TWI784815B - Calculation System of Gait Balance Index of Waist Inertial Sensing Device - Google Patents

Abstract

An inertial sensing device is installed on the back and waist of the subject and can measure and output attitude information Information; a walk test program, comprising the following steps: in a walk test period, the inertial sensing device measures the posture information of the subject's torso when walking, and records the posture information and the time point at which the posture information is measured To obtain timing information related to the attitude information, the timing information has multiple peaks and troughs; calculate the average time from the trough to the adjacent peak in the timing information, which is defined as the right tilt time TR, and from the peak to the phase The average time adjacent to the trough is defined as the left tilt time TL; the absolute value of the difference between the right tilt time TR and the left tilt time TL is divided by the height of the subject to obtain a height-corrected left and right time difference RDH gait balance index.

Description

Calculation System of Gait Balance Index of Waist Inertial Sensing Device

An inertial sensor, especially a gait balance index pusher of a waist inertial sensor calculation system.

Stroke patients have varying degrees of difficulty walking due to limb weakness. And because of the different conditions of stroke recovery, the compensatory gait is also different. In addition, clinicians or therapists assess the degree of recovery of stroke patients, often using functional assessments, such as the Fugl-Meyer Assessment scale (FMA scale) or the Berg balance scale (Berg balance scale or BBS scale). Most of these two scales require extra time for the therapist to evaluate, and the results of the evaluation are "ordinal data (ordinal data)", which is less likely to detect small changes. That is, these functional scales require a trained therapist or physician to perform the examination. Due to their own obstacles, stroke patients have already caused inconvenience in seeking medical treatment. In addition, the assessment of these scales is time-consuming and requires professional personnel to perform. Therefore, few doctors or therapists are able to assess each patient's medical treatment. Complete assessment of patient function.

Conventional inertial sensors used to assess the gait of stroke patients mostly focus on obtaining kinematics data. However, due to the complexity of gait problems after stroke, and the correlation between kinematic data and clinical scales is still unclear, the two are often used together in clinical practice.

Although the optical motion capture system can be used to observe and obtain the kinematic data of stroke patients, at the same time, related commercial software can calculate the gait related data of stroke patients, including the step distance during walking, the number of steps per minute, The asymmetry of the left and right feet, etc.; however, there are many clinical studies on the analysis and functional evaluation of stroke gait based on inertial sensors. The advantage of inertial sensors is that they are easy to implement in outpatient clinics and can be obtained The result is a continuous variable, an objective number, and it is possible to clearly know the relevant numbers of walking kinematics. However, because the compensatory state of stroke gait is related to the neural The recovery state is really complicated. For example, the age of the stroke patient, the location of the stroke, the size and type of the affected area, etc. will all affect the patient's gait. In addition, during the recovery process of the limbs, there are still spastic tension, walking aids, etc. Problems such as use will cause kinematic data to be unable to directly evaluate the recovery status of walking function of stroke patients; therefore, the current inertial sensor measurements and clinical evaluation scales, except for walking speed, cannot find objective Calculate metrics to make the two correspond to each other.

Therefore, how to make the measurement data of the inertial sensor correspond to the clinical scale more accurately, so that it is enough to measure the walking kinematics of stroke patients with an inertial sensor that is easier to operate, without using There is an urgent need for a more complex optical motion capture system to measure the gait of stroke patients.

In order to solve the above problems, the present invention discloses a gait balance index estimation system of a waist inertial sensing device, which includes the following technical content: an inertial sensing device can measure a posture message and output the posture message, the inertial sensing device The measuring device is arranged on the back and waist of a subject; the one-step test procedure includes the following steps: Step 1: In a walking test period, the inertial sensing device measures the torso of the subject when walking. Attitude information, and record the attitude information and measure the time point of the attitude information to obtain a timing information related to the attitude information, the timing information system has a plurality of peaks and valleys; step 2: a host through the inertial sensing The device receives the timing information, and calculates an average time from a trough to an adjacent peak in the timing information, and defines it as a right tilt time TR, and an average time from a peak to an adjacent trough, and defines it as Left tilt time TL; step 3: the host divides the absolute value of the difference between the right tilt time TR and the left tilt time TL by the subject's height to obtain a gait balance index of height-corrected left-right time difference RDH.

