Patent Application
20230127412
The present invention relates to a method of preventing a fall risk and an apparatus for performing the method. More specifically, the present invention relates to a method of preventing a fall risk, which is capable of preprocessing gait data and providing information used for preventing a fall that may occur while a user is walking to the user beforehand, and an apparatus for performing the method.
With the development of various smart technologies, data on personal daily activities can be recorded and personal life can be managed more efficiently based on the recorded data. Amid this, interest in health is increasing, and thus health-related data logging is being focused on. Many users are already generating and utilizing various pieces of health-related data, such as the users' exercise, diet, sleep, and the like, through user devices such as smartphones and wearable devices. In the past, health-related data was generated and managed only by medical institutions, whereas users have now started to generate and manage their own health-related data through user devices such as smartphones or wearable devices.
Health-related data logging is often performed through wearable devices. A wearable device is a user device that is carried or attached to a user's body. Wearable devices are being widely used to collect health-related data due to the development of the Internet of Things and the like. A wearable device can collect information on changes in a user's body and data on an environment surrounding the user through a device, and can provide advice necessary for the user's health on the basis of the collected data.
Currently, a procedure for providing feedback using health-related data acquired through a wearable device cannot be elaborated and thus cannot be utilized for specific medical practices. However, according to the development of user devices capable of collecting various pieces of health-related data in addition to the wearable devices and the refinement of decision algorithms based on the health-related data obtained through the user devices, the health-related data obtained through the user devices can be used for actual medical practices.
Health-related data logging also enables analysis of risks that can occur in a user's life. Specifically, it is possible to determine a fall risk through a wearable device and provide information on the fall risk beforehand to a user. There is a need for specific research and development on techniques for performing fall estimation based on data.
The present invention is directed to solving all of the above problems.
Further, the present invention is directed to collecting gait data of a user and estimating a fall risk that may occur for the user to prevent a fall.
Further, the present invention is also directed to more accurately estimating a fall risk that may occur for a user in consideration of a gait speed of the user through preprocessing of gait data of the user.
A representative configuration of the present invention for achieving the above objects is as follows.
According to an aspect of the present invention, there is provided a method of preventing a fall risk, including receiving, by a fall prevention apparatus, gait data, generating, by the fall prevention apparatus, gait analysis data on the basis of analysis of the gait data, and generating, by the fall prevention apparatus, fall prevention data on the basis of the gait analysis data.
Meanwhile, analysis of the gait analysis data may be performed based on a maximum peak and a minimum peak appearing in the gait data, and the gait analysis data may include data on a gait speed and balance of both feet.
Further, the gait speed may be determined based on a step interval time determined based on the maximum peak, and the balance of both feet may be determined using an impulse calculated based on an amplitude between the maximum peak and the minimum peak.
According to another aspect of the present invention, there is provided a fall prevention apparatus for preventing a fall risk, including a gait data input unit configured to receive gait data, a gait data analysis unit configured to generate gait analysis data on the basis of analysis of the gait data, and a fall prevention unit configured to generate fall prevention data on the basis of the gait analysis data.
Meanwhile, analysis of the gait analysis data may be performed based on a maximum peak and a minimum peak appearing in the gait data, and the gait analysis data may include data on a gait speed and balance of both feet.
Further, the gait speed may be determined based on a step length and a step interval time which are determined based on the maximum peak and the minimum peak, and the balance of both feet may be determined using an impulse calculated based on an amplitude between the maximum peak and the minimum peak.
The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:
The detailed description of the present invention will be made with reference to the accompanying drawings showing examples of specific embodiments of the present invention. These embodiments will be described in detail such that the present invention can be performed by those skilled in the art. It should be understood that various embodiments of the present invention are different but are not necessarily mutually exclusive. For example, a specific shape, structure, and characteristic of an embodiment described herein may be implemented in another embodiment without departing from the scope and spirit of the present invention. In addition, it should be understood that a position or arrangement of each component in each disclosed embodiment may be changed without departing from the scope and spirit of the present invention. Accordingly, there is no intent to limit the present invention to the detailed description to be described below. The scope of the present invention is defined by the appended claims and encompasses all equivalents that fall within the scope of the appended claims. Like reference numerals refer to the same or like elements throughout the description of the figures.
Hereinafter, in order to enable those skilled in the art to practice the present invention, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In
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The gait data input unit 100 may be implemented to receive gait data. The gait data may be generated by a separate wearable device (e.g., a smart belt) and transmitted to the gait data input unit 100, or the gait data may be directly generated by the fall prevention apparatus and transmitted to the gait data input unit 100.
