Patent Description:
The availability and dissemination of non-prescriptive hearing devices offering hearing loss compensation and speech enhancement, such as over-the-counter (OTC) hearing aids or consumer earbuds, are expected to substantially grow in the coming years (cf. As no hearing care professional is involved in the fitting of those devices, a prominent challenge is to ensure that users are offered a tuning of the sound processing capabilities of the devices in a relevant and satisfying way. This procedure is referred to as "self-fitting". Multiple self-fitting principles are known.

According to one example a pure-tone hearing test is provided and the gain and compression curves are calculated accordingly; this is available in commercial devices such as Apple AirPods Pro, Jabra Enhance Plus and Nuheara IQbuds2 MAX.

According to <CIT> a questionnaire is provided to the user of a hearing aid from which a score is derived and mapped to a pure tone average and speech recognition performance.

According to <CIT> two stimuli modified by different sound processing are presented to the user of a hearing aid and the user is requested to indicate a preference; this procedure is iterated until it converges to an optimal and personal fitting.

According to <CIT> multiple environmental situations are shown to the user of a hearing aid on a display without sound, so that the user can rate the relevance and report hearing difficulties encountered in every scene; a hearing loss class is associated with each situation, which steers the fitting of the hearing aids.

According to <CIT> audio signals from a fitting soundscape are presented to the user of a hearing aid at loud and soft levels and fitting is performed in-situ based on the user's perceptual assessment of the output of the hearing aid.

According to <CIT> speech samples are synthesized and altered for testing or optimizing hearing device parameters.

<CIT> relates to fitting of hearing devices, wherein speech audio samples including semantics are presented to the user for being recognized by the user who then speaks back the recognized sentences/words/syllables; the system may test user's own speech production. A similar fitting method is described in <CIT>, wherein stimuli which may e.g. include VCV nonsense words are sent to a user and the user's response is measured.

According to <CIT> a hearing care professional adjusts the parameter setting of a hearing system according to user feedback on spatial perception of audio sequences from real life sound sources reproduced via the hearing system; in addition, the user may be provided synchronously with the audio sequence with a visualization of a scene to which said audio sequence belongs.

<CIT> describes acoustic representation of a virtual environment which may comprise a plurality of sources, such as multiple people speaking, which all may be represented such that their location can be perceived realistically.

<CIT> describes the detection by a hearing device user of e.g. transitions between different phonems to indicate a hearing performance.

<CIT> relates to a method of generating spatial audio signals for earphones coupled with a handheld portable electronic device, wherein coordinates of a location of the handheld portable electronic device with respect to the user are determined and this location is saved as a sound localization point. During the telephone call, a voice of another person is convolved so the voice externally localizes to the person as a binaural sound at the sound localization point.

<CIT> relates to a method for adjusting at least one hearing device by a user comprising the steps of: recording a current real-world environment thereby obtaining a real-world recording; augmenting the real-world recording by adding an augmentation thereby obtaining an augmented recording; presenting the augmented recording to the user; and adjusting at least one sound processing parameter of the at least one hearing device by the user using at least one user control.

<CIT> relates to a method for selecting and presenting binaural acoustic stimuli in spatialized mode for hearing diagnostics and rehabilitation, comprising the steps of: synthesizing audio signals, including primary audio signals comprising pure tones and speech, and secondary audio signals comprising background noise and other competing sources, wherein said synthesized audio signals are presented according to individualized transfer functions that include a hearing aid faceplate, and any of an individual's effects of body, head, and ear on incoming signals; controlling spatialization parameters of said audio signals, including any of the position of each source in space in terms of any of distance, azimuth, and altitude; and acoustic boundary parameters including room size, reflection properties, reverberation, atmospheric absorption, and spreading loss roll-off; presenting such spatialized stimuli to an individual; and performing any of hearing diagnostics, hearing aid prescription, hearing aid simulation, and hearing aid fitting with an audiometric module.

It is an object of the invention to provide for a method of self-fitting of a binaural hearing system which allows to substantially preserve the user's spatial sound identification ability. It is a further object to provide for a corresponding self-fitting arrangement.

According to the invention, these objects are achieved by a method as defined in claim <NUM> and an arrangement as defined in claim <NUM>.

The invention is beneficial in that, by monitoring the user's ability of spatial sound identification during the fitting process by using a motion sensor of the binaural hearing system, a negative impact of certain fitting configurations on the user's ability of spatial sound identification can be easily recognized, so that user's ability of spatial sound identification can be preserved, for example by excluding such detrimental fitting configurations.