Preferably, the posture information refers to a sagittal plane rotation angle of the subject's torso when walking.

Preferably, wherein the inertial sensing device includes: an inertial sensing module, including: a microcontroller and a memory, a three-axis gyroscope, and an accelerometer in three directions, and can measure and output the Timing information; a communication module, electrically connected to the inertial sensing module, receiving the timing information and outputting the timing information to a host through wireless or wired transmission; a battery module, and the inertial sensing module and the communication module are electrically connected to provide power to the inertial sensing module and the communication module; an indicator light module is electrically connected to the inertial sensing module, the communication module, and the battery module , to display the running status of the inertial sensing device.

1: Inertial sensing device

2: Host

11: Inertial sensing module

12: Communication module

13: Battery module

14: Indicator light module

15: shell

21: The first inertial sensing device

22: Second inertial sensing device

23: The third inertial sensing device

24: The fourth inertial sensing device

25: Velcro

26: back

27: Right side of the body

28: left side of the body

31: clockwise

32: counterclockwise

FIG. 1 is a schematic diagram of an inertial sensing device of the present invention.

2A-2C are schematic diagrams of four inertial sensing devices of the present invention arranged at different positions of the human body.

FIG. 3 is a schematic diagram of the inertial sensing device of the present invention disposed on the lower back.

FIG. 4 is a schematic diagram of the clockwise/counterclockwise rotation direction of the inertial sensing device of the present invention disposed on the waist of the lower back.

Fig. 5 is a schematic diagram of the walking test of the subject of the present invention.

FIG. 6 is the measurement result of the inertial sensing device in the walking test of the subjects of the present invention.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of an inertial sensing device 1 of the present invention. The inertial sensing device 1 of the present invention includes an inertial sensing module 11, a communication module 12, a battery module 13, An indicator light module 14 and a casing 15 . Wherein the inertial sensing module 11 and the communication module 12, the The battery module 13 is electrically connected to the indicator light module 14, the communication module 12 is further electrically connected to the battery module 13 and the indicator light module 14, and the battery module 13 is further electrically connected to the indicator light module 14. connect. The shell 15 is used to accommodate and protect the inertial sensing module 11 , the communication module 12 , the battery module 13 , and the indicator light module 14 .

The inertial measurement module 11 has an inertial measurement unit (Inertial Measurement Unit, IMU), a microcontroller and a memory. The inertial measurement unit has a three-axis gyroscope and an accelerometer in three directions, which can be used to measure Angular velocity and acceleration of an object in three-dimensional space, and deduce the posture of this object accordingly, for example described inertial measurement unit and described accelerometer can be respectively, but not limited to, InvenSense company's ITG-3200 (micro-electromechanical Three-axis gyroscope) and Analog Devices' IADXL345 (low-power three-axis accelerometer). The inertial sensing module 11 can output the measured and calculated attitude data of an object to the communication module 12, and then send it to a host 2 through the communication module 12, the host 2 has an application program and A graphical interface, the user controls the host 2 through the application program and the graphical interface to receive, integrate and calculate the attitude data of objects from multiple inertial sensing modules 11, and integrate the integrated And the calculated result is displayed on a display device. The host 2 can be a server, a personal computer or a mobile device such as a mobile phone or a tablet computer.

The communication module 12 supports wireless communication technologies such as Bluetooth (Bluetooth) or ZigBee (ZigBee) or general wired communication technologies such as USB, I2C, GPIO, RS-232, etc., and can communicate with the host 2 to Information is transmitted between the inertial sensing module 11 and the host 2 . The battery module 13 provides power to the inertial sensing module 11 , the communication module 12 and the indicator light module 14 . The indicator light module 14 has a plurality of LED lights, and the plurality of LED lights can emit light according to the instructions of the inertial sensing module 11 and the communication module 12 to reflect the inertial sensing module 11 and the communication module 12. The current usage status of the module 12 enables the user to know whether the inertial sensing module 11 is operating normally.

