System and method for detecting malfunctions of the neurovascular coupling of a user

Abstract

The invention relates to a system (1) and method for detecting malfunctions of the neurovascular coupling of a user of a device that can be worn or implanted on the head, in particular a hearing aid (2), long-term monitoring being carried out with the aid of a device worn by the user, in particular a hearing aid. The device has a signal processing unit (8) and a memory (16). The system (1) also has at least two sensors (18, 20, 22), namely a sensor (20) for detecting brain activity and a blood sensor (18, 22) for detecting blood flow to the brain. The at least two sensors (4, 18, 20, 22) are connected to the signal processing unit (8) for transmitting sensor data (A, B), namely brain activity data (A) and blood flow data (B). The signal processing unit (8) is designed to process the sensor data (A, B) in such a way that characteristic data, in particular a characteristic value (K) for a correlation, in particular a time delay between increased brain activity and increased blood flow caused thereby, is determined, and reference characteristic data and in particular a reference characteristic value (RK) are formed therefrom over a relatively long observation period (Z) as a measure of the time delay Z. The reference characteristic data are compared with instantaneous characteristic data recorded later and a warning signal (W) is emitted in the event of an inadmissible deviation.

Description

[0001] FDST Patent Attorneys, Nuremberg Page 1

[0002] P230905P-MD / JB

[0003] Description

[0004] System and method for detecting functional disorders of a user's neurovascular coupling

[0005] The invention relates to a system and a method for detecting functional disorders of the neurovascular coupling of a user.

[0006] Neurovascular coupling is a well-known physiological mechanism for regulating blood supply to the brain. It increases blood flow to meet the increased demand of activated nerve tissue for oxygen and energy-providing substances such as glucose. Such increased demand arises, for example, from heightened brain activity in specific brain regions.

[0007] Correlations, particularly temporal correlations, can be observed between increased brain activity and increased blood flow. The increased blood flow is therefore a response to the increased brain activity. In healthy individuals, the time delay between increased brain activity and increased blood flow is typically a few seconds, for example, 2-5 seconds.

[0008] Changes in this correlation can be signs or precursors of a disease, such as high blood pressure, diabetes, Alzheimer's disease, vascular damage, or nerve damage. Age-related changes in this correlation also occur. Such changes, particularly an increased time lag between increased brain activity and increased blood supply, are considered here to be a dysfunction of neurovascular coupling.

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[0010] The examination of neurovascular coupling with regard to such functional disorders is generally known and is already carried out in patients as part of medical diagnostics.

[0011] For example, US patent 2021 / 0282694 A1 describes an analytical method for such neurovascular coupling, in which brain waves are measured using electroencephalography (EEG) to infer increased brain activity. An increased blood flow is detected and evaluated via a blood flow sensor, specifically a functional near-infrared spectroscopy (fNIRS) sensor, and characteristic parameters for the coupling are determined. However, such fNIRS systems are expensive and require significant space and energy, so they are typically only used in stationary settings. Standard procedures include rheoencephalography (REG) and electrical impedance plethysmography (EIP).

[0012] The increase in blood flow is a local reaction in the brain, a direct result of vasodilation (increased blood vessel diameter). It is unrelated to the heart or an increase in blood pressure, as such reactions are significantly delayed. In particular, the heart's response is not only significantly delayed but also very weak because other parts of the body dominate blood flow. It is precisely this local limitation of neurovascular coupling that enables such measurements of this coupling.

[0013] Such investigations of neurovascular coupling are regularly very complex and are carried out, for example, as part of an examination in a laboratory.

[0014] Based on this, the invention aims to enable a simplified examination of a user's neurovascular coupling.

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[0016] The problem is solved according to the invention by a system and a method for detecting functional disorders of the neurovascular coupling of a user with the features of claim 1 or claim 15.