According to one example, the method may be iterated for different fitting configurations so as to optimize the fitting configuration regarding the user's ability of spatial sound identification by minimizing the deviation between an expected head movement and the measured head movement.

According to one example, the virtual auditory scene may include a second audio source arranged at a second angular position relative to the user, wherein the user is instructed to turn the head towards the second audio source, wherein the respective head movement of the user is measured via the at least one motion sensor, and wherein the user's ability of spatial sound identification with the present fitting configuration of the hearing system is estimated from the measured head movement. For example, the first audio source may be a target talker and the second audio source may be a competing talker. In addition, the virtual auditory scene may include diffuse noise.

According to one example, the parameters of the virtual auditory scene, in particular levels, distances and/or yaw angles of the first audio source and/or the second audio source and/or the level of diffuse noise, may be varied for performing different head movement measurements.

According to one example, the user may be instructed via instruction audio signals reproduced by the binaural hearing system.

According to one example, the user may provide voice feedback to the instruction audio signals which is recognized via automatic speech recognition. For example, the automatic speech recognition may recognize words from a database limited to not more than <NUM> words. Further, each of the hearing devices may comprise a microphone arrangement for capturing the user's voice feedback. For example, the capturing of the user's voice feedback may utilize acoustic beamforming and/or extraction of speech features based on previous recordings of the user's voice. The binaural hearing system may transmit audio signals representative of the user's voice feedback to an accessory device which performs the automatic speech recognition. The instruction audio signals may include key words presented by the first audio source, wherein the user may be instructed to repeat the key words, and wherein the voice feedback may include the repetition of the key words by the user.

According to one example, prior to the start of the measuring of head movements the user may undergo a calibration process to provide an absolute reference for the head movements.

According to one example, the at least one motion sensor may comprise a first inertial sensor in the first hearing device and a second inertial sensor in the second hearing device. For example, the first and second inertial sensors may comprise accelerometers and/or gyroscopes. Further, each hearing device may include a magnetometer for assisting the inertial sensors.

According to one example, the spatialized binaural audio signal may be generated by using a default set of head related transfer functions (HRTFs). According to another example, the spatialized binaural audio signal may be generated by using a set of generic HRTFs selected from a plurality of pre-sets such that it matches best with the user's perception. According to a further example, the spatialized binaural audio signal may be generated by using a set of HRTFs measured using the binaural hearing system worn by the user and an accessory device.

According to one example, fitting parameters of the fitting configuration may include an amount of wide dynamic range compression, as determined by the compression kneepoints, beamformer pattern, an amount of noise reduction, and/or an amount of reverberation reduction.

According to one example, the generating of the spatialized binaural audio signal representative of the virtual auditory scene; the estimating, from the measured head movement, the user's ability of spatial sound identification with the present fitting configuration of the hearing system; and/or the assessing the present fitting configuration based on the estimated user's ability of spatial sound identification with the present fitting configuration may be performed on an accessory device communicatively coupled with binaural hearing system. For example, the accessory device may be a smartphone.

Hereinafter, examples of the invention will be illustrated by reference to the attached drawings, wherein:.

A "hearing device" as used hereinafter is any ear level element suitable for reproducing sound by stimulating a user's hearing, such as an electroacoustic hearing aid, a bone conduction hearing aid, an active hearing protection device, a hearing prostheses element such as a cochlear implant, a wireless headset, an earbud, an earplug, an earphone, etc..

A certain "fitting configuration" of the binaural hearing system as used hereinafter is a certain setting of values of fitting parameters, i.e., audio signal processing parameters, such as compression kneepoints, the amount of noise reduction and/or beamformer pattern.

A "spatialized binaural audio signal" is as used hereinafter an audio signal which, when reproduced by the binaural hearing system to the user, creates a spatial sound perception by the user.

A user's "ability of spatial sound identification" as used hereinafter is the ability of the user to identify perceived directions of sound sources in a spatialized binaural audio signal reproduced by the binaural hearing system worn by the user.

A user's "ability of spatial sound segregation" as used hereinafter is the ability of the user to discriminate two adjacent (with regard to their angular position, in particular with regard to azimuth) sound sources in a spatialized binaural audio signal reproduced by the binaural hearing system worn by the user as separate sound sources.

