ANALYSING SYMMETRY OF LIMB FUNCTION

Abstract

Systems and methods for analysis of symmetry between sides of a body. A wearable device includes a body mounting portion structured and arranged to, in use, be mounted to one or more parts of a body of a patient on one side of the body. The wearable device includes at least one sensor configured to output a signal indicative of at least one physiological parameter from a side of the body to which the wearable device is mounted. At least one processor is configured to receive at least one physiological parameter from the wearable device while mounted to a first side of the body, and at least one physiological parameter from the wearable device while mounted to a second side of the body. An indicator of symmetry between the first side and the second side of the body is determined based at least in part on the at least one physiological parameter from the first side of the body and the at least one physiological parameter from the second side of the body.

Claims

1. A method of analysing symmetry between sides of a body, the method including: mounting a wearable device to one or more parts of a body of a patient on a first side of the body, the wearable device including at least one sensor configured to output a signal indicative of at least one physiological parameter from the side of the body to which the wearable device is mounted; recording a first data set from the at least one sensor while the patient performs at least one activity while the wearable device is mounted on the first side; mounting the wearable device to one or more parts of a body of the patient on a second side of the body contralateral to the first side; recording a second data set from the at least one sensor while the patient performs at least one activity while the wearable device is mounted on the second side; and determining an indicator of symmetry between the first side and the second side of the body based at least in part on analysis of the first data set and the second data set.

2. The method of claim 1, including determining symmetry between the first side and the second side of the body based on the indicator of symmetry.

3. The method of claim 2, wherein determining symmetry includes comparing the indicator of symmetry to a threshold value.

4. The method of claim 3, wherein determining symmetry includes a binary determination of whether the indicator of symmetry exceeds the threshold value.

5. The method of claim 3, wherein determining symmetry includes determining a relative categorisation of symmetry based on a differential between the indicator of symmetry and the threshold value.

6. The method of claim 1, wherein the indicator of symmetry is a differential between a first value of the at least one physiological parameter from the first side of the body and a second value of the at least one physiological parameter from the second side of the body.

7. The method of claim 1, wherein the at least one sensor is removably attached to a body mounting portion of the wearable device, and the method includes positioning the sensor on a first side of the body mounting portion prior to recording the first data set, and positioning the sensor on a second side of the body mounting portion prior to recording the second data set.

8. The method of claim 1, wherein the at least one sensor includes a first sensor configured to output a signal indicative of a first physiological parameter, and a second sensor configured to output a signal indicative of a second physiological parameter, and the method includes determining an indicator of symmetry for each of the first physiological parameter and the second physiological parameter.

9. The method of claim 8, wherein the wearable device is configured to be mounted to a knee of the user, and the first physiological parameter is knee range of motion, and the second physiological parameter is thigh range of motion.

10. The method of claim 1, including determining the side of the body to which the first data set and the second data set relates.

11. The method of claim 10, wherein determining the side of the body to which the first data set and the second data set relates is performed automatically.

12. A system for analysis of symmetry between sides of a body, the system including: a wearable device, the wearable device including: a body mounting portion structured and arranged to, in use, be mounted to one or more parts of a body of a patient on one side of the body; and at least one sensor configured to output a signal indicative of at least one physiological parameter from a side of the body to which the wearable device is mounted; at least one processor configured to: receive at least one physiological parameter from the wearable device while mounted to a first side of the body; receive at least one physiological parameter from the wearable device while mounted to a second side of the body; determine an indicator of symmetry between the first side and the second side of the body based at least in part on the at least one physiological parameter from the first side of the body and the at least one physiological parameter from the second side of the body.

13. The claim of claim 12, wherein the wearable device is one of an orthosis or an exoskeleton.

14. The system of claim 12, wherein the wearable device includes a body mounting portion, and the at least one sensor is configured to be removably attached to the body mounting portion.

15. The system of claim 14, wherein the body mounting portion has a first side and a second side, and the at least one sensor is configured to be selectively attached to the first side or the second side of the body mounting portion.

16. The system of claim 12, wherein the at least one sensor includes a first sensor configured to output a signal indicative of a first physiological parameter, and a second sensor configured to output a signal indicative of a second physiological parameter.

17. The system of claim 12, wherein the at least one processor is configured to determine symmetry between the first side and the second side of the body based on the indicator of symmetry.

18. The system of claim 17, wherein the system includes a display device configured to display at least one of the indicator of symmetry and the symmetry.

