WO2020078486A1 - Dispositif de mesure de la force musculaire, procédé de détermination de la fonction musculaire, procédé de test de la performance musculaire d'athlètes, procédé de test de préparations pour le traitement et la prévention de la sarcopénie et son utilisation - Google Patents

Dispositif de mesure de la force musculaire, procédé de détermination de la fonction musculaire, procédé de test de la performance musculaire d'athlètes, procédé de test de préparations pour le traitement et la prévention de la sarcopénie et son utilisation Download PDF

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Publication number
WO2020078486A1
WO2020078486A1 PCT/CZ2019/050045 CZ2019050045W WO2020078486A1 WO 2020078486 A1 WO2020078486 A1 WO 2020078486A1 CZ 2019050045 W CZ2019050045 W CZ 2019050045W WO 2020078486 A1 WO2020078486 A1 WO 2020078486A1
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WO
WIPO (PCT)
Prior art keywords
muscle
measured
pressure
pressure pad
limb
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PCT/CZ2019/050045
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English (en)
Inventor
Zdenek Zadak
Martin VALIS
Oldrich VYSATA
Tomas VIZNER
Adolf Felzmann
Original Assignee
Fakultni Nemocnice Hradec Kralove
Mikroklima S.R.O.
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Application filed by Fakultni Nemocnice Hradec Kralove, Mikroklima S.R.O. filed Critical Fakultni Nemocnice Hradec Kralove
Publication of WO2020078486A1 publication Critical patent/WO2020078486A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
    • A61B5/1107—Measuring contraction of parts of the body, e.g. organ, muscle
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/22—Ergometry; Measuring muscular strength or the force of a muscular blow
    • A61B5/224—Measuring muscular strength
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
    • A61B5/4519—Muscles
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/0404—Electrodes for external use
    • A61N1/0408—Use-related aspects
    • A61N1/0452—Specially adapted for transcutaneous muscle stimulation [TMS]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/0404—Electrodes for external use
    • A61N1/0472—Structure-related aspects
    • A61N1/0484—Garment electrodes worn by the patient
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/36003—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation of motor muscles, e.g. for walking assistance
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/36014—External stimulators, e.g. with patch electrodes
    • A61N1/3603—Control systems
    • A61N1/36031—Control systems using physiological parameters for adjustment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
    • A61B5/4538—Evaluating a particular part of the muscoloskeletal system or a particular medical condition
    • A61B5/4595—Evaluating the ankle

Definitions

  • the present invention relates to a device for objectively measuring muscle strength, a method for determining muscle function (measurement of muscle strength and determination of muscle fatigue), a method for testing athletes' muscle performance and use thereof.
  • Measurements of muscle strength and muscle fatigue are significant parameters that are important for maintaining muscle mass and function.
  • Sarcopenia or loss of muscle mass is a common phenomenon that occurs in every individual after age 30 in healthy people and progresses very quickly during disease.
  • sarcopenia worsens, so around age 80, muscle mass is reduced by 25 - 30 percent compared to youth.
  • the ratio of muscle mass loss can be well measured, but with the development of sarcopenia also a disorder of muscle function (muscle strength, muscle fatigue) develops significantly.
  • the author’s certificate no. CZ 169225 discloses a muscle strength measuring device which evaluates the deformation of a flexible body provided with a sensor connected to a transducer with an evaluation device, in which there is a frame with a carriage equipped with two flexible bodies to which the sensors are connected, switchable to a single transducer.
  • This device describes standard dynamometry requiring a cooperation of the patient, so it is designed to measure the muscle strength of the conscious and willing person.
  • EP 1 095 670 Bl discloses an electrical neuromuscular stimulator measuring the response to an electrical stimulus pulse.
  • the device comprises an electrical pulse generator, electrodes, and at least one sensor responsive to muscle responses caused by electrical stimulation, which is mechanically connected to one of the electrodes.
  • the device described is not a device for measuring muscle strength, but measures the electrical and mechanical response of a muscle to direct stimulation at a motor point.
  • US 2003/0176808 Al discloses a device for measuring bioelectric impedance relating to information about the state within a living organism by measuring an electrical signal on the surface of a living organism. It is an impedometer to measure the ratio of muscle versus fat mass in the body.
  • the device comprises electrodes to be attached to a body surface, means for generating a radiofrequency current within the body through electrodes, measuring electrodes, a voltage meter and a computer for calculating bioelectric impedance.
  • US 2011/0105941 Al claims a device comprising three electrodes (two measuring and one reference) arranged at fixed distances from each other and adapted to be applied to the skin of an individual, wherein the device is capable of receiving and monitoring electrical signals and providing electrical stimulation. It is used as a biofeedback to eliminate grinding teeth.
  • US 5,012,820 relates to a device for determining the change in mechanical magnitude and for correlating it with the change in electrical magnitude of nerves and muscle during muscle contraction in a part of the body having a joint.
