Operation method of eating and swallowing function evaluation system

Abstract

To improve evaluation of an eating / swallowing function allowing a user to evaluate it even at a bed side or in home medical care without any risk of radiation exposure, etc., and to acquire which part moves in what a manner when eating / swallowing with a small number of swallows, and which muscles cooperatively move at any stage of the eating / swallowing at what level of activity, timing, and time.SOLUTION: An operation method of an eating / swallowing function evaluation system includes a sensor part and an analysis part. The analysis part captures time-series changes in a feature amount of the suprahyoid muscle group biosignal and a feature amount of the infrahyoid muscle group biosignal; specifies at least the stage from the start to the end of swallowing; and acquires a combination of relative activities of individual muscles of the suprahyoid muscle group and the infrahyoid muscle group in coordinated movement of swallowing organs corresponding to the stage, a magnitude of the activity, timing of the activity, and changes in the activity over time, to analyze the eating / swallowing function.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an operating method of an eating and swallowing function evaluation method that detects biological signals from the start of eating and swallowing to the end of eating and swallowing, extracts features from the detected biological signals, and identifies the stages of eating and swallowing to evaluate eating and swallowing function. [Background technology]

[0002] Swallowing involves a series of actions that involve perceiving food, bringing it to the mouth, chewing it in the oral cavity, and transporting it through the pharynx and esophagus to the stomach. Its basic mechanism can be explained in five stages (anticipatory, preparatory, oral, pharyngeal, and esophageal) known as the "five-stage model." Other models include the "four-stage model," which explains the process of chewing and swallowing in four stages (oral preparatory, oral transport, pharyngeal, and esophageal), and the "process model," which explains the process of chewing and swallowing in four stages (stage I transport, processing, stage II transport, and swallowing). Swallowing is a complex action consisting of the coordinated movements of numerous organs, but it is a mixture of voluntary and involuntary movements. First, the tongue is pressed against the palate, a voluntary movement, to transport the bolus into the pharynx. This triggers the swallowing reflex, which then transitions to involuntary movements.

[0003] In involuntary movements, the suprahyoid muscles shown in Figure 1 are the main players, pulling the hyoid bone forward and upward. At the same time, the thyrohyoid muscle, one of the infrahyoid muscles, pulls the larynx to its highest position as a reflex movement in response to contraction of the suprahyoid muscles, and by inverting the epiglottis, closes the larynx (airway) and prevents the inflow of a bolus into the airway. This series of actions is carried out in approximately one second by coordinated movements of the various swallowing organs, as shown in Figure 2.

[0004] A known technique for evaluating such eating and swallowing functions is the eating and swallowing function evaluation technique disclosed in Patent Document 1. The eating and swallowing function evaluation technique of Patent Document 1 is a method for evaluating eating and swallowing function by detecting biosignals from the start to the end of eating and swallowing, extracting feature values ​​from the detected biosignals, and using machine learning to identify eating and swallowing movements from the feature values ​​to evaluate eating and swallowing function. The biosignals used are suprahyoid muscle biosignals due to muscle activity of the suprahyoid muscles and infrahyoid muscle biosignals due to muscle activity of the infrahyoid muscles, and feature values ​​are extracted from the suprahyoid muscle biosignals and infrahyoid muscle biosignals. However, because machine learning is required, it is necessary to repeatedly acquire biosignals during swallowing by the subject several dozen times.

[0005] The success or failure of eating and swallowing is greatly influenced by the presence or absence of problems with oral movement, which is a voluntary movement, and the breakdown of the swallowing reflex, which is an involuntary movement. Therefore, determining at which stage of eating and swallowing the problem is occurring can be said to be a fundamental approach to evaluating eating and swallowing function. The following techniques are known as such eating and swallowing function evaluation techniques:

[0006] Videofluoroscopic examination of swallowing (VF) is the gold standard for assessing swallowing function. VF involves having patients eat food containing a contrast agent, and observing the movement of the food bolus and the various swallowing organs under X-ray fluoroscopy. This test allows for the observation of the entire process of swallowing, including each stage. However, it carries the risk of radiation exposure and aspiration of food containing contrast agents, and requires an X-ray fluoroscopy device, making it unsuitable for bedside or home care. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-208629 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above, the present invention aims to provide an eating and swallowing function evaluation technology that does not involve the risk of radiation exposure or aspiration of food containing contrast agents, does not take up much space, can be used for evaluation at the bedside or in home medical care, and can improve eating and swallowing function evaluation by determining which parts move and how during eating and swallowing with a small number of swallowing attempts, and at which stage of eating and swallowing which muscles move in coordination with what level of activity, timing, and duration. [Means for solving the problem]

[0009] [1] A method for operating an eating and swallowing function evaluation system that includes a sensor unit that detects biosignals from at least the start of swallowing to the end of a series of actions from the start of eating and swallowing to the end, and an analysis unit that extracts feature amounts from the biosignals, identifies the stage of eating and swallowing from the feature amounts, and evaluates eating and swallowing function, the sensor unit includes a suprahyoid muscle group electromyogram sensor that is disposed in the suprahyoid muscle groups and detects suprahyoid muscle group biosignals due to muscle activity of the suprahyoid muscle groups, and an infrahyoid muscle group electromyogram sensor that is disposed in the infrahyoid muscle groups and detects infrahyoid muscle group biosignals due to muscle activity of the infrahyoid muscle groups, extracting feature amounts from the suprahyoid muscle group biosignals detected by the suprahyoid muscle group electromyography sensor and the infrahyoid muscle group biosignals detected by the infrahyoid muscle group electromyography sensor, an analysis unit that captures time-series changes in the feature amounts of the biosignals of the suprahyoid muscles and the infrahyoid muscles to identify the stage from at least the start to the end of the swallowing, and analyzes the eating and swallowing function by capturing the relative activity combinations of the individual muscles of the suprahyoid muscles and the infrahyoid muscles in the coordinated movements of the swallowing organs corresponding to the stage, the magnitude of the activity, the timing of the activity, and the change over time of the activity; and a display unit that displays the analyzed results.

[0010] With this configuration, by capturing time-series changes in the feature amounts of the biosignals of the suprahyoid muscles and the infrahyoid muscles, the stages from the start of swallowing to the end of swallowing can be identified, and the feeding and swallowing function can be analyzed by capturing the relative activity combinations of the individual muscles of the suprahyoid and infrahyoid muscles in the coordinated movements of the swallowing organs corresponding to each stage, as well as the magnitude, timing, and time changes of that activity.Since no X-ray fluoroscopy device is required, there is no risk of radiation exposure or aspiration of food containing contrast agents, and the device does not take up much space, allowing analysis to be done at the bedside or in home medical care.