[0017] The system and the procedure each employ a head-worn or implantable device, in particular a hearing aid, with a signal processing unit and a memory. The system further includes two sensors: one for recording brain activity and one for monitoring blood levels in the brain. The two sensors communicate with the signal processing unit either wirelessly or via a wired connection and transmit sensor data to it, namely brain activity data and blood data.

[0018] The signal processing unit is designed to process the sensor data and perform the following steps:

[0019] - Determination of key parameters, in particular a key figure for the correlation between increased brain activity and the resulting increased blood flow. The increased brain activity is determined by evaluating the brain activity data in a known manner. The increased blood flow is also determined in a known manner based on the transmitted blood data. For the determination of the key parameters, a data pair consisting of the brain activity data and the corresponding blood data is used.

[0020] - The sensor data and / or the determined characteristic data are stored in memory.

[0021] From the sensor data or the determined parameters obtained over a long-term observation period, reference parameters are generated, and in particular a reference parameter for the correlation between increased brain activity and the resulting increased blood flow. These reference parameters are preferably stored in memory. "Long-term" here refers to a period of at least several days, preferably several weeks or even several months.

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[0023] - Current key data are determined from sensor data that are recorded later and especially at the moment compared to these sensor data from the long-term observation period.

[0024] - The current parameters are compared with the reference parameters, and a warning signal is issued if there is an impermissible deviation between the current parameters and the reference parameters.

[0025] For the characteristic data, in particular the characteristic value, the time delay between the increased brain activity and the increased blood flow is used in a preferred embodiment. An impermissible deviation is understood to mean that the characteristic data, specifically the characteristic value and thus, for example, this time delay, deviates by a predetermined tolerance value from the reference characteristic data, specifically the reference delay previously determined as the reference characteristic value.

[0026] In this context, a blood sensor is understood to be any sensor suitable for detecting properties of blood in the brain. These properties primarily concern blood flow, i.e., the amount of blood flowing through a blood vessel per unit of time. This is measured directly, in particular, by a blood flow sensor.

[0027] However, one property could also be, for example, the amount of blood contained locally in a blood vessel and, in particular, its change.

[0028] Types of blood sensors used to detect blood properties in the brain include, for example, so-called PPG sensors (photoplethysmogram sensors) or bioimpedance sensors.

[0029] The blood sensor is suitable for placement directly on the device, especially the hearing aid, and / or at suitable locations on the head, and is designed to specifically cover regions where the properties can be measured accurately. Specifically, at least one blood sensor is positioned in the area of ​​an artery, particularly the internal carotid artery.

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[0031] ICA) attachable and / or in the area of ​​the three paired branches MCA (Middle Cerebral Artery), PCA (Posterior Cerebral Artery), ACA (Anterior Cerebral Artery).

[0032] The particular advantage of the system and procedure described here lies in the use of a head-worn or implantable device, especially a hearing aid, which is worn regularly on the ear. The term "head-worn device" generally encompasses all devices, including functional clothing items such as headbands, that are designed with the aforementioned functions. Functional headbands for meditation purposes are particularly well-known.

[0033] This also includes medical diagnostic devices that are preferably worn continuously, such as epilepsy diagnostic devices or EEG devices (e.g., UNEGG).

[0034] Hearing aids are used specifically. In this context, the term "hearing aid" generally refers to both (normal) headphones and assistive hearing devices. Assistive hearing devices are designed and configured to compensate for a user-specific hearing impairment.

[0035] The invention is described below, without limiting the generality, using a hearing aid as an example.

[0036] In close proximity to such a hearing aid, the necessary sensor data—both brain activity and blood flow data—can be readily obtained. Another crucial advantage of a hearing aid, especially a hearing assistance device, is that it is worn almost continuously and for extended periods, making it ideally suited for long-term monitoring. "Long-term" in this context refers to a period of at least several weeks, preferably several months, and ideally several years.

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[0038] Such long-term monitoring can therefore be achieved simply using a hearing aid. A particular advantage here is that changes in the user's condition compared to previous periods can be easily tracked by creating user-specific reference data and comparing it with subsequently recorded sensor data and current characteristics.