Please refer to shown in Fig. 2A-2C, Fig. 2A-2C shows first to the 4th inertial sensing device 21-24 of the present invention is fixedly arranged on the body position of a subject, to measure the subject's walking test in the gait. Wherein, as shown in Figure 2A, the first inertial sensing device 21 is fixedly arranged at the fifth spinous process of the subject's back, waist, and lumbar spine, as shown in Figure 2B, the second inertial sensing device 22 is Fixedly arranged on the outside of the thigh above the subject's knee, the third inertial sensing device 23 is fixedly arranged on the outside of the calf above the subject's ankle, as shown in Figure 2C, the fourth inertial sensing device 24 is It is fixedly arranged on the instep of the subject. Among them, the first to fourth inertial sensing devices 21-24 that are fixedly arranged on the subject's body, their respective X-axis, Y-axis and Z-axis directions for orientation are all shown in Figs. 2A-2C As indicated, it can be known that the X-axis direction is the walking direction of the subject.

The application program and the graphical interface will first perform the inertial sensing error correction of the inertial measurement unit in the first to fourth inertial sensing devices 21-24, and make the first to fourth inertial sensing devices 21 -24 Synchronize the data transmission with the host 2 to confirm that the measured posture data itself is correct and the time corresponding to the measured posture data is also correct, and then the subject can start walking Then the application program will start to receive the data from the first to fourth inertial sensing devices 21-24 and record the data and the time of receiving the data until the subject completes the walking test .

Please refer to Fig. 3, in Fig. 3, the first inertial sensing device 21 is fixedly arranged on the subject's back 26 waist with a hook and loop fastener 25, wherein the indicator light module A plurality of LED lights 14 display the working status of the first inertial sensing device 21 .

Please refer to shown in Fig. 4, in Fig. 4, this inertial sensing device 21 is fixedly arranged on the back 26 waist of this subject, when this subject walks forward, the back tilts toward the right side of the body 27, then the inertial Sexual sensing device 21 can sense the rotation of a clockwise direction 31, and when the subject walks forward, the back leans toward the left side of the body 28, then this inertial sensing device 21 can sense the rotation of a counterclockwise direction 32 , wherein the clockwise direction 31 and the counterclockwise direction 32 are determined by observing the rotation of the sagittal plane (Sagittal plane) of the subject's torso from the back of the subject, and the inertial plane can also be viewed from the back of the subject. The positioning of the sexual sensing device 21 is determined by the rotation of the X-axis (equivalent to a roll in the three-dimensional attitude).

Please refer to shown in Fig. 5, Fig. 5 shows the walking test of the subject of the present invention, the subject begins to formally measure its gait after walking two meters from the starting point, after a walking test distance of 6 meters, the subject Start slowing down two meters before the finish line, then stop walking after two more meters. It can be seen that the walking test system of the present invention is very simple.

Please refer to Figure 6. Figure 6 is the walking test result of a 31-year-old male subject with left hemiplegia due to stroke. A measurement result of an inertial sensing device 21 . The vertical axis among Fig. 6 is the angle of rotation of described sagittal plane, is referred to as Euler angle (Euler angle), represents the degree that its back leans toward the left or right side of the body during the walking test of the subject; and The horizontal axis in FIG. 6 is the time axis in seconds, representing the process of the subject's walking test. In Figure 6, the slope of the white arrow is positive, representing clockwise rotation, that is, the subject’s back is tilted to the right, and the time from the trough to the peak is marked as TA; vice versa, the slope of the dark arrow is negative, representing inverse rotation. The hour hand rotates, that is, the subject's back tilts to the left, and the time from the peak to the trough is marked as TB.