[0011] Furthermore, it is possible to determine which muscles are moving in coordination at which stage of eating and swallowing, and with what level of activity, timing, and duration. This will improve the assessment of eating and swallowing function. Furthermore, by using multiple sensors in an array, it is possible to detect the entire series of movements from laryngeal elevation to descent, enabling a more detailed assessment of eating and swallowing function corresponding to each stage of eating and swallowing.

[0012] [2] Preferably, the sensor unit uses at least one of the suprahyoid muscle group electromyographic sensor or the infrahyoid muscle group electromyographic sensor, and the suprahyoid muscle group electromyographic sensor and the infrahyoid muscle group electromyographic sensor use an array electrode in which multi-channel electrodes are aligned. Either the suprahyoid muscle group electromyographic sensor or the infrahyoid muscle group electromyographic sensor may be used, but using both is preferable for detailed swallowing function evaluation.

[0013] In conventional electromyography, electrodes are attached and their positions are determined based on anatomical knowledge such as the course of the muscles, their origins and insertions, which requires time and effort. In this regard, the above-described configuration, by using an array electrode, makes it possible to identify the muscles beneath which the electrode positions correspond to each stage of eating and swallowing, as well as the number of muscles involved.

[0014] [ 1Preferably, the analysis unit uses, as the feature quantity, feature quantities (spatial patterns or temporal patterns) converted based on the muscle synergy hypothesis, which states that the individual muscles of the suprahyoid muscles and the infrahyoid muscles are not controlled individually, but are controlled by the coordinated movement of multiple muscles.

[0015] This configuration uses the muscle synergy hypothesis, which states that muscles are not controlled individually but through the coordinated movement of multiple muscles. By extracting and visualizing muscle synergies, it is possible to evaluate the eating and swallowing function by determining which electrode position corresponds to each stage of eating and swallowing, and the activity level and timing of the coordinated movement, without strictly determining the electrode positions. Furthermore, by focusing on muscle synergies before the onset of the swallowing reflex, it is possible to evaluate the eating and swallowing function in the stage related to voluntary movements such as feeding a bolus. Furthermore, by focusing on muscle synergies after the onset of the swallowing reflex, it is possible to evaluate the eating and swallowing function in the stage related to involuntary movements such as the swallowing reflex.

[0016] Furthermore, because dysphagia is caused by problems with either voluntary or involuntary movements, or both, it can be identified by focusing on muscle synergies.Furthermore, by focusing on muscle synergies when the amount or physical properties of food are changed, it is possible to evaluate differences in response to swallowed materials, ease of fatigue, characteristics of age-related changes, and characteristics of people with dysphagia.

[0017] [ 3 Preferably, the analysis unit calculates the muscle synergies by nonnegative matrix factorization (NMF). Features Extract.

[0018] With this configuration, nonnegative matrix factorization NMF is equivalent to a statistical method of principal component analysis with a nonnegative constraint. Because nonnegative matrix factorization NMF is nonnegatively constrained and corresponds to the characteristic that muscles exert force only in the contraction direction, the results are easy to interpret, and visualization can make the results even easier to understand.

[0019] [ 4 Preferably, the analysis unit Features is composed of a spatial pattern that represents the relative combination of activities of each muscle in the coordinated movement of the muscles, and a time pattern that represents the time-series weighting coefficients for the spatial pattern and the timing of muscle activity.

[0020] With this configuration, for example, muscle synergies can be extracted and visualized by displaying spatial patterns in three dimensions. Visualization makes it easy to identify the muscles under which the electrodes correspond to each stage of eating and swallowing, the activity level, timing, and duration of coordinated movements, and the number of muscles involved. [Effects of the Invention]

[0021] There is no risk of radiation exposure or aspiration of food containing contrast agents, the device does not take up much space and can be used for evaluation at the bedside or in home care. It can improve the evaluation of eating and swallowing function by showing which parts move and how they move during eating and swallowing, and which muscles move in coordination at which stage of eating and swallowing, with what level of activity, timing, and duration. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is an explanatory diagram showing the suprahyoid and infrahyoid muscles. [Figure 2] FIG. 1 is an explanatory diagram showing the mechanism of swallowing, which consists of voluntary and involuntary movements. [Figure 3] FIG. 1 is an explanatory diagram showing the risk of aspiration. [Figure 4] FIG. 1 is an explanatory diagram showing redundancy of hyoid movement. [Figure 5]FIG. 1 is an explanatory diagram showing muscle synergies. [Figure 6] 1 is a block diagram showing the overall configuration of an eating and swallowing function evaluation system according to the present invention. [Figure 7] 1 is an explanatory diagram showing a myoelectric sensor for the suprahyoid muscles and a myoelectric sensor for the infrahyoid muscles; FIG. [Figure 8] FIG. 2 is an explanatory diagram showing a laryngeal behavior sensor. [Figure 9] FIG. 2 is an explanatory diagram showing an electrode jig. [Figure 10] 1 is a configuration diagram of an eating and swallowing function evaluation system according to the present invention. [Figure 11] FIG. 2 is an explanatory diagram showing a state in which a sensor unit is attached to a person. [Figure 12] FIG. 2 is an explanatory diagram showing target muscle groups of electrodes. [Figure 13] FIG. 1 is an explanatory diagram showing the configuration of muscle activities in the muscle synergy hypothesis. [Figure 14] FIG. 1 is an explanatory diagram illustrating a muscle synergy extraction method. [Figure 15] FIG. 10 is an explanatory diagram showing cutting out of a motion section. [Figure 16] FIG. 10 is an explanatory diagram showing a flow of extracting muscle synergies from surface myoelectric potentials. [Figure 17] FIG. 10 is an explanatory diagram showing the movement of the hyoid bone and the signal of the laryngeal movement sensor. [Figure 18] FIG. 1 is an explanatory diagram illustrating non-negative matrix factorization (NMF). [Figure 19] FIG. 1 is an explanatory diagram showing the boundary between voluntary movement and involuntary movement. [Figure 20] FIG. 1 is an explanatory diagram showing a surface myoelectric potential (sEMG) signal during eating and swallowing. [Figure 21] FIG. 10 is an explanatory diagram showing a signal from a laryngeal behavior sensor. [Figure 22] FIG. 10 is an explanatory diagram showing a spatial pattern. [Figure 23] FIG. 10 is an explanatory diagram showing synergy analysis. [Figure 24] FIG. 1 is an explanatory diagram showing a spatial pattern and a temporal pattern. [Figure 25]FIG. 10 is an explanatory diagram showing the spatial pattern of the sum of RMS signals and each synergy at the start of lifting. [Figure 26] FIG. 10 is an explanatory diagram showing the spatial pattern of each synergy and the sum of RMS signals 0.25 seconds after the start of lifting. [Figure 27] FIG. 10 is an explanatory diagram showing the spatial pattern of each synergy and the sum of RMS signals 0.5 seconds after the start of lifting. [Figure 28] FIG. 10 is an explanatory diagram showing the spatial pattern of each synergy and the sum of RMS signals 0.75 seconds after the start of lifting. [Figure 29] FIG. 10 is an explanatory diagram showing the spatial pattern of each synergy and the sum of RMS signals 1.0 seconds after the start of lifting. [Figure 30] FIG. 10 is an explanatory diagram showing spatial and temporal patterns of muscle synergies according to the strength of voluntary swallowing. [Figure 31] 1A and 1B are explanatory diagrams showing the relationship between an RMS signal and a laryngeal behavior sensor, and diagrams showing the transition of each synergy. [Figure 32] FIG. 1 is an explanatory diagram showing the relationship between muscle synergies and muscles. [Figure 33] FIG. 1 is an explanatory diagram showing the relationship between muscle synergies and hyoid bone movement. [Figure 34] FIG. 1 is an explanatory diagram showing the relationship between muscle synergy and swallowing mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to the accompanying drawings, which conceptually (schematically) illustrate the general configuration of an eating and swallowing function evaluation system. [Example]