[0039] The warning signal is, for example, a visual or audible message that is output directly to the user. This involves, for instance, accessing the functions of the hearing aid and using a corresponding output unit for an audible warning.

[0040] Alternatively, the warning signal can also be transmitted to another device, such as a smartphone, which is also paired with the hearing aid. This device then saves the warning signal for later analysis and / or outputs it audibly or visually. Finally, the warning signal can also be transmitted to another device, particularly a computer, for example via the internet.

[0041] Such a hearing aid therefore forms a platform for health monitoring, specifically for monitoring bodily functions, namely the neurovascular coupling of the hearing aid user. This allows, for example, the derivation and creation of a health index for the user's brain.

[0042] Preferably, to determine the sensor data, several individual measurements are taken of at least one of the two sensors, and in particular of both sensors. The average value is then calculated from these individual measurements and used as the sensor data. This increases the measurement accuracy and suppresses interfering effects such as noise or short-term blood flow variations relative to the signal. Such short-term blood flow variations can

[0043] (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg Page 7, for example, are in the range of a few percent, typically 1-8% and usually less than 10%. The mean value is calculated, in particular, from at least 5, preferably at least 10, and further preferably at least 30 individual measurements, which are taken within a measurement period of, for example, a maximum of one second.

[0044] Preferably, sensor data is recorded over a certain period, and a trend profile of the sensor data is created, which is then used for further analysis. Therefore, not only individual (measured) values ​​are considered, but also the temporal progression of a large number of individual measurements.

[0045] In particular, relative signal changes from the sensors with respect to an initial value are determined and used for evaluation. Alternatively or additionally, the shape of the profile is evaluated, and relevant parameters such as gradient and duration of ascent / decline are extracted. Diagnostically relevant information can be obtained from this.

[0046] Preferably, the respective trend profile is analyzed using pattern recognition. The trend profile is then compared with a previously obtained reference profile. Specifically, the trend profiles are classified, for example, using AI / neural networks.

[0047] In a preferred configuration, the reference parameters are generated by averaging multiple stored sensor data sets and / or multiple stored characteristic data sets. This process establishes a baseline or base reference, which serves as the basis for subsequent comparisons. The reference parameters are derived from sensor data / characteristic data acquired at different times, for example, over several days, weeks, or months. Specifically, data pairs acquired at different times, consisting of brain activity data and corresponding blood flow data, are used for averaging.

[0048] (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg Page 8. In the simplest case, an average value is calculated from the characteristic values ​​for the time delay as a reference characteristic value.

[0049] Over time, for example, several such reference indicators of different ages are created, thus covering different time periods. This also allows for the determination of a temporal development of the reference indicators.

[0050] In a preferred embodiment, a so-called bioimpedance sensor is used as the blood sensor. This sensor has several electrodes, typically four. These electrodes are attached to suitable positions on the user's head, particularly in the immediate vicinity of the hearing aid. Such bioimpedance sensors are generally known. For example, such a bioimpedance measurement is described in:

[0051] “An Accurate Bioimpedance Measurement System for Blood Pressure Monitoring”, Toan Huu Huynh, Roozbeh Jafari, Wan-Young Chung, published in Sensors 2018, 18 7), 2095 (https: / / doi.Org / 10.3390 / s18072095).

[0052] This is made possible by such a bioimpedance sensor, especially when it is placed in the ear area, and specifically behind the ear. This is because the internal carotid artery, which supplies approximately 90% of the brain's blood, runs in close proximity to this position.

[0053] The procedures for measuring blood flow are also known as rheoencephalography (REG) or electrical impedance plethysmography (IPG) and represent standard procedures.

[0054] Bioimpedance sensors generally perform an impedance measurement (bioelectrical impedance analysis). For this, an alternating current is introduced into the body through two electrodes. The voltage is then measured at two other electrodes. This measurement principle is fundamentally well-established.

