Method and device for determining movement patterns of a person

Abstract

The invention relates to a device for determining movement patterns of an e.g. resting or sleeping person, wherein magnetic fields generated by the person's muscles are contactlessly detected as measurement signals by a sensor device integrated in or arranged on the surface. The surface is designed such that the person can lie on the surface and can be in the form of e.g. a mattress, part of a mattress, or as a topper or underlayer for a mattress. The detected measurement signals are transferred to an evaluation unit, wherein the evaluation unit determines movement patterns of the person from the measurement signals. According to the invention, the sensor device is in the form of a magnetic field sensor device and is integrated or arranged in the surface on which the person rests or sleeps in such a way that temporally and / or spatially changing magnetic fields caused by muscular movement, in particular of the leg muscles, of the person are detected in the form of measurement signals.

Description

[0001] Description

[0002] title

[0003] Method and device for determining movement patterns of a person

[0004] The present invention relates to a method and a device for determining movement patterns of a resting, in particular sleeping, person, wherein magnetic fields generated by the person's muscles are detected as measurement signals by a sensor device integrated in a support without contact, wherein the measurement signals are transmitted to an evaluation unit, wherein the evaluation unit determines movement patterns of the person from the measurement signals

[0005] Furthermore, the present invention relates to a bed comprising a support, in particular a mattress and an evaluation unit.

[0006] State of the art

[0007] Sleep-associated 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 extremities that disrupt sleep. The diagnosis of these movement disorders is based primarily on patient interviews (anamnesis) and sleep laboratory examinations, as described, for example, in Trenkwalder, C., Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder, in Guidelines for Diagnostics and Therapy in Neurology (2012). To record leg movements, an electromyogram (EMG) can be recorded from both tibialis anteriores muscles using surface electrodes; see Frigerio, SB, & Mathis, J. (2008). Restless Legs Syndrome: Approaches to Diagnosis. The most important differential diagnoses must be systematically considered. Ars medici-Swiss Journal of General Practice, (24), 1070-1074.Capacitive EMG methods are also known that aim to record EMG using sensors that do not need to be permanently attached to the skin, see, for example, Ng, C. L, Reaz, MBI, Crespo, M. L, Cicuttin, A., & Chowdhury, MEH (2020). Characterization of capacitive electromyography biomedical sensor insulated with porous medical bandages. Scientific reports, 10(1), 1 -12.

[0008] US Pat. No. 10,210,409 B1 discloses a system for contactless detection of an electrodermal potential integrated into a motor vehicle. The electrodermal potential can be used to determine whether a vehicle occupant is awake or asleep.

[0009] Disclosure of the invention

[0010] The present invention is based on the object of providing a device and a method for determining movement patterns of a resting, particularly sleeping, person, which enables precise measurements and is easy to use without impairing the person. The invention represents a system that can be used to diagnose or monitor sleep-associated movement disorders by recording the magnetic fields generated by muscles and drawing conclusions about their electrophysiological activity. It can be used particularly in the home, such as in an armchair or in bed.

[0011] To achieve the object underlying the invention, a device is proposed for determining movement patterns of, for example, a resting or sleeping person, wherein magnetic fields generated by the person's muscles are recorded as measurement signals in a contactless manner by a sensor device integrated into a support or arranged on the support. The support is designed so that the person can lie on the support and can be designed, for example, as a mattress, as part of a mattress, or as an overlay or as an underlay for a mattress. The recorded measurement signals are transmitted to an evaluation unit, wherein the evaluation unit determines the person's movement patterns from the measurement signals. According to the invention, the sensor device is designed as a magnetic field sensor device and is integrated or arranged in the support on which the person rests or sleeps.arranged in the support so that temporally and / or spatially changing magnetic fields caused by a muscle movement, in particular of the leg muscles, of the person are recorded as measurement signals.

[0012] The evaluation unit can preferably draw conclusions about the person's potential movement disorders from the movement patterns. In particular, the evaluation of the measurement signals and movement patterns enables the reliable differentiation and diagnosis of medically relevant movement disorders, as well as the observation of the progression and severity of a movement disorder, thus enabling targeted treatment.

[0013] It is preferably provided that the magnetic field sensor device is a gradiometer with at least two magnetic field sensors arranged at positions spaced apart from one another, wherein the at least two magnetic field sensors measure a magnetic field at the spaced apart positions and generate the measurement signal, wherein the movement pattern is further preferably determined by means of the difference signal of the measurement signals of the at least two magnetic field sensors.