[0024] As shown in Figures 1 and 2, eating and swallowing is a series of actions that involve recognizing food, bringing it to the mouth, chewing it in the oral cavity, and transporting it through the pharynx and esophagus to the stomach, and is divided into five stages: the anticipatory stage, preparatory stage, oral stage, pharyngeal stage, and esophageal stage. Swallowing refers to the stages from the oral stage to the esophageal stage, and is achieved by a complex physiological mechanism in which voluntary and reflex movements coexist. Note that eating and swallowing function also includes chewing function.

[0025] Voluntary movement primarily refers to the movement of the tongue to send the bolus formed by mastication into the pharynx. Reflex movement refers to the movement of the swallowing reflex to pass the bolus through the pharynx into the esophagus. The swallowing reflex is realized by the CPG (central pattern generator) in the medulla oblongata, creating a highly reproducible pattern movement. Therefore, whether or not a person can swallow is largely dependent on whether or not there are problems with oral movement or a breakdown in the swallowing reflex.

[0026] The time required for swallowing, including the oral and pharyngeal stages, is said to be about one second, and during this short time, the following events occur consecutively in a set order: 1) closing of the lips, 2) the tongue transferring the food bolus to the pharynx, 3) closure of the nasopharynx, 4) fixing of the mandible in a closed position, 5) laryngeal closure due to elevation of the larynx and inversion of the epiglottis, 6) opening of the lower pharynx due to forward movement of the larynx, 7) closure of the glottis and increase in expiratory pressure, and 8) relaxation of the sphincter at the entrance to the esophagus.

[0027] The suprahyoid muscles elevate the hyoid bone and larynx upward and forward. The infrahyoid muscles are activated by the reflex movement of the suprahyoid muscles, and contraction of the thyrohyoid muscle elevates the larynx to its highest position and inverts the epiglottis (laryngeal closure). At this time, the hyoid bone in particular is considered to be an important bone in closing the airway.

[0028] As shown in Figure 3, eating and swallowing function generally declines due to cerebrovascular disorders, neuromuscular diseases, muscle weakness due to aging, and changes in the position of the swallowing organs. Furthermore, if swallowing problems arise due to systemic diseases, food boluses may remain in the pharynx, penetrate the larynx, or be aspirated, resulting in an increased risk of developing aspiration pneumonia.

[0029] It is known that people with impaired eating and swallowing function have the following: (1) hyoid and laryngeal ptosis (the position of the Adam's apple drops, requiring a greater amount of lift to close the larynx); (2) a decrease in the amount of lift and forward movement of the hyoid and larynx (insufficient lift prevents adequate laryngeal closure); (3) a delay in laryngeal elevation due to a decrease in laryngeal elevation speed (delay in the timing of laryngeal closure); (4) a delay or absence of the swallowing reflex (the reflex is difficult to initiate, delaying the timing of laryngeal closure, or the reflex does not occur and the larynx cannot be closed); and (5) a decrease in endurance and ability to respond to changes in the volume and physical properties of a single swallow (a decrease in endurance and the ability to appropriately adjust the movement of the swallowing organs to suit the food).

[0030] Traditionally, electromyography (EMG) measurements during swallowing have long been used to evaluate swallowing function, but only the maximum amplitude (related to the strength of muscle activity) or the integration of amplitude (related to the amount of muscle activity) of the series of muscle activity from the start to the end of swallowing have been evaluated. This has prevented detailed evaluation of how each muscle constituting the swallowing organs corresponds to each stage of swallowing, or which muscles coordinate with what activity level, timing, and duration. Detailed evaluation requires synchronized measurement of muscle activity and videofluoroscopic swallowing (VF) studies, but as mentioned above, VF involves the risk of contrast aspiration and radiation exposure.

[0031] Therefore, the inventors focused on the hyoid muscles, which are composed of the suprahyoid muscles (digastric, stylohyoid, mylohyoid, and geniohyoid) and the infrahyoid muscles (sternohyoid, omohyoid, sternohyoid, and thyrohyoid), which control the hyoid bone, which is important for laryngeal closure.

[0032] As shown in Figure 4, there are 14 muscles that control the movement of the hyoid bone, including the suprahyoid and infrahyoid muscles. The hyoid bone, on the other hand, has six degrees of freedom: translational movement along the X, Y, and Z axes, and rotational movement around each axis. This means that the hyoid bone is controlled by a redundant system. These muscles are concentrated in the anterior neck, making it impractical to simultaneously and separately evaluate the activity of all of the muscles during swallowing. Therefore, we attempted to evaluate the activity of the hyoid muscles using synergy analysis, which can estimate coordination patterns from the combined signals of multiple muscles. The synergy hypothesis is a method for analyzing human movement based on muscle synergy.

[0033] As shown in Figure 5, humans have many muscles and joints. In order to perform a desired movement, it is necessary to control all of them. However, when the degrees of freedom of muscles and joints are greater than the degrees of freedom of the desired movement, there are countless combinations of muscle output and joint angles when determining the movement, making it difficult to determine the control commands. This kind of redundancy in the body is called the "Bernstein problem."