The average value of the time TA from the trough to the crest in the 6-meter walking test distance of the above-mentioned subjects formally measuring their gait is defined as a right tilt time TR, and the above-mentioned subjects formally measure their 6-meter walking distance The mean of time TB from peak to trough in the walking test distance was defined as a left tilt time TL. The absolute value of the time difference between the right tilt time TR and the left tilt time TL can be defined as a left and right time difference RD, and the relative ratio between the left tilt time TL and the right tilt time TR can be defined as a left and right time ratio RR. The left-right time difference RD divided by the subject's height Height is a height-corrected left-right time difference RDH. The left-right time difference RD, the left-right time ratio RR, and the height-corrected left-right time difference RDH are all the gait symmetry index of the subject, and the formula is as follows: RD = | TR - TL |

Among them, height correction left and right time difference RDH is a new gait symmetry index disclosed by the present invention, which is the key point of the present invention, and it has a great effect on calculating the gait symmetry of the subject.

Table 1 is the evaluation data of the lower limbs Fogelmeier Movement Scale (abbreviated as FMA-L) and Burger's Balance Scale (abbreviated as BBS) of 23 subjects.

Table 2 shows the Spearman's rank correlation coefficient (Spearman's rank correlation coefficient) γ between the FMA-L evaluation value and walking speed and the BBS evaluation value and walking speed of the 23 subjects in Table 1. The Spearman rank correlation coefficient γ in Table 2 is used to measure the correlation between two variables, its value is between +1 and -1, if there are no repeated values in the data, and when the two variables are completely monotonously correlated When γ is +1 (positive correlation) or -1 (negative correlation); the interpretation of the correlation strength of the coefficient γ is as follows: 0.00-0.01 is negligible, 0.1-0.39 is weak, 0.4-0.69 is moderate, 0.7-0.89 is strong, and 0.9-1.0 is very strong. The smaller the p-value in Table 2, the more the assumption of no correlation between the two variables should be overturned. Here the p-value is less than 0.01, so the assumption of no correlation between the two variables should be overturned. From the data in Table 2 (n=23, p<0.01), it can be seen that the gamma coefficients between walking speed and clinically assessed FMA-L and BBS are: 0.62 and 0.68, both of which are between [0.4-0.69], so the The coefficient γ points to a medium positive correlation, that is, the FMA-L evaluation value of the 23 subjects in Table 1 has a moderate positive correlation with their walking speed, as well as their BBS evaluation value and their walking speed; as for the "significance" in Table 2 One column evaluates whether there is a statistically significant association.

Table 3 to Table 6 can be seen in Table 1 for the Spearman rank correlation coefficient γ between the other exercise variables of the 23 subjects and their FMA-L evaluation values and BBS evaluation values.

Table 3 shows the Spearman rank correlation coefficient between the FMA-L evaluation value of the 23 subjects in Table 1, the range of motion of the hip joint (ROM for short) and the range of motion of the knee joint. It can be seen from Table 3 that there is no statistically significant correlation between the subject's exercise variables such as hip ROM and knee ROM and the subject's FMA-L evaluation value.

Table 4 is the Spearman rank correlation coefficient between the BBS evaluation value of the 23 subjects in Table 1, the range of motion of the hip joint and the range of motion of the knee joint. It can be seen from Table 4 that there is no statistically significant correlation between the subject's exercise variables such as hip ROM and knee ROM and the subject's BBS evaluation value.

Table 5 is the Spearman rank correlation coefficient between the FMA-L evaluation value of the 23 subjects in Table 1 and the three-dimensional range of motion of the lower back. It can be seen from Table 5 that there is no statistically significant correlation between the three-dimensional range of motion of the subject's lower back and the FMA-L evaluation value of the subject.

Table 6 is the Spearman rank correlation coefficient between the BBS evaluation value and the three-dimensional range of motion of the lower back of the 22 subjects in Table 1 (excluding the third subject). It can be seen from Table 6 that there is no statistically significant correlation between the three-dimensional range of motion of the subject's lower back and the BBS evaluation value of the subject.