[0014] The magnetic fields generated by a muscle movement have a strength in the range of 100 pT. These magnetic field strengths are significantly lower than typical ambient magnetic field strengths. For example, the Earth's magnetic field strength is approximately 50 pT. By designing the magnetic field sensor device as a gradiometer with two magnetic field sensors arranged at spaced-apart positions, these ambient interference fields can be eliminated. For this purpose, the magnetic field is measured simultaneously with two magnetic field sensors. The ambient interference fields, which have the same field strength at both positions of the magnetic field sensors, can be eliminated by subtracting the measurement signals from the at least two magnetic field sensors. In the difference signal, only the magnetic field generated by the muscle under consideration remains.

[0015] The differential signal can be generated directly by the magnetic field sensor device. However, it is also possible for the differential signal to be generated in the evaluation unit, in which case the measurement signals from the magnetic field sensors are transmitted to the evaluation unit.

[0016] It is preferably provided that the at least two magnetic field sensors are spaced apart from one another by 0.5 cm to 2 cm, more preferably by 1 cm to 1.5 cm.

[0017] Investigations by the applicant have shown that biomagnetic fields, such as those generated by a muscle, can be ideally measured at a distance of between 0.5 cm and 2 cm.

[0018] It can further be advantageous for the magnetic field sensor device to have a plurality of magnetic field sensors forming a sensor array. This advantageously allows for spatial resolution of the measurement signals and thus improved determination of the movement patterns.

[0019] It can further advantageously be provided that a plurality of sensor devices, in particular a plurality of magnetic field sensor devices, are provided, which are arranged in different areas of the support, so that measurement signals from different muscles or muscle groups of the person can be recorded. Alternatively or additionally, further sensor devices can be provided which record other measured variables of the person and which include, for example, pressure sensors and / or temperature sensors. The measured variables recorded by such additional sensors can be included in the determination of movement patterns and / or the detection of clinical pictures, for example to enable an improvement in the reliability of a diagnosis.

[0020] Preferably, the magnetic field sensors are nitrogen vacancy sensors, with each nitrogen vacancy sensor preferably comprising a diamond, optical filters, and photodetectors, and more preferably a microwave resonator and / or a light source, in particular a laser. However, the microwave resonator and / or the light source can also be arranged at a distance from the magnetic field sensor device or from the magnetic field sensors.

[0021] In principle, it is possible to use TMR, GMR, or Hall sensors, SQUID sensors, or vapor cell magnetometers to measure the magnetic fields used to determine the magnetic cardiogram signals. However, such sensors generally do not have sufficiently high sensitivity. Highly sensitive, superconducting SQUID sensors, while sufficiently accurate, require active cooling with liquid nitrogen or helium and are therefore less suitable for use in normal environments, such as a bedroom. Vapor cell magnetometers, while offering the required sensitivity, have a limited dynamic range.

[0022] Preferably, the magnetic field sensors are nitrogen vacancy sensors. Nitrogen vacancy sensors are based on the measurement of a fluorescence spectrum of nitrogen centers in a diamond. The spectrum of a diamond with nitrogen vacancies exhibits fluorescence in the red wavelength range upon optical excitation. If microwave radiation is applied in addition to the optical excitation, a drop in fluorescence occurs at 2.88 GHz, since the electrons in this case are s = 0 level of the 3A state to the m s = + / -1 level of the 3E state and from there recombine non-radiatively. In an external magnetic field, the m s-levels, the so-called Zeeman splitting, and when the fluorescence is plotted against the frequency of the microwave excitation, two dips are observed in the fluorescence spectrum, the frequency spacing of which is proportional to the magnetic field strength. The magnetic field sensitivity is defined by the minimum resolvable frequency shift and can reach up to 1 pT. Since the nitrogen vacancy center in single-crystal diamond has four possible arrangements in the crystal lattice, the presence of a directed magnetic field causes the nitrogen vacancy centers present in the crystal to

[0023] Vulnerability centers react to the external magnetic field with varying degrees of intensity depending on their position in the crystal. As a result, at most four corresponding pairs of fluorescence minima can appear in the spectrum, from whose shape and relative positions the magnitude and direction of the magnetic field can be unambiguously determined.

[0024] The structure and functioning of a nitrogen vacancy sensor are also known to the person skilled in the art

[0025] It can be further advantageously provided that the measurement signals are filtered by the evaluation unit with a high-pass and / or low-pass filter, and / or that the evaluation unit determines a bias drift of the magnetic field sensors, in particular by averaging the measurement signals over a period of time which is greater than an expected time constant of the movement pattern.

[0026] By filtering with a low-pass filter, noise components with frequencies significantly above the heart rate are eliminated. The bias drift can also be subtracted from the high-pass and / or low-pass filtered signal, resulting in a clean magnetic cardiogram signal.

[0027] It is furthermore preferably provided that the evaluation unit detects pathological movement disorders, e.g. a Periodic Limb Movement Disorder (PLMD) or a Restless Legs Syndrome (RLS), based on the movement patterns.