[0034] In response to this, Bernstein proposed the muscle synergy hypothesis, which states that muscles and joints are not controlled separately, but that multiple muscles and joints are modularized and controlled collectively. A modularized system that operates in the same pattern is called a synergy, and muscle synergy is called muscle synergy. Various movements of the human body have been analyzed for synergy, and it has been shown that muscle synergy can be extracted from surface electromyography (sEMG) signals of multiple muscles, and that muscle coordination patterns can be estimated by evaluating this.

[0035] Furthermore, muscle synergies have been evaluated not only in healthy individuals but also in patients with paralysis or other diseases, and quantitative understanding of the differences and characteristics between healthy individuals and patients has been progressing. However, most of these evaluations have focused on upper and lower limb movements, and muscle synergy evaluation in the stomatognathic region, including eating and swallowing, has not progressed. Therefore, the inventors applied the muscle synergy hypothesis to the coordinated movements of the suprahyoid and infrahyoid muscles, which are closely related to eating and swallowing function, and obtained findings.

[0036] The purpose of this study was to extract muscle synergies in the control of the hyoid bone by the hyoid muscles, which can be considered a redundant system, in order to quantify the decline in eating and swallowing function due to aging or disease and to identify the causes of eating and swallowing disorders.As a first step toward this, muscle synergies were extracted from sEMG signals of the suprahyoid and infrahyoid muscles, which can be measured from the anterior neck of healthy young people, and by using this, we considered the type of coordinated movement that pulls the hyoid bone during swallowing.

[0037] Next, the overall configuration of the eating and swallowing function evaluation system 10 according to the embodiment of the present invention will be described. 6 and 10, the eating and swallowing function evaluation system 10 includes a sensor unit 20 that detects biosignals at least from the start to the end of swallowing, out of the period from the start to the end of eating and swallowing, a multifunctional electromyography measuring device 30 that extracts feature quantities from the detected biosignals, an analysis unit 40 that identifies the stage of eating and swallowing from the feature quantities and evaluates eating and swallowing function, a recording unit (not shown) that records the evaluation results, a display unit (not shown) that displays the evaluation results, and batteries 31, 41 that supply power to these. The analysis unit 40 may be configured to include a substrate 30. The analysis unit 40 may also be provided with a recording unit and a display unit.

[0038] As shown in Figures 7 to 12, the sensor unit 20 of the eating and swallowing function evaluation system 10 includes a suprahyoid muscle electromyography sensor 21 that is placed in the suprahyoid muscle group area and detects suprahyoid muscle biosignals due to muscle activity of the suprahyoid muscle group, a subhyoid muscle electromyography sensor 22 that is placed in the infrahyoid muscle group area and detects infrahyoid muscle biosignals due to muscle activity of the infrahyoid muscle group, and a laryngeal behavior sensor 25 that is placed in the laryngeal area and detects laryngeal behavior signals due to elevation of the larynx.

[0039] The myoelectric sensor 21 for the suprahyoid muscles uses an array electrode in which multi-channel electrodes 21a are aligned. The myoelectric sensor 22 for the infrahyoid muscles uses an array electrode in which multi-channel electrodes 22a are aligned.

[0040] The analysis unit 40 extracts feature quantities from the suprahyoid muscle group biosignals detected by the suprahyoid muscle group electromyography sensor 21a, the infrahyoid muscle group biosignals detected by the infrahyoid muscle group electromyography sensor 22a, and the laryngeal behavior signal detected by the laryngeal behavior sensor 25.

[0041] Furthermore, the analysis unit 40 identifies the stages from the start of swallowing to the end of swallowing by capturing time-series changes in the features (i.e., the spatial and temporal patterns of muscle synergies) extracted from the biosignals of the suprahyoid muscles and the infrahyoid muscles, and evaluates the eating and swallowing function by capturing the combination of relative activity levels of each muscle in the coordinated movement of the swallowing organs corresponding to each stage, as well as time and state changes such as the magnitude, timing, and duration of that activity.

[0042] In detail, the eating and swallowing function evaluation system 10 is composed of a 22-channel flexible electrode as an electromyographic sensor 21a for the suprahyoid muscles and an electromyographic sensor 22a for the infrahyoid muscles, an elastic strain sensor as a laryngeal behavior sensor 25, and a multi-function electromyographic measuring device 30 included in the analysis unit 40.

[0043] The sEMG signals from each electrode of the 22-channel flexible electrode connected to the multifunctional myoelectric potential measuring device 30 are derived by differentially amplifying the potential difference between an indifferent electrode attached to an earlobe and each electrode of the 22-channel flexible electrode, with the ground electrode attached to the other earlobe as the potential reference. The common-mode noise component derived from the indifferent electrode is inverted and amplified, and fed back to an RLD (Right Leg Drive) electrode attached to the seventh cervical vertebra, thereby canceling out noise that was mixed in during measurement.

[0044] The gain of the sEMG signal was set to 125. The elastic strain sensor 25 output an analog voltage corresponding to the expansion and contraction from a power supply voltage of 3 V supplied from the multifunctional myoelectric potential measuring device 30. The signal gain was set to 0.5 so as not to exceed the measurement range. All signals were simultaneously sampled by a 16-bit AD converter installed in the multifunctional myoelectric potential measuring device 30 and input into the analysis unit (PC) 40. The sampling frequency was set to 2 kHz.

[0045] Two types of 22-channel flexible electrodes are connected to the multifunctional myoelectric potential measurement device 30 for use. The 22-channel flexible electrode (a) for the suprahyoid muscles is shaped so as not to interfere with the occipital region and can also measure the muscle activity of the stylohyoid muscle located deep at the base of the mandible. The 22-channel flexible electrode (b) for the infrahyoid muscles is shaped so as not to interfere with the movement of the laryngeal prominence. The substrate itself is approximately 120 μm thick, and the entire substrate is covered with silicon to protect it. sEMG signals are extracted via silver electrodes embedded in the silicon. The silver electrodes are 2 mm in diameter and 3.5 mm high. The 22-channel flexible electrode (a) is embedded at intervals of 8 mm vertically and 11.5 mm horizontally, and is arranged to cover the entire mandible.

[0046] The 22-channel flexible electrodes (b) were embedded at intervals of 8 mm vertically and 8 mm horizontally, with 22 electrodes arranged to cover the front of the neck. In addition, a ground electrode (not shown) and an insensitive electrode of the bipolar electrode were placed on the left and right earlobes, and an RLD electrode was placed on the seventh cervical vertebra. During measurement, a paste (Elefix, Nihon Kohden) was applied to the electrode surface to reduce contact resistance. The 22-channel flexible electrodes were attached to the subject, and the obtained signals were sent to a multi-function myoelectric potential measuring device after undergoing impedance conversion using an operational amplifier.

