In-ear multi-mode sensing system for continuously monitoring brain activity and sweat lactic acid

Abstract

The utility model discloses an in-ear multi-mode sensing system for continuously monitoring brain activity and sweat lactic acid. The in-ear multi-mode sensing system comprises an earphone body, a substrate, a wire, an insulating layer, an electrophysiological sensor, an electrochemical sensor and a circuit board, the substrate is bonded with the earphone body, and a plurality of wires are arranged on the substrate; the insulating layer is arranged on the upper side of the wire, one end of the wire is connected with an electrical interface, and the other end of the wire is respectively connected with corresponding electrodes of the electrophysiological sensor and the electrochemical sensor; the electrochemical sensor is covered with sweat collecting hydrogel, and the circuit board is covered on the wire. The earphone sensor for continuously monitoring brain activity and sweat lactic acid provided by the utility model has a smaller appearance size, reduces interference to daily activities of a user, integrates a multi-mode sensor, can monitor an electroencephalogram state and dynamic sweat lactic acid metabolism at the same time, and ensures efficient and accurate data collection.

Description

Technical Field

[0001] The utility model relates to the field of integrated earphone sensing monitoring, and particularly relates to an in-ear multimodal sensing system for continuously monitoring brain activities and sweat lactic acid. Background Art

[0002] Electroencephalogram (EEG) can be regarded as a time-series signal of brain activities. Different electroencephalogram microstates can exactly correspond to different functional network characteristics of the brain, and the abnormal activation or damage of the brain functional network is an important manifestation of many mental and psychological problems. Lactic acid is an important metabolite in sweat and a biomarker of stress ischemia, which can be used to track the exercise state of the human body. Medical research shows that changes in some daily cognitive states, such as stress and emotion, and neurodegenerative diseases, such as epilepsy and Alzheimer's disease, can trigger characteristic patterns of electrophysiological brain state monitoring and produce abnormal metabolic characteristics in individuals. The two can assist each other to achieve various purposes such as early disease detection, health monitoring, improvement of physical performance, neuromodulation, and rehabilitation. Due to their large form factors, traditional integrated electroencephalogram and metabolic monitoring devices usually need to cover a large part of the body, such as headbands or head-mounted devices, which are not convenient for daily and mobile monitoring and are difficult to meet the requirements of comfort and mobility.

[0003] At present, the sweat lactic acid monitoring system is an enzyme-free lactic acid electrochemical sensor: The advantages of this kind of sensor are that the preparation method and integration process are relatively simple and the cost is relatively low. However, harmful intermediate products may be generated during the process of the electrocatalyst generating current, which affects the safe use; and it lacks selectivity for metabolites and may respond to other metabolites in sweat, such as glucose. There are implantable electroencephalogram monitoring devices: Electrodes need to be implanted into the cerebral cortex of the human body. Generally, the electroencephalogram signals obtained in this form have good resolution in time and space, rich information, and can be used for operations with high precision requirements. However, the implementation difficulty is large and there are many safety problems in implanting electrodes into the cerebral cortex. Content of the Utility Model

[0004] Purpose of the utility model: The utility model provides an in-ear multimodal sensing system for continuously monitoring brain activities and sweat lactic acid, which can monitor in multiple modalities to provide more comprehensive health data and reduce the interference with the daily activities of users.

[0005] Technical solution: An in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactic acid according to the present utility model includes an in-ear headphone body, a base, a wire, an insulating layer, an electrophysiological sensor, an electrochemical sensor, and a circuit board; the base is bonded to the in-ear headphone body, and a plurality of wires are provided on the base; the insulating layer is provided above the wire, one end of the wire is connected to an electrical interface, and the other end is respectively connected to corresponding electrodes of the electrophysiological sensor and the electrochemical sensor; a sweat collecting hydrogel is covered on the electrochemical sensor, and the circuit board is covered on the wire.

[0006] Preferably, the electrical interface is located on the circuit board.