[0028] Various methods can be used to determine movement disorders based on the measurement signals. For example, it is possible to use a pattern comparison based on a predefined table with corresponding standard movement patterns, whereby the standard movement patterns can be taken from clinical diagnostics or clinical studies.

[0029] Furthermore, a data-driven evaluation or interpretation is possible using a statistical classification method. A decision tree method or a random forest method can be used for this. Another option is to use neural networks for analysis. Preferably, further measures are taken based on the assessment. These further measures may include making an emergency call and / or transmitting the movement patterns to medical personnel.

[0030] Furthermore, it can preferably be provided that the evaluation unit sends the movement patterns and / or the clinical pictures to other devices, in particular to a clinical diagnostic system, to a health management system or to a comfort system.

[0031] For example, if the movement patterns and / or symptoms are forwarded to a comfort system, a massage function, a scented bedroom or ambient lighting can be activated.

[0032] The assessment can be provided with a confidence value that reflects the statistical certainty of the classification result or assessment.

[0033] In an advantageous embodiment, it can be provided that the magnetic field sensor device or also the magnetic field sensor device and the evaluation unit are arranged in one bed.

[0034] The evaluation device can advantageously be implemented in the form of a software module in a control unit or computer. This makes it possible to integrate the evaluation device into a computer, for example, a mobile device such as a smartphone or tablet PC, or a personal computer, which can be connected to the sensor device via discrete lines via a wireless interface.

[0035] A further solution to the problem underlying the invention consists in providing a bed comprising a support, such as a mattress, and an evaluation unit designed to carry out a method as described above. A method for determining movement patterns of a resting, in particular sleeping, person is also advantageous, wherein magnetic fields generated by the person's muscles are recorded as measurement signals without contact by means of a sensor device integrated in a support, wherein the measurement signals are transmitted to an evaluation unit, wherein the evaluation unit determines movement patterns of the person from the measurement signals. The sensor device is designed as a magnetic field sensor device and is integrated into the support on which the person sleeps in such a way that temporally and / or spatially changing magnetic fields caused by muscle movement, in particular of the leg muscles, of the person are recorded as measurement signals.

[0036] All functions, features and configurations explained in connection with the device described above can also be transferred to the method in a corresponding manner.

[0037] The core of the invention is therefore a system that includes magnetic field sensors that are placed near the muscles of a resting person. These are located in a support, for example, in the mattress of a bed, and record, for example, the activity of the leg muscles. Monitoring at other locations (e.g., on the back) is also possible.

[0038] Upper arm muscles (see 2 in Fig. 2) is conceivable. This data can then be compiled and analyzed with regard to the presence and severity of a sleep-associated movement disorder. Long-term observations are also conceivable. The invention can also be used to detect and monitor physiological and disease-related fasciculations. Furthermore, the recording of the magnetic and thus electrical signal can be supplemented by long-term monitoring of the movement patterns. Magnetic field sensors and additional sensors, such as pressure sensors, can be used for this purpose. The invention is explained in more detail below with reference to the attached figures.

[0039] It shows

[0040] Fig. 1 shows a bed with a magnetic field sensor device, Fig. 2 shows an anatomical representation of a human leg, Fig. 3 shows a flow chart of the method.

[0041] A device 10 for determining movement patterns of a sleeping person is explained in more detail below with reference to the figures.

[0042] Fig. 1 shows a bed frame 12 with a support 15 designed as a mattress. Two magnetic sensor devices 14 and 14' are integrated into the support 15. The first magnetic sensor device 14 is arranged such that the measurement signals detected by the magnetic sensor device 14 represent muscle movements of one or both legs 3 of a person 2 sleeping in the bed 12 on the support 15, wherein temporally and / or spatially changing magnetic fields caused by the muscle movement are detected by the magnetic sensor device 14. A second magnetic sensor device 14' is arranged such that the measurement signals detected by the magnetic sensor device 14' represent muscle movements of one or both upper arms of the person 2 sleeping in the bed 12 on the support 15.The measurement signals generated by the magnetic sensor devices 14 and 14' are transmitted via data lines 16 to an evaluation unit 19, either in preprocessed form or as raw data. Alternatively, wireless transmission of the measurement signals to the evaluation unit 19 is conceivable, for example, using known methods such as WiFi, Bluetooth, or NFC.

[0043] The evaluation unit 19 is configured to determine movement patterns of the sleeping person 2 from the received measurement signals of the magnetic sensor devices 14 and 14' and, in particular, to detect a movement disorder and, if appropriate, a specific clinical picture, for example, a periodic limb movement disorder (PLMD) or restless legs syndrome (RLS), by comparing the determined movement patterns with reference patterns stored in the evaluation unit 19. Statistical, data-driven methods based, for example, on machine learning methods or neural networks can be used for this purpose.