It is expected that the main consumers for OTC hearing aids, as well as consumer earbuds with speech enhancement features, are those with a self-declared hearing disorder; these self-reported hearing difficulties are mostly coming from individuals with hidden hearing loss and to a lesser extent to mild/moderate losses (cf. , for example, <NPL>).

It is well documented that traditional hearing tests (e.g. audiogram) are suboptimal to fit hearing devices in an adequate way for those with a hidden hearing loss. As an example, some specific suprathreshold tasks have been shown to elicit significant difficulties in individuals with hidden hearing loss, such as extracting the voice of a speaker of interest in competing spatially-separated speech streams (i.e., spatial release from masking). This is hypothesized to come from some impairment in the time processing performed by the auditory system, such as pitch discrimination and fine sound localization (see <NPL>. for a review).

A self-fitting approach based on spatial sound, in particular speech, identification or segregation is expected to be of particular efficiency to optimize fitting of hearing device parameters. Such approach may be supported by the following measures: (<NUM>) presenting consistent stimuli through the hearing devices to the user, (<NUM>) tracking responsive head motion of the user by using inertial sensors of the hearing devices, and (<NUM>) collecting user feedback in a way which does not demand the user to look at a screen during the self-fitting time.

<FIG> is a schematic representation of an example of a self-fitting arrangement comprising a binaural hearing system <NUM> and an accessory device <NUM> which are communicatively coupled via wireless links <NUM>.

The binaural hearing system <NUM> comprises a first hearing device <NUM> including a first output transducer <NUM> for stimulating a first ear of a user <NUM> and a second hearing device <NUM> including a second output transducer <NUM> for stimulating a second ear of the user. The hearing devices <NUM>, <NUM> are communicatively coupled via a wireless binaural link <NUM>. Each of the hearing devices <NUM>, <NUM> further comprises a microphone arrangement <NUM>, <NUM> for capturing audio signals from ambient sound, an audio signal processing unit <NUM>, <NUM> for processing the captured audio signals according to a present fitting configuration stored in a memory <NUM>, <NUM>, an inertial sensor <NUM>, <NUM> and a wireless interface <NUM>, <NUM> for establishing the wireless links <NUM>, <NUM>.

The audio signal processing unit may apply acoustic beamforming, a hearing loss dependent gain model including suitable compression, such as wide dynamic range compression (WDRC), noise reduction, reverberation reduction, etc. Parameters of such audio signal processing include, for example, compression kneepoints, the amount of noise reduction, beamformer pattern, amount of wide dynamic range compression and reverberation reduction strength. Also the output of the inertial sensors <NUM>, <NUM> may be used in the audio signal processing. The hearing devices may coordinate their audio signal processing by exchanging data and/or audio signals via the binaural link <NUM>. The processed audio signals are reproduced, after amplification, by the output transducers <NUM>, <NUM> to the user <NUM>.

The inertial sensors <NUM>, <NUM> act as motion sensors of the binaural hearing system <NUM>. While in the present example each of the hearing devices <NUM>, <NUM> comprises a separate motion / inertial sensor, there may be examples in which a single motion sensor of binaural hearing system is sufficient, in which case only of one of the hearing devices <NUM>, <NUM> would include a motion / inertial sensor.

The accessory device <NUM> comprises wireless interface <NUM> for establishing the wireless link <NUM> with the hearing devices <NUM>, <NUM>, a processing unit <NUM>, a memory <NUM>, and a user interface <NUM>, such as a touchscreen, for the user <NUM>. The accessory device <NUM> also may comprise an interface <NUM> for connecting via the internet <NUM> to a server <NUM> of the manufacturer of the hearing devices <NUM>, <NUM> for downloading a self-fitting app and/or data required for conducting a self-fitting procedure of the hearing devices <NUM>, <NUM>. According to one example, the accessory device <NUM> may be a smartphone.

In the self-fitting procedure, a present fitting configuration <NUM> is implemented in the binaural hearing system by setting certain values of the respective audio signal processing parameters in the binaural hearing system <NUM>, for example in the memories <NUM>, <NUM> of the hearing devices <NUM>, <NUM>. A spatialized binaural audio signal representative of a virtual auditory scene including at least a first audio source arranged at a first position relative to the user is generated, for example in the accessory device <NUM>, and is reproduced to the user <NUM> via the output transducers <NUM>, <NUM> of the hearing devices <NUM>, <NUM> (the spatialized binaural audio signal may be transmitted to the hearing devices <NUM>, <NUM> via the wireless link <NUM>). Further, an instruction audio signal instructing the user to turn the head towards the first audio source is generated (for example in the accessory device <NUM>) and is reproduced to the user <NUM> via the output transducers <NUM>, <NUM> of the hearing devices <NUM>, <NUM>. The position of the audio source relative to the user may be characterized by the angular position relative to the user and the distance from the user, wherein the angular position is determined by azimuth (yaw) and the elevation (pitch). Typically, the elevation will be less relevant than the azimuth and may relatively small and substantially constant in the tests, i.e., in many cases the virtual auditory scene may be substantially located in a horizontal plane.