The gait data analysis unit 110 may be implemented to analyze the input gait data. The gait data analysis unit 110 may determine a gait step on the basis of analysis of the gait data and determine a gait speed on the basis of the gait step. Further, the gait data analysis unit 110 may determine an impulse on the basis of the gait data and determine a balance of both feet on the basis of the impulse. That is, the gait data analysis unit 110 may analyze the gait data to determine the gait speed and the balance of both feet.
Specifically, the gait data analysis unit 110 may process the gait data by performing a preprocessing operation on gait data, a peak detection operation, an erroneous detection removal operation, and an additional peak detection operation, extract gait analysis data such as the gait speed and the balance of both feet appearing in the gait data, and transmit the gait analysis data to the fall prevention unit 120.
The fall prevention unit 120 may be implemented to prevent falls on the basis of the gait analysis data. The fall prevention unit 120 may generate fall prevention data on the basis of the gait analysis data. The fall prevention data may include data on the likelihood of the user falling and prevention data for avoiding falls.
The fall prevention data generated by the fall prevention unit 120 may be provided to the user to inform the user of a fall risk. For example, the fall prevention apparatus may transmit the fall prevention data to a user device such as a smartphone of the user so that the user prepares for a fall beforehand.
The processor 130 may be implemented to control the operations of the gait data input unit 100, the gait data analysis unit 110, and the fall prevention unit 120.
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The gait data may be signal vector magnitude (SVM) data on each of x-, y-, and z-axis acceleration signals. SVM data 220 is data obtained by offsetting direction components of 3-axis acceleration data 200 with respect to gravity and extracting a magnitude of a signal vector. The SVM data 220 may be determined regardless of the mixed loss in the axial direction of the sensor.
Equation 1 below is an equation for determining the SVM data 220.
SVM=√{square root over (ACCx2+ACCy2+ACCz2)} <Equation 1>
ACCx denotes an x-axis acceleration value, ACCy denotes a y-axis acceleration value, and ACCz denotes a z-axis acceleration value.
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Further, the gait data analysis unit may determine an impulse on each foot on the basis of a difference in amplitude between a maximum peak (or upper peak) and a minimum peak (or lower peak) that are generated when one foot and the other foot touch the ground in the gait data obtained from a 3-axis acceleration sensor, and the gait data analysis unit may determine the balance of both feet on the basis of the impulses on both feet.
Hereinafter, a detailed operation of the gait data analysis unit is disclosed.
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The linear detrend process 410 may be used to extract the gait data from which a linear component is removed. The normalization process 420 is a process for matching ranges of a large amount of different gait data or making distributions similar, and the normalization process 420 may be performed through a process of dividing a value obtained by subtracting a mean from the gait data by variance. A difference of 1 when the distributions are similar is different from a difference of 1 when the distribution of values is very large. Therefore, in the present invention, the value obtained by subtracting a mean from the gait data is divided by the variance through the normalization process 420, and thus an effect due to the spread of the original distribution may be offset.
In the preprocessing operation 400, the linear detrend process 410 and the normalization process 420 are performed on the gait data, and then a filtering process 430 may be performed. A band-pass filter (e.g., a fourth-order finite impulse response (FIR) band-pass filter) having a cutoff frequency (e.g., 0.5 to 5 Hz) may be applied to the gait data, and thus the gait data may be processed to more easily detect the peaks in the peak detection operation later.
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The peak detection may be performed in units of 1 step 500, and a section from one peak to the next peak and then the next peak after that may be defined as 1 stride 520. That is, the 1 stride 520 may include 2 step units.
Referring to
In the present invention, peaks for determining a gait step and an impulse may be a minimum peak 560 and a maximum peak 570. In the peak detection operation 550, an operation for detecting a candidate minimum peak 560 and a candidate maximum peak 570 may be performed. The candidate minimum peak 560 and the candidate maximum peak 570 which are detected in the peak detection operation 550 may be peaks before fake peaks are removed.
The candidate maximum peak 570 and the candidate minimum peak 560 may be detected by setting lower and upper thresholds (e.g., 0.5) and finding local maxima and local minima from among the preprocessed gait data having a value greater than or equal to the thresholds.
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As results obtained by detecting the peaks after the removing of the fake peak 630,
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In the present invention, the erroneous detection removal operation 600 may be adaptively performed according to the gait speed. When the gait speed is relatively slow, relatively more peaks are generated due to the generation of several frequency components. Therefore, in order to prevent such erroneous detection of peaks, artificial-intelligence-based peak extraction learning modeling according to a gait speed may be generated, and fake peaks may be adaptively removed according to the gait speed.
The gait data analysis unit may determine a gait step on the basis of the maximum peak 660 and the minimum peak 650 after the fake peaks are removed through the erroneous detection removal operation 600.
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Information on additional gait characteristics may be extracted based on a plurality of additional peaks, which are generated in the gait data, except for the maximum peak and the minimum peak.