Description

5 BRIEF DESCRIPTION OF THE DRAWINGS

[0047] One or more embodiments of the disclosure will be described below by way of example only, and without intending to be limiting, with reference to the following drawings, in which:

[0048] FIG. 1 is a schematic diagram showing features of a symmetry analysis system according to an aspect of the present disclosure;

[0049] FIG. 2-1 is a front perspective view of an exemplary wearable device in the form of a knee brace according to an aspect of the present disclosure;

[0050] FIG. 2-2 is a front perspective view of another exemplary wearable device in the form of a knee brace;

[0051] FIG. 3 is a front view of an exemplary wearable device in the form of an elbow brace according to an aspect of the present disclosure;

[0052] FIG. 4 illustrates transference of a wearable device between legs of a patient as part of a method of analysing symmetry according to an aspect of the present disclosure;

[0053] FIG. 5 is a flow diagram of a first exemplary method of analysing symmetry according to an aspect of the present disclosure;

[0054] FIG. 6 is a front view of a human patient demonstrating positioning of wearable devices and reference sensors according to an aspect of the present disclosure; and

[0055] FIG. 7 is a flow diagram of a second exemplary method of analysing symmetry according to an aspect of the present disclosure.

6 DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

[0056] It will be understood that the particular examples described herein are not intended to be limiting to all embodiments of the present technology. The various examples may share one or more common characteristics and/or features. It should be appreciated that one or more features of any one example may be combinable with one or more features of one or more other examples.

[0057] 6.1 Symmetry Analysis System

[0058] FIG. 1 is a schematic showing features of a symmetry analysis system 100 according to an embodiment of the present disclosure. The system 100 includes one or more wearable devices 102 (for example, knee orthosis 102-1 and/or elbow orthosis 102-2) configured to be mounted to a corresponding body part (s) of a body of a patient 104 in use.

[0059] The system 100 further includes one or more reference sensors, including intelligent user devices 106 (for example, smart phone 106-1 and/or smart watch 106-2) and/or dedicated reference sensor devices 108 (for example, an inertial measurement unit (IMU) 108-1 and/or smart insole 108-2).

[0060] In exemplary embodiments, data from one or more of the wearable devices 102, user devices 106, and/or reference sensor device 108 may be communicated to a remote processing service 110 via a network 112 (for example a cellular network, or another network potentially comprising various configurations and protocols including the Internet, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more companies—whether wired or wireless, or a combination thereof). For example, the smart phone 106-1 may operate an application capable of interfacing with the data management service 110.

[0061] Among other functions, the remote processing service 110 may record data, perform analysis on the received data, and report to one or more user devices. In this exemplary embodiment, the remote processing service 110 is illustrated as being implemented in a server—for example one or more dedicated server devices, or a cloud based server architecture. By way of example, cloud servers implementing the remote processing service 110 may have processing facilities represented by processors 114, memory 116, and other components typically present in such computing environments. In the exemplary embodiment illustrated the memory 116 stores information accessible by processors 114, the information including instructions 118 that may be executed by the processors 114 and data 120 that may be retrieved, manipulated or stored by the processors 114. The memory 116 may be of any suitable means known in the art, capable of storing information in a manner accessible by the processors, including a computer-readable medium, or other medium that stores data that may be read with the aid of an electronic device. The processors 114 may be any suitable device known to a person skilled in the art. Although the processors 114 and memory 116 are illustrated as being within a single unit, it should be appreciated that this is not intended to be limiting, and that the functionality of each as herein described may be performed by multiple processors and memories, that may or may not be remote from each other.

[0062] The instructions 118 may include any set of instructions suitable for execution by the processors 114. For example, the instructions 118 may be stored as computer code on the computer-readable medium. The instructions may be stored in any suitable computer language or format. Data 120 may be retrieved, stored or modified by processors 114 in accordance with the instructions 118. The data 120 may also be formatted in any suitable computer readable format. Again, while the data is illustrated as being contained at a single location, it should be appreciated that this is not intended to be limiting—the data may be stored in multiple memories or locations. The data 120 may include databases 122 storing data such as historical data associated with one or more of the one or more of the wearable devices 102, user devices 106, and/or reference sensor devices 108, and the results of analysis of same.

[0063] It should be appreciated that in exemplary embodiments the functionality of the remote processing service 110 may be realized in a local application (for example, on smart phone 106-1, or another personal computing device 124), or a combination of local and remote applications. Further, it should be appreciated that data may be transferred from one or more of the devices by other means—for example wired communication links, or transfer of storage devices such as memory cards.

[0064] The results of analysis, and/or underlying data, may be displayed on any suitable display device—for example smart phone 106-1, or computing device 124.

