Hearing aid for adjusting processing parameters

Abstract

A hearing aid for adjusting a processing parameter, the hearing aid comprising an input unit for providing an input audio signal indicative of a hearing aid ambient environment and a processor configured to obtain a hearing aid audio signal based on the input audio signal, determine a first audio parameter based on the input audio signal, obtain a first sensor signal indicative of a first biological parameter of a user, determine the first biological parameter based on the first sensor signal, determine a first correlation between the first audio parameter and the first biological parameter, and set a processing parameter of the hearing aid based on the first correlation.

Description

Technical Field

[0001] This application pertains to the field of hearing aids. Background Technology

[0002] Individuals with hearing loss have difficulty hearing in noisy and chaotic environments. Hearing aids with noise reduction algorithms can help suppress unwanted noise and improve the user's perceived signal-to-noise ratio.

[0003] Furthermore, noise reduction algorithms can set the level of noise suppression based on the ambient signal-to-noise ratio and sound pressure level (e.g., Oticon Open Sound Navigator™). However, this ignores the user's state. In other words, does the user truly need stronger noise reduction or not? While the environment may be noisy and turbulent, this alone is insufficient to determine whether the end-user desires enhanced noise reduction from the hearing aid.

[0004] Studies have shown that human heart rate (HR) is sensitive to changes in listening conditions as defined by the characteristics of ambient sound. Specifically, an increase in ambient sound intensity (sound pressure level) translates into a linear increase in heart rate, while an increase in sound clarity (signal-to-noise ratio) corresponds to a decrease in heart rate. This latter effect is even more pronounced in generally noisy environments where the sound pressure level is higher than the most typical observation for hearing aid users (60 dB).

[0005] The sensitivity of heart rate to environmental sounds (e.g., changes in heart rate per minute corresponding to changes in sound pressure level per decibel or signal-to-noise ratio) can be considered a stress response, stemming from both direct biological and indirect cognitive mechanisms. Summary of the Invention

[0006] In one aspect of this application, a hearing aid is provided. The hearing aid may include an input unit for providing an input audio signal indicative of the environment surrounding the hearing aid. The hearing aid may include a processor. The processor is configured to: acquire a hearing aid audio signal based on the input audio signal; determine a first audio parameter based on the input audio signal; acquire a first sensor signal indicative of a first biometric parameter of a user; determine the first biometric parameter based on the first sensor signal; determine a first correlation between the first audio parameter and the first biometric parameter; and set processing parameters of the hearing aid based on the first correlation.

[0007] This provides an improved hearing aid. By monitoring changes in one or more of the user's biometric parameters caused by changes in ambient sound, it can be determined whether the current sound exposure is causing stress or other discomfort. Information regarding the correlation between the sound environment and the user's response to sound can be fed into the hearing aid's processor to help set the processing mode to better suit the individual. Therefore, the hearing aid according to the present invention can set processing parameters based on the hearing aid user's biometric parameters.

[0008] The first audio parameter can be the signal-to-noise ratio (SNR) determined based on the input audio signal. The first audio parameter can be the sound pressure level (SPL) determined based on the input audio signal. The first audio parameter can be the change in SNR over time. The first audio parameter can be the change in SPL over time. The first sound parameter can be the sound modulation level (SML). The first audio parameter can be a cumulative noise measure. The cumulative noise measure can be a measure of the time a user is exposed to noise over a period of time. The measure of when a user is exposed to noise can be determined by setting a threshold that limits when the user is exposed to noise. The aforementioned time period can be one hour, two hours, one day, one week, or one month. The first audio parameter can be a determination of whether the user is listening to speech or noise. This determination can be made using a voice activity detector (VAD) implemented in the hearing aid.

[0009] The first biometric parameter can be the user's heart rate (HR). The first biometric parameter can be the user's pulse. The first biometric parameter can be the user's body temperature. The first biometric parameter can be the user's perspiration rate. The first biometric parameter can be the user's electrical skin activity rate. The first biometric parameter can be the user's electroencephalogram (EEG). The first biometric parameter can be the user's photoplethysmography (PPG). The first biometric parameter can be the user's respiratory rate. The first biometric parameter can be the user's self-spoken voice. The first biometric parameter can be one or more voice characteristics of the user. The first biometric parameter can be the user's pupillary dilation. The first biometric parameter can be the user's fatigue rate.

[0010] The first biometric parameter can be estimated based on signals from multiple first sensors. The first biometric parameter can be estimated as a joint parameter based on signals from multiple first sensors. Multiple first sensor signals provide redundancy, thus avoiding over-reliance on signals from a single sensor. The multiple first sensor signals can be provided by multiple first sensors included in the hearing aid. The multiple first sensor signals can be provided by multiple first sensors external to the hearing aid. The multiple first sensor signals can be provided by multiple first sensors both external to and included in the hearing aid. For example, if the hearing aid is part of a binaural hearing aid system, one or more first sensor signals can be received by the processor of any hearing aid from each hearing aid in the binaural hearing aid system, thereby allowing the processor to estimate the joint parameter based on the first sensor signals from each hearing aid.