  • the device comprises a potentiometer, two pairs of electrodes attachable to the body surface, a stethoscope and a microphone, and means for simultaneously recording values from the potentiometer, electrodes and microphone.
  • This device includes multimodal monitoring of strength of muscle contraction created by electrical stimulation at the muscle motor point.
  • US 7,431,702 B2 discloses an apparatus for examining the musculoskeletal system of a human or animal body by determining the functional ability of the muscular system.
  • the device comprises a unit securing the examined body parts in a fixed position, a voltage source and a stimulation unit, mechanical and electrical measuring means including dynamometers, accelerometers, muscle length meters, sensors to record the electrical potential of fluctuations, body temperature, acoustic signals and vibrations.
  • the device does not measure muscle strength directly, but only by measuring the acceleration of the loaded limb with the accelerometer.
  • the present invention solves the problems of the prior art by describing a muscle strength measuring device that uses a change in air pressure depending on muscle activity to detect muscle activity, wherein muscle strength is defined as the response of a measured muscle to electrical stimulation at a motor point.
  • muscle strength is defined as the response of a measured muscle to electrical stimulation at a motor point.
  • the maximum attainable muscle strength is then the muscle response to supramaximal electrical stimulation at the motor point, which is determined by gradually increasing the intensity of the stimulation and measuring the magnitude of the muscle response until the next two pulses produce a non-increasing muscle response.
  • Muscle strength measurements can also be used to determine muscle fatigue, using submaximal intermittent stimulation with a series of stimuli at a frequency of about 20 Hz, with the highest muscle response measured in each series and from these highest values the fatigue curve is reconstructed.
  • the device of the present invention measures the strength and fatigue of a substantially constant volume of a portion of muscle, determined by the area of the stimulation electrode.
  • the quality of muscle contraction of a defined number of muscle fibres is measured, and this also implies independence of the measurement on height, weight and total muscle volume, or sex.
  • this device is capable of measuring strength in:
  • the device of the present invention tests involuntary muscle contraction without the influence of peripheral and central motoneuron, allows evaluation of the peripheral component of muscle fatigue during long-term submaximal muscle stimulation and offers significantly less discomfort compared to tetanus stimulation of the peripheral nerve.
  • the object of the present invention is a muscle strength measuring device comprising an electrostimulator provided with at least two electrodes for placing on the skin of the measured subject at the motor point of the measured muscle, a sensor and an analyser, wherein the sensor is adapted to transmit signals, proportional to muscle response to electrostimulation pulses, to the analyser, wherein the sensor comprises fixation means allowing joint movement of the measured limb, provided with at least one pressure pad, preferably a pressure compression strap, connected to a source of compressed air, and wherein the analyser with a pressure sensor is connected to the pressure pad (pressure compression strap) by a pressure hose for analysing changes in air pressure of the pressure pad.
  • the analyser and sensor are feedback-coupled to the electrostimulator and electrodes, which allows for synchronization of pressure response measurements and determination of e.g. muscle response time after stimulation pulse and reduces recording size requirements.
  • the pressure sensor is integrated in the analyser and converts the pressure of gas in the pressure pad carrying the muscle strength information to an electrical quantity.
  • Motor point means an anatomically defined location from which muscle contraction can be induced, which location is positioned on the measured limb across the joint from the measured muscle.
  • electrostimulation pulses are applied at a motor point that is located outside the measured muscle, and a limb joint is present between the measured muscle and the motor point.
  • Motor points of individual muscles are known to those skilled in the art.
  • the electrostimulator is an electrical pulse generator and is connected by an electrical conductor to at least one pair of electrodes that receive electrical pulses produced by the electrostimulator.
  • the electrostimulator comprises an FPGA (field-programmable gate array) control module, a microcontroller, a metering module for measuring stimulation currents and voltages on the electrodes, an Ethernet and an optional wireless connection (WiFi, Bluetooth) to transfer data files and set up of the device.
  • It also includes a voltage source ranging from 0 to 300 V, an H-bridge for pulse polarity switching and a control panel.
  • it includes a display that shows information about electrostimulation programmes and/or information about electrical pulses used to measure muscle activity.
  • PC control unit
  • the pressure pad e.g. in the form of a pressure compression strap, transmits information about the induced muscle response to the analyser by changing the air pressure in the pressure pad.
  • the stimulated muscle performs joint movement of the measured limb, which changes the air pressure in the pressure pad located on the same limb at a distance across the joint (meaning just one joint) from the motor point of the measured muscle.
  • This change in pressure, indicating muscle response to electrostimulation, is recorded and evaluated by the analyser attached to the pressure pad of the sensor via a pressure hose.
  • the analyser comprises a pressure sensor, means for processing signals received in response to muscle activity (muscle responses to electrical stimulation), optionally a control panel, and a display showing pressure information depending on muscle activity.
  • the analyser can be connected to a PC, allowing remote processing of measurement data.
