Method and device for determining motion pattern of person

Abstract

According to the invention, a device is proposed for determining a movement pattern of a person, for example in rest or sleep, in which a magnetic field generated by muscles of the person is detected as a measurement signal in a contactless manner by a sensor device integrated in or arranged on a support. The support is configured to enable a person to lie on the support and may be configured, for example, as a mattress, part of a mattress, or a cover or bottom layer of a mattress. The detected measurement signal is transmitted to an evaluation unit, from which the motion pattern of the person is ascertained. According to the invention, the sensor device is designed as a magnetic field sensor device and is arranged on and / or integrated in a support on which a person rests or sleeps, in order to be able to detect a temporally and / or spatially varying magnetic field generated by a movement of the person's muscle, in particular a movement of the leg muscle, as a measurement signal.

Description

Technical Field

[0001] The invention relates to a method and a device for determining the movement pattern of a person who is resting, in particular sleeping, wherein a magnetic field generated by the person's muscles is detected contactlessly by a sensor device integrated in a support as a measurement signal, wherein the measurement signal is transmitted to an evaluation unit, wherein the evaluation unit determines the person's movement pattern from the measurement signal.

[0002] The invention further relates to a bed comprising a support, in particular a mattress, and an evaluation unit. Background Art

[0003] Sleep-related movement disorders, such as periodic limb movement disorder (PLMD) and restless legs syndrome (RLS), are characterized by abnormal movements and sensations in the lower or upper limbs that interfere with sleep. The diagnosis of these movement disorders is mainly based on an interview with the patient (medical history) and studies in the sleep laboratory, for example, Trenkwalder, C., in the Guidelines for the Diagnosis and Treatment of Neurological Disorders (2012), for restless legs syndrome (RLS) and periodic limb movement disorder. In this case, in order to detect leg movements of the two tibialis anterior muscles, an electromyogram (EMG) can be derived with the help of surface electrodes, see Frigerio, SB, & Mathis, J. (2008). Restless legs syndrome: diagnostic approach, the most important differential diagnoses should be systematically considered. Ars medici-Swiss Journal of Family Medicine, (24), 1070-1074.

[0004] In addition, capacitive EMG methods are also well known, which aim to derive electromyographic information using sensors that do not need to be permanently fastened to the skin, see, for example, Ng, C. L., Reaz, M. B. I., Crespo, M. L., Cicuttin, A., & Chowdhury, M. E. H. (2020). Characterization of capacitive electromyographic biomedical sensors insulated with porous medical bandages. Scientific Reports, 10(1), 1-12.

[0005] US 10,210,409 B1 discloses a system for contactless detection of skin potential, which is integrated in a motor vehicle. From the skin potential, it is possible to find out whether the person in the vehicle is awake or asleep. Summary of the invention

[0006] The object of the present invention is to provide a device and a method for determining the movement patterns of a person at rest, in particular during sleep, which method enables precise measurements and is easy to use without causing harm to the person. The invention provides a system for diagnosing or monitoring sleep-related movement disorders by recording the magnetic field generated by the muscles and drawing conclusions about the electrophysiological activity of the muscles. The system can be used in particular at home, for example in an armchair or in bed.

[0007] In order to achieve the object on which the invention is based, a device for determining the movement pattern of a person who is resting or sleeping is proposed, wherein a magnetic field generated by the muscles of the person is contactlessly detected as a measurement signal by a sensor device integrated in a support or arranged on the support. The support is designed so that a person can lie flat on it, for example, it can be designed as a mattress, a part of a mattress or the top or bottom layer of a mattress. The detected measurement signal is transmitted to an evaluation unit, wherein the evaluation unit ascertains the movement pattern of the person from the measurement signal. According to the invention, the sensor device is designed as a magnetic field sensor device and is integrated into a support on which the person is resting or sleeping or is arranged in the support so that it detects a temporally and / or spatially varying magnetic field caused by the muscle movements of the person, in particular the leg muscle movements, as a measurement signal.

[0008] The evaluation unit can preferably infer possible movement disorders of the person from the movement pattern. In particular, by evaluating the measurement signals and the movement pattern, medically relevant movement disorders can be reliably distinguished and diagnosed, and the progression and severity of the movement disorder can be observed, so that targeted treatment can be carried out.

[0009] The magnetic field sensor device is preferably a gradiometer having at least two magnetic field sensors arranged at positions spaced apart from one another, wherein the at least two magnetic field sensors measure the magnetic field at the spaced apart positions and generate measurement signals, wherein the movement pattern is further preferably determined with the aid of a differential signal of the measurement signals of the at least two magnetic field sensors.

