APPARATUS AND METHOD FOR GAIT TRAINING

Abstract

Arrangement for training the gait, comprising a predetermined walking surface, kick-on location sensing means for determining actual kick-on locations where a patient kicks his feet on the walking surface, which kick-on sensing means are associated to the walking surface, a training program memory for storing a gait training program which comprises data for predetermining a sequence of instructed kick-on locations for the feet of the patient on the walking surface, a display apparatus for displaying images which show the instructed kick-on locations, and a display synchronizing apparatus, which at its input side is connected to the training program memory and to the kick-on location sensing means and at its output side with the display apparatus to output data of the kick-on location sensing means in such manner that the display of the instructed kick-on locations is continuously adapted to sensed actual kick-on locations.

Description

The present invention relates to an arrangement and a method for training the gait.

Prior art apparatus for the detection of pressure and force distributions which are disclosed, for example, in DE 36 42 088 C2 and DE 25 29 475 C3, can be used as platforms for biomechanical gait analysis, which is being used for examining and analyzing the gait of a vertebrate, especially of a human being. There is the drawback, however, that only one single step and one single flexing action of the foot can be recorded. To obtain a natural gait behavior it is necessary, however, to record the gait over a longer time period.

Likewise, apparatus and methods for the gait analysis are well-known, which offer the possibility of such registration and analysis and which make use of a treadmill. Reference is here made, for example, to DE 40 27 317 C1 or U.S. Pat. No. 6,010,465 A.

In R. Kram and A. J. Powell: “A treadmill-mounted force platform” Appl. Physiol. 67 (4): 1692-1698 (1989), an apparatus is being described as previously disclosed, wherein a treadmill belt is drawn over a measuring platform or measuring surface, respectively, thereby permitting a continuous detection of forces applied by a patient's feet.

Further known is the use of display devices, such as display screens, in treadmill systems.

Known from EP 1 145 1682 A2 are a rehabilitation apparatus and method based on the treadmill technology, wherein an adaptation of the function of the treadmill to the current status of a patient's walking or running ability to be restored is provided. Specifically, the speed of the treadmill is adapted to a personal step cycle of the user and, at the same time, the apparatus is to give the user a feedback. In a specific embodiment, also the detection of pressure forces exerted during a step as well as the analysis thereof are provided as part of an overall program. The publication also describes the use of a display screen in connection with a keyboard, to display the footprints generated on the treadmill belt and to adjust treadmill belt parameters on the basis of this display.

U.S. Pat. No. 6,231,527 B1 likewise discloses the use of a display screen in a treadmill apparatus for use in sports medicine and rehabilitation, wherein the images of different cameras can be displayed, which record the movements of the sportsman/patient on the treadmill.

Also EP 2 352 462 and WO 2010/057552 of the applicant describes a treadmill system for use in sports medicine and rehabilitation based on an image display technology, which additionally allows that pressure distribution patterns generated by a person walking on the treadmill are recorded and analyzed synchronously with the displayed images.

The invention is based on the object to provide a further improved apparatus of the last-mentioned type, which is particularly suited for sports-medical and rehabilitation purposes. It is one aim to further develop the system to obtain a flexibly usable training/therapy apparatus while simultaneously increasing the user acceptance as well as the physiotherapeutic effect.

This object is solved, according to its device aspects, with an arrangement according to the features of claim 1, and in its method aspects, with a method according to the features of claim 12. Useful improvements of the inventive thought are each defined in the dependent claims.

The invention includes the idea, not only to rigidly prescribe a step sequence as his training program to an exercising patient, but rather to take his training status and his current efforts into account. Furthermore, the invention includes the idea that, for this purpose, the steps of the patient or, more precisely, the locations (points) where he actually sets (kicks) his feet onto the walking surface (subsequently called sensed kick-on locations) be detected and taken into account when offering the training program to him. This leads to the further idea that an image display of prescribed steps or, more precisely, prescribed kick-on locations of the feet of the patient (subsequently called instructed kick-on locations) be synchronized to the detected actual steps (sensed kick-on locations).

Hence, under device aspects an arrangement is being proposed which comprises, besides a predetermined walking surface (which can exist independently from the measuring arrangement), kick-on location sensing means for determining actual kick-on locations where a patient kicks his feet on the walking surface, which kick-on sensing means are associated to the walking surface, a training program memory for storing a gait training program which comprises data for predetermining a sequence of instructed kick-on locations for the feet of the patient, a display apparatus for displaying images which show the instructed kick-on locations, and a display synchronizing apparatus, which at its input side is connected to the training program memory and to the kick-on location sensing means.