  • pressure hose is meant an air pressure hose known to the person skilled in the art, as well as the materials from which it is made.
  • the fixation means is adapted in shape and size to fix various limbs (e.g., ankle joint, knee joint, elbow joint) in various measured subjects (human, animal, e.g., horse).
  • limbs e.g., ankle joint, knee joint, elbow joint
  • the device of the present invention can also be advantageously used in humans or animals under anaesthesia without peripheral muscle relaxants.
  • the fixation means is a splint and/or an ergonomic sleeve, wherein the fixation means is preferably provided with compression straps.
  • the fixation means ensures a firm connection of the measured body part with the electrodes for their repeatable accurate positioning.
  • the compression straps are used for accurate and firm fixation of the fixation means to the measured limb.
  • the fixation means and the pressure pad are made of a material that is easy to sterilize. More preferably, the fixation means is made of an aluminium tape reinforced plastic, and the pressure pad is more preferably made of an airtight fabric.
  • the compressed air source is selected from the group consisted of a balloon, a pressurized balloon, a compressed air distribution system, optionally provided with a manostat, a pressure gas bottle and a compressor.
  • the electrodes are reusable gel electrodes.
  • the electrodes are flat electrodes, more preferably having a diameter ranging from 30 to 70 mm, most preferably 50 mm.
  • the compressed air source is not directly connected to the analyser, but is connected directly to the pressure pad via a separate pressure hose.
  • the pressure hose for conveying air from the source of compressed air to the pressure pad is therefore different in this embodiment from the pressure hose for conveying compressed air from the pressure pad (pressure compression strap) to the analyser.
  • the pressures in the hose do not increase suddenly in the period between refilling air and taking measurement.
  • the compressed air source is connected to the pressure pad (pressure compression strap) and analyser by a common pressure hose.
  • the device of the present invention can also be used in testing preparations for the treatment and prevention of sarcopenia, which comprises the following steps:
  • test preparation for treating and preventing sarcopenia is administered to the test subject;
  • the sensor’s fixation means is fastened to the measured limb, preferably with compression straps, so as to allow joint movement of the measured limb;
  • Electrodes attached to the electrostimulator are placed on the skin of the measured limb of the test subject at the motor point of the muscle being measured;
  • the pressure pad of the sensor is attached to the measured limb at a point which is spaced from the electrode placement across the joint of the measured limb (preferably the joint is a knee, ankle, elbow or wrist);
  • the electrostimulator sends to the electrodes an electrical stimulation pulse that stimulates the muscle whose strength is measured;
  • the stimulated muscle performs joint movement of the measured limb, which changes the air pressure in the pressure pad;
  • Determination of the degree of sarcopenia is performed, for example, by comparison with earlier muscle strength values of the test subject as measured prior to administration of the test preparation to the subject being tested.
  • the effectiveness of the test preparation in the treatment of sarcopenia is evaluated by comparing the muscle strength measured before and after administration of the test preparation for the treatment and prevention of sarcopenia to the test subject.
  • the method for testing the preparations for treating and preventing sarcopenia of the present invention is not a diagnostic or therapeutic method that would be a direct treatment of sarcopenia.
  • the purpose of this method is not therapeutic or diagnostic, but the purpose is to develop new medicaments.
  • the measurement is independent of the influence of the will or consciousness of the test subject, i.e. the human or animal being measured.
  • the moment of strength transmitted through a lever mechanism (through the joint) from the muscle motor point to the movable part of the human or animal limb is measured.
  • the moment of strength transmitted by the lever mechanism through the knee, ankle, elbow or wrist is measured.
  • Muscle stimulation can be performed once, by measuring one specific value not affected by muscle fatigue accompanying repeated measurements.
  • a programmable series of pulses of increasing intensity preferably ranging from 0 to 100 mA (corresponds to the range of 0 to 300 V), is used to assess the maximum muscle strength with an optional pulse intensity step ranging from 1/100 to 1/5 of the total pulse intensity range (corresponds to the pulse intensity step of 1 to 20 mA) and a frequency in the range of 5 to 20 Hz.
  • a feedback evaluation of the muscle response amplitude of the last 2 pulses can be used to automatically stop stimulation when measuring muscle strength (the criterion is the non-increasing muscle strength amplitude as pulse intensity increases against the average of the previous 2 pulses).
  • This feedback evaluation of the muscle response amplitude is advantageous to be turned on only after reaching an above threshold value of the measured muscle response (usually above 15 mA) to the muscle stimulation in order to avoid turning off at the beginning of stimulation. If this value is not reached, stimulation turns off when the stimulation voltage or current threshold is reached.
  • the threshold setting is made before the measurement starts and depends on the electrical resistance of the measured subject's skin and the distance from the muscle motor point, e.g., the thickness of the subcutaneous fat layer. Preferably, the threshold is set to 60 mA.
  • muscle fatigue can be determined.