[0047] Additionally, the laryngeal behavior sensor (hereafter referred to as the stretchable strain sensor) 25 used was C-STRETCH (F51FS01, Bando Chemical Industries, Ltd.). This sensor is a capacitance-type strain sensor consisting of an elastomer film and a protective film, and when a power supply voltage is input, it linearly outputs an analog voltage corresponding to the stretch. The stretchable part of the sensor is 50 mm long and 5 mm wide. The stretch range is 0 to 100%.

[0048] The multifunctional myoelectric potential measuring device 30 is a measuring device for monitoring biological activity, designed to use multiple different sensors simultaneously. It is capable of simultaneously sampling up to 64 channels of sensors. It is connected to an analysis unit (PC) 40 for importing measurement data via a USB 2.0 (High Speed) interface. The device can also be controlled from any application software. It operates on a DC 12 (V) AC adapter or external battery input power supply.

[0049] As shown in Figures 9 and 11, when attaching the 22-channel flexible electrode (a) and the 22-channel flexible electrode (b), they were taped and then fixed with a jig (hat and band) for electrode (a) as a jig 27 for the myoelectric sensor for the suprahyoid muscles, and a jig (band) for electrode (b) as a jig 28 for the myoelectric sensor for the infrahyoid muscles.

[0050] Next, the muscle synergy extraction algorithm will be explained. As shown in Figure 13, the muscle synergy hypothesis assumes that muscle activity is composed of a combination of muscle modules that work in concert with each other and their activity patterns. This can be expressed by Equation 1.

[0051]

number

[0052] Here, M is the muscle activity matrix, the number of measurement channels is ch, the number of measurement samples is T, and the muscle activity for each channel is expressed by the following equation:

[0053]

number

[0054] Using this, the muscle activation matrix is ​​expressed as Equation 3

[0055]

number

[0056] Here, the number of muscle synergies, which is the number of muscle modules, is set to s. The maximum number of s is the same as the number of channels. Each module is expressed in the form of a weight for each channel.

[0057]

number

[0058] Furthermore, the activity patterns of each module are

[0059]

number

[0060] Then, the spatial pattern W and the temporal pattern C are

[0061]

number

[0062]

number

[0063]

number

[0064] When ch>s, it can be seen that the time series activity pattern is decreasing. At this time, the muscle activity m i teeth,

[0065]

number

[0066] In this study, muscle contraction was considered positive, and M, W, and C were all treated as non-negative matrices. Then, non-negative matrix factorization (NMF) was used to decompose the muscle activity matrix M, which is a non-negative matrix, into non-negative matrices W and C, and muscle synergies were extracted.

[0067] The main flow of muscle synergy extraction is shown in Figure 14. MATLAB (registered trademark) R2019b (Math Works Japan) was used for signal processing.

[0068] Next, full-wave rectification will be described. The measured sEMG signals were filtered using a sixth-order Butterworth filter with a cutoff value of 30-500 Hz to remove noise. Then, RMS (Root Mean Square) processing was performed for every 128 ms frame, resulting in full-wave rectification. Even during periods of no movement, minute potentials were measured, resulting in signals that were not zero. Therefore, the RMS signal was offset based on the average value of the periods of no movement, with negative values ​​set to zero. The signals were then smoothed using a 10-point moving average, and this processing was performed for all channels.

[0069] Next, the extraction of the motion section will be described. Threshold processing was performed on the laryngeal movement signal obtained from the elastic strain sensor 25, and the laryngeal lift start point was calculated as shown in Figure 15. In this invention, we attempted to capture laryngeal movement by directly applying a C-STRETCH, which has a fast and accurate stretch response, to the neck. To verify the validity of this approach, a VF test was performed using an elastic strain sensor. The results are shown in Figure 15. Along with the movement of the hyoid bone, the difference between the time of the velocity change and the lift start point determined by the elastic strain sensor 25 was approximately 30 ms, indicating that this approach is valid. Note that in Figure 15, the RMS signal was extracted for a total of 2 seconds, assuming that voluntary movement occurs 0.5 seconds before the lift start point and involuntary movement occurs 1.5 seconds after.

[0070] Next, we will explain muscle synergy extraction using NMF. NMF is equivalent to a statistical method of principal component analysis with a non-negative constraint. In the present invention, the alternating least squares method is used as the factorization algorithm. When Formula 1 is solved for W and C,

[0071]

number

number

[0072] These equations are equivalent to applying the least squares method to one of W and C as a constant and the other as a constant.

[0073]

number

number

[0074] It is transformed as follows. W0 is determined randomly as the initial value. C1 is calculated from W0 and M using formula 13. Next, W1 is calculated from C1 and M using formula 14. W and C are updated alternately in this way. When updating, a non-negative constraint is imposed by setting all negative components to 0. W n-1 and W n or C n-1 and C n This update was continued until the change in W became small. In this way, the least squares method was applied alternately to find the optimal W and C.

[0075] With this algorithm, the update may occasionally end at a local solution, resulting in W and C of a lower rank than the specified rank. In addition, the decomposition result is not uniquely determined, and even if the update completes successfully, the decomposition result may change slightly each time it is re-decomposed. Therefore, in order to obtain reproducible decomposition results, NMF was repeated 20 times for one swallowing data, and the decomposition result with the largest total correlation coefficient with the other 19 decomposition results was considered to be the most reproducible.

[0076] Using NMF, the muscle activity matrix (44 channels × number of samples) was decomposed into a spatial pattern (44 channels × number of components) and a temporal pattern (number of components × number of samples). The number of components was increased from 1 to 4. A total of six components were identified across all subjects, and those shared by many subjects and with high activity levels were labeled as muscle synergies of the hyoid muscles during eating and swallowing. From these, it was predicted that one swallowing session would be composed of approximately three muscle synergies. Therefore, muscle synergies were extracted by decomposing the matrix into three components. However, because the extracted components and their order are not consistent with NMF, noise components may be resolved. In such cases, components that could be determined to be muscle synergies were selected from the results of the four-component decomposition. The extracted muscle synergies were organized for each label as the mean ± standard deviation of 10 sessions of each eating and swallowing movement.

[0077] To verify whether the decomposition results can reproduce swallowing movements, the muscle activity matrix reconstructed from W and C when decomposed into components is defined as M', and the muscle activity for each channel is calculated as in Equation 2.