[0065] 6.2 Knee Brace

[0066] FIG. 2-1 shows an exemplary wearable device in the form of an orthosis system particularly suited for mounting proximate a knee (not shown) of the patient (not shown)—herein referred to as first knee brace 200-1—as described in PCT application PCT/NZ2018/050085, the contents of which are incorporated herein by reference.

[0067] In this embodiment, the knee brace 200-1 includes a body mounting portion having a first brace portion 202-1 and a second brace portion 202-2. In use, the first brace portion 202-1 is mounted upwardly of the knee of the patient and the second brace portion 202-2 is mounted downwardly of the knee of the patient.

[0068] The first brace portion 202-1 and the second brace portion 202-2 are pivotably coupled via pivot assemblies 204-1 and 204-2. This makes the orthosis system 200-1 suited to use in bracing a pivoting joint of the body, such as the knee.

[0069] In other embodiments of the invention the first and second brace assemblies are moveably coupled in some other manner, for example through a sliding coupling. Such embodiments may be suitable for use in bracing an extendable part of the body, for example. In yet other embodiments, the brace of an orthosis system may be provided as a flexible sleeve, such as a continuous compression sleeve. A first portion of the sleeve is a first body mounting portion to be worn on one side of the user's joint, and a second portion of the sleeve coupled to (i.e. integrally formed with) the first portion is a second body mounting portion to be worn on an opposite side of the user's joint.

[0070] In the embodiment illustrated, modules 206-1 and 206-2 are removably coupled to the pivot assemblies 204-1 and 204-2. One or both of the modules 206-1 and 206-2 may be configured as sensing modules. While the modules 206-1 and 206-2 are illustrated as being on the sides of the patient's knee, in other embodiments the orthosis system may be configured to mount modules in other positions in relation to the body.

[0071] FIG. 2-2 shows a second knee brace 200-2 includes a body mounting portion having a first brace portion 202-1 and a second brace portion 202-2. In use, the first brace portion 202-1 is mounted upwardly of the knee of the patient and the second brace portion 202-2 is mounted downwardly of the knee of the patient. In this exemplary embodiment, the brace portions 202 are stiff arms (for example made of aluminium) having strap mounting features (for example slots 208) for positioning flexible straps (not illustrated) for mounting the knee brace 200-2 to a user.

[0072] In this embodiment, sensing module 206 is removably coupled to the pivot assembly 204 of the knee brace 200-2. The sensor module 206 includes a rotational knee movement sensor, and an IMU for sensing of thigh movement.

[0073] 6.3 Elbow Brace

[0074] FIG. 3 shows an exemplary wearable device particularly suited for mounting proximate an elbow (not shown) of the patient (not shown)—referred to herein as elbow brace 300—as described in PCT application PCT/NZ2018/050085, the contents of which are incorporated herein by reference.

[0075] It will be noted that the body mounting portion in this embodiment comprises a first brace portion 302-1 configured to wrap around a first portion of the patient's arm. Similarly, the second brace portion 302-2 is configured to wrap around another portion of the patient's arm. The first brace portion 302-1 and the second brace portion 302-2 are pivotably coupled via pivot assembly 304-1, to which a sensor module 206 is mounted.

[0076] 6.4 Sensing Module

[0077] Exemplary embodiments of the sensing module 206 comprises sensor components configured to detect, record, process and/or transmit data relating to the movement and/or rotation of the orthosis system or components thereof.

[0078] The sensor components may additionally or alternatively detect, record, process and/or transmit data pertaining to the patient's physical activity and/or physiology. This may include parameters such as joint kinematics (such as joint angle, joint velocity, joint torque, and/or joint acceleration), limb accelerations, limb rotations, limb and/or joint loads, muscle force, muscle strength, muscle velocity, electrical activity, temperature, pH, perspiration, heart rate, blood pressure and/or other bio-signals. Example sensors include rotary encoder, optical and magnetic sensors.

[0079] The sensing module 206 may comprise further components to enable the detection and recording of such data. For example, the sensing module 206 may comprise an accelerometer, gyroscope and/or magnetometers. The sensing module 206 may additionally or alternatively comprise physiological sensors, for example a thermometer, electromyography (EMG) sensor, heart rate sensor, blood pressure sensor, blood oxygen level sensor, etc.

[0080] Sensing module 206 may comprise a transmitter for transmitting data and/or signals obtained by or through the sensor components to a remote location, for example by RF, Bluetooth, Wi-Fi or any other remote communication protocol. Sensing module 206 may also comprise one or more processors configured to process the data/signals.