Then the resulting head movement of the user <NUM> (which typically will be substantially a yaw head movement) is determined via the first and second inertial sensor <NUM>, <NUM> (for example, the respective sensor signals may be sent via the wireless link <NUM> to the accessory device <NUM> where the head movement is calculated). From the measured head movement the user's ability of spatial sound identification with the present fitting configuration of the hearing system can be estimated by comparing the measured head movement with the angular position of the first audio source in the virtual auditory scene. The inertial sensors <NUM>, <NUM> may be formed by accelerometers and/or gyroscopes; further, each hearing device <NUM>, <NUM> may include a magnetometer for assisting the inertial sensors <NUM>, <NUM>.

The present fitting configuration then may be assessed based on the estimated user's ability of spatial sound identification with the present fitting configuration, and, depending and the result of the assessment, the present fitting configuration may be maintained (if the result is satisfactory) or it may be modified (if the result indicates that the user's ability of spatial sound identification is deteriorated by the present fitting configuration).

An example of such self-fitting procedure is illustrated in <FIG>, wherein <FIG> shows an example of a typical virtual scene that is synthesized as a spatialized binaural audio signal. When such spatialized binaural audio signal is reproduced, the user <NUM> perceives a virtual environment which may contain at least three components: a target talker <NUM> (forming a first audio source oriented at first angle - as already mentioned above, in many cases the yaw will be much more important than the pitch - and at a first distance relative to the user <NUM>), the speech of whom conveys the message the user has to focus on, a competing talker <NUM> spatially separated from the target talker <NUM> (forming a second audio source oriented at second angle and at a second distance relative to the user <NUM>), the speech of whom is interfering with the target talker <NUM>, and some diffuse noise, such as babble noise. Such scene is typically encountered in a bar or a restaurant, where the understanding of speech is challenged.

The spatialization of the sound sources <NUM>, <NUM> can be achieved using generic spatial filters by a so-called binaural synthesis engine <NUM> (see <FIG>). A default HRTF (Head Related Transfer Function) set may be used for every user. Alternatively, the user may first select a set of generic HRTFs among multiple available pre-sets so that the simulated location of the selected set match the location that the user perceives. According to a further alternative, the HRTFs of the user may be recorded via a measurement mechanism relying on the hearing devices and a smartphone, as shown, for example, in <CIT>. It is noted that a selected set of well-matching HRTFs may be used for other purposes, such as creating 3D sound effect in streaming, as already offered by Apple AirPods Pro.

The parameters characterizing the virtual auditory scene may be systematically varied so as to implement different virtual auditory scenes. In particular, the angle (in particular, the yaw) and the distance between the user and the talkers <NUM>, <NUM>, the speech levels of the talkers <NUM>, <NUM> and the diffuse noise level may be varied for optimizing the self-fitting process.

Spatial identification and segregation are key processes in the intelligibility of speech in real environments. Inappropriate settings of certain fitting parameters may have a negative impact on the spatial identification and segregation capability of the user. For example, wide dynamic range compression (WDRC) used in hearing devices is known to decrease the interaural level difference, which is a cue used by the auditory system to localize sound sources in space. An excessive WDRC strength may therefore impair the ability of the user to perform sound segregation. Thus, the amount of WDRC should be adjusted in a way that the speaker segregation performance of the user is preserved (in practice, the amount of WDRC is determined by the compression kneepoint, so that the amount of WDRC can be adjusted by adjusting the compression kneepoint accordingly). Similarly, excessive WDRC and/or reverberation reduction algorithm strength may lead to poorer speaker discrimination in distance. The associated parametrization hence should be in a way so as to ensure that the distance discrimination capabilities of the user are preserved. Also certain beamformer patterns may rely on the ability of the user to discriminate spatially-separated sound sources.