[0010] The strength of the magnetic field generated by muscle movement is in the range of 100 pT. These magnetic field strengths are significantly lower than the usual magnetic field strengths in the environment. The Earth's magnetic field strength is about 50 μT. By designing the magnetic field sensor device as a gradiometer with two magnetic field sensors arranged at mutually spaced positions, interference fields from the environment can be eliminated. For this purpose, two magnetic field sensors can be used to measure the magnetic field simultaneously. Interference fields from the environment have the same field strength at two positions of the magnetic field sensors, which can be eliminated by forming a difference between the measurement signals of at least two magnetic field sensors. Only the magnetic field generated by the observed muscle remains in the differential signal.

[0011] The differential signal can be generated directly by the magnetic field sensor device. However, the differential signal can also be generated in the evaluation unit, wherein in this case the measurement signal of the magnetic field sensor is transmitted to the evaluation unit.

[0012] Preferably, the distance between the at least two magnetic field sensors is between 0.5 cm and 2 cm, more preferably between 1 cm and 1.5 cm.

[0013] Studies by the applicant have shown that biomagnetic fields, such as those generated by muscles, can be ideally measured at a distance of 0.5 cm to 2 cm.

[0014] It is further advantageous if the magnetic field sensor device has a plurality of magnetic field sensors which form a sensor array. This can advantageously increase the spatial resolution of the measurement signal and thus better determine the movement pattern.

[0015] It is further advantageous to provide a plurality of sensor devices, in particular a plurality of magnetic field sensor devices, which are arranged in different areas of the support so that measurement signals from different muscles or muscle groups of the person can be detected. Alternatively or additionally, further sensor devices can be provided for detecting other measured variables of the person, such as pressure sensors and / or temperature sensors. When determining the movement pattern and / or recognizing the clinical picture, the measured variables detected by these additional sensors can be included in order to be able to, for example, increase the reliability of the diagnosis.

[0016] Preferably, the magnetic field sensors are nitrogen vacancy sensors, wherein each nitrogen vacancy sensor preferably comprises diamond, an optical filter and a photodetector and further preferably comprises a microwave resonator and / or a light source, in particular a laser.

[0017] However, the microwave resonator and / or the light source can also be arranged at a distance from the magnetic field sensor device or the magnetic field sensor.

[0018] In principle, the magnetic field can be measured using TMR, GMR or Hall sensors, SQUID sensors or steam battery magnetometers to pinpoint the magnetocardiogram signal. However, such sensors are usually not sensitive enough. Highly sensitive superconducting SQUID sensors have sufficient accuracy, but require active cooling using liquid nitrogen or helium, making them less suitable for use in normal environments such as bedrooms. While steam battery magnetometers have the required sensitivity, their dynamic range is limited.

[0019] Therefore, the magnetic field sensor is preferably a nitrogen vacancy sensor. Nitrogen vacancy sensors are based on measuring the fluorescence spectrum of nitrogen centers in diamond. When optically excited, the spectrum of diamond containing nitrogen vacancies will show fluorescence in the red wavelength range. If microwave radiation is used at the same time as optical excitation, the fluorescence collapses at 2.88 GHz, because in this case the electrons are transferred from the 3A state to the m s = 0 level rises to 3E state m s = + / -1 level and recombine from there in a non-radiative manner. In the case of an applied magnetic field, m s The so-called Zeman splitting occurs when the fluorescence is compared with the microwave excitation frequency, and two points appear in the fluorescence spectrum, and their frequency interval is proportional to the magnetic field strength. The magnetic field sensitivity is determined by the minimum resolvable frequency shift, which can reach up to 1pT. Since the nitrogen vacancy center in a single crystal diamond has four possibilities for arrangement in the lattice, in the presence of a directional magnetic field, the nitrogen vacancy center in the crystal responds to the external magnetic field with different intensities depending on its position in the crystal. Therefore, up to four pairs of fluorescence minima can appear in the spectrum, and the size and direction of the magnetic field can be clearly determined from their shape and position.

[0020] In addition, the design and working mode of nitrogen vacancy sensors are also well known to technicians.

[0021] It is further advantageous if the evaluation unit filters the measurement signal using a high-pass and / or low-pass filter and / or if the evaluation unit ascertains a bias drift of the magnetic field sensor, in particular by averaging the measurement signal over a period of time greater than an expected time constant of the movement pattern.

[0022] By filtering with the aid of a low-pass filter, noise components with frequencies significantly higher than the heart rate are eliminated. The bias drift can also be subtracted from the high-pass filtered and / or low-pass filtered signal to obtain a clean magnetocardiogram signal.

[0023] It is also preferred that the evaluation unit recognizes a pathological movement disorder, such as periodic limb movement disorder (PLMD) or restless legs syndrome (RLS), based on the movement pattern.