[0081] The sensor components may further comprise a receiver configured to receive data/signals remotely from an external source, such as external control signals. Data may be stored or received by the sensing module 206 through a physical data storage device such as a memory card, USB stick or the like.

[0082] Other sensors may be provided, comprised in or separate from a sensing module 206. For example, the wearable device 200 may also comprise a torque sensing module comprising one or more sensors for monitoring joint interaction torque between the patient and the body mounting portion. For example, such a sensor(s) may monitor relative displacement between two or more components of the device 200, for example the first and second brace portions respectively, to enable a torque sensor to sense torque between the first and second brace portions. Torque sensing may be performed when the first and second brace portions are locked, or there is some resistance between them. It should therefore be appreciated that a torque sensing module may also incorporate a locking mechanism to substantially prevent movement (e.g. rotation) between the first and second brace portions, such as described in PCT application PCT/NZ2018/050085.

[0083] A person skilled in the art will understand that a number of sensor types may be suitable for measuring characteristics of a patient's biomechanics. For example, a rotary encoder may be used to measure an angle of displacement between the first and second brace portions. Alternatively or additionally an inertial measuring unit(s) (IMU) may be attached to one or each of the first and second brace portions to measure the angle of displacement. An angle of displacement may be used to infer a resistance to motion level, by calibration of a known resistance element with respect to the amount of relative movement between the brace assemblies, or conversely a resistance measurement such as torque or force may be used to infer angle. A strain gauge may be provided to a compliant/resilient element such as a spring or elastomeric block to measure force or torque, and/or a position of a spring element may be used to indicate a resistance to motion level.

[0084] 6.5 First Exemplary Method of Analysing Symmetry

[0085] FIG. 4 and FIG. 5 illustrate a method of analysing symmetry between limbs of patient 104, demonstrated in terms of symmetry between the patient's legs. The method 500 of FIG. 5 will be described herein with reference to FIG. 4.

[0086] In a first step 502, a wearable device 400 (including body mounting portion 402 and sensor 404) is mounted to a first leg of the patient 104 (herein referred to as right leg 402-1). In a second step 504, data output from the sensor 404 during activity by the patient 104 is recorded. By way of example, the activity may be a performance of a specific task—such as a hop test, or a walk test over a designated distance—or general activity of the patient.

[0087] In a third step 506, the wearable device 400 is taken from the right leg 402-1 of the patient 104 and mounted to the contralateral leg of the patient (herein referred to as left leg 402-2). In exemplary embodiments, the wearable device 400 may be reconfigured for use with the contralateral leg. For example, where output of the sensor 404 is influenced by the side of the knee to which it is attached, the sensor 404 may be detached and applied to the other side of the body mounting portion 402.

[0088] In a fourth step 508, data output from the sensor 404 during activity by the patient 104 is recorded. The activity may correspond to that performed while the wearable device 400 was mounted to the right leg 402-1—but it is envisaged that this may not be necessary.

[0089] In exemplary embodiments, the side from which data is collected may be designated manually (for example, operating one or more buttons or switches on the wearable device 400, or inputting a selection of a side via a graphical user interface displayed on smart phone 106-1), or automatically (for example, by analysis of physiological data).

[0090] In a fifth step 510, the first set of data from the right leg 402-1 and the first set of data from the left leg 402-1 may be analysed to determine target physiological parameters for the respective legs. In a sixth step 512, at least one indicator of symmetry between the left and right sides of the patient 104 may be determined based an analysis of the physiological parameters.

[0091] By way of example, it is envisaged that for all joints the characteristics for comparison to obtain the metric(s) of symmetry may include one or more of: range of motion, joint speed, strength, and fatigue. By way of example in relation to assessment of symmetry between knees, comparison may be made between one or more of: joint load and moment during gait events, varus and/or vulgus angles during an activity such as squats, or symmetry of a task (e.g. distance in a hop test performed on each leg). It is envisaged that symmetry of upper limbs may be based on an assessment of coordination, and smoothness of joint motion to perform a task (e.g. reach and grasp tasks). It should be appreciated that these are discussed by way of exemplification of embodiments of the present disclosure and are not intended to be limiting to all embodiments.