[0078]

number

[0079] year,

[0080]

number

[0081] The decomposition results were evaluated using VAF (variability accounted for), which was defined as follows:

[0082] Next, the muscle synergy extraction methods described above will be explained in detail with reference to the drawings. As shown in Fig. 16, the muscle activity matrix obtained from the suprahyoid muscle group bio-signals detected by the suprahyoid muscle group EMG sensor 21 and the infrahyoid muscle group bio-signals detected by the infrahyoid muscle group EMG sensor 22 is decomposed using NMF to obtain the spatial pattern and the temporal pattern of each muscle synergy, which are features.

[0083] At this time, the movement section is extracted by calculating the start of laryngeal lift using a threshold value from the laryngeal movement signal of the elastic strain sensor as the laryngeal movement sensor 25, as shown in FIG. 17, and the movement section is defined as 0.5 seconds before and 1.5 seconds after that point.

[0084] As shown in Fig. 18, the spatial and temporal patterns of the three muscle synergies are obtained from the RMS signals by non-negative matrix factorization (NMF). W and C are each calculated as the mean ± standard deviation of 10 measurements.

[0085] As shown in Figure 19, the boundary between voluntary and involuntary movement is measured by measuring the change in position of the laryngeal prominence as the expansion and contraction of an elastic strain sensor, which is a laryngeal behavior sensor 25. In this study, the elastic strain sensor was wrapped around the position of the laryngeal prominence at rest, so laryngeal elevation was measured as a decrease in neck circumference.

[0086] As shown in Fig. 11, the experimental method for extracting muscle synergies during eating and swallowing movements was to attach electromyography sensors 21 for the suprahyoid muscles, electromyography sensors 22 for the infrahyoid muscles, and laryngeal behavior sensors 25 to multiple subjects, and have them swallow 1 ml, 3 ml, and 6 ml of water at a time by natural swallowing and effortful swallowing, and measure the biosignals of the suprahyoid muscles, biosignals of the infrahyoid muscles, and laryngeal behavior signals.

[0087] Next, the results will be explained. Figure 20 shows sEMG signals (biosignals of the suprahyoid muscles and infrahyoid muscles) obtained when a subject swallowed 6 ml of water naturally. Figure 21 shows laryngeal behavior signals of the elastic strain sensor when a subject swallowed 6 ml of water naturally. Three components of muscle synergy were obtained.

[0088] As shown in FIG. 22, spatial patterns are obtained from the measurements of the suprahyoid muscle group myoelectric sensor 21 (suprahyoid muscle group electrode 21a) and the infrahyoid muscle group myoelectric sensor 22 (infrahyoid muscle group electrode 22a).

[0089] As shown in Fig. 23, by decomposing using NMF, muscle synergies A, B, and C in three components are extracted, and the spatial and temporal patterns of these three muscle synergies A, B, and C are shown in Fig. 24. In the temporal pattern, the temporal patterns of the three muscle synergies A, B, and C are displayed with three lines (mean, mean + standard deviation, mean - standard deviation).

[0090] For the hyoid muscle synergies A, B, and C during eating and swallowing under a given condition, the RMS signals of all 44 channels before decomposition at every 0.25 s from the onset of laryngeal movement are multiplied by the spatial and temporal patterns of the decomposed three-component muscle synergies A, B, and C. The waveforms obtained by multiplying the RMS signals of all 44 channels before decomposition at every 0.25 s from the onset of laryngeal movement are shown in Figure 25 at 0 s, in Figure 26 at 0.25 s, in Figure 27 at 0.5 s, in Figure 28 at 0.75 s, and in Figure 29 at 1.0 s. From these waveforms, the activity state of each muscle corresponding to each synergy can be determined. The RMS signals of all 44 channels can be restored by multiplying the temporal and spatial patterns of the three-component muscle synergies A, B, and C, respectively, and then adding them all together.

[0091] Figure 30 also shows three muscle synergies during effortful swallowing of 6 ml of water by different subjects.

[0092] As shown in Figure 31, the muscle activity of each of the three muscle synergies A, B, and C can be determined at time points (1), (2), and (3) after the start of laryngeal elevation, based on the muscle activity of each synergy. This shows that the activity level of muscle synergy A is high at time point (1), approximately 0.5 s after the start of elevation, the activity level of muscle synergy B is high at time point (2), approximately 0.75 s after the start of elevation, and the activity level of muscle synergy C is high at time point (3), approximately 1.0 s after the start of elevation. This analysis allows us to identify each stage of eating and swallowing, from the start to the end.

[0093] As shown in Figure 32, the spatial pattern of synergy A shows high activity mainly in the left and right suprahyoid muscles. Based on the relationship between the electrode positions where activity is observed and the muscle course, synergy A can be said to represent the activity of the mylohyoid muscle. The spatial pattern of synergy B shows high activity mainly in the center of the suprahyoid muscles, which can be said to represent the activity of the digastric and geniohyoid muscles. The spatial pattern of synergy C shows high activity mainly in the upper part of the infrahyoid muscles, which can be said to represent the activity of the thyrohyoid muscle. By looking at the distribution of activity in this way, it is possible to associate it with muscles, and to know which parts move and how during swallowing, and which muscles move at which stage of swallowing.

[0094] As shown in Figure 33, VF testing revealed that hyoid bone elevation during swallowing begins with retraction and then transitions to rapid forward movement. Each of these movements is thought to involve different muscles, and when compared with the extracted muscle synergies, the retraction movement is due to the action of the stylohyoid and mylohyoid muscles, which are the first to activate, and can be considered the activity of muscle synergy A. The forward movement is due to the significant action of the remaining suprahyoid muscles, and can also be considered the activity of muscle synergy B. In addition, combined with the activity of muscle synergy C of the thyrohyoid, which pulls the larynx, it can be seen that the elevation of the hyoid bone and larynx can be expressed by three muscle synergies. As shown, there is a correspondence with the currently known movements of the hyoid bone, and it can be said that the extracted results of this invention and the muscle correspondence are valid.

[0095] As shown in Figure 34, muscle synergies A and B correspond to the stages in which the suprahyoid muscles elevate the hyoid bone, and muscle synergy C corresponds to the stage in which the infrahyoid muscles elevate the larynx.

[0096] Based on the muscle synergy hypothesis, the relationship between each synergy and the swallowing mechanism can be explained as follows: The mylohyoid muscle initiates elevation of the hyoid bone (muscle synergy A), and the tongue first holds the bolus and transports it to the pharynx. At this time, the swallowing reflex is triggered. Subsequently, other suprahyoid muscles join in, further pulling and lifting the hyoid bone (muscle synergy B). Contraction of the suprahyoid muscles triggers a reflex movement in the infrahyoid muscles, contracting the thyrohyoid muscle and lifting the larynx to its highest position (muscle synergy C). The hyoid bone and larynx reach their maximum elevation, completely closing the airway and allowing the bolus to pass. After the bolus has completely passed, the hyoid bone and larynx return to their original positions, completing the swallow.