  • intermittent stimulation is preferably used with a series of adjustable intensity pulses with repetition at 5 to 20 pulses per second (usual series e.g. 12 seconds on, 8 seconds off) with a programmable duration of intermittent stimulation (with a frequency ranging from 5 to 20 Hz).
  • the maximum of muscle response to individual pulses and the total maximum in the series are evaluated to reconstruct the curve of sensor-measured pressure values as a function of the number of repetitions of the stimulation series.
  • the difference between the initial and final muscle strength value is measured and expressed as a percentage.
  • the sensor’s fixation means is fastened to the measured limb of the subject being tested, preferably with compression straps, so as to allow joint movement of the measured limb;
  • Electrodes attached to the electrostimulator are placed on the skin of the measured limb at the motor point of the muscle being measured;
  • the pressure pad of the sensor is attached to the measured limb at a point which is spaced from the electrode placement across the joint of the measured limb (preferably the joint is a knee, ankle, elbow or wrist);
  • the electrostimulator sends to the electrodes an electrical stimulation pulse that stimulates the muscle whose strength is measured;
  • the stimulated muscle performs joint movement of the measured limb, which changes the air pressure in the pressure pad;
  • the analyser data is evaluated and processed to a desired format from which the muscle performance of the test subject is subsequently determined.
  • the method for testing the muscle performance of athletes of the present invention is not a diagnostic or therapeutic method.
  • the purpose of this method is not therapeutic or diagnostic, but the purpose is to test the muscle performance of athletes, i.e. to measure a priori healthy subjects to determine their performance or to change and modify training.
  • the measurement is independent of the will or consciousness of the person or animal being measured.
  • the moment of strength transmitted through the lever mechanism (through the joint) from the muscle motor point to the movable part of the human or animal limb is measured.
  • muscle stimulation can be performed once, by measuring one specific value not affected by muscle fatigue accompanying repeated measurements or the muscle strength and its loss over time can be determined to determine muscle fatigue.
  • the present invention further provides a method for measuring muscle strength to diagnose sarcopenia, which comprises the following steps:
  • fixation means of the sensor (2) is fastened to the measured limb of the subject, preferably with compression straps, so as to allow joint movement of the measured limb of the subject;
  • Electrodes (1.1) attached to the electrostimulator (1) are placed on the skin of the measured limb of the subject at the motor point of the muscle being measured;
  • the pressure pad (2.3) of the sensor (2) is attached to the measured limb at a point which is spaced from the electrode (1.1) placement across the joint of the measured limb;
  • the electrostimulator (1) sends to the electrodes (1.1) an electrical stimulation pulse that stimulates the muscle whose strength is measured;
  • the stimulated muscle performs joint movement of the measured limb, which changes the air pressure in the pressure pad (2.3);
  • the analyser data is evaluated and processed to a desired format from which the muscle strength is subsequently determined.
  • the present invention further provides a method for measuring muscle fatigue for diagnosing sarcopenia, which comprises the following steps:
  • fixation means of the sensor (2) is fastened to the measured limb of the subject, preferably with compression straps, so as to allow joint movement of the measured limb of the subject;
  • Electrodes (1.1) attached to the electrostimulator (1) are placed on the skin of the measured limb of the subject at the motor point of the muscle being measured;
  • the pressure pad (2.3) of the sensor (2) is attached to the measured limb at a point which is spaced from the electrode (1.1) placement across the joint of the measured limb; v) The electrostimulator (1) sends to the electrodes (1.1) an electrical stimulation pulse that stimulates the muscle whose strength is measured;
  • the stimulated muscle performs joint movement of the measured limb, which changes the air pressure in the pressure pad (2.3);
  • the analyser data is evaluated and processed to a desired format from which the muscle strength is subsequently determined;
  • Steps v) to viii) are repeated, preferably at least five times in a precise time period;
  • Muscle strength from the first and last measurements is compared, and muscle fatigue is evaluated from their difference.
  • the present invention further provides a method for measuring muscle fatigue for diagnosing sarcopenia, which comprises the following steps:
  • fixation means of the sensor (2) is fastened to the measured limb of the subject, preferably with compression straps, so as to allow joint movement of the measured limb of the subject;
  • Electrodes (1.1) attached to the electrostimulator (1) are placed on the skin of the measured limb of the subject at the motor point of the muscle being measured;
  • the pressure pad (2.3) of the sensor (2) is attached to the measured limb at a point which is spaced from the electrode (1.1) placement across the joint of the measured limb;
  • the electrostimulator (1) sends to the electrodes (1.1) an electrical stimulation pulse for at least 10 seconds, wherein the electrical stimulation pulse stimulates the muscle whose muscle strength is measured;
  • the stimulated muscle performs joint movement of the measured limb, which changes the air pressure in the pressure pad (2.3);
  • the analyser data is evaluated and processed to a desired format from which the muscle strength at the beginning and at the end of the electrical stimulation pulse is subsequently determined;
  • Muscle strength at the beginning and at the end of the electrical stimulation pulse is compared, and muscle fatigue is evaluated from their difference. It is a further object of the present invention to use the muscle strength measuring device of the present invention to determine the maximum attainable muscle strength and/or muscle fatigue of a subject.