[0011] The primary biometric parameter can be measured by appropriate sensors included in the hearing aid or by an external device that communicates with the hearing aid. The external device can be a smart device that includes one or more biosensors. The external device can be paired with the hearing aid.

[0012] The primary correlation can be the relationship or association between the first audio parameter and the first biological parameter. The primary correlation defines how the first audio parameter is related to the first biological parameter. The primary correlation can be a mathematical correlation. The primary correlation can be determined as the product of the covariance of the first biological parameter and the first audio parameter divided by their standard deviations, which can be expressed as:

[0013]

[0014] Where BP1 represents the first biological parameter and AP1 represents the first audio parameter. This represents the correlation between the first audio parameter and the first biological parameter, with the expected value E representing the mean.

[0015] Processing parameters set by the processor can be related to hearing loss compensation algorithms, such as amplification or compression. Processing parameters set by the processor can be related to noise reduction algorithms, such as beamformers, filter coefficients, or update rates. Processing parameters set by the processor can be related to feedback suppression algorithms, such as feedback path estimation.

[0016] In this invention, setting parameters can be understood as fixing the value of a parameter, changing the value of a parameter to a new value, or maintaining the value of a parameter.

[0017] In one embodiment, the hearing aid includes a first biosensor configured to determine a first sensor signal.

[0018] The first biosensor may be a photoplethysmography (PPG) sensor. The first biosensor may be a heart rate sensor. The first biosensor may be disposed within the housing of the hearing aid. The biosensor may be disposed outside the housing of the hearing aid. The first biosensor may be defined by one or more microphones included in the hearing aid. The first biosensor may be a camera. The first biosensor may be one or more electrodes configured to measure the user's electroencephalogram (EEG). The first biosensor may be an optical sensor. The first biosensor may be an accelerometer configured to monitor the user's heart rate.

[0019] In one embodiment, the first biosensor includes an inwardly facing microphone.

[0020] By using a microphone as the primary biosensor, the need to add additional sensors to the hearing aid can be avoided, as the microphone already included in the hearing aid can be used as a biosensor.

[0021] An inward-facing microphone can be understood as one in which the microphone's entrance faces the user's ear, ear canal, or eardrum when the user is wearing a hearing aid.

[0022] In this embodiment, the first correlation is determined continuously across multiple time windows.

[0023] The first correlation can be determined continuously across overlapping time windows. The duration of the time window can vary. The article "The everyday acoustic environment and its association with human heart rate: evidence from real-world data logging with hearing aids and wearables" by Christensen, Jeppe H. et al. (Royal Society Open Science, Vol. 8, No. 2, 2021, 201345) provides an example of how to determine correlations continuously. The duration of the time window can be 30 seconds, 1 minute, 5 minutes, 1 hour, 2 hours, or a day.

[0024] In this embodiment, the first biological parameter includes the user's heart rate.

[0025] In this embodiment, the first audio parameter includes the sound pressure level.

[0026] In one embodiment, the processor is configured to set the strength of the noise reduction algorithm based on a first correlation.

[0027] The strength of a denoising algorithm can be viewed as a trade-off between the risk-averse intention to reduce noise and the risk of introducing processing artifacts. For example, a high strength indicates low aversion to introducing processing artifacts, while a low strength indicates high aversion. Strength can be given as the update rate of the denoising algorithm, such as the update rate of one or more adaptive filters and / or the update rate of the beamformer. A high update rate indicates high strength, and a low update rate indicates low strength. Strength can be given as a smoothing parameter of the denoising algorithm. Strength can be given as the maximum permissible gain variation introduced by the denoising algorithm. A large maximum permissible gain variation indicates high strength, and a small maximum permissible gain variation indicates low strength. Strength can be given as the signal-to-noise ratio (SNR) for enabling the denoising algorithm. A low SNR for enabling the denoising algorithm indicates high strength, and a high SNR for enabling the denoising algorithm indicates low strength.

[0028] In one embodiment, the processor is configured to compare a first correlation with a first threshold range, and if the first correlation exceeds the first threshold range, increase the strength of the hearing aid's noise reduction algorithm.

[0029] The first threshold range can be a personalized range set during hearing aid fitting. Alternatively, the first threshold range can be a preset range set during hearing aid manufacturing.

[0030] In one embodiment, the processor is configured to determine a first estimate of the causal relationship between a first audio parameter and a first biological parameter, and to set the processing parameters of the hearing aid based on the first estimate of the causal relationship.