[0097] The average time from the start of muscle synergy A activity to the end of the peak of muscle synergy B, which is thought to correspond to the time from the start of hyoid elevation to its maximum elevation during one swallowing movement, was 0.769±0.173 s across all subjects. VF tests showed that the time from the start of hyoid elevation to the end of its maximum elevation was approximately 0.6 to 1 s. The subjects of the present invention were young, and this is considered appropriate for the muscle activity of sEMG signals measured from the anterior neck.

[0098] VF studies have shown that hyoid elevation during swallowing begins with retraction and then transitions to rapid forward elevation. These correspond to hyoid elevation associated with tongue movement and hyoid elevation for laryngeal closure, respectively. The forward elevation, particularly involving the geniohyoid muscle, is thought to be sufficiently reflected in muscle synergy B activity. This suggests that the onset of muscle synergy B activity may correspond to the onset of the swallowing reflex (the point at which the hyoid bone rapidly accelerates). Given that the thyrohyoid muscle contraction in the reflex often begins immediately after the onset of synergy B activity, this assessment is likely valid.

[0099] Next, the feeding and swallowing function evaluation method and feeding and swallowing function evaluation system according to the present invention and their effects will be described.

[0100] [1] A method for operating an eating and swallowing function evaluation system that includes a sensor unit that detects biosignals from at least the start of swallowing to the end of a series of actions from the start of eating and swallowing to the end, and an analysis unit that extracts feature amounts from the biosignals, identifies the stage of eating and swallowing from the feature amounts, and evaluates eating and swallowing function, the sensor unit includes a suprahyoid muscle group electromyogram sensor that is disposed in the suprahyoid muscle groups and detects suprahyoid muscle group biosignals due to muscle activity of the suprahyoid muscle groups, and an infrahyoid muscle group electromyogram sensor that is disposed in the infrahyoid muscle groups and detects infrahyoid muscle group biosignals due to muscle activity of the infrahyoid muscle groups, extracting feature amounts from the suprahyoid muscle group biosignals detected by the suprahyoid muscle group electromyography sensor and the infrahyoid muscle group biosignals detected by the infrahyoid muscle group electromyography sensor, an analysis unit that captures time-series changes in the feature amounts of the biosignals of the suprahyoid muscles and the infrahyoid muscles to identify the stage from at least the start to the end of the swallowing, and analyzes the eating and swallowing function by capturing the relative activity combinations of the individual muscles of the suprahyoid muscles and the infrahyoid muscles in the coordinated movements of the swallowing organs corresponding to the stage, the magnitude of the activity, the timing of the activity, and the change over time of the activity; and a display unit that displays the analyzed results.

[0101] This configuration identifies stages from the start to the end of swallowing by capturing time-series changes in features (i.e., spatial and temporal patterns of muscle synergies) extracted from the suprahyoid and infrahyoid biosignals. This allows for analysis of swallowing function by capturing the relative activity levels of individual muscles in the suprahyoid and infrahyoid muscles in the coordinated movements of the swallowing organs corresponding to each stage, as well as the magnitude, timing, and temporal changes of those activities. Because no X-ray fluoroscopy device is required, there is no risk of radiation exposure or aspiration of food containing contrast agents. The device does not require space and can be used for analysis at the bedside or in home care. Furthermore, unlike machine learning, there is no need to repeat swallowing dozens of times under the same swallowing conditions.

[0102] Furthermore, it is possible to determine which muscles are moving in coordination at which stage of eating and swallowing, and with what level of activity, timing, and duration. This will improve the assessment of eating and swallowing function. Furthermore, by using multiple sensors in an array, it is possible to perform a more detailed assessment of eating and swallowing function corresponding to each stage of eating and swallowing.

[0103] [2] Preferably, the sensor unit uses at least one of the electromyographic sensor for the suprahyoid muscles or the electromyographic sensor for the infrahyoid muscles, and the electromyographic sensor for the suprahyoid muscles and the electromyographic sensor for the infrahyoid muscles use an array electrode in which multi-channel electrodes are arranged.

[0104] In conventional electromyography, electrodes are attached and their positions are determined based on anatomical knowledge such as the course of the muscles, their origins and insertions, which requires time and effort. In this regard, the above-described configuration, by using an array electrode, makes it possible to identify the muscles beneath which the electrode positions correspond to each stage of eating and swallowing, as well as the number of muscles involved.

[0105] [ 1Preferably, the analysis unit uses, as the feature quantity, a feature quantity converted based on the muscle synergy hypothesis, which states that each muscle of the suprahyoid muscle group and the infrahyoid muscle group is not controlled individually, but is controlled by the coordinated movement of multiple muscles.

[0106] This configuration uses the muscle synergy hypothesis, which states that muscles are not controlled individually but through the coordinated movement of multiple muscles. By extracting and visualizing muscle synergies, it is possible to evaluate the eating and swallowing function by determining which electrode position corresponds to each stage of eating and swallowing, and the activity level and timing of the coordinated movement, without strictly determining the electrode positions. Furthermore, by focusing on muscle synergies before the onset of the swallowing reflex, it is possible to evaluate the eating and swallowing function in the stage related to voluntary movements such as feeding a bolus. Furthermore, by focusing on muscle synergies after the onset of the swallowing reflex, it is possible to evaluate the eating and swallowing function in the stage related to involuntary movements such as the swallowing reflex.

[0107] Furthermore, because dysphagia is caused by problems with either voluntary or involuntary movements, or both, it can be identified by focusing on muscle synergies.Furthermore, by focusing on muscle synergies when the amount or physical properties of food are changed, it is possible to evaluate differences in response to swallowed materials, ease of fatigue, characteristics of age-related changes, and characteristics of people with dysphagia.

[0108] [ 3 Preferably, the analysis unit calculates the muscle synergies by nonnegative matrix factorization (NMF). Features Extract.

[0109] With this configuration, nonnegative matrix factorization NMF is equivalent to a statistical method of principal component analysis with a nonnegative constraint. Because nonnegative matrix factorization NMF is nonnegatively constrained and corresponds to the characteristic that muscles exert force only in the contraction direction, the results are easy to interpret, and visualization can make the results even easier to understand.

[0110] [ 4 Preferably, the analysis unit Features is composed of a spatial pattern that represents the relative combination of activities of each muscle in the coordinated movement of the muscles, and a time pattern that represents the time-series weighting coefficients for the spatial pattern and the timing of muscle activity.