  • the device of the invention is an objective dynamometer which measures the moment of strength transmitted by the lever mechanism through the joint to the movable part of the limb during the muscle contraction induced by electrical stimulation at the muscle motor point.
  • the muscle stimulator is located outside the muscle on which the muscle strength moment is detected and analysed.
  • This device can be used to determine the status and condition of muscle activity by measuring a particular muscle, independent of the influence of will of the person or animal being measured.
  • the maximum attainable muscle strength can be determined by a unique measurement that is not affected by muscle fatigue due to repeated measurements and/or muscle fatigue can be determined when muscle strength loss over time is determined by repeated measurements.
  • muscle strength can be objectively tested in metabolic myopathies, because while inflammatory and necrotizing myopathies destroy muscle fibres and the muscle involvement can be quantified by quantitative analysis of motor units, in metabolic myopathies, muscle contractility is impaired without altering electrophysiological parameters and such disability could not be objectified according to the prior art.
  • the device of the present invention allows an objective measurement of the degree of muscle involvement.
  • Another application of the present invention is the field of muscle strength testing in conduction block and acute denervation. Direct stimulation of muscle fibres does not require intact innervation to induce muscle contraction. Using the present invention, it is possible to estimate the muscle repair potential of denervated muscles in complete or partial conduction block, after neurotension or axonotmesis. When taking measurements with the device of the present invention, the problems of the prior art with a large inter-individual measurement variability and hence the difficulty in determining normative data are avoided, since the pressure compression strap adjusts its shape to the surface to be measured and evenly distributes the pressure caused by muscle contraction.
  • the pressure pad such as a pressure compression strap
  • the means of fixation can be easily sterilized by standard procedures, making it suitable for use even in an infectious environment in intensive care units.
  • the device is easy and quick to install on the measured muscle, it is light and easy to carry. Measurement using the device of the present invention is independent of peripheral nerve function and their damage (independent of the presence of neuropathy) and independent of will, motivation or state of consciousness of the measured subject (independence of the state of pharmacological inhibition or unconsciousness).
  • the device of the present invention makes it possible to measure muscle performance (strength, fatigue in relation to muscle mass). Muscle performance and muscle fatigue are not directly proportional to muscle mass.
  • Measurement of muscle mass is known in the art and can be performed using a non- invasive impedance method.
  • the combination of the impedance method of measuring muscle mass and measuring muscle performance (i.e., muscle strength and/or muscle fatigue) by the device of the present invention allows to create a new quantitative relationship between the measured quantities by an algorithm that allows to quantify the relationship of muscle strength, muscle fatigue and muscle mass.
  • the present invention enables, inter alia, objective testing of novel metabolic and nutritional preparations (nutraceuticals, functional foods) in the process of preventing and treating sarcopenia, particularly in intensive care patients and those who are chronically ill and immobilized in the long term.
  • the present invention is also applicable in a number of other medical fields and areas (metabolism, nutrition, myology, rehabilitation, intensive care, sports medicine, pharmacology) or in the testing of muscular system performance in athletes. It allows to evaluate objectively and independently of the motivation and voluntary abilities the individual's performance, especially in the discrepancy between muscle function and the actual performance of the individual.
  • Figure 1 Diagram of the muscle strength measuring device, wherein 1 is an electrostimulator with electrodes 1.1; a sensor 2 comprises a fixation means 2J_, compression straps 12 and a pressure pad 2.3; an analyser 3 feedback-coupled to an electrostimulator J_, to which a compressed air source 3J_ is connected.
  • FIG. 2 The muscle strength measuring device prior to measurement (A) and during electrostimulation (B); FT are the electrodes, 2 is the pressure pad, 3 is the analyser and _ is a pressure hose.
  • Figure 6 Curve of pressure in the pressure pad 23_ when measuring maximum contraction.
  • Figure 8 Typical shape of curve when using stimulation intensities up to 150 mA. Stimulation was turned off after supramaximal stimulation was reached at 104 mA
  • Figure 9 Example of muscle fatigue curve. In each of the 16 series of stimulations, the maximum muscle value measured is plotted. The curve has a uniform course; after post-tetanic potentiation, there is a monotonous decrease in muscle strength.
  • Example 1 Device for measuring the muscle strength on the lower limb - stimulation of the muscle in the front of the lower leg (musculus tibialis anterior) and measuring the dorsal flexion of the foot
  • a device (Figs. 1 and 2) was developed for measuring muscle tension (muscle strength and/or muscle fatigue), comprising a programmable electrical stimulator l with at least two electrodes l. E with feedback tracking of muscle response to stimulation and interruption of stimulation at supramaximal voltage/current. Supramaximal stimulation voltage/current is a voltage/current that does not lead to a further increase in the contraction strength of the muscle being tested. This device displays the muscle activity during electrostimulation of the anterior tibial muscle.
