance of the receiver 4 as determined by measuring the impedance of the receiver 4 when the hearing device is being properly (e.g. sealingly) worn in the ear canal of the user as well as when the hearing device is not being worn. These one or more peaks are for instance determined during fitting of the hearing device to the needs and preferences of the user. This reference data is then stored in a non-volatile memory (e.g. EEPROM) of the hearing device.
If the hearing device determines that a fault condition is present it may provide an optical fault indication signal to the user, for instance by means of a light emitting diode (LED). Alternatively, it may provide an acoustic signal via the receiver to the user, in particular when no fault condition has been detected and the hearing device is ready for fitting. In this way the notification is a “hearing device working fine” confirmation. Otherwise, the acoustic confirmation would not be sent, because it would very likely not be heard by the user due to the fault condition, e.g. improper insertion, bad connection of the receiver, wrong receiver type or clogged receiver. Moreover, the hearing device may disable adjusting of one or more hearing device settings or disable at least one function of the hearing device when the presence of a fault condition has been detected.
In order to ensure reliable measurements the measurement bridge circuit 5 comprises a resistor R as a minimal load when no receiver 4 is connected to the hearing device or when the receiver 4 is incorrectly connected to the hearing device.
For AC impedance measurements to determine improper insertion of the receiver 4 into the ear canal or receiver contamination, the AC signal is generated by the signal processor 2 for instance with the aid of a sound generator capable of producing a frequency sweep or a polyphonic signal, e.g. in the form of a hearing device start-up melody (“jingle”). The latter has the advantage of not being regarded as an unpleasant disturbance by the user. A self-test/check could be done at each start-up of the hearing device. Likewise, also the DC impedance measurement, in particular to determine faulty receiver connectivity and an incorrect receiver type, could be done at each start-up of the hearing device. Moreover, the self-test could also be triggered each time a fitting session is started, e.g. while detecting the hearing device.
The present invention proposes a self-test method that helps to check a hearing device's readiness for fitting and notify the fitter or user accordingly. Hearing device readiness in this context means that possible fault conditions such as improper insertion of the hearing device into the user's ear canal, wrong receiver type, bad receiver connection or receiver contamination by earwax have been checked and can be excluded. Otherwise, the fitting process is locked if the self-test is not successful in order to ensure that the hearing device is not incorrectly fitted.
The self-test according to the present invention is also important and convenient for remote support/fitting as well as self-fitting. In such cases the hearing care professional cannot (visually) check or inspect the hearing device prior to fitting.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/071908 | 8/31/2017 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2019/042557 | 3/7/2019 | WO | A |
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| Number | Date | Country | |
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| 20200260194 A1 | Aug 2020 | US |