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[0056] For recording brain activity data, an EEG sensor is typically used, which usually has several, especially two, electrodes. The use, function, and construction of such EEG sensors, as well as the evaluation of this data, are widely known. These electrodes are also placed in close proximity to the ear during use.

[0057] A particular advantage lies in the fact that the temporal lobes of the brain, which are responsible for the language center, among other things, are located in close proximity to the ear. Increased brain activity resulting from speaking and / or listening can therefore be directly detected by this EEG sensor.

[0058] In a preferred embodiment, the EEG sensor and the bioimpedance sensor share electrodes; that is, at least two of the electrodes used for the EEG sensor are also used for the bioimpedance sensor. This reduces the complexity and the number of electrodes required.

[0059] In a preferred embodiment, a blood flow sensor, and in particular a so-called PPG sensor (photoplethysmogram sensor), is used as the blood sensor. These sensors are optical sensors (IR sensors) that can be used, for example, to detect changes in blood flow volume for pulse measurement. Such PPG sensors are known and are already used in some hearing aids, for example, to determine the oxygen content in the blood (pulse oximeter). They are also used in smartwatches.

[0060] Such a PPG sensor measures, in particular, the blood flow in the external carotid artery (ECA). The blood flow through the external carotid artery allows conclusions to be drawn about the blood flow through the internal carotid artery, which is ultimately crucial for supplying brain regions with increased brain activity and is therefore of interest for determining the correlation. This is because the

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[0062] Total blood flow is divided between the internal and external carotid arteries. This means that a decrease in blood flow in the external carotid artery correlates with an increase in blood flow in the internal carotid artery, suggesting increased blood supply to the brain.

[0063] The PPG sensor therefore allows at least an indirect measurement of blood flow to the brain.

[0064] The PPG sensor is used, for example, as an alternative to the bioimpedance sensor or in addition to it.

[0065] The PPG sensor is integrated directly into the hearing aid in the preferred design. Therefore, it does not need to be attached separately in the ear area.

[0066] In a preferred embodiment, at least one of the sensors selected from a blood flow sensor and / or a brain activity sensor is integrated into the hearing aid. They are therefore installed inside the housing or in the housing shell, or at least attached to the outside of the hearing aid's housing shell. For example, the EEG sensor and / or the bioimpedance sensor are also integrated into the hearing aid. The electrodes of the EEG sensor and / or the bioimpedance sensor are attached to the outside of the housing and are specifically and securely connected to it.

[0067] Due to the direct placement of the hearing aid in the area of ​​the ear (e.g. around the ear or in the ear) and especially behind the ear, regular skin contact is achieved, so that the electrodes make sufficient contact with the skin and the measurements can be carried out.

[0068] As an alternative to this integrated design, the electrodes are arranged outside the hearing aid and connected to the signal processing unit, for example via electrode wires or wirelessly, to transmit the sensor data.

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[0070] In its functional design, the hearing aid includes a microphone that serves as a brain activity sensor. The microphone transmits a signal to the signal processing unit, which in turn generates a brain activity signal and transmits brain activity data that is then evaluated by the signal processing unit.

[0071] This is based on the idea that conscious, active listening (listening) or speaking stimulates the language center and thereby increases brain activity. Such speaking or listening to acoustic signals is detected via the microphone. The signal processing unit is designed to recognize whether the user is speaking or receiving auditory signals.

[0072] Based on this data, conclusions can therefore be drawn about increased brain activity. Since such a microphone is a standard component, especially in hearing aids but also frequently in regular hearing aids such as headsets, this simply utilizes an existing hardware component of the hearing aid.

[0073] In practical applications, the microphone is preferably used (only) as a supplement to an EEG sensor. The microphone signal is then preferably used for verification and comparison with the EEG signal. The signal processing unit is therefore configured to compare and, in particular, verify the brain activity signal transmitted by the EEG sensor with the microphone signal. This improves the accuracy in determining increased brain activity.