[0092] Table 1 below includes the results from a 10 m Walk Test performed while wearing a knee brace having a knee rotational sensor for obtaining knee data, and an IMU for the thigh data (including both coronal and sagittal rotation). In this instance, the range of motion (i.e. maximum angle and minimum angle) of each parameter was obtained and compared between left and right limbs to obtain an indicator of symmetry in the form of a differential between the respective values. The indicators were then each compared against a symmetry threshold to arrive at a binary determination of whether they were symmetrical, or not. In this example, the value of the symmetry threshold is universal, however it should be appreciated that in exemplary embodiments the symmetry threshold may differ between parameters, e.g. the symmetry threshold may be a percentage of an expected range of motion of a target joint.

TABLE-US-00001 TABLE 1 Results of 10 m Walk Test Left Right Indicator range of range of of Symmetry Sym- Joint motion motion Symmetry threshold metric Max Knee 58 65 7 10 YES Angle Thigh- 3 12 9 10 YES Coronal Thigh- 48 34 14 10 NO Sagittal Min Knee 0 0 0 10 YES Angle Thigh- −31 −18 13 10 NO Coronal Thigh- −32 −24 8 10 YES Sagittal

[0093] 6.6 Second Exemplary Method of Analysing Symmetry

[0094] FIG. 6 and FIG. 7 illustrate another method of analysing symmetry between limbs of patient 104. The method 700 of FIG. 7 will be described herein with reference to FIG. 6.

[0095] In FIG. 6, the patient is illustrated as having a wearable device (e.g. knee orthosis 102-1 and/or elbow orthosis 102-2) mounted to a limb on a first side of their body. The patient also has at least one reference sensor mounted to their body, for example: smart phone 106-1 carried in a pocket of clothing (for example, compression shorts) or strapped to an arm or leg; smart watch 106-2; belt mounted IMU 108-1; smart insole 108-2; or wearable GPS module 108-3.

[0096] It should be appreciated that in exemplary embodiments, certain reference sensors need not be mounted on the contralateral side of the patient's body relative to the wearable device(s). Further, it should be appreciated that while multiple wearable devices and reference sensors are illustrated, all of said devices may not be worn (or used) simultaneously.

[0097] In a first step 702-1, data output from the sensor of the wearable device 102 during activity by the patient 104 is recorded. By way of example, the activity may be a performance of a specific task—such a walk test over a designated distance—or general activity of the patient.

[0098] In a second step 702-2, data output from the reference sensor during the activity by the patient 104 is recorded—i.e. from the same time period as the data collected from the wearable device 102.

[0099] In a third step 704, an indicator of symmetry between the limb on which the wearable device is mounted and the contralateral limb may be determined based at least in part on analysis of the first data set and the second data set.

[0100] In a first example, the respective data sets from the wearable device and reference sensor may include comparable parameters. For example, the patient may undergo a 10 metre walk test, with parameters (such as the distance travelled, speed, number of steps, step length, etc.) measured from both the wearable device and the reference sensor, and then compared to determine the indicator of symmetry. As an example, the indicator of symmetry may be the difference in one or more of these parameters between legs.

[0101] In a second example, the data set from the wearable device may be analysed to determine a reference parameter which may be compared with reference parameters from the reference sensor to infer a physiological parameter of the contralateral parts of the body. For example, the patient's activity may include community walking. Total distance travelled may be measured using GPS module 108-3, with the wearable device 102-1 measuring parameters such as step length and step count. The expected distance travelled based on step length of the wearable device leg may be compared with the GPS distance travelled to infer the step length of the contralateral leg. The indicator of symmetry may be the difference in step length.

[0102] In a third example, the wearable device may measure one or more physiological parameters of the first leg, and the reference sensor may measure one or more different physiological parameters. The parameters from the reference sensor, in combination with those from the wearable sensor, may be used to infer parameters for the contralateral leg equivalent to those measured by the wearable device.

[0103] For example, the reference sensor may be the belt mounted IMU 108-1, or smart insole 108-2, and detect heel strike events during activity by the patient. These may be used with kinematics measured by the wearable device for one leg to infer equivalent kinematics for the contralateral leg, from which indicators of symmetry may be determined.

[0104] In a fourth example, the wearable device may measure one or more physiological parameters of the first leg, and the reference sensor may measure one or more special-temporal parameters. The parameters from the reference sensor, in combination with those from the wearable sensor, may be used to infer parameters for the contralateral leg equivalent to those measured by the wearable device.

[0105] For example, the reference sensor may be used to determine over ground velocity during activity by the patient. These may be used with kinematics measured by the wearable device for one leg to infer equivalent kinematics for the contralateral leg, from which indicators of symmetry may be determined.

[0106] Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”.

[0107] The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

[0108] Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

[0109] Aspects of the present technology may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

[0110] Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

[0111] It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present technology.