[0007] Preferably, the electrophysiological sensor includes electrophysiological electrodes, a first pair of electrodes, and a first reference electrode; the electrochemical sensor includes electrochemical electrodes, a second pair of electrodes, and a second reference electrode.

[0008] Preferably, the base is bonded to the in-ear headphone body through an adhesive.

[0009] Preferably, a plurality of openings are provided on the insulating layer, and the plurality of wires are connected to the corresponding electrodes through the openings.

[0010] Preferably, the base is polyurethane, polyimide, or polydimethylsiloxane.

[0011] Preferably, the insulating layer is a styrene-ethylene-butylene-styrene block copolymer.

[0012] Preferably, the electrochemical electrodes and the second pair of electrodes in the electrochemical sensor are Prussian blue electrodes, and the second reference electrode is a silver electrode; the electrophysiological sensors are all silver electrodes.

[0013] Preferably, the sweat collecting hydrogel is a polyvinyl alcohol hydrogel, an alginate hydrogel, or a carboxymethyl cellulose hydrogel.

[0014] Beneficial effects: The significant improvements of the present utility model compared with the prior art: 1. Comfort and form factor: The monitoring system adopts a fully in-ear integrated design, having a small form factor. This makes the device less noticeable and more comfortable to wear, reducing the interference with the user's daily activities compared with traditional scalp electroencephalogram monitoring devices or other sweat lactic acid meters.

[0015] 2. Multimodal integration: The electrochemical sensor is used for lactic acid monitoring and is placed in the tragus area where sweat secretion is more in the ear canal. The electrophysiological sensor is used for electroencephalogram monitoring and is placed in an area close to the temporal lobe where sweat secretion is less and signal interference is smaller. Description of the drawings

[0016] Figure 1 Schematic diagram of the sensor hierarchical structure of the present utility model;

[0017] Figure 2 Schematic diagram of the position of the electrophysiological sensor;

[0018] Figure 3 Schematic diagram of the position of the electrochemical sensor;

[0019] Figure 4 Schematic diagram after the assembly of the present utility model. Specific implementation manners

[0020] According to the appended Figures 1-4 The embodiments of the present utility model are further described.

[0021] The present utility model is an in-ear multimodal sensing system for continuously monitoring brain activities and sweat lactic acid, which is integrated on an earphone for health monitoring. Two sensors are integrated on a substrate 3 and a circuit board 9 and are connected to an electrical interface 4 by wires 4. It includes an in-ear earphone body 1, an adhesive 2, a substrate 3, wires 4, an insulating layer 5, an electrophysiological sensor 6, an electrochemical sensor 7, a circuit board 9, and an electrical interface 10; the substrate 3 is fixed on the in-ear earphone body 1 by the adhesive 2, and a plurality of wires 4 are provided on the substrate 3; an insulating layer is provided on the upper side of the wires 4, one ends of the plurality of wires 4 are all connected to the electrical interface 10, and the other ends of the wires 4 are respectively connected to a plurality of electrodes of the electrophysiological sensor 6 and the electrochemical sensor 7; a sweat collecting hydrogel 8 is covered on the electrochemical sensor 7, and the circuit board 9 is covered on the wires 4. An electrical interface 10 is provided on the circuit board 9. The electrophysiological sensor 6 includes an electrophysiological electrode 61, a first pair of electrodes 62, and a first reference electrode 63; the electrochemical sensor 7 includes an electrochemical electrode 71, a second pair of electrodes 72, and a second reference electrode 73.