The proposed solution has major advantages: It is a drawback of prior art arrangements that the patient (who is typically heavily handicapped) must initially “synchronize” for the measurements, i.e. must take care that his foot meets a projected image. Since he starts from an arbitrary position, this is very difficult. Once he has met a projected image with his foot, he must continuously correct each respective subsequent step, once he has made a mistake (i.e. not appropriately met the prescribed location). This correction step, however, is not that step which should be trained but is shorter or longer or possibly includes an increased or decreased step breadth (lateral distance of the feet) or a rotation of the foot. This is even more difficult, if the image is not projected onto the treadmill belt itself but onto a screen.

In the invention, mistakes in setting the feet onto the surface are no longer important, since the system always automatically outputs predetermined steps which are to be learned. Herein, the step width (step length) is an important parameter; besides this the proposed solution can also adapt the timely aspects of the gait training program to the actual status of a specific patient.

The measuring means for determining the current position can preferably be implemented with the well-known arrangement of a matrix-type pressure distribution sensor plate or pressure switch plate. However, alternatively measuring systems based on light barrier arrays of the reflective or transmissive type, 2D or 3D cameras etc. can be used. Preferably the arrangement is operated on a treadmill. If the images are projected directly onto the measuring surface, the arrangement can even be used on an fixed walking surface, which optionally can be provided with exchangeable surfaces and/or specific obstacles.

In a further embodiment of the invention, a sequence of sensed kick-on locations is sequentially detected, in a timely resolved manner, and the image display is being synchronized for displaying the instructed kick-on locations in adaptation to the sequence of the sensed kick-on locations. Under device aspects, hence, the kick-on location sensing means comprise a memory unit for, in a timely resolved manner, storing a sequence of sequentially sensed actual kick-on locations and the display synchronizing apparatus is adapted for loading the sequence and for adapting the instructed kick-on locations to be displayed to the sensed sequence. Alternatively, it is proposed that one or more gait parameters of the patient, which have been determined based on previously detected kick-on locations, can be stored and the display synchronizing apparatus be operated on the basis of an evaluation of this parameter or parameters.

In a further embodiment, the arrangement comprises a feedback unit for detecting contacts of the walking surface by the subject at the place where predetermined image elements are displayed, or at places where no predetermined image element is displayed, and for outputting a warning or information signal in response thereto. Additionally or even independent from the latter embodiment, a user guide unit for the visual and/or audible output of display-accompanying instructions, particularly by means of earphones and/or text projections by the display unit, can be provided. In addition to the inventive adaptation of the training program to the actual step sequence of the patient, herewith a supplementary support can be provided to the patient's training.

In the framework of the invention, several algorithms can be implemented for taking the collumnly sensed kick-on locations of the feet of the patient or gait parameters derived therefrom into account, for adapting the training program to the real situation of the patient. An embodiment which appears to be preferred, includes a moving adaptation of a predetermined instructed step width to a sensed step width. Additionally or, should the situation arise, alternatively a step-wise adaptation with respect to the step width or a moving or step-wise adaptation with respect to one or more other gait parameters can be implemented, specifically regarding the step frequence or lateral distance of the feet.

The implementation of training or rehabilitation programs can be as follows: Initially, the patient walks in accordance with his accustomed walking style. By means of the pressure sensor matrix integrated in the treadmill the characteristic gait parameters are detected, especially the length of the steps, the track width, the foot rotation angle or applied force values. These parameters may then be used as starting values for the training. Based on this setting, the patterns projected onto the treadmill belt are then automatically adapted to the target value desired by the therapist within one training process. The alteration of the values may be linear, exponential or be accomplished with any other mathematical function. Subsequently, an automatic analysis based on a target-performance comparison can be performed, i.e. it is checked how good the patient was at complying with the defaults. If the patient is to vary the applied force in partial regions of the foot or of the whole foot he is instructed by an acoustic signal or a voice output, for example, an instruction to put more or less weight on a foot.

In a specific embodiment predefined step widths or breadths can be steadily varied (e.g. increased) during a training process so as to make the patient slowly approach the training goals. This is accomplished by an embodiment in which the display process controller comprises a program memory for storing a plurality of predetermined display processes and/or speed and/or relative position adjusting means for adjusting the speed of a display process and for predefining relative positions between image elements of a display. Advantages and useful features of the invention will be explained in the following description of preferred embodiments by means of figures. In the figures:

FIG. 1 shows a schematic representation of a first embodiment of the invention,

FIG. 2 shows a schematic representation of a second embodiment of the invention,

FIG. 3 shows a detailed view of another embodiment,

FIG. 4 shows a detailed view of another embodiment, and

FIG. 5 shows an image as may be provided during a training program on the walking surface of the arrangement.