[0111] With this configuration, for example, muscle synergies can be extracted and visualized by displaying spatial patterns in three dimensions. Visualization makes it easy to identify the muscles under which the electrodes correspond to each stage of eating and swallowing, the activity level, timing, and duration of coordinated movements, and the number of muscles involved.

[0112] Furthermore, according to the embodiment of the present invention, it is possible to identify what muscle synergies corresponding to each stage are composed of coordinated movements of what muscles, and to identify the relative activity combinations of individual muscles of the suprahyoid and infrahyoid muscles in the coordinated movements of the swallowing organs corresponding to each stage, as well as the magnitude, timing, and duration of the activity, from the characteristics of the spatial and temporal patterns of the muscle synergies. Furthermore, by extracting muscle synergies (and drawing a 3D graph thereof) from information on multi-channel electrodes appropriately attached without using anatomical knowledge, it is possible to identify which electrodes correspond to which muscles based on the relationship between the electrode positions where muscle activity is observed and the muscle paths at each stage.

[0113] Furthermore, by focusing on muscle synergies, it is possible to evaluate dysphagia function by focusing on the stages of bolus transport by the tongue through mastication and voluntary movements, and the stages from transport to the onset of the swallowing reflex. Furthermore, by focusing on muscle synergies, it is possible to evaluate dysphagia function by focusing on the stages from the onset of the swallowing reflex to the larynx reaching its highest position, and the stages during and after laryngeal closure. Furthermore, by focusing on the characteristics of spatial and temporal patterns, such as the activity time of each synergy, the time to the peak of each synergy, the time difference between the peak values ​​of each synergy, and the reproducibility and standard deviation of the temporal patterns, it is possible to quantify detailed dysphagia function. Furthermore, by focusing on the above changes when swallowing volume, physical properties, and swallowing frequency are changed, it is possible to evaluate dysphagia function, such as differences in response to swallowed materials, susceptibility to fatigue, characteristics of age-related changes, and characteristics of individuals with dysphagia. It can also be used to confirm the effects of swallowing rehabilitation and training.

[0114] In the embodiments, the laryngeal behavior sensor is an elastic strain sensor, but is not limited thereto. The laryngeal movement sensor may be a pressure sensor, an acceleration sensor, a non-contact sensor, or the like. Regarding muscle synergies, multiple components are extracted using non-negative matrix factorization (NMF). However, the present invention is not limited thereto. Other methods include so-called independent component analysis (ICA), principal component analysis (PCA), factor analysis (FA), and dimension reduction methods and mathematical analysis techniques based on or combining these. In the embodiments, the suprahyoid muscle group electromyographic sensors and the infrahyoid muscle group electromyographic sensors are array-shaped electrodes. However, the suprahyoid muscle group electromyographic sensors and the infrahyoid muscle group electromyographic sensors do not need to be array-shaped at equal intervals, and multiple electrodes (at least two channels) may be provided in order to obtain muscle synergies. In the above description and drawings, even when referring to eating and swallowing, the term "swallowing" is used where appropriate.

[0115] That is, the present invention is not limited to the examples as long as the functions and effects of the present invention are exhibited. [Industrial Applicability]

[0116] The present invention is suitable for an eating and swallowing function evaluation technology that detects biological signals from the start to the end of eating and swallowing, extracts features from the detected biological signals, and identifies each stage of eating and swallowing to evaluate eating and swallowing function. [Explanation of symbols]

[0117] 10...Eating and swallowing function evaluation system, 20...Sensor unit, 21...Electromyographic sensor for suprahyoid muscles, 21a...Electrode, 22...Electromyographic sensor for infrahyoid muscles, 22a...Electrode, 25...Laryngeal behavior sensor (elastic strain sensor), 30...Multifunctional electromyographic measuring device, 40...Analysis unit.

Claims

1. A method for operating an eating and swallowing function evaluation system including: a sensor unit that detects biological signals at least from the start of swallowing to the end of a series of actions from the start of eating and swallowing to the end; and an analysis unit that extracts feature amounts from the biological signals, identifies the stage of eating and swallowing from the feature amounts, and evaluates eating and swallowing function, the sensor unit includes a suprahyoid muscle group electromyogram sensor that is disposed in the suprahyoid muscle groups and detects suprahyoid muscle group biosignals due to muscle activity of the suprahyoid muscle groups, and an infrahyoid muscle group electromyogram sensor that is disposed in the infrahyoid muscle groups and detects infrahyoid muscle group biosignals due to muscle activity of the infrahyoid muscle groups, extracting feature amounts from the suprahyoid muscle group biosignals detected by the suprahyoid muscle group electromyography sensor and the infrahyoid muscle group biosignals detected by the infrahyoid muscle group electromyography sensor, an analysis unit that captures time-series changes in the feature amounts of the biosignals of the suprahyoid muscles and the infrahyoid muscles to identify the stage from at least the start to the end of the swallowing, and analyzes the eating and swallowing function by capturing the relative activity combinations of the individual muscles of the suprahyoid muscles and the infrahyoid muscles in the coordinated movements of the swallowing organs corresponding to the stage, the magnitude of the activity, the timing of the activity, and the change over time of the activity; a display unit that displays the analyzed results, A method for operating an eating and swallowing function evaluation system, characterized in that the analysis unit uses, as the feature, a feature converted based on muscle synergy, in which each muscle of the suprahyoid muscle group and the infrahyoid muscle group is not controlled individually, but is controlled by the coordinated movement of multiple muscles.

2. A method for operating the eating and swallowing function evaluation system according to claim 1, A method for operating an eating and swallowing function evaluation system, characterized in that the sensor unit uses at least one of an electromyographic sensor for the suprahyoid muscles or an electromyographic sensor for the infrahyoid muscles, and the electromyographic sensor for the suprahyoid muscles and the electromyographic sensor for the infrahyoid muscles use array electrodes in which multi-channel electrodes are arranged.

3. A method for operating the eating and swallowing function evaluation system according to claim 1 or 2, comprising: The method for operating a swallowing function evaluation system is characterized in that the analysis unit extracts features from the muscle synergies by nonnegative matrix factorization (NMF).

4. A method for operating the eating and swallowing function evaluation system according to claim 3, comprising: The analysis unit is characterized in that the feature of the muscle synergy is composed of a spatial pattern representing a combination of relative activities of each muscle in the coordinated movement of the muscles, and a time pattern representing a time-series weighting coefficient for the spatial pattern and a timing of muscle activity.

Images