[0031] By estimating the causal relationship between a first audio parameter and a first biological parameter, a higher level of confidence can be provided for setting the basis of processing parameters. For example, if a high correlation is measured between a biological parameter and an audio parameter, it may indicate that the user has made a biological response to changes in the sound environment; however, this could also be a coincidence. By estimating the strength of the causal relationship estimate, further information can be provided about whether the correlation is a coincidence or a causal outcome.

[0032] Causality can be estimated using structural causal models (SCM), Rubin causal models, or similar methods.

[0033] In this embodiment, the first estimate of causality is a measure of temporal Granger causality.

[0034] An example of how to estimate Granger causality by incorporating biological parameters can be found in the article “Cardiovascular control and time domain Granger causality: insights from selective autonomic blockade” by Porta, Alberto et al. (Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2013, Vol. 371, No. 1997: 20120161). Another example of using Granger causality can be found in the article “Distinct influence of everyday noise on cardiovascular stress” by Christensen, J., Andersson, K., & Neher, T. (February 2023) (INTER-NOISE and NOISE-CON Congress and Conference Proceedings, Institute of Noise Control Engineering, Vol. 265, No. 7, pp. 242-247).

[0035] In one embodiment, the processor is configured to: acquire a second sensor signal indicating the user's activity level, determine the activity level based on the second sensor signal, and set processing parameters of the hearing aid based on the activity level.

[0036] By incorporating activity levels into the decision-making process for setting processing parameters, further information can be provided about why changes in biological parameters are observed, rather than relying solely on audio parameters. For example, activity levels can indicate that a user is running, which is precisely what causes an increase in heart rate.

[0037] Activity level can be a user's walking speed. Activity level can be a specific distance a user moves within a time period. Activity level can be gait analysis.

[0038] In one embodiment, the hearing aid includes a second sensor configured to determine a second sensor signal.

[0039] The second sensor may include an inertial motion unit (IMU). The second sensor may include a gyroscope. The second sensor may include a global positioning system (GPS). The second sensor may include an accelerometer. Examples of hearing aids with a second sensor capable of tracking motion can be found, for example, in the Oticon Intent hearing aid.

[0040] In an embodiment, the processor is configured to: store a plurality of first biological parameters over a period of time, determine user characteristics based on the plurality of first biological parameters, and set processing parameters based on the user characteristics.

[0041] Therefore, further information is provided to the processor when deciding whether to set the processing parameters to new values ​​or maintain the current processing parameters. For example, a high correlation between the first biological parameter and the first audio parameter may indicate a stress response, which may suggest that the processing parameters need to be changed. However, if the user characteristics are still within the user's normal range, it may not be necessary to change the processing parameters yet, and the processing parameters may only need to be changed if the first biological parameter exceeds the user's normal range.

[0042] The first user characteristic can be the mean of a first biological parameter measured within that time period. The first user characteristic can be a range, defined by the mean and standard deviation of the first biological parameter, for example, expressed as [E[BP1]-σ]. BP1 E[BP1] +σ BP1 The first user characteristic could be the user's resting heart rate.

[0043] In an embodiment, the processor is configured to: determine a second audio parameter based on an input audio signal, determine a second correlation between the second audio parameter and a first biological parameter, and set processing parameters of the hearing aid based on the second correlation.

[0044] Additional audio parameters can be used to set hearing aid processing parameters and how to set the confidence level of those parameters.

[0045] In this embodiment, the second audio parameter includes the signal-to-noise ratio.

[0046] In an embodiment, the processor is configured to compare a first correlation with a first threshold range and a second correlation with a second threshold range. If the first correlation is within or below the first threshold range and the second correlation is within or below the second threshold range, the strength of the noise reduction algorithm of the hearing aid is reduced.

[0047] The second threshold range can be a personalized range set during hearing aid fitting. Alternatively, the second threshold range can be a preset range set during hearing aid manufacturing.

[0048] In an embodiment, the processor is configured to compare a first correlation with a first threshold range and a second correlation with a second threshold range. If the first correlation is within or below the first threshold range and the second correlation is within or above the second threshold range (unless the first correlation and the second correlation are within the first threshold range and the second threshold range, respectively), then the processing parameters are maintained.

[0049] Table 1 below illustrates how different correlations can indicate different user states and how hearing aids can intervene based on the identified correlations. In the table below, The first measure of correlation between heart rate (HR) and sound pressure level (SPL) This represents a second correlation measure between heart rate (HR) and signal-to-noise ratio (SNR). "High+" indicates a positive correlation measure above the threshold range, 0 indicates a correlation measure within the threshold range, and "High-" indicates a negative correlation measure below the threshold range. The first threshold range can be compared with... Relatedly, the second threshold range can be associated with Related.