[0074] Specifically, situations that activate the language center are deliberately used and exploited for monitoring and determining key data. In general, only situations that lead to increased brain activity in the language center (temporal lobe) are preferred.

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[0076] In the preferred configuration, users are not presented with any active stimuli. Therefore, no artificially generated stimuli are offered to induce increased brain activity. Rather, the system and procedure described here are used solely and exclusively in normal everyday life and situations where the brain is stimulated by natural, everyday occurrences. Specifically, no explicit medical examination is conducted in which the user is presented with active stimuli to generate increased brain activity, for example, by playing audio samples, assigning specific tasks, etc. Thus, active stimulation followed by measurement of the expected increased blood flow is not performed in a laboratory or treatment room.

[0077] The present invention is based precisely on the fact that the monitoring is carried out continuously and constantly in the user's normal everyday life.

[0078] In its preferred configuration, the hearing aid is—as already mentioned—a hearing aid device. Specifically, a so-called BTE (Behind the Ear) hearing aid device is used, in which the main part of the hearing aid is worn behind the ear. This main part typically integrates the signal processing unit and the memory. When a PPG sensor is used, it is integrated into this main part, specifically into the outer shell, so that optical measurement can be performed.

[0079] Such a hearing aid is generally designed to compensate for the user's hearing impairment. An input signal, for example, an acoustic input signal received by the microphone, which is converted into an electronic and, in particular, digital input signal, is processed appropriately, especially by the signal processing unit, according to the user's specific hearing impairment, so that the user's specific hearing impairment is compensated for. Subsequently, a correspondingly processed electronic and, in particular, digital output signal is output, which

[0080] (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg Page 13 for example, is transmitted to an electroacoustic output converter (receiver / speaker), via which the acoustic signal is then output to the user.

[0081] An embodiment of the invention is explained in more detail below with reference to the figures. These show simplified illustrations of:

[0082] FIG 1 a block diagram of a system for detecting neurovascular coupling dysfunction in a user using a hearing aid, FIG 2 a flowchart to explain the procedure for detecting neurovascular coupling dysfunction.

[0083] A system 1, shown in FIG. 1, for detecting functional impairments of a user's neurovascular coupling comprises a hearing aid 2. This hearing aid has a housing 3 in which a microphone 4 is integrated. The microphone 4 receives acoustic signals and converts them, for example, into an analog input signal. This input signal is then converted, for example, via an A / D converter 6 into a split input signal, which is transmitted to a digital signal processing unit 8. During normal operation of the hearing aid, the digital input signal is processed in the digital signal processing unit according to the user's specific hearing impairment in a manner known per se, and a digital output signal is generated. This digital output signal is preferably converted into an analog output signal by a D / A converter and forwarded to a receiver 10 (loudspeaker) designed as an electroacoustic output converter.

[0084] Preferably, the hearing aid 2 is a behind-the-ear hearing aid. In this type, the sound is typically channeled into a sound tube 12, at the end of which, for example, an earmold is attached and inserted into the ear canal. There are also variants in which the receiver 10 is inserted directly into the ear canal. In this case, it is connected to a main part of the hearing aid 2, which is formed in particular by the housing 3 with the components arranged therein (except for the receiver 10).

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[0086] The hearing aid also features a processor 14 as part of the digital signal processing unit 8, which is designed to perform the signal processing processes.

[0087] In addition, the hearing aid 2 also has an integrated memory 16.

[0088] Furthermore, the system has two additional sensors: a blood flow sensor 18 and an EEG sensor 20. In the exemplary embodiment, these are arranged outside the housing 3 of the hearing aid 2 and are connected to the signal processing unit 8, in particular by wiring.

[0089] The flow sensor 18 is in particular a bioimpedance sensor with typically a total of four electrodes.

[0090] The EEG sensor 20, for example, has two electrodes. Preferably, these two electrons of the EEG sensor 20 are also used simultaneously for the bioimpedance sensor 18, so that they are used together.