The additional peaks may be divided by one waveform on the basis of the extracted maximum peak and then additionally extracted within the divided section. Through such an additional peak extraction process, n additional peaks (e.g., n=3) may be extracted in the segmented section.
As a result, in gait speed data of 1.5 km/h, five feature points such as a foot flat 710, a push-off 720, a toe-off 740, a mid-stance 730, and a heel contact 750 may be detected as the maximum peak, the minimum peak, and the additional peaks. The five feature points may be used to extract additional gait features such as a swing phase and a stance phase. The additional peaks may be used to reduce the likelihood of the user falling by additionally determining the gait characteristics of the user.
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A maximum peak that is generated first is defined as a left foot and a maximum peak that is generated next is defined as a right foot, and a step interval time may be determined by multiplying the number of samples between steps by an acceleration sensor coefficient (e.g., 0 or 1).
Specifically, x-, y-, and z-axis acceleration signals that determine the gait data may be collected at 10 Hz (10 times per second), and ten pieces of gait data may be generated per second. In the case in which a peak-to-peak sample size is six, in consideration of the fact that six pieces of acceleration data are collected, 6*0.1=0.6 seconds, that is, 1 step time from a time the left foot is placed on the ground to a time the right foot touches the ground, may be regarded as 0.6 seconds, and it can be determined that the step interval time is 0.6 seconds.
Since the step interval time is determined, when a moving distance is determined through the steps, the gait speed may be determined by dividing a step length by the step interval time.
As the method of determining the gait speed, methods using height data or other pieces of body data (e.g., hip acceleration data) may be used. In the present invention, for convenience of description, a method of determining a gait speed using height data is disclosed.
The method of determining the gait speed using the height data has a small amount of computation and is simple, and thus the method makes it easy to collect long-term data. A method of determining a gait speed using hip acceleration data is a regression formula application method in which a change in center of mass of a vertical axis of an acceleration sensor is used as a variable, and thus the method makes it easy to collect short-term data.
In the present invention, step length estimation is performed based on the height data. The gait speed may be determined by dividing the estimated step length by the step interval time. The method of performing the step length estimation using the height data may be performed by applying a regression analysis result according to sex which is calculated based on a plurality of subjects.
Specifically, in the method of performing the step length estimation using the height data, a stride length may be determined by applying the regression analysis result according to sex calculated based on the plurality of subjects.
Equation 2 below shows equations for calculating male/female stride lengths based on the regression analysis result.
Male=(0.415×height)
Female=(0.413×height) <Equation 2>
The step length used in the present invention may be calculated by multiplying the stride length by a step coefficient (e.g., 1/2). The step coefficient may be a value having a correlation in a critical confidence interval for a relationship between the stride length and the step length.
When the step length is calculated, the gait data analysis unit may determine the gait speed by dividing the step length by the step interval time.
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The following is a description of data obtained by calculating impulses for nine subjects.
The experiment was performed three times each for nine subjects, and a plurality of first impulses 915 on a plurality of first steps and a plurality of second impulses 925 on a plurality of second steps, which are calculated from a total of 27 one-minute walking signals, may be collected. A mean value of the plurality of first impulses 915 and a mean value of the plurality of second impulses 925 may be determined.
Balance 950 of both feet may be determined by dividing the relatively larger mean value among the mean value of the plurality of first impulses 915 and the mean value of the plurality of second impulses 925 by the relatively smaller mean value.
As the balance 950 of both feet approaches 1, the impulses 915 and 925 of both feet are similar, and thus it is determined that balance of the body is good. As the balance 950 of both feet is further away from 1, the impulses 915 and 925 of both feet are different, and thus it is determined that the balance of the body is not good.
The gait data analysis unit may determine information on the impulses 915 and 925 and the balance 950 of both feet and transmit the information to the fall estimation unit.
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In the present invention, the balance 1050 of both feet may be expressed as distribution information for a specific speed. For example, when the gait speed 1000 of the user is x m/s, the balance 1050 of both feet may be expressed as a distribution when the user is walking at x m/s. For example, when it is assumed that the balance 1050 of both feet with the same impulse on the right foot and the left foot is 0, the balance 1050 of both feet may be set to have a negative value when the balance is shifted to the left foot based on 0, and to have a positive value when the balance is shifted to the right foot based on 0.
The fall risk degree may be determined as a numerical value based on the balance 1050 of both feet and the gait speed 1000. A score, the balance 1050 of both feet for determining the score, and a range of the gait speed 1000 are exemplary and may vary.
Table 2 below shows a first fall risk score 1020 according to the gait speed 1000.
As the gait speed 1000 decreases, the fall risk degree may be relatively high and a lower score may be assigned.
Table 3 below shows a second fall risk score 1060 according to the balance 1050 of both feet.