[0050] Table 1: Potential Outcomes and Corresponding Interventions

[0051] instruct Potential Intervention High+ 0 Increased sound pressure level leads to increased heart rate – a stress response triggered by high sound pressure levels. Enhanced noise reduction High+ High+ Increased sound pressure level and signal-to-noise ratio both increase heart rate—a stress response triggered by high sound pressure level and high signal-to-noise ratio. Enhanced noise reduction High+ high- Increased sound pressure level raises heart rate, but increased signal-to-noise ratio (SNR) lowers heart rate—this is the stress response triggered by high sound pressure level, but relieved by increased SNR. Enhanced noise reduction but not enhanced amplification high- 0 Increased sound pressure level causes a decrease in heart rate -- no stress response Non-intervention high- High+ Increased sound pressure level lowers heart rate, but increased signal-to-noise ratio increases heart rate—a stress response triggered by speech-like sounds. No intervention required high- high- Increased sound pressure level and signal-to-noise ratio both decrease heart rate – a stress relief response. Reduce noise 0 0 Sound pressure level or signal-to-noise ratio has no effect on heart rate -- no stress response Reduce noise 0 High+ Increased signal-to-noise ratio leads to increased heart rate -- a stress response triggered by speech-like sounds. No intervention required 0 high- Increased signal-to-noise ratio leads to decreased heart rate -- a stress relief response induced by speech-like sounds. Reduce noise

[0052] Hearing aids may be adapted to provide frequency-varying gain and / or level-varying compression and / or frequency shifting (with or without frequency compression) from one or more frequency ranges to one or more other frequency ranges to compensate for a user's hearing loss. Hearing aids may include a signal processor for amplifying the input signal and providing a processed output signal.

[0053] The hearing aid may include an output unit for providing stimulation, perceived by the user as an acoustic signal, based on processed electrical signals. The output unit may include an output transducer. The output transducer may include a receiver (speaker) for providing the stimulation as an acoustic signal to the user. The output transducer may include a vibrator for providing the stimulation as mechanical vibrations of the skull to the user. The output unit may include a transmitter for transmitting sound picked up by the hearing aid to another device, such as a remote communication partner.

[0054] Hearing aids may include an input unit for providing an input audio signal representing sound. The input unit may include an input transducer, such as a microphone, for converting input sound into an input audio signal. The input unit may include a wireless receiver for receiving wireless signals that include or represent sound and providing an input audio signal representing sound.

[0055] Wireless receivers and / or transmitters may be configured, for example, to receive and / or transmit electromagnetic signals in the radio frequency range (3 kHz to 300 GHz). Wireless receivers and / or transmitters may be configured, for example, to receive and / or transmit electromagnetic signals in the optical frequency range (e.g., infrared light 300 GHz to 430 THz or visible light such as 430 THz to 770 THz).

[0056] Hearing aids may include directional microphone systems adapted to spatially filter sound from the environment, thereby enhancing a target sound source among multiple sound sources in the local environment of the hearing aid wearer. The directional system may be adapted to detect the direction from which a specific portion of the microphone signal originates. This can be achieved, for example, in a variety of different ways described in the prior art. In hearing aids, microphone array beamformers are commonly used to spatially attenuate background noise sources. Beamformers may include linearly constrained minimum variance (LCMV) beamformers. Many beamformer variations can be found in the literature. Minimum variance distortionless response (MVDR) beamformers are widely used in microphone array signal processing. Ideally, an MVDR beamformer preserves the signal from the target direction (also known as the line of sight) while attenuating sound signals from other directions to the greatest extent possible. A generalized sidelobe canceller (GSC) structure is an equivalent representation of an MVDR beamformer, offering computational and digital representation advantages over a direct implementation of the original form.

[0057] Hearing aids may include antennas and transceiver circuitry that enables the establishment of wireless links to entertainment devices, communication devices, wireless microphones, external processing devices, or other hearing aids. The hearing aid can thus be configured to wirelessly receive direct electrical signals from another device. Similarly, the hearing aid can be configured to wirelessly transmit output signals to another device. Input or output signals may represent or include audio signals and / or control signals and / or information signals.

[0058] Generally, the wireless link established by the antenna and transceiver circuitry of a hearing aid can be of any type. The wireless link can be a near-field communication-based link, such as an inductive link based on inductive coupling between the antenna coils of the transmitter and receiver sections. The wireless link can also be based on far-field electromagnetic radiation. Preferably, the frequency used to establish the communication link between the hearing aid and another device is below 70 GHz, for example, in the range from 50 MHz to 70 GHz, or above 300 MHz, for example, in the ISM range above 300 MHz, or in the 900 MHz range, or in the 2.4 GHz range, or in the 5.8 GHz range, or in the 60 GHz range (ISM = Industrial, Scientific and Medical, such standardized ranges are defined, for example, by the International Telecommunication Union ITU). The wireless link can be based on standardized or proprietary technologies. The wireless link can be based on Bluetooth technology (e.g., Bluetooth Low Energy technology, such as LE Audio) or Ultra Wideband (UWB) technology.