[0044] Fig. 2 schematically shows a human leg 20 and the tibialis anterior muscle 22, the activity of which can be recorded and monitored during sleep by means of a device 10 according to the invention.

[0045] Fig. 3 shows a method 100 according to the invention for determining movement patterns of a sleeping person as a flow chart. In step 110, magnetic fields generated by certain muscles of the sleeping person are recorded as measurement signals without contact by means of a magnetic field sensor device integrated into a support on which the person lies. In step 120, the measurement signals are transmitted to an evaluation unit. In step 130, the evaluation unit determines a movement pattern of the person from the measurement signals. In step 140, the evaluation unit compares the determined movement pattern with reference movement patterns in order to derive a movement disorder. In step 150, a movement disorder is detected and assigned. In step 160, further measures are initiated, e.g., transmission of the movement patterns to a treating physician and / or further monitoring of the person.

Claims

Claims 1. Device (10) for determining movement patterns of a resting, in particular sleeping, person (2), comprising at least one sensor device integrated into a support (15) or arranged on the support, which is designed to detect magnetic fields generated by muscles (22) of the person (2) as measurement signals in a contactless manner, wherein the support (15) is designed such that the person can lie on the support, further comprising an evaluation unit (19), wherein the measurement signals are transmitted to the evaluation unit (19) and wherein the evaluation unit (19) is designed to determine movement patterns of the person (2) from the measurement signals, characterized in that the sensor device is designed as a magnetic field sensor device (14, 14') and is arranged on the support (15) and / or integrated into the support (15) in such a way that temporally and / or spatially changing magnetic fields caused by a muscle movement, in particular a movement of the leg muscles (22),the person (2) are generated, can be recorded as measurement signals., 2. Device according to claim 1, characterized in that the magnetic field sensor device (14) is a gradiometer with at least two magnetic field sensors arranged at mutually spaced positions, wherein the at least two magnetic field sensors measure a magnetic field at the spaced positions and generate the measurement signals, wherein the measurement signal is preferably determined as a difference signal of the measurement signals of the at least two magnetic field sensors.

3. Device (10) according to claim 1 or 2, characterized in that several magnetic field sensor devices (14, 14') are provided which are each assigned to specific muscle groups of the person (2) and / or that the magnetic field sensor device (14, 14') in the support is automatically positioned near a muscle to be monitored, in particular a leg muscle (22), of the person (2). 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 a diamond, optical filters, and photodetectors, and more preferably a microwave resonator and / or a light source, in particular a laser. Device (10) according to one of the preceding claims, characterized in that the evaluation unit (19) is designed to filter the measurement signals with a high-pass and / or low-pass filter, and / or that the evaluation unit is designed to determine a bias drift of the magnetic field sensors, in particular by averaging the measurement signals over a period of time that is greater than an expected movement rate of the muscles.Device (10) according to one of the preceding claims, characterized in that the evaluation unit (19) is designed to recognize clinical pictures, in particular a periodic limb movement disorder (PLMD) or a restless legs syndrome (RLS), from the measurement signals and / or the movement patterns. Device (10) according to one of the preceding claims, characterized in that the evaluation unit (19) is designed to send the movement patterns and / or the clinical pictures to further devices. Device (10) according to one of the preceding claims, characterized in that the device (10) has a plurality of sensor devices, of which at least one is designed as a magnetic field sensor device (14, 14') and a further sensor device is designed as a device for measuring a pressure and / or a temperature, wherein the measurement signals which are detected by the further sensor device are sent to the. The data are transmitted to the evaluation unit (19) and taken into account when determining the movement pattern. Device (10) according to one of the preceding claims, characterized in that at least one magnetic field sensor device (14, 14') has a plurality of magnetic sensors arranged as a sensor array. A support (15), in particular a mattress, with at least one integrated magnetic field sensor device (14, 14') designed to be used in a device according to one of claims 1 to 9.Method (100) for determining movement patterns of a resting, in particular sleeping, person (2), wherein magnetic fields generated in a contactless manner by muscles (22) of the person (2) are detected as measurement signals by means of a sensor device integrated in a support (15), wherein the measurement signals are transmitted to an evaluation unit (19), wherein the evaluation unit (19) determines movement patterns of the person (2) from the measurement signals, characterized in that the sensor device is designed as a magnetic field sensor device (14, 14') and is integrated into the support (15) on which the person (2) lies in such a way that temporally and / or spatially changing magnetic fields caused by a muscle movement, in particular of the leg muscles (22), of the person (2), are detected as measurement signals.

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