[0024] Various methods can be used to determine movement disorders based on the measured signals. For example, a pattern comparison can be performed based on a predefined table with corresponding standard movement processes, wherein the standard movement processes can come from clinical diagnosis or clinical research. In addition, data-driven evaluation or interpretation can be performed with the help of statistical classification methods. In this case, decision tree methods or random forest methods can be used. Another method is to use neural networks for evaluation.

[0025] Preferably, further measures are taken depending on the evaluation, wherein the further measures may include making an emergency call and / or transmitting the movement pattern to medical personnel.

[0026] Preferably, the evaluation unit can also transmit the movement pattern and / or the clinical picture to other devices, in particular a clinical diagnostic system, a health management system or a comfort system.

[0027] For example, if a sports mode and / or clinical picture is forwarded to the comfort system, a massage function, bedroom fragrance or ambient lighting can be activated.

[0028] An assessment may be provided with a confidence value that reflects the statistical reliability of the classification result or assessment.

[0029] In an advantageous embodiment, the magnetic field sensor device or the magnetic field sensor device and the evaluation device can be arranged on the bed.

[0030] The evaluation device can advantageously be implemented in the form of a software module in a control unit or a computer. Thus, the evaluation device can be integrated into a computer, for example into a mobile device such as a smartphone or tablet or a personal computer, which is connected to the sensor device via a wireless interface via discrete lines.

[0031] A further solution to the object on which the present invention is based is to provide a bed comprising a support, such as a mattress, and an evaluation device for carrying out the above-described method.

[0032] The invention also advantageously relates to a method for determining the movement pattern of a person at rest, in particular sleeping, wherein a magnetic field generated by the muscles of the person is contactlessly detected as a measurement signal by means of a sensor device integrated in a support, wherein the measurement signal is transmitted to an evaluation unit, wherein the evaluation unit ascertains the movement pattern of the person from the measurement signal. The sensor device is designed as a magnetic field sensor device and is integrated into the support on which the person sleeps, so that a temporally and / or spatially varying magnetic field caused by the muscle movements of the person, in particular the leg muscles, can be detected as a measurement signal.

[0033] All functions, features and embodiments described above in connection with the device can also be transferred to the method in a corresponding manner.

[0034] The core of the invention is therefore a system comprising magnetic field sensors which are mounted near the muscles of a person at rest. These sensors are located in a support, such as the mattress of a bed, and record the activity of leg muscles, etc. It is also possible to record the activity of other positions (such as upper arm muscles, see Figure 22) in the above. Then, these data can be combined to analyze whether there is a sleep-related movement disorder and its severity. In addition, it is also conceivable to observe the progress over a long period of time. The present invention can also be used to detect and monitor physiological and disease-related convulsions. In addition, the detection of magnetic and electrical signals can be supplemented by monitoring (long-term) movement patterns. Magnetic field sensors and additional other sensors (such as pressure sensors) can also be used for this purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be described in more detail below with reference to the accompanying drawings.

[0036] in:

[0037] Figure 1 shows a bed with a magnetic field sensor device,

[0038] Figure 2 shows an anatomical diagram of a human leg,

[0039] Figure 3 A flow chart of the method is shown. DETAILED DESCRIPTION

[0040] A device 10 for determining movement patterns of a sleeping person is described in more detail below with reference to the accompanying drawings.

[0041] Figure 1 A bed frame 12 with a support 15 designed as a mattress is shown. Two magnetic sensor devices 14 and 14' are integrated in the support 15. The first magnetic sensor device 14 is arranged so that the measurement signal detected by the magnetic sensor device 14 represents the muscle movement of one or both legs 3 of a person 2 sleeping on the support 15 on the bed 12, wherein the magnetic field that changes in time and / or space caused by the muscle movement is detected by the magnetic sensor device 14. The second magnetic sensor device 14' is arranged so that the measurement signal detected by the magnetic sensor device 14' represents the muscle movement of one or both upper arms of the person 2 sleeping on the support 15 on the bed 12. The measurement signals generated by the magnetic sensor devices 14 and 14' are transmitted to an evaluation unit 19 via a data line 16 in a preprocessed form or as raw data. Alternatively, the measurement signals can also be transmitted wirelessly to the evaluation unit 19, for example by means of known methods such as WiFi, Bluetooth or NFC.

[0042] The evaluation unit 19 is designed to ascertain movement patterns of the sleeping person 2 from the received measurement signals of the magnetic sensor devices 14 and 14 ′, in particular to identify movement disorders and possible specific clinical pictures, such as periodic limb movement disorder (PLMD) or restless legs syndrome (RLS), by comparing the ascertained movement patterns with comparison patterns stored in the evaluation unit 19. For example, statistical data-driven methods based on machine learning methods or neural networks can be used here.