Table 7 shows the relationship between the FMA-L evaluation value and BBS evaluation value of the 23 subjects in Table 1 and the three gait balance indicators of the testees: left-right time difference RD, left-right time ratio RR, and height-corrected left-right time difference RDH. The Spearman rank correlation coefficient γ between . Wherein, the left-right time difference RD and the left-right time ratio RR have no statistical correlation with clinical evaluation results, such as FMA-L and BBS. However, the γ coefficients between the gait balance index of height-corrected left-right time difference RDH and the clinical evaluation of FMA-L and BBS are: -0.51 and -0.52, and their absolute values are between [0.4-0.69], so they are medium Negative correlation, as shown in Table 7. Among them, the negative value of the γ coefficient indicates good trunk stability and good recovery in neuromotor and motor function.

The gait balance index based on the physiology of the height correction RDH disclosed by the present invention is very intuitive, and it is also easy to obtain the measurement data of the subject's walking test from the inertial sensing device disclosed by the present invention. , also proves that the present invention incorporates the necessity of height into gait balance index simultaneously. Therefore, using the inertial sensing device of the present invention to measure the physiological data of the subject's walking test, combined with the gait balance index of height-corrected left-right time difference RDH disclosed in the present invention, can accurately correspond to the clinical scale. It is not necessary to use an optical motion capture system for measurement, which can improve the convenience and feasibility of measurement and achieve the purpose of the present invention.

1: Inertial sensing device

2: Host

11: Inertial sensing module

12: Communication module

13: Battery module

14: Indicator light module

15: Shell

Claims (10)

A gait balance index calculation system of a waist inertial sensing device, which includes: an inertial sensing device, arranged on the back and waist of a subject, and the inertial sensing device includes: an inertial sensing module, capable of measuring A posture message of the subject; a communication module electrically connected to the inertial sensing module; a walking test procedure including the following steps: Step 1: During a walking test period, the inertial sensing module is Measuring the posture information of the subject's torso when walking, and recording the posture information and the time point at which the posture information is measured, so as to generate a time series information related to the posture information, the time series information has a plurality of peaks and The trough, the communication module receives the attitude information and outputs the timing information by wireless or wired transmission; Step 2: a host receives the timing information through the inertial sensing device, and calculates the timing information, from the valley to the An average time of the next adjacent peak, and it is defined as the right-dipping time, and an average time from the peak to the next adjacent trough, and it is defined as the left-dipping time; Step 3: the host computer and the right-dipping time The absolute value of the difference of the left leaning time is divided by the height of the subject to obtain a height-corrected left and right time difference gait balance index. The gait balance index estimation system of the waist inertial sensing device as described in claim 1, wherein the posture information refers to a sagittal plane rotation angle of the subject's torso when walking. The gait balance index estimation system of the waist inertial sensing device as described in claim 1, wherein the inertial sensing device further includes: a battery module electrically connected to the inertial sensing module and the communication module, to provide power to the inertial sensing module and the communication module; An indicator light module is electrically connected with the inertial sensing module, the communication module, and the battery module to display the running state of the inertial sensing device. The gait balance index estimation system of the waist inertial sensing device as described in claim 3, wherein the host computer receives the timing information through the communication module. The gait balance index estimation system of the waist inertial sensing device as described in claim 3, wherein the inertial sensing module includes: a microcontroller and memory, a three-axis gyroscope, and accelerations in three directions count. The gait balance index estimation system of the waist inertial sensing device as described in claim 3, wherein before the step 1, it further includes: before recording the posture information, first setting the back and waist of the subject The inertial sensing module of the inertial sensing device performs inertial sensing error correction. The gait balance index estimation system of the waist inertial sensing device as described in claim 1, wherein the inertial sensing device is arranged on the back and waist of the subject through a hook and loop. The gait balance index estimation system of the waist inertial sensing device as described in claim 1, wherein before the step 1, it further includes: before recording the posture information, first setting the back and waist of the subject The inertial sensing device performs inertial sensing error correction. The gait balance index estimation system of the waist inertial sensing device as described in claim 1, wherein before the step 1, it further includes: before recording the posture information, making the back and waist of the subject set The data transmission between the inertial sensing device and the host is synchronized. The gait balance index estimation system of the waist inertial sensing device as described in Claim 1, wherein the subject's back waist refers to the fifth spinous process of the subject's back waist and lumbar vertebrae.

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