FIG. 1 shows a treadmill training system 1, comprising a treadmill belt 2b running over two rollers 2a, underneath the upper surface of which, which is used by the user as walking surface 2c, a pressure detection plate 3 with a high spatial resolution and having a plurality of (not individually designated) pressure sensors is provided, which pressure sensors are arranged in a matrix-type manner and detect pressure detection images generated by the user as he steps on the treadmill. One of the two rollers 2a is driven and pulls the treadmill belt 2b at a predetermined speed, which is adjusted by a processing and control unit 4 of the arrangement and by a speed controller 5. Moreover, it is possible to adjust an inclination of the treadmill as a whole according to need or, optionally, slightly raise only the front portion thereof by means of a suited inclination actuator 6, which can likewise receive interference signals from the processing and control unit 4 (this is merely symbolically illustrated in the figure).

In the embodiment illustrated in FIG. 1, which is strongly simplified, signals characterizing the adjusted speed value of the treadmill are reported back from the speed controller 5 to the processing and control unit 4, where they serve the synchronization of an image displayed on the walking surface 2c by means of a projector (laser beamer) 7, the image being generated from prestored image elements and/or image sequences (see below).

The image is controlled on the basis of the speed signals in such a way that—especially in connection with another specific embodiment described below—the user is presented an altogether harmonious simulation of a walking environment, preferably combined with the insertion of markings to be touched by the feet and/or with the simulation of obstacles to be climbed over or avoided. Diverging from the representation in the figure, the actual speed of the treadmill can also be detected by a suitable (non-illustrated) sensor system, and the measured value can be supplied to the processing and control unit 4 in order to obtain a (virtually feedback) process control of the image display and synchronized analysis of the pressure distribution patterns.

It is shown in the figure that the projector 7 is fixed to a wall holder 7a in an adjustable manner with respect to angles, so that the direction of the projection encloses with the plane of the treadmill a variable angle. In order to avoid distortions of the images or image elements, which are provided by the processing and control unit 4, due to the acute angle of projection an image signal distortion corrector 7b is connected upstream of the projector 7. This distortion corrector 7b can operate dependent on the actual angular position of the projector 7 in the holder 7a, which is not shown in the figures, however, for reasons of clarity. Moreover, in order to round up the user interface an audio stage 8 is provided (here symbolized as a loudspeaker), by means of which the person doing the workout can receive additional acoustic training instructions. The audio stage 8 can also be realized, for example, bidirectionally in form of a headset, so that the person doing the workout can give an acoustic feedback (e.g. an acknowledgment of received instructions or answers to questions he is asked).

For performing training tasks on the treadmill system it may be of interest to detect the lifting height of the feet from the belt, for example, when the subject is to climb over a virtual obstacle. In another embodiment the subject therefore has a sensor 9 attached to each of his feet, the signals of which can be detected by means of a (non-illustrated) position detection sensing system, which is known per se, so as to draw conclusions on the position or the height of the feet, respectively. Preferably, the sensors are operated time-synchronized with the sensors of the pressure distribution matrix. If appropriate, a precise time synchronization can be generated by means of an infrared or radio signal or by a detection of the moment when the feet contact the belt.

The sensors 9 may be designed as acceleration sensors or multi-axis acceleration sensors and, if appropriate, are wirelessly connected to the analyzing computer 4. The position of the feet can be calculated from the acceleration signals, especially if the time and position dependence of the pressure distribution patterns can be additionally included in the calculation. In extended arrangements, inertial sensor systems may be employed, in which gyroscopes or sensors for detecting the earth magnetic field are used additionally. Of course, such sensors can also be attached to other body sections, so that the movement of the complete lower extremities or of the whole body can be measured and represented. However, the sensors 9 may also be operated in accordance with other measuring principles, e.g. on the basis of active or passive light markers recorded by stationary cameras, magnetic field sensors, or sensors emitting or receiving ultrasonic waves to or from stationary receivers and determining the position of the feet from the propagation time of the sound.

The pressure sensors of the pressure detection plate may optionally be provided with an analog or—according to a simpler and more inexpensive embodiment—a digital response characteristic (on/off characteristic). Both options are eligible for certain applications, and the system designer will choose one of the options in accordance with the primary use requirements.

FIG. 2 shows a modification of the arrangement shown in FIG. 1 and described above. Insofar as the same components of the latter are employed, they are designated with the same reference numbers used in FIG. 1 and will not be explained again below.