  • the measurement can be divided according to the method of muscle stimulation into measurement of muscle strength (specific measured value in a single measurement (Fig. 3), which is not affected by muscle fatigue caused by repeated measurements) and measurement of muscle fatigue (Figs. 4 and 5, the muscle strength and its loss over time is measured).
  • the method for measuring muscle fatigue is performed either:
  • the resulting value is the initial strength of the first measurement and the subtracted value of the initial strength of the last measurement at regular period, expressed in % (in the example the difference between the first and fifth measurements), or
  • the device further comprises a sensor 2 composed of a fixed part - fixation means 2J_ (a splint, preferably a plastic ergonomic sleeve) provided with a plurality of compression straps 2.2 fixing the leg in the lower part.
  • the compression straps 2_32 ensure a firm connection of the tibial part of limb to the splint and allow correct and repeatable placement of the electrodes 1.1.
  • a pressure pad 2 in the form of a pressure compression strap (hereinafter referred to as PCS) with a source 3J_ of compressed air (pressure bag) and a pressure hose _ connection.
  • PCS pressure compression strap
  • the device comprises an analyser 3 in the form of a compact unit connected by a pressure hose 332 to PCS.
  • the pressure hose 332 is connected to a pressure balloon (can be replaced by connecting it to a compressed air distribution system via a manostat), which ensures the required working air pressure.
  • the analyser 3 shows the air inlet pressure setting when switched on (measurement is only made if the air inlet pressure is within the desired range).
  • the analyser 3 is feedback- coupled to the electrostimulator l and responds to changes in air pressure in PCS 2.3.
  • the measurement time is Tong’ and the final value of strength at the stimulation end point is calculated as well. Subsequently, the muscle fatigue is expressed as a muscle strength loss in %. If the measurement is repeated with a tolerance in the period of 5 times in succession, it is a measurement of muscle fatigue by A method and, as in the previous case, the value of muscle strength loss in % is displayed after the measurement.
  • the device of Example 1 comprises the following parts:
  • Sensing unit (analyser 3) meets safety requirements according to CSN EN 60601-1 ed.2:
  • the muscle at the motor point is stimulated by means of a voltage or current-controlled electrostimulator ⁇ with a maximum voltage of 300 V, a maximum current of 100 mA and an adjustable value for maximum current intensity at which stimulation is turned off regardless of previous failure to achieve the criteria for supramaximal muscle stimulation.
  • Stimulation pulse is a filtered biphasic rectangular pulse (200 ps duration), best adjustable in the range of 50 to 300 ps
  • a programmable series of pulses of increasing intensity of 0 to 100 mA (0 to 300 V) with a selectable intensity step in the range of 1/100 to 1/5 (e.g. 1 to 20 mA) of the range and frequency in the range of 5 to 20 Hz is used to evaluate the maximum muscle strength.
  • the feedback evaluation of muscle response amplitude - the last 2 pulses - is used to automatically stop stimulation when measuring muscle strength (the criterion of non-increasing amplitude at increasing intensity compared to the average of the previous 2 pulses). This criterion is turned on only after reaching an above-threshold value for muscle stimulation, in order not to turn off at the beginning of stimulation. If this value is not reached, stimulation is turned off when the stimulation voltage or current threshold is reached.
  • an intermittent stimulation programme is used with a series of adjustable intensity pulses of 5 to 20 seconds (typical series e.g. 12 seconds on, 8 seconds off) with a programmable duration of intermittent stimulation.
  • the maximum response to the individual pulses and the total maximum in the series are evaluated to reconstruct the curve of pressure values measured in the analyser 3 depending on the number of repetitions of the stimulation series.
  • the board with a processor communicates with the parent computer over Ethernet (allows the stimulation parameters to be set).
  • the board has an integrated pressure sensor and an ADC converter for the voltage reached at the capacitor (biphasic pulse) and an ADC converter measuring the current in the positive and negative parts of the stimulation pulse.
  • the electrostimulator l further comprises a board with a high voltage generator (this is the‘voltage at the capacitor’) and a bridge switch board with a current sensor.
  • Example 2 Device for measuring the muscle strength of extension in the knee joint and flexion and extension in the elbow joint
  • An analogous device can be used to measure the strength of extension in the knee joint when musculus rectus femoris is stimulated.
  • the fixation splint has a cut-out on the ventral side of the thigh to accommodate stimulation electrodes.
  • the pressure compression strap is located in the middle of the ventral part of the lower leg.
  • three active electrodes located above the motor points of m. rectus femoris, m. vastus medialis and m. vastus lateralis against a common reference electrode in the suprapatellar region can be used to stimulation to reach the maximum motor effect of stimulation.
  • one splint with one pressure compression strap fitting closely to the distal third of the forearm can be advantageously used.