[0059] Hearing aids may include signal paths for processing audio signals. The signal processor may be adapted to provide frequency-varying gain according to the user's specific needs. Some or all signal processing may be performed in the frequency domain, in which case the hearing aid includes appropriate analysis and synthesis filter banks. Some or all signal processing may be performed in the time domain.

[0060] Hearing aids may include multiple sensors configured to provide status signals relating to the hearing aid's current network environment, and / or the current state of the user wearing the hearing aid, and / or the current state or operating mode of the hearing aid. Alternatively or additionally, one or more sensors may form part of an external device that communicates with the hearing aid. External devices may include, for example, another hearing aid, a remote control, an audio transmission device, a telephone, external sensors, etc.

[0061] Hearing aids may include a voice activity detector (VAD) for estimating whether the input signal includes a voice signal. In this specification, a voice signal may be understood to include speech signals from a human being. It may also include other forms of vocalization produced by the human speech system. The voice activity detector unit may be adapted to classify the user's current acoustic environment as a "voice" or "no-voice" environment.

[0062] Hearing aids may include a self-voice detector for estimating whether a particular input sound originates from the user's voice. The microphone system of the hearing aid may be adapted to distinguish between the user's own voice and the voice of another person, as well as from non-voice sounds.

[0063] Hearing aids may include acoustic feedback control or echo cancellation systems. Adaptive feedback cancellation is capable of tracking changes in the feedback path over time. It typically estimates the feedback path based on a linear time-invariant filter, but the filter weights are updated over time. The filter update can be computed using stochastic gradient algorithms, including some form of least mean square (LMS) or normalized LMS (NLMS) algorithm. Both have the property of minimizing the difference signal in terms of mean square, and NLMS further normalizes the filter update with respect to the square of the Euclidean norm of a reference signal.

[0064] Hearing aids may also include other suitable functions for the application in question, such as compression and noise reduction.

[0065] Hearing aids may include hearing instruments, such as hearing instruments adapted to be located in the user's ear or wholly or partially in the ear canal.

[0066] In this specification, a hearing aid, such as a hearing instrument, refers to a device suitable for improving, enhancing, and / or protecting a user's hearing ability, which achieves this by receiving sound signals from the user's environment, generating corresponding audio signals, possibly modifying the audio signals, and providing the possibly modified audio signals as audible signals to at least one ear of the user. The audible signals may be provided, for example, as sound signals radiated into the user's outer ear, and / or as sound signals transmitted as mechanical vibrations through the bone structures of the user's head and / or through portions of the middle ear to the user's inner ear.

[0067] Hearing aids can be configured to be worn in any known manner, such as as a unit worn behind the ear (having a tube that directs radiated sound signals into the ear canal or having an output transducer, such as a speaker, arranged close to or located within the ear canal), as a unit wholly or partially arranged in the auricle and / or ear canal, or as a unit connected to a fixed structure implanted in the skull, such as a vibrator. Hearing aids may include a single unit or several units that communicate with each other. The speaker may be housed within the housing along with other components of the hearing aid, or it may be an external unit itself.

[0068] Hearing aids can be adapted to the specific needs of users, such as those with hearing loss. The configurable signal processing circuitry of a hearing aid can be adapted to apply frequency- and level-variable compression amplification of the input signal. Customized frequency- and level-variable gain can be determined during the fitting process using the fitting system based on the user's hearing data, such as an audiogram, and employing basic fitting principles. This frequency- and level-variable gain can be reflected, for example, in processing parameters uploaded to the hearing aid via an interface to a programming device and used by a processing algorithm executed by the hearing aid's configurable signal processing circuitry. Attached Figure Description

[0069] Various aspects of the invention will be best understood from the following detailed description taken in conjunction with the accompanying drawings. For clarity, these drawings are schematic and simplified, showing only the details necessary for understanding the invention while omitting other details. Throughout the specification, the same reference numerals are used for the same or corresponding parts. Features of each aspect may be combined with any or all features of other aspects. These and other aspects, features, and / or technical effects will be apparent from and illustrated in the following figures, wherein:

[0070] Figure 1 schematically illustrates an exemplary block diagram of a hearing aid according to the present invention;

[0071] Figure 2 shows an exemplary block diagram of a processor according to the present invention.

[0072] The scope of the invention will become apparent from the detailed description given below. However, it should be understood that while the detailed description and specific examples illustrate preferred embodiments of the invention, they are given for illustrative purposes only. Other embodiments of the invention will become apparent to those skilled in the art based on the following detailed description. Detailed Implementation

[0073] The detailed description below, taken in conjunction with the accompanying drawings, serves as a description of various different configurations. This detailed description includes specific details to provide a thorough understanding of several different concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. Several aspects of the apparatus and method are described by various different blocks, functional units, modules, elements, circuits, steps, processes, algorithms, etc. (collectively, "elements"). Depending on the application, design constraints, or other reasons, these elements may be implemented using electronic hardware, computer programs, or any combination thereof.