The essential modification consists in using a large-surface electro-optical touchscreen 7′ as display device instead of a projector. The upper surface of the touchscreen defines a display surface 2c′ located, in use, underneath the upper section of the endless belt 2b. At the same time, the touchscreen defines a novel pressure detection plate 3′. According to a modified version of the touchscreen principle, and in the light of the actual costs for the arrangement, this combined display/pressure detection device may be replaced by a matrix-type alternating arrangement of a plurality of smaller electro-optical display elements (e.g. LCD displays) and respective adjacent smaller pressure detection plates, or a flexible display screen insensitive to pressure (e.g. of the OLED type) may be placed over a normal pressure detection plate.

In all cases the endless belt (2b) is to be formed of a transparent material, at least in the central portion of its lateral extension, in order to allow the person doing the workout a perception of the images displayed on the display surface 2c′.

FIG. 3 shows a detailed representation of essential components of the processing and control unit 4 of the arrangement illustrated in FIG. 1 or 2. Not included is here the image signal distortion corrector separately shown in FIG. 1, which is used only in an embodiment of the arrangement where the projector is inclined relative to the treadmill.

In a display control part 4A the processing and control unit 4 comprises an image element storing unit 41 and a video memory 42, with an image element mixer 43 and finally a video image element mixer 44 for generating image sequences with predetermined image element insertions being connected downstream thereof. In addition, it is symbolically shown that both mixers 43, 44 can moreover be influenced by control signals of a random generator 45. Also, a display process controller 46 is connected downstream of the second mixer 44, which is assigned a process program memory 47 and a synchronizing unit 48. An image element position controller 49 is connected, in terms of control signals, to the image element mixer 43 and acts on the same so as to vary relative positions of image elements in the ultimate representation.

The synchronizing unit 48 can be influenced by signals of the speed controller 5 of the treadmill (not shown in this figure). Primarily, however, the coordinate values of sensed kick-on locations of the feet of the patient are input into the synchronizing unit, which coordinates or (as mentioned further above) calculated from the pressure sensing images which are created on the pressure distribution plate 3 according to FIG. 1 by the feet of the patient. Additionally, the signals of sensors 9 in FIG. 1 can (what is not shown in the figure) input into the synchronizing unit 48 as further input signals. This serves for finally synchronizing the display, in particular as far as it shows instructed kick-on locations for the feet of the patient, to the speed of the treadmill as well as to the sensed kick-on locations of the feet of the patient and optionally to further motional parameters of the feet of the patient. Regarding the adaptation of the displays presented to the patient to his actual motions, the display process controller 46 and the synchronizing unit 48 can together be considered as a display synchronizing apparatus of the arrangement.

At the same time, these signals are supplied to a system control unit 50 of the arrangement, which synchronizes the different control procedures of the display and analysis functions and performs necessary adaptations of the data streams and data formats. In the figure this is symbolized by the double arrows pointing to the display control part 4A and the analyzing section 4B.

Moreover, the final image signal provided at the output of the display process controller and, on the other hand, the (space-time-resolved) output signal of the pressure distribution plate 3 are supplied to the analyzing section 4B. The output signal of the pressure distribution plate 3 is freed from interference signals and artefacts in a pressure signal preprocessing stage 51, is synchronized with the image signals in terms of time in a pressure signal time adaptation stage 52 and in terms of space in a pressure signal position adaptation stage 53, and is processed in a training analysis stage (main processing stage) 53 on the basis of a predetermined training analysis program, and the results are outputted on a separate display unit 10 of the therapist. Moreover, they can be processed—together with instructions inputted via an input unit 11 of the therapist—to instructions for the person doing the workout in a user guide stage 54, which instructions are outputted by the display unit 7 or T assigned to the person doing the workout and, optionally, by the audio stage 8.

FIG. 4 shows in a detail view parts of a further arrangement 1′ according to an embodiment of the invention, which parts are essential to the implementation of the present invention. These are a fixed, limited walking surface 2′ to which surface—immediately above the surface—as core component of a kick-on location sensing apparatus a laser light barrier 12 is associated, which means can use a laterally spread-out laser beam or which can work according to the principle of multiple reflections and which, by these means, is modified to become a large-area light barrier. Once a user (patient), within the area of detection of this light barrier, sets (kicks) his feet onto the walking surface, this will be detected by means of the light barrier by providing plural single (commercially available and inexpensive) light barriers or by using means with high positional resolution the kick-on location (actual kick-on location) of the feet of the patient can be detected. The coordinates of the kick-on locations which have been detected over a predetermined time period can be stored in a kick-on location storing unit 13, which is connected to the output of the laser light barrier means 12, in a time-dependent manner. This storing unit can work according to the FIFO-principle and, in this way, be automatically updated.