  • the stimulation of flexion takes place at the motor point of the m. biceps brachii against the reference electrode in the cubite.
  • the stimulation of extension can be performed, as with the quadriceps stimulation, by either one pair of electrodes located above the lateral head of triceps brachii with a reference electrode in the area of insertion to the olecranon, or three active electrodes located above each head of triceps brachii against the same reference.
  • the measurement of muscle strength takes place in a relaxed lying or sitting position to eliminate the effect of antagonist tension.
  • the limb is attached to the fixation means 2J_ (splint) with compression straps 2.2 (Velcro fixation straps) to limit limb movement during muscle stimulation.
  • a pressure pad 23 with compressed air is placed on the measured surface instead of the fixing strap. It is pre-inflated to the air pressure value to ensure good adhesion to the limb surface. This value is within the linear characteristic area of sensor 2 (sensing pressure sensor).
  • above-threshold stimulation intensity reduces the patient’s discomfort by reducing the number of pulses and avoids turning off measurement when two consecutive zero differences are measured (can also be treated algorithmically by testing a supramaximal pulse up to detecting an increasing sequence of pressure differences). The measurement is repeated 3 times with a 3 -minute break to verify the reproducibility of the results. After use, the splint with the pressure pad 23 and the supply pressure hose(s) 33 is chemically sterilized.
  • muscle fatigue we measure muscle fatigue (Figs. 4 and 5) in a relaxed patient in a lying or sitting position.
  • the muscle strength measuring device of the present invention is attached to the subject to be measured as in Example 3.
  • the maximum tolerable stimulation intensity we allow the patient to turn off the stimulation of increasing intensity during discomfort with a control button.
  • the potentiometer should allow the patient to change the stimulation intensity up to the maximum tolerated. This value is stored and used as constant stimulation intensity for repetitive stimulation.
  • Example 5 Measuring the course of air pressure in the pressure pad 2 _ when measuring the maximum contraction
  • a healthy person was measured lying down in a relaxed state.
  • An L-shaped fixation splint with a pressure pad 23 (pressure compression strap) across the instep was attached to the right lower limb (Figs. 1 and 2).
  • the compression strap is attached at a fixed distance from the splint angle.
  • An active round gel self-adhesive electrode FT with a diameter of 40 mm was stuck to the motor point of musculus tibialis anterior.
  • a reference electrode FT of the same type and size was stuck medially therefrom across the proximal tibia. The distance of electrode centres was 80 mm.
  • stimulation with an increasing voltage from 30 V with a 20 V step at 5 Hz frequency up to a supramaximal value was used, in this case 150 V.
  • Example 6 Measuring maximum pressures of pressure pad 23 in the mode of measuring muscle fatigue by method A (see Example 1)
  • the placement of the electrodes is the same as when measuring the maximum contraction in Example 5.
  • the initial air pressure in the pressure compression strap pressure pad 2.3 was about 164 kPa (23.75 Psi).
  • the maximum tolerable stimulation intensity was first set, not necessarily the supramaximal stimulation intensity. In this case, the supramaximal intensity was tolerated. This value (152 V) was kept constant throughout the stimulation.
  • the stimulation frequency was 20 Hz repeatedly in the mode of 12 seconds on, 8 seconds off.
  • the graph of Fig. 7 contains maximum muscle contraction values for repetitive stimulation in 7 consecutive series.
  • Example 7 Testing the device on healthy volunteers
  • Stimulation parameters used in electromyographic devices and commercial myostimulators were tested. Trapezoid pulses having duration of 50 to 300 psec were filtered for better tolerance of stimulation (sharp leading edges of pulses are the main source of discomfort during stimulation). Stimulation intensities of 0 to 150 mA were used to achieve supramaximal muscle stimulation at the motor point of musculus tibialis anterior. The curves obtained were biphasic, in which a rapid increase in muscle strength corresponded to muscle stimulation between the stimulation and reference electrodes, and a slower phase of the potential corresponded to the propagation of electrical potential into the electrodes surrounding with an exponential loss of intensity. Stimulation was automatically turned off when supramaximal stimulation was reached (see Fig. 8). For low robustness of algorithms for recognition of supramaximal stimulation against local minima, fixed stimulation of 0 to 100 mA was chosen. Fixed stimulation up to 150 mA was accompanied by unpleasant feelings.
  • I is the current measured and po ...p 3 are polynomial coefficients.
  • stimulation frequencies 20 to 50 Hz are used. At least 16 cycles of 30 Hz stimulation lasting 2 seconds with 1 second of interruption were required to achieve a reproducible decrease in muscle strength.
  • Muscle fatigue is defined as the ratio of decrease in muscle strength to maximum muscle strength.
  • Muscle strength was measured using a fixed series of 10 stimulation pulses with an increase in intensity of 10 mA in the range of 0 to 100 mA. The measured value was normalized to cuff pressure; atmospheric pressure was converted to sea level. When measuring muscle fatigue, the highest measured value of muscle strength was recorded in each of the 16 stimulation series with a fixed intensity of 70 mA at a frequency of 30 Hz, duration of 2 seconds in each series with a 1 second break.