[0074] Electronic hardware may include microelectromechanical systems (MEMS), (e.g., application-specific integrated circuits), microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), gating logic, discrete hardware circuits, printed circuit boards (PCBs) (e.g., flexible PCBs), and other suitable hardware configured to perform the various functions described in this specification, such as sensors for sensing and / or recording the physical properties of the environment, devices, users, etc. Computer programs should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, programs, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or other names.

[0075] This invention proposes a hearing aid that uses one or more bio-parameters as a proxy for the current level of listening effort and informs the user's needs to a noise reduction algorithm. The one or more bio-parameters may include a continuous heart rate measured from an in-ear hearing aid sensor (e.g., a sensor for measuring photoplethysmography (PPG)). The one or more bio-parameters may include sensor measurements taken by a wearable device other than the hearing aid (e.g., a wrist-worn device). The one or more bio-parameters may include a continuous heart rate measured from an inward-facing microphone of the hearing aid.

[0076] If photoplethysmography (PPG) measurements are performed, these measurements can be conducted by an in-ear diode included in the hearing aid. The hearing aid can acquire PPG signals from the ear canal or behind the ear and extract the peak-to-peak PPG time as an indicator of instantaneous heart rate (HR). If one or more biometric parameters are measured by an external device, these parameters can be transmitted via Bluetooth to a companion smartphone, which then relays the information to the hearing aid for further analysis.

[0077] The processor of a hearing aid can calculate the correlation and causal relationship between changes in one or more biological parameters and fluctuations in estimated environmental audio parameters such as sound pressure level (SPL) and signal-to-noise ratio (SNR). One or more audio parameters can be determined by an estimator as part of the processing performed by the hearing aid. The correlation between one or more biological parameters and one or more audio parameters can be estimated continuously across overlapping time windows of variable duration (correlation coefficients). The correlation between biological parameters and audio parameters can be quantified by dividing the covariance of the two parameters by their standard deviation.

[0078] The threshold at which the estimated correlation is considered to be different from 0 (e.g., negative or positive correlation) can be learned from data, such as data in the form of feedback from hearing aid users about whether the current treatment meets their needs.

[0079] The time window chosen for the above calculations may vary depending on the application. Longer time scales (e.g., hours) can be used for daily assessments, while shorter time windows (e.g., 5-10 minutes) can be used for adaptive correction to continuous changes in sound environments or the physiological state of hearing aid users.

[0080] In some embodiments, the setting of one or more processing parameters is performed only when both a correlation measure and a causality measure are present. An example of a causality measure is causal directionality, which can be estimated using the Granger Directionality Index (DI), as illustrated by Porta, Alberto et al. in “Cardiovascular control and timedomain Granger causality: insights from selective autonomic blockade” (Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 371, No. 1997, 20120161). The Granger causality test determines whether the future value of a time series can be better predicted by a combination of its own past values ​​and those of other time series than by its own past values ​​alone. This statistical test is traditionally based on the Wald test for the difference in explained variance between two predictive regression models; one model includes only past values ​​up to a selected lag, while the other model also includes past values ​​from another time series. Then, the direction of causality between the two time series X and Y is inferred by testing two hypotheses: H01: X Granger causes Y, or H02: Y Granger causes X. If both H01 and H02 are accepted, there is no linear causal relationship between X and Y. If H01 is accepted but H02 is rejected, there is a one-way linear causal relationship from Y to X. If H01 is rejected but H02 is accepted, there is a one-way linear causal relationship from X to Y. Finally, if both H01 and H02 are rejected, there is a reciprocal Granger causal relationship between X and Y, indicating a feedback relationship or that changes in X and Y are driven by a common latent variable. To calculate a continuous measure of Granger causality, this assessment can be based on a direct comparison between F-values ​​assessed in opposite causal directions, see Paluš, Milan, and Aneta Stefanovska's article "Direction of coupling from phases of interacting oscillators: an information-theoretic approach" *Physical Review E 67.5 (2003): 055201*. Therefore, the directionality index (DI) can be defined as:

[0081]

[0082] Here, 𝐹𝑋→𝑌 and 𝐹𝑌→𝑋 represent the F-values ​​evaluated from X to Y and from Y to X, respectively. 𝐷𝐼𝑋→𝑌>0 indicates that the causal direction from X to Y is more significant than the reverse causal direction, while 𝐷𝐼𝑌→𝑋<0 indicates the opposite. A value close to 0 may indicate: (1) X and Y are completely decoupled; (2) there is a closed-loop interaction between X and Y, and neither causal direction is actually dominant; (3) there is synchronicity between X and Y. The correlation estimation results, combined with corroborating information on causality, can help adjust the processing parameters of the hearing aid.