In the present self-fitting method the user's ability of spatial sound identification may be monitored during the fitting process by presenting a virtual auditory scene to the user so as to assess the respective fitting configuration regarding its performance for preserving the user's ability of spatial sound identification. Thereby deterioration of the user's ability of spatial sound identification as a result of an inappropriate fitting parameter setting can be avoided. In addition, also the user's ability of spatial sound segregation may be monitored during the fitting process by using the virtual auditory scene so as to assess the respective fitting configuration also regarding its performance for preserving the user's ability of spatial sound segregation.

For example, the amount of WDRC (by adjusting compression kneepoints) and/or the amount of reverberation reduction and/or the amount of noise reduction and/or beamformer pattern may be set in a way that preserves or even improves the user's ability of spatial sound identification.

An example of head movement tracking for assessment of the ability of a user <NUM> to spatially discriminate a target talker <NUM> and an interfering/competing talker <NUM> is illustrated in <FIG>, wherein the user <NUM> is instructed, by an appropriate audio signal presented via the hearing devices <NUM>, <NUM>, to first look in the direction of the target talker <NUM> (see <FIG>) and then in the direction of the competing talker <NUM> (see <FIG>). The resulting head rotation is measured via the inertial sensors <NUM>, <NUM> and is compared to the angular positions of the talkers <NUM>, <NUM> in the virtual auditory scene. The degree of deviation of the measured head rotation is indicative of the user's ability of spatial sound identification: little deviation indicates good spatial sound identification ability, while large deviation indicates poor spatial sound identification ability. This concept does not require speech understanding tests; rather, it is sufficient that the user can identify the direction/position of the respective (virtual) talker <NUM>, <NUM>. It is noted that a head tracking algorithm usually will require the user <NUM> to first go through a calibration process to provide the system with an absolute reference (e.g. pointing to the front to define the <NUM>° orientation).

In addition, the virtual auditory scene may be also used to assess the user's ability of spatial sound segregation with the respective fitting configuration. To this end, the angle between the sound sources/talkers <NUM> and <NUM> may be varied so as to find minimum angle between them which still allows the user to perceive the sound sources <NUM>, <NUM> as spatially separate sound sources. This minimum angle is indicative of the user's ability of spatial sound segregation: the smaller this angle is, the better is the user's ability of spatial sound segregation.

During the self-fitting procedure, and in particular during the assessment of the user's ability of spatial sound identification, any interaction of the user with the accessory device <NUM> resulting in head movement should be avoided so as to not interfere with the head rotation measurements. Thus, the instructions to the user <NUM> should be provided acoustically via the hearing devices <NUM>, <NUM>. Further, also the user's feedback to tests may be provided acoustically to the hearing devices <NUM>, <NUM> and the accessory device.

For example, the user <NUM> may provide voice feedback to the instruction audio signals which is recognized via automatic speech recognition (ASR), which, as such, is a well-established technique with various commercial applications, like smartphones or user control systems in cars. An example of such user feedback is schematically illustrated in <FIG>, wherein the user <NUM> indicates by speaking the word "done" that that he/she has finalized the previously instructed task of pointing the head towards the (virtual) target talker <NUM>, so that the self-fitting procedure can be continued. Such voice feedback eliminates a need of the user to look towards the accessory device <NUM>, thereby avoiding head movements not caused by the instructions of the self-fitting process.

In addition, ASR may be used for conducting speech understanding tests with the user <NUM> when listening to the virtual auditory scene, wherein the virtual target talker <NUM> presents key words with or without the presence of an interfering talker <NUM> and/or diffuse noise, wherein the user <NUM> is instructed to repeat the key words and wherein the user's voice feedback including the repetition of the key words undergoes ASR so as to recognize whether the user correctly understands the key words. The key words can comprise syllables or words that are generally easily misrecognized acoustically as e.g. "immigrate/emigrate". The key words can form key phrases including semantics wherein the user is required to speak back the whole key phrases. Also in this case the use of ASR allows the user to provide feedback without having to interact, for example, with a display of the accessory device <NUM>, thereby avoiding undesired head movements.

Since ASR works particularly well when the system must recognize words from a limited database, the words to be recognized may be limited specifically, for example to not more than <NUM> words.

The user's voice feedback may be captured by the microphone arrangements <NUM>, <NUM> of the hearing devices <NUM>, <NUM>; the capturing of the user's voice feedback may utilize acoustic beamforming (which may be implemented in the audio signal processing unit <NUM>, <NUM>), so as to increase the SNR of the captured audio signals. The captured user's voice feedback, i.e. the processed audio signals as provided by audio signal processing unit <NUM>, <NUM>, may be transmitted via the wireless link <NUM> the to the accessory device <NUM> which then performs the ASR. Extraction of speech features based on previous recordings of the user's voice may be utilized to improve ASR.