  • Table 2 p-values of correlations between the parameters of maximum strength, fatigue and monitored physiological parameters and fitness of probands (* values significant at 5% significance level)
  • Correlations to age were not performed as this is mostly a homogeneous age sample of students.
  • the measured data show that modelling the curve shape using a third degree polynomial better reflects the correlations to the studied physiological parameters and fitness than simple measurement of maximum strength.
  • the insignificance of most correlations is due to the homogeneity of a sample of probands of similar age and lifestyle.
  • the effect of strength training is reduced by the fact that most probands do not perform this type of training. Endurance training is more common and also correlates best with the shape of the curves to evaluate the maximum contraction.
  • the present invention is applicable, for example, to the objectivization of treatment of sarcopenia in clinical trials - potential users are pharmaceutical companies developing drugs for sarcopenia and companies involved in the development and manufacture of nutraceuticals used in the prevention of sarcopenia. Furthermore, the device can be used for objectifying training results in athletes and monitoring the course of treatment of critically ill patients with neuromyopathy and sarcopenia at the intensive care units and is subsequent rehabilitation care.
  • Maintaining muscle function is part of improving the quality of life, self-care ability of an individual and leads to a reduction in the economic cost of the health complications associated with an aging population. For this reason, objective monitoring of muscle function should be standard equipment in gerontological and geriatric establishments and all institutions that deal with the care of an aging population.

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Abstract

L'objet de la présente invention est un dispositif de mesure de la force musculaire comprenant un électrostimulateur (1) pourvu d'au moins deux électrodes (1.1) destiné à être placé sur la peau d'un sujet mesuré au niveau du point moteur du muscle mesuré, un capteur (2), et un analyseur (3) ; le capteur (2) est adapté pour transmettre des signaux, proportionnels à la réponse musculaire à des impulsions d'électrostimulation, à l'analyseur (3), et comprend un moyen de fixation permettant le mouvement d'articulation du membre mesuré, le moyen de fixation étant pourvu d'au moins un coussin de pression (2.3) relié à une source (3.1) d'air comprimé. L'analyseur (3) pour analyser les changements de pression d'air du coussin de pression (2.3) est relié au coussin de pression (2.3) par l'intermédiaire d'un tuyau de pression (3.2). L'analyseur (3) et le capteur (2) sont couplés par rétroaction au stimulateur électrique (1) et aux électrodes (1.1). La présente invention concerne par ailleurs un procédé de mesure de la force musculaire et son utilisation.
PCT/CZ2019/050045 2018-10-19 2019-10-07 Dispositif de mesure de la force musculaire, procédé de détermination de la fonction musculaire, procédé de test de la performance musculaire d'athlètes, procédé de test de préparations pour le traitement et la prévention de la sarcopénie et son utilisation WO2020078486A1 (fr)

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CN112285445A (zh) * 2020-09-04 2021-01-29 江苏大学 一种变刚度双模式输出的人工肌肉的测试装置和方法
WO2022096493A1 (fr) * 2020-11-06 2022-05-12 Myocene Procédé et système de détermination de fatigue musculaire
WO2022258263A1 (fr) * 2021-06-09 2022-12-15 Myocene Procédé de détermination de fatigue musculaire
WO2023108881A1 (fr) * 2021-12-15 2023-06-22 南京伟思医疗科技股份有限公司 Stimulateur magnétique de modelage
US11864898B2 (en) 2020-11-06 2024-01-09 Myocene Muscle fatigue determination method and system

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EP1424938A1 (fr) * 2001-03-21 2004-06-09 Tmg-Bmc D.O.O. Methode de detection selective et non-invasive du processus de contraction des muscles du squelette
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112285445A (zh) * 2020-09-04 2021-01-29 江苏大学 一种变刚度双模式输出的人工肌肉的测试装置和方法
CN112285445B (zh) * 2020-09-04 2022-09-16 江苏大学 一种变刚度双模式输出的人工肌肉的测试装置和方法
WO2022096493A1 (fr) * 2020-11-06 2022-05-12 Myocene Procédé et système de détermination de fatigue musculaire
WO2022096480A1 (fr) * 2020-11-06 2022-05-12 Myocene Procédé de détermination de fatigue musculaire
WO2022096482A1 (fr) * 2020-11-06 2022-05-12 Myocene Procédé de détermination de fatigue musculaire
US11864898B2 (en) 2020-11-06 2024-01-09 Myocene Muscle fatigue determination method and system
WO2022258263A1 (fr) * 2021-06-09 2022-12-15 Myocene Procédé de détermination de fatigue musculaire
WO2023108881A1 (fr) * 2021-12-15 2023-06-22 南京伟思医疗科技股份有限公司 Stimulateur magnétique de modelage

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