[0022] The electrophysiological sensor 6 is used for electroencephalogram monitoring, including an electrophysiological electrode 61, i.e., a working electrode, a first pair of electrodes 62, and a first reference electrode 63. The three assist each other to complete the electroencephalogram monitoring work. The electrophysiological electrode is used to detect electrophysiological signals and is usually made of improved stretchable silver ink. The first reference electrode 63 provides a stable reference potential for comparing signal measurements. The first pair of electrodes 62 is used to suppress common-mode interference and improve signal quality. The electrical signals detected by each electrophysiological electrode 61 are transmitted to a data acquisition system through connecting wires and are measured relative to the first reference electrode 63. The first pair of electrodes 62 is used to detect common-mode signals and generate inverted signals, which are fed back to the ear to suppress external common-mode interference, such as power line noise.

[0023] The electrochemistry sensor 7 is used for the dynamic monitoring of sweat lactic acid, and includes an electrochemistry electrode 71, namely a working electrode, a second pair of electrodes 72, and a second reference electrode 73. The three assist each other to complete the work of dynamic monitoring of sweat lactic acid. The electrochemistry electrode 71 is modified with lactate oxidase and is responsible for detecting lactic acid in sweat. The second pair of electrodes 72 is used to complete the electrochemical reaction. The second reference electrode 73 is made of a modified stretchable silver ink and is used to provide a stable potential reference. These electrode materials are covered with a layer of polyvinyl alcohol hydrogel to enhance sweat collection. Sweat is secreted by eccrine sweat glands in the ear canal and is absorbed by the polyvinyl alcohol hydrogel. The lactate oxidase-modified working electrode undergoes an enzymatic reaction with lactic acid in sweat, oxidizing lactic acid into pyruvic acid and hydrogen peroxide. Hydrogen peroxide is reduced on the surface of the Prussian blue-modified working electrode to generate hydroxide ions, and the generated current is proportional to the lactic acid concentration. The generated current is detected by an electrochemical method (chronoamperometry), thereby quantifying the lactic acid concentration in sweat.

[0024] The adhesive 2 fixes the sensor on the earphone, ensuring stable contact between the sensor and the skin. The substrate 3 has chemical resistance and ductility, enabling the sensor to remain stable under mechanical loads. Polyurethane, polyimide, or polydimethylsiloxane can be selected. The wire 4 is the conduction path for the electrophysiological sensor 6 and the electrochemistry sensor 7, ensuring electrical conductivity and ductility. A conductive polymer can be selected, and silver is preferably used. An insulating layer covers the top of the connecting wire, providing electrical insulation and flexibility. A styrene-ethylene-butylene-styrene (SEBS) block copolymer can be selected.

[0025] The electrophysiological sensor 6 includes an electrophysiological electrode 61 for detecting electrophysiological signals, a first reference electrode 63 providing a stable reference potential for comparing signal measurements, and a first pair of electrodes 62 for suppressing common-mode interference and improving signal quality. Silver electrodes can be used.

[0026] The electrochemistry sensor 7 includes an electrochemistry electrode 71 responsible for detecting lactic acid in sweat. The second pair of electrodes 72 is used to complete the electrochemical reaction, and the second reference electrode 73 is used to provide a stable potential reference. The electrochemistry electrode 71 and the second pair of electrodes 72 are made of Prussian blue, the second reference electrode 73 uses silver, and the electrochemistry electrode 71 is modified with lactate oxidase. Both silver and Prussian blue have a certain degree of flexibility and ductility, can adapt to the complex shape of the ear, and ensure normal operation during movement.

[0027] The sweat collection hydrogel 8 covers the electrochemistry biosensor 7, enhancing sweat collection and sensing performance, and transmitting the collected sweat secreted from the tragus area to the electrochemistry sensor 7. Polyvinyl alcohol hydrogel, alginate hydrogel, carboxymethyl cellulose hydrogel, etc. can be used. The hydrogel needs to have good water absorption, biocompatibility, and mechanical properties with a certain strength. The circuit board 9 also includes an electrical interface 10. The circuit board 9 is used to connect the electronic components of each part of the sensor to achieve data acquisition and transmission. Flexible printed circuit boards can be prepared using polyimide-protected copper. The protective layer can be replaced with polyethylene terephthalate, and the copper can also be replaced with silver. These materials can meet the requirements of high flexibility, high reliability, and biocompatibility.