[0043] Figure 2 Schematically shown is a human leg 20 and a tibialis anterior muscle 22 , the activity of which can be detected and monitored during sleep by means of the device 10 according to the invention.

[0044] Figure 3 A method 100 according to the invention for determining a movement pattern of a sleeping person is shown in the form of a flow chart. In this case, in step 110, a magnetic field generated by specific muscles of the sleeping person is contactlessly detected as a measurement signal by means of a magnetic field sensor device integrated in a support on which the person lies. In step 120, the measurement signal is transmitted to an evaluation unit. In step 130, the evaluation unit ascertains the movement pattern of the person from the measurement signal. In step 140, the evaluation unit compares the ascertained movement pattern with a reference movement pattern in order to derive a movement disorder. In step 150, a movement disorder is identified and assigned. In step 160, further measures are initiated, such as, for example, transmitting the movement pattern to a attending physician and / or further monitoring of the person.

Claims

1. A device (10) for determining the movement pattern of a person (2) at rest, in particular sleeping, comprising at least one sensor device integrated in a support (15) or arranged on the support, the sensor device being configured to contactlessly detect a magnetic field generated by muscles (22) of the person (2) as a measurement signal, wherein: The support (15) is designed to enable the person to lie flat on it, the device further comprising an evaluation unit (19), wherein the measurement signal is transmitted to the evaluation unit (19), and wherein the evaluation unit (19) is designed to determine the movement pattern of the person (2) from the measurement signal, The invention is characterized in that the sensor device is constructed as a magnetic field sensor device (14, 14') and is arranged on the support (15) and / or integrated in the support (15) so as to be able to detect a temporally and / or spatially varying magnetic field generated by muscle movements of the person (2), in particular movements of leg muscles (22), as a measurement signal.

2. The device according to claim 1, characterized in that The magnetic field sensor device (14) is a gradiometer having at least two magnetic field sensors arranged at positions spaced apart from one another, wherein the at least two magnetic field sensors measure the magnetic field at the spaced apart positions and generate the measurement signal, wherein the measurement signal is preferably determined as a differential signal of the measurement signals of the at least two magnetic field sensors.

3. The device (10) according to claim 1 or 2, characterized in that A plurality of magnetic field sensor devices (14, 14') are provided, each of which is assigned to a specific muscle group of the person (2), and / or the magnetic field sensor devices (14, 14') are automatically positioned on the support in the vicinity of the muscles to be monitored, in particular the leg muscles (22) of the person (2).

4. The device (10) according to claim 2 or 3, characterized in that The magnetic field sensors are nitrogen vacancy sensors, wherein each nitrogen vacancy sensor preferably comprises diamond, an optical filter and a photodetector, and further preferably comprises a microwave resonator and / or a light source, in particular a laser.

5. The device (10) according to any one of the preceding claims, characterized in that The evaluation unit (19) is designed to filter the measurement signal using a high-pass and / or low-pass filter and / or to determine an offset drift of the magnetic field sensor, in particular by averaging the measurement signal over a time period that is greater than an expected movement rate of the muscle.

6. The device (10) according to any one of the preceding claims, characterized in that The evaluation unit (19) is designed to detect a clinical picture, in particular periodic limb movement disorder (PLMD) or restless legs syndrome (RLS), from the measurement signals and / or the movement patterns.

7. The device (10) according to any one of the preceding claims, characterized in that The evaluation unit (19) is designed to transmit the movement pattern and / or the clinical picture to another device.

8. The device (10) according to any one of the preceding claims, characterized in that The device (10) has a plurality of sensor devices, at least one of which is designed as a magnetic field sensor device (14, 14') and another of which is designed as a device for measuring pressure and / or temperature, wherein a measurement signal detected by the other of which is transmitted to the evaluation unit (19) and taken into account when determining the movement pattern.

9. The device (10) according to any one of the preceding claims, characterized in that At least one magnetic field sensor device (14, 14') has a plurality of magnetic sensors which are arranged in a sensor array.

10. A support (15), in particular a mattress, having at least one integrated magnetic field sensor device (14, 14'), which is designed for use in a device according to any one of claims 1 to 9.

11. A method (100) for determining a movement pattern of a person (2) at rest, in particular sleeping, wherein: A sensor device integrated in a support (15) is used to contactlessly detect a magnetic field generated by muscles (22) of the person (2) as a measurement signal, wherein the measurement signal is transmitted to an evaluation unit (19), wherein the evaluation unit (19) determines the movement pattern of the person (2) from the measurement signal, characterized in that the sensor device is designed as a magnetic field sensor device (14, 14') and is integrated in a support (15) on which the person lies, in order to detect a temporally and / or spatially varying magnetic field caused by muscle movements of the person (2), in particular movements of leg muscles (22), as a measurement signal.

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