[0091] Alternatively, or – as shown – additionally, another blood sensor is arranged, which is designed as a so-called PPG sensor 22. This is integrated directly into the housing of the hearing aid device 2.

[0092] The EEG sensor 20 and the bioimpedance sensor 18 can also be integrated into the hearing aid 2 according to an alternative variant not shown here. For this purpose, the electrodes are, for example, permanently attached to the outside of the housing 3.

[0093] During operation, brain activity data A is transmitted from the EEG sensor 20 and blood flow data B from the blood sensors 18, 22 to the signal processing unit 8 and evaluated there.

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[0095] This evaluation uses brain activity data A to determine whether there is an increase in brain activity and therefore elevated brain activity.

[0096] Preferably, the brain activity data A from the EEG sensor 20 is compared and, in particular, verified against a microphone signal M provided by the microphone 4. For example, only those brain activity data A are used for evaluation where, simultaneously, the microphone signal M indicates the presence of a speech signal, either from the user themselves (own voice detection) or from a conversation partner of the user.

[0097] If such an increase in brain activity is detected, the simultaneously recorded blood flow data B(bio), B(PPG) from at least one of the two blood flow sensors 18, 22 are checked to determine whether an increased blood flow is present. The individual sensors 18, 20, 22 have the same time base, so that the temporal correlation between the increase in brain activity and the increase in blood flow can be determined. This time delay constitutes a parameter K for the correlation between increased brain activity and a resulting increase in blood flow.

[0098] Preferably, a large number of such characteristic values ​​K are determined over time and stored in memory 16 as characteristic data.

[0099] Within a long-term observation period Z of at least several days and especially several weeks, reference parameters and in particular a reference parameter RK are determined and stored from the parameters K, for example by averaging.

[0100] The resulting reference parameters serve as a basis for comparison for later, especially currently determined, instantaneous parameters (instantaneous parameters Km).

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[0102] These values ​​are compared with the reference parameters in a comparison step. If an impermissible deviation occurs, a warning signal W is issued, as previously explained.

[0103] Specifically, the key indicator used here is a time delay between the detection of increased brain activity and a resulting increase in blood flow, particularly via the internal carotid artery (ICA).

[0104] The reference value RK establishes a baseline for the delay time, which, for example, lies between 2 and 5 seconds for healthy individuals. If, for instance, an increase in this delay is detected that exceeds a predefined tolerance threshold, the warning signal W is triggered.

[0105] Increased brain activity is automatically detected if it rises by a predefined value. Similarly, increased blood flow is detected if it increases by a predefined percentage.

[0106] In addition to the time delay, a degree of increased brain activity and / or a degree of increased blood supply, etc., are also recorded as further parameters in a preferred configuration.

[0107] The following describes, based on FIG 2, the process and procedure for detecting dysfunctions of neurovascular coupling in the user of hearing aid 2:

[0108] A time axis is plotted vertically on the left side of the image. During the long-term observation period Z, which extends over at least several days, preferably several weeks or even several months, measurements are taken at repeated time points (e.g.,

[0109] (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg Page 17 (at least one day apart) each captures a signal pair from the brain activity data A1.. An and blood flow data B1.. Bn.

[0110] Based on brain activity data A1..., it is determined whether increased brain activity is present. This means that, for example, an increase in brain activity by a predefined threshold is recorded, and exceeding this threshold, which might be a 20 percent increase, is interpreted as the presence of increased brain activity. Ideally, brain activity is monitored continuously so that an increase from a previous value can be determined.

[0111] If such increased brain activity is detected, the monitoring and evaluation of blood flow data B is preferably triggered, and a time interval (delay) is measured until increased blood flow is detected. Here, too, increased blood flow is defined as an increase in blood flow (derived from the blood flow data B) by a predefined threshold (for example, a 20% increase). The point at which this predefined threshold is exceeded defines the end time of the delay. The total delay is thus measured, for example, between the exceedance of the threshold for brain activity and the exceedance of the threshold for blood flow. This delay constitutes the characteristic value K1 .. Kn for each signal pair.