[0083] To improve the accuracy of hearing aid processing parameter settings, activity levels can be estimated using motion sensors. This will help determine the correlation coefficient. The high value is caused by a specific change in sound pressure level and signal-to-noise ratio associated with sustained physical activity, such as high-intensity exercise accompanied by sustained high sound pressure levels. Activity level can be estimated by the vector sum of the accelerometers on the hearing aid or by the GPS of the accompanying smartphone in meters per second. If the activity level is high (e.g., above a threshold learned from the data) and the causality directivity index is low, the hearing aid's processing parameters may not need to be interfered with.

[0084] Used to determine the correlation coefficient The thresholds, which are 0, high +, or high - (see Table 1), can be determined by learning from individual user data. After a period of use, the thresholds are set so that adjustments to the processing parameters can cause one or more biological parameters to change toward the user's mean.

[0085] Figure 1An exemplary block diagram of a hearing aid 1 according to the present invention is shown. The hearing aid 1 is configured for wear by a user 2. The hearing aid 1 includes an input unit 10 for providing an input audio signal indicative of the hearing aid's surrounding environment. The hearing aid 1 includes a processor 11. The processor is configured to acquire a hearing aid audio signal based on the input audio signal. The processor 11 is configured to determine a first audio parameter based on the input audio signal. The processor 11 is configured to acquire a first sensor signal indicative of a first biometric parameter of the user. The processor 11 is configured to determine the first biometric parameter based on the first sensor signal. The processor 11 is configured to determine a first correlation between the first audio parameter and the first biometric parameter. The processor 11 is configured to set processing parameters of the hearing aid 1 based on the first correlation. The hearing aid 1 may include a first biosensor 12 configured to determine the first sensor signal. The first biosensor 12 may include an optical sensor and / or an inwardly facing microphone. If the first biosensor 12 includes a microphone, the microphone may be integrated into the input unit 10 of the hearing aid. The processor 11 may be configured to continuously determine the first correlation across multiple time windows. The first biometric parameter may include the user's heart rate. The first audio parameter may include sound pressure level. Processor 11 is configurable to set the strength of the noise reduction algorithm of hearing aid 1 based on a first correlation. Processor 11 is configurable to compare the first correlation with a first threshold range. Processor 11 is configurable to increase the strength of the noise reduction algorithm of hearing aid 1 if the first correlation exceeds the first threshold range. Processor 11 is configurable to determine a first estimate of the causal relationship between a first audio parameter and a first biological parameter. Processor 11 is configurable to set processing parameters of hearing aid 1 based on the first estimate of the causal relationship. The first estimate of the causal relationship may be a measure of Granger causality. Processor 11 is configurable to acquire a second sensor signal indicating a user's activity level. Processor 11 is configurable to determine the activity level based on the second sensor signal. Processor 11 is configurable to set processing parameters of hearing aid 1 based on the activity level. The hearing aid may include a second sensor 13 configured to determine the second sensor signal. Processor 11 is configurable to store multiple first biological parameters over a period of time. Processor 11 is configurable to determine user characteristics based on multiple first biological parameters. Processor 11 is configurable to set processing parameters based on user characteristics. Processor 11 is configurable to determine a second audio parameter based on an input audio signal. Processor 11 is configurable to determine a second correlation between the second audio parameter and a first biological parameter. Processor 11 is configurable to set processing parameters of the hearing aid based on the second correlation. The second audio parameter may include the signal-to-noise ratio. Processor 11 is configurable to compare the first correlation with a first threshold range. Processor 11 is configurable to compare the second correlation with a second threshold range. Processor 11 is configurable to reduce the intensity of the noise reduction algorithm of the hearing aid 1 if the first correlation is within or below the first threshold range, and the second correlation is within or below the second threshold range.Processor 11 is configured to compare a first correlation with a first threshold range. Processor 11 is configured to compare a second correlation with a second threshold range. Processor 11 is configured to maintain existing processing parameters if the first correlation is within or below the first threshold range, while the second correlation is within or above the second threshold range (except where the first correlation and the second correlation are simultaneously within the first threshold range and the second threshold range, respectively).

[0086] Figure 2 An exemplary block diagram of a processor 11 according to the present invention is shown. The processor 11 is configured to receive an input audio signal 2 indicative of the surrounding environment of a hearing aid 1 worn by a user 3. The processor 11 is configured to determine (111) a first audio parameter from the received input audio signal 2. The first audio parameter may be the sound pressure level of the input audio signal. The input audio signal 2 may be acquired via an input unit 10 communicatively connected to the processor 11. The processor 11 is configured to receive a first sensor signal. The processor 11 is configured to determine (112) a first biometric parameter of the hearing aid user 3 based on the received first sensor signal 2. The first biometric parameter may be the heart rate of the hearing aid user 3. The first sensor signal may be from a sensor equipped with the hearing aid 1 or from a sensor equipped with a wearable device worn by the hearing aid user 3. The processor 11 is configured to determine (113) a first correlation based on the first audio parameter and the first biometric parameter. The processor 11 is configured to set (114) processing parameters of the hearing aid 1 based on the determined first correlation.