RFP denotes the impulse on the right foot, and LFP denotes the impulse on the left foot. The second fall risk score 1060 may be determined based on a value obtained by dividing an absolute value of a value obtained by subtracting the impulse on the left foot from the impulse on the right foot, or abs(RFP−LFP), by a maximum value among the impulse on the right foot and the impulse on the left foot, or max(RFP, LFP).
Table 4 below shows the fall risk degree 1080 based on the first fall risk score 1020 and the second fall risk score 1060.
A total score for estimating the likelihood of falling may be the sum of the first fall risk score 1020 and the second fall risk score 1060. The total score for estimating the likelihood of falling may be a value from 0 to 10, and it may be determined that the fall risk degree 1080 increases as the total score decreases.
Further, in the present invention, in addition to the likelihood of falling, information on the balance 1050 of both feet may be provided to the user as evaluation information on the balance of both feet, size information on the balance of both feet, and deviation information on the balance of both feet.
The evaluation information on the balance of both feet may be provided as shown in Table 5 below.
The balance of both feet may be evaluated based on an absolute value of a difference between the RFP and the LFP and may be provided in five levels (GOOD, FAIR, WORRIED, POOR, and BAD).
The deviation information on the balance of both feet may be provided as shown in Table 6 below.
A degree to which the balance is shifted to the left foot or the right foot with respect to the center of the difference value may be provided based on the deviation information on the balance of both feet.
The size information on the balance of both feet may be provided as shown in Table 7 below.
Based on a mean value of the impulses on the left foot and the right foot, information on the impulses generated in both feet may be provided based on the size information on the balance of both feet.
Further, according to the embodiment of the present invention, information on each of the 3-axis accelerations that generate the above-described gait data may be used for fall estimation.
When an x-axis acceleration is called Ax(t), a y-axis acceleration is called Ay(t), and a z-axis acceleration is called Az(t), a fall may be estimated more accurately based on a magnitude of movement by eliminating an effect of gravity.
Therefore, the fall estimation may be performed using Equation 3 below considering only a weight in a direction of gravity as shown below.
θ(t) denotes a left/right angle formed with the direction of gravity, and ψ(t) denotes a forward/rearward angle formed with the direction of gravity. ADVSM(t) denotes an amount of changes in acceleration. AθGDSVM(t) denotes a value obtained by amplifying a signal on the basis of θ(t) when the user is falling, and AψGDSVM(t) denotes a value obtained by amplifying a signal on the basis of ψ(t) when the user is falling.
When one of AθGDSVM(t) and AψGDSVM(t) exceeds a threshold value, a warning of the likelihood of falling may be provided to the user, when AθGDSVM(t) is greater than the threshold value, a warning of the likelihood of falling forward/rearward may be provided to the user, and when AψGDSVM(t) is greater than the threshold value, a warning of the likelihood of falling left/right may be provided to the user.
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Evaluation information on balance of both feet, size information on the balance of both feet, and deviation information on the balance of both feet may be provided on a second screen.
The information on the total score for estimating the likelihood of falling, the evaluation information on the balance of both feet, the size information on the balance of both feet, and the deviation information on the balance of both feet may be provided on a third screen and a fourth screen.
According to the present invention, by collecting gait data of a user, a fall risk that may occur for the user can be estimated, and thus falls can be prevented.
Further, according to the present invention, by performing preprocessing of the gait data of the user, a fall risk that may occur for the user can be estimated more accurately in consideration of a gait speed of the user, and thus falls can be prevented.
The embodiments of the present invention described above may be implemented in the form of program instructions that can be executed through various computer units and recorded on computer readable media. The computer readable media may include program instructions, data files, data structures, or combinations thereof. The program instructions recorded on the computer readable media may be specially designed and prepared for the embodiments of the present invention or may be available instructions well known to those skilled in the field of computer software. Examples of the computer readable media include magnetic media such as a hard disk, a floppy disk, and a magnetic tape, optical media such as a compact disc read only memory (CD-ROM) and a digital video disc (DVD), magneto-optical media such as a floptical disk, and a hardware device, such as a ROM, a RAM, or a flash memory, that is specially made to store and execute the program instructions. Examples of the program instruction include machine code generated by a compiler and high-level language code that can be executed in a computer using an interpreter and the like. The hardware device may be configured as at least one software module in order to perform operations of embodiments of the present invention and vice versa.
While the present invention has been described with reference to specific details such as detailed components, specific embodiments and drawings, these are only examples to facilitate overall understanding of the present invention and the present invention is not limited thereto. It will be understood by those skilled in the art that various modifications and alterations may be made.
Therefore, the spirit and scope of the present invention are defined not by the detailed description of the present invention but by the appended claims, and encompass all modifications and equivalents that fall within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0142549 | Oct 2021 | KR | national |