[0112] The brain activity data A and the blood flow data B are preferably determined from several individual measurements, for example, at least 5, at least 10, or at least 50 individual measurements. These are performed within a short measurement period of, for example, a maximum of one second.

[0113] The reference characteristic value RK is specifically formed by averaging the sensor data A, B, and especially the characteristic values ​​K determined therefrom, which were recorded during the observation period Z.

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[0115] Over time, a type of monitoring is then carried out, with repeated instantaneous measurements being taken. Each instantaneous signal pair, i.e., instantaneous brain activity data (Am) and instantaneous blood flow data (Bm), is recorded. From these, a corresponding instantaneous value (Km) is determined for the instantaneous delay between increased brain activity and increased blood flow.

[0116] In a comparison step, this current characteristic value Km is compared with the reference characteristic value RK.

[0117] If the current characteristic value Km deviates from this reference characteristic value RK by a predetermined threshold, for example by 20%, this is recognized as an impermissible deviation and the described warning signal W is issued.

[0118] This monitoring is carried out continuously. For this purpose, the current sensor data A, B are recorded continuously or at specific intervals, for example after a certain number of days / weeks / months, and a current characteristic value K is determined and compared with the reference characteristic value RK.

[0119] The system and procedure described here enables simple, continuous monitoring with comparatively little effort, thus allowing for particularly effective monitoring with regard to a dysfunction of the user's neurovascular coupling.

[0120] The use of hearing aid 2, which the user wears long-term anyway, supports this monitoring in a particularly advantageous way. The placement of the hearing aid behind the ear is also especially beneficial, as it allows for the easy detection of both the increased brain activity of the temporal lobes and the blood flow through the internal carotid artery, the brain's main blood supply.

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[0122] Specifically, so-called BTE (Behind The Ear) hearing aids are particularly well-suited as measurement platforms for both blood flow and brain activity. This is because the hearing aid 2, placed behind the ear, is ideally positioned above the internal carotid artery, which supplies approximately 90% of the brain's blood supply. Furthermore, such a hearing aid 2 is located in close proximity to the temporal lobes, allowing for particularly good recording of speech-related brain activity. This, especially in conjunction with an analysis of the microphone signal M, enables a reliable correlation between the brain activity data A measured by the EEG sensor 20 and increased brain activity resulting from stimulation of the speech center. Specifically, these brain activity data A from the EEG sensor 20 can be verified using the microphone signals.

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[0124] Reference symbol list

[0125] 1 system

[0126] 2 Hearing aid

[0127] 3 cases

[0128] 4 microphones

[0129] 6 A / D converters

[0130] 8 Signal processing unit

[0131] 10 receivers

[0132] 12 sound tubes

[0133] 14 processor

[0134] 16 storage

[0135] 18 Blood flow sensor

[0136] 20 EEG sensors

[0137] 22 PPG sensor

[0138] M microphone signal

[0139] A brain activity data

[0140] B Blood flow data

[0141] K characteristic value

[0142] Z Observation period

[0143] K characteristic value

[0144] Current mileage reading

[0145] RK Reference Value

[0146] W Warning signal

[0147] (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024

Claims

FDST Patent Attorneys, Nuremberg, page 21 Claims 1. System (1) for detecting dysfunctions of the neurovascular coupling of a user of a head-worn or implantable device, in particular a hearing aid (2), with - a device, in particular a hearing aid (2) in which a signal processing unit (8) and a memory (16) are integrated, - at least two sensors (18, 20, 22), namely with - a sensor (20) for recording brain activity, - a blood sensor (18, 22) for detecting blood conditions in the brain, wherein - which are connected to at least two sensors (4, 18, 20, 22) with the signal processing unit (8) for the transmission of sensor data (A, B), namely brain activity data (A) and blood flow data (B), - the signal processing unit (8) is configured to process the sensor data (A, B) such that: o characteristic data, in particular a characteristic value (K) for a correlation between increased brain activity and the resulting increased blood flow, is determined; o the sensor data (A, B) and / or the characteristic data are stored in the memory (16); o reference characteristic data and in particular a reference characteristic value (RK) are generated from sensor data (A, B) or the determined characteristic data obtained in a long-term observation period (Z); o instantaneous characteristic data are determined from subsequently acquired sensor data (A, B); o the instantaneous characteristic data are compared with the reference characteristic data; and o a warning signal (W) is issued in the event of an impermissible deviation between the instantaneous characteristic data and the reference characteristic data. (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg, page 22 2. System (1) according to the preceding claim, wherein the characteristic value (K) is a time delay between the increased brain activity and the resulting increased blood flow.