[0087] When appropriately replaced by a corresponding process, the structural features of the apparatus described above, in detail in the "Detailed Description" section, and as defined in the claims can be combined with the steps of the method of the present invention.

[0088] Unless explicitly stated otherwise, the singular forms “a” and “the” used herein include the plural forms (i.e., meaning “at least one”). It should also be understood that the terms “having,” “comprising,” and / or “including” as used in the specification indicate the presence of 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 combinations thereof. It should be understood that, unless explicitly stated otherwise, when an element is referred to as “connected” or “coupled” to another element, it may be a direct connection or coupling to the other element, or there may be intermediate inserting elements. The term “and / or” as used herein includes any and all combinations of one or more of the listed related items. Unless otherwise explicitly stated otherwise, the steps of any method disclosed herein do not necessarily need to be performed in the exact order disclosed.

[0089] It should be understood that references to "an embodiment," "an embodiment," "an aspect," or "may" in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Furthermore, particular features, structures, or characteristics may be suitably combined in one or more embodiments of the invention. The foregoing description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications will be apparent to those skilled in the art.

[0090] The claims are not limited to the aspects shown herein, but encompass the full scope consistent with the language of the claims, wherein, unless expressly stated otherwise, an element referred to in the singular does not mean "one and only one," but rather "one or more." Unless expressly stated otherwise, the term "some" means one or more.

Claims

1. A hearing aid for a user to wear, comprising: The input unit is used to provide input audio signals that indicate the surrounding environment of the hearing aid; and The processor is configured as follows: Acquire hearing aid audio signals based on input audio signals; The first audio parameter is determined based on the input audio signal; Acquire a first sensor signal that indicates the user's first biological parameter; The first biological parameter is determined based on the signal from the first sensor. Determine the first correlation between the first audio parameter and the first biological parameter; and The processing parameters of the hearing aid are set based on the first correlation.

2. The hearing aid of claim 1, comprising a first biosensor configured to determine a first sensor signal.

3. The hearing aid according to claim 2, wherein, The first biosensor includes an optical sensor and / or an inward-facing microphone toward the user's eardrum.

4. The hearing aid according to claim 1, wherein, The first audio parameter includes the sound pressure level.

5. The hearing aid according to claim 1, wherein, The processor is configured as follows: The strength of the noise reduction algorithm for the hearing aid is set based on the first correlation.

6. The hearing aid according to claim 1, wherein, The processor is configured as follows: A first estimate is used to determine the causal relationship between the first audio parameter and the first biological parameter; and The processing parameters of the hearing aid are set based on the first estimate of causality.

7. The hearing aid according to claim 6, wherein, The first estimate of causality is Granger causality measure.

8. The hearing aid according to claim 1, wherein, The processor is configured as follows: Acquire a second sensor signal that indicates the user's activity level; Activity level determined based on signals from the second sensor; and The processing parameters of the hearing aid are set based on the activity level.

9. The hearing aid of claim 8, comprising a second sensor configured to determine a second sensor signal.

10. The hearing aid according to claim 1, wherein, The processor is configured as follows: Storing multiple primary biological parameters over a period of time; User characteristics are determined based on multiple primary biometric parameters; and Processing parameters are set based on user characteristics.

11. The hearing aid according to claim 1, wherein, The processor is configured as follows: The second audio parameter is determined based on the input audio signal; Determine a second correlation between the second audio parameter and the first biological parameter; and The processing parameters of the hearing aid are set based on the second correlation.

12. The hearing aid according to claim 11, wherein, The second audio parameter includes the signal-to-noise ratio.

13. The hearing aid according to claim 11, wherein, The processor is configured as follows: Compare the first correlation with the first threshold range; Compare the second correlation with the second threshold range; and If the first correlation is within or below the first threshold range, and the second correlation is within or below the second threshold range, then the strength of the hearing aid's noise reduction algorithm is reduced.

14. The hearing aid according to claim 11, wherein, The processor is configured as follows: Compare the first correlation with the first threshold range; Compare the second correlation with the second threshold range; and If the first correlation is within or below the first threshold range, and the second correlation is within or above the second threshold range, the processing parameters are maintained, except where the first correlation and the second correlation are within the first threshold range and the second threshold range, respectively.

15. The hearing aid according to claim 14, wherein, The second audio parameter includes the signal-to-noise ratio, and the first audio parameter includes the sound pressure level.

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