A schematically illustrated in <FIG>, the binaural synthesis engine <NUM> generates the virtual auditory scene and the instructions presented to user <NUM> via the output transducers <NUM>, <NUM> of the hearing devices <NUM>, <NUM>. The user <NUM> responds to such audio stimuli by head movement detected by the inertial sensors <NUM>, <NUM> of the hearing devices <NUM>, <NUM> and/or by voice feedback captured by the microphone arrangements <NUM>, <NUM> of the hearing devices <NUM>, <NUM>. The output of the inertial sensors <NUM>, <NUM> is supplied to a head tracking unit <NUM> which determines head movements, and the audio signals representative of the user's voice feedback provided by the hearing devices <NUM>, <NUM> are supplied to an ASR unit <NUM> for recognizing the words/speech contained in the audio signals. The output of the ASR unit <NUM> is supplied to the head tracking unit <NUM> so that the head tracking unit <NUM> can recognize, for example, when the user has finalized a given task. The output of the head tracking unit <NUM> is used for assessment of the present fitting configuration and for respective adjustment of the audio signal processing parameters used by the binaural synthesis engine <NUM>.

A slightly more detailed schematic illustration of an example of a self-fitting procedure is shown in <FIG>.

The user's voice is captured by the hearing device microphones <NUM>, <NUM>, possibly using a beamformer. The associated audio signals may be processed to extract speech features only (for example, previous recordings of the user's voice can drive this enhancement), as indicated by a speech enhancement unit <NUM>. The processed audio signals then are supplied to the ASR unit <NUM>, which identifies keywords of a closed set or the indication from the user that the direction identification task has been performed. The signals of the motion/inertial sensors <NUM>, <NUM> are processed in the head tracking unit <NUM> to determine the user's head yaw and track the rotation of the user's head in real-time.

The outputs of the ASR unit <NUM> and head tracking unit are supplied as input to a performance assessment unit <NUM> which determines, based on these inputs, performance of the user (with the present fitting configuration and with the present virtual auditory scene) is estimated, such as the ability to correctly repeat key words in a given simulated environment (i.e., in the given virtual auditory scene), the ability to point in the direction of the target talker <NUM> and/or interfering talker <NUM> with a given set of sound processing parameters (i.e., the present fitting configuration), etc. Depending on the estimated user's performance, some parameters of the virtual auditory scene (indicated at unit 70A, e.g., distance between user <NUM> and target talker <NUM>, angle between interfering talker <NUM> and target talker <NUM>, etc.) and/or some parameters of the hearing device audio signal processing (indicated at unit 70B, e.g., compression kneepoints, amount of noise reduction, beamformer pattern, etc.) are adjusted to provide a new binaural audio output to the user's ears. The process is reiterated until it converges to an optimal fitting that maximizes the estimated performance of the user.

It is noted that most of the signal processing can be externalized on the accessory device <NUM> to reduce battery consumption in the hearing devices <NUM>, <NUM> and get access to more processing power; this includes, for example all blocks/units illustrated in grey in <FIG>, namely, speech enhancement (unit <NUM>), ASR (unit <NUM>), head tracking (unit <NUM>), performance assessment (unit <NUM>) and generation of the virtual auditory scene (unit 70A).

Claim 1:
A method of self-fitting of a binaural hearing system (<NUM>) worn by a user (<NUM>), comprising a first hearing device (<NUM>) including a first output transducer (<NUM>) for stimulating a first ear of the user, and a second hearing device (<NUM>) including a second output transducer (<NUM>) for stimulating a second ear of the user, the binaural hearing system (<NUM>) further comprising at least one motion sensor (<NUM>, <NUM>), the method comprising:
- implementing a present fitting configuration in the binaural hearing system;
- generating a spatialized binaural audio signal representative of a virtual auditory scene including at least a first audio source (<NUM>) at a given angular position relative to the user;
- reproducing the spatialized binaural audio signal via the binaural hearing system to the user; the method being characterized by:
- instructing the user to turn the head towards the first audio source;
- measuring the respective head movement of the user via the at least one motion sensor;
- estimating from the measured head movement the user's ability of spatial sound identification with the present fitting configuration of the binaural hearing system; and
- maintaining or modifying the present fitting configuration based on the estimated user's ability of spatial sound identification.