[0028] The sensor is prepared by the method of layer-by-layer screen printing. The flexible substrate material is cut into a sheet substrate suitable for the shape of the inner ear canal through photolithography or laser cutting technology. Conductive silver ink is used to print a conductive pattern on the flexible substrate, and through heat treatment or light curing, the silver ink is cured and made conductive on the substrate. The stretchable insulating layer and the stretchable Prussian blue electrochemical electrode are continuously printed and cured in sequence. A 3D stretchable silver electrophysiological electrode is manufactured using a 3D printed thick and tough polylactic acid mold. Then, the sensor is connected to the flexible printed circuit board using silver liquid solder for electrical connection. The sensor and the flexible printed circuit board are then assembled onto a general-purpose in-ear headphone.

[0029] The beneficial effects of the present utility model compared with the prior art:

[0030] 1. Comfort and form factor: The monitoring system adopts a fully in-ear integrated design with a small form factor. This makes the device less noticeable and more comfortable to wear, reducing interference with the user's daily activities compared to traditional scalp electroencephalogram monitoring devices or other sweat lactometers.

[0031] 2. Multimodal integration: The electrochemistry sensor for lactate monitoring is placed in the tragus area where sweat secretion is relatively high in the ear canal. The electrophysiological sensor for electroencephalogram monitoring is placed in the area close to the temporal lobe where sweat secretion is less and signal interference is smaller. 3. Improvement of the electrode-ear interface: The 3D electrophysiological electrode design is adopted, improving the electrode-ear interface, reducing the possibility of contact loss, and increasing the effective contact area.

Claims

1. An in-ear multimodal sensing system for continuous monitoring of brain activity and sweat lactate, characterized in that: The invention comprises an in-ear earphone body (1), a base (3), a wire (4), an insulating layer (5), an electrophysiological sensor (6), an electrochemical sensor (7), and a circuit board (9); the base (3) is bonded to the in-ear earphone body (1), and a plurality of wires (4) are arranged on the base (3); the insulating layer (5) is arranged on the upper side of the wire (4); one end of the wire (4) is connected to an electrical interface (10), and the other end is respectively connected to corresponding electrodes of the electrophysiological sensor (6) and the electrochemical sensor (7); the electrochemical sensor (7) is covered with a sweat collecting hydrogel (8), and the circuit board (9) covers the wire (4).

2. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 1, characterized in that: The electrical interface (10) is located on the circuit board (9).

3. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 1, characterized in that: The electrophysiological sensor (6) comprises an electrophysiological electrode (61), a first pair of electrodes (62) and a first reference electrode (63); the electrochemical sensor (7) comprises an electrochemical electrode (71), a second pair of electrodes (72) and a second reference electrode (73).

4. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 1, characterized in that: The base (3) is bonded to the in-ear earphone body (1) via an adhesive (2).

5. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 1, characterized in that: The insulating layer (5) is provided with a plurality of openings, and the plurality of wires (4) are connected to the corresponding electrodes through the openings.

6. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 1, characterized in that: The substrate (3) is polyurethane, polyimide or polydimethylsiloxane.

7. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 1, characterized in that: The insulating layer (5) is a polystyrene-ethylene-butylene-styrene block copolymer.

8. The in-ear multimodal sensing system for continuously monitoring brain activity and sweat lactate according to claim 3, characterized in that: The electrochemical electrode (71) and the second pair of electrodes (72) in the electrochemical sensor (7) are Prussian blue electrodes, and the second reference electrode (73) is a silver electrode; the electrophysiological sensors (6) are all silver electrodes.

9. The in-ear multimodal sensing system for continuous monitoring of brain activity and sweat lactate according to claim 1, characterized in that: The sweat collecting hydrogel (8) is polyvinyl alcohol hydrogel, alginate hydrogel or carboxymethyl cellulose hydrogel.

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