3. System (1) according to one of the preceding claims, wherein several individual measurements are carried out to determine the sensor data (A, B) and an average value is formed.

4. System (1 according to one of the preceding claims, wherein the sensor data (A,B) are recorded over a period of time and a trend profile of the sensor data is determined.

5. System (1) according to one of the two preceding claims, wherein the reference characteristics are formed by averaging.

6. System (1) according to any of the preceding claims, wherein a bioimpedance sensor is used as the blood sensor (18).

7. System (1) according to the preceding claim, wherein the bioimpedance sensor (18) has several, in particular four, electrodes.

8. System (1) according to one of the preceding claims, wherein an EEG sensor is used as the brain activity sensor (20), which has several, in particular two, electrodes.

9. System (1) according to claims 5 and 6, wherein the bioimpedance sensor (18) and the EEG sensor (20) share electrodes 10. System (1) according to any of the preceding claims, wherein a PPG sensor (22) is used as the blood sensor.

11. System (1) according to one of the preceding claims, wherein at least one of the sensors (4, 18, 20, 22) and preferably all sensors (4, 18, 20, 22) are integrated into the device, in particular hearing aid (2). (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg, page 23 12. System (1) according to one of the preceding claims, wherein the hearing aid (2) has a microphone (4) and this is used as a sensor (4) for detecting brain activity, wherein a microphone signal (M) is transmitted as a brain activity signal (A) to the signal processing unit (8).

13. System (1) according to one of the preceding claims and according to claim 8, wherein the device, in particular the hearing aid (2), has a microphone (4) and wherein the signal processing unit (8) is configured to compare a signal from the EEG sensor with a microphone signal (M), in particular to verify it.

14. System (1) according to any of the preceding claims, wherein no active stimuli are presented to the user.

15. System (1) according to one of the preceding claims, wherein the device is a hearing aid (2), namely a hearing aid device, in particular a BTE hearing aid device.

16. Method for detecting dysfunctions of the neurovascular coupling of a user of a head-worn or implantable device, in particular a hearing aid (2), in which - the device, in particular a hearing aid (2), is used, in which a signal processing unit (8) and a memory (16) are integrated, - two sensors are used, namely - a sensor for recording brain activity - a blood sensor to detect blood flow in the brain, whereby - the two sensors transmit sensor data (A, B) to the signal processing unit (8), namely brain activity data (A) and blood flow data (B), - the signal processing unit (8) processes the sensor data (A, B), whereby (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024 FDST Patent Attorneys, Nuremberg Page 24 o characteristic data, in particular a characteristic value (K) for a correlation between increased brain activity and a resulting increased blood flow, is determined, o the sensor data (A, B) and / or the characteristic data are stored in memory (16), o reference characteristic data and in particular a reference characteristic value (RK) are formed from sensor data (A, B) or the determined characteristic data obtained in a long-term observation period (Z), o instantaneous characteristic data are determined from subsequently recorded sensor data (A, B), o the instantaneous characteristic data are compared with the reference characteristic data, and o in the event of an impermissible deviation between the instantaneous characteristic data and the reference characteristic data, a warning signal (W) is issued. (\\fs2012\gsi-software\winpat5\document\amt\3962418 docx) Last saved: August 12, 2024

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