The training program memory 14 is provided for storing training programs for training the gait, which programs can in particular be specified by a predetermined step sequence and width and optionally further parameters, such as the lateral distance of the feet. The kick-on storing unit 13 (as part of the kick-on sensing apparatus) as well as the training program memory 14 are connected to inputs of a display synchronizing apparatus 15 for synchronizing gait instructions which are shown to the patient with his actual motions.

The display synchronizing apparatus 15 comprises a calculating stage 15a for calculating relevant gait parameters from a timely sequence of sensed kick-on locations loaded from the kick-on location memory 13, as well as an adaptation stage 15b for adapting a predetermined step sequence, which is being loaded from the training program memory, to the gait parameters of the patient. The synchronizing apparatus outputs a sequence of coordinates of instructed kick-on locations for the further gait on the walking surface 2′, which sequence is adapted to the actual motions of the patient, and this is done by means of a display control unit 16 of a large screen 17 onto which the patient looks during his gait training.

Exemplifying an image to be provided for the person doing the workout on the walking surface FIG. 5 shows (in a simplified manner) a series of footprints f′, combined with ground features A (puddle or “soft” spot) and B (stone or hard elevation). It follows from the above explanations that the impression of these obstacles is not only conveyed by a visual perception, but in combination therewith also by a tactile perception, which is realized by means of an array of actuators in the walking surface of the type shown in FIG. 4.

The realization of the invention is not limited to the above-described examples, but is also possible in a plurality of modifications within the framework of the competent action of the skilled person.

Claims

1. Arrangement for training the gait, comprising: a predetermined walking surface,kick-on location sensing means for determining actual kick-on locations where a patient kicks his feet on the walking surface, which kick-on sensing means are associated to the walking surface,a training program memory for storing a gait training program which comprises data for predetermining a sequence of instructed kick-on locations for the feet of the patient on the walking surface,a display apparatus for displaying images which show the instructed kick-on locations, anda display synchronizing apparatus, which at its input side is connected to the training program memory and to the kick-on location sensing means and at its output side with the display apparatus to output data of the kick-on location sensing means in such manner that the display of the instructed kick-on locations is continuously adapted to sensed actual kick-on locations.

2. Arrangement of claim 1, wherein the kick-on location sensing means comprise a memory unit for, in a timely resolved manner, storing a sequence of sequentially sensed actual kick-on locations or a parameter which characterizes such sequence, and the display synchronizing apparatus is adapted for loading the sequence and for adapting the instructed kick-on locations to be displayed to the sensed sequence.

3. Arrangement of claim 1, wherein the display apparatus comprises a display or projection screen which is positioned above the walking surface.

4. Arrangement of claim 3, wherein the display apparatus comprises an image projector and the walking surface is adapted to serve as projection screen.

5. Arrangement of claim 1, comprising a feedback unit for detecting contacts of the walking surface by the subject at the place where predetermined image elements are displayed, or at places where no predetermined image element is displayed, and for outputting a warning or information signal in response thereto.

6. Arrangement of claim 1, comprising a user guide unit for the visual and/or audible output of display-accompanying instructions, particularly by means of earphones and/or text projections onto the area of the walking surface.

7. Arrangement of claim 1, comprising an endless belt guided over at least two rollers and serving as a treadmill, the one surface of which serves as the walking surface.

8. Arrangement of claim 1, wherein the kick-on location sensing means comprise: a force measurement plate located underneath the walking surface, which is provided with a plurality of pressure/force sensors on the side facing the endless belt, an analyzing unit connected, on the input side, to the pressure/force sensors, which detects pressure distributions processing unit connected on the input side, to the analyzing unit, which determines the actual kick-on locations from the pressure distributions.

9. Arrangement of claim 1, wherein the kick-on location sensing means comprises optical detector means for detecting the position of the feet of the patient at the point of time of kicking-on to the walking surface, in particular a camera or light barrier unit.

10. Arrangement of claim 1, wherein the data concerning the determination of the sequence of instructed kick-on locations comprise an instructed step width and/or wherein the parameter for characterizing the sequence of instructed kick-on locations is an actual step width.

11. Arrangement of claim 10, wherein in the display synchronizing apparatus an algorithm for movingly adapting a pre-programmed instructed step width to a sensed step width is implemented.

12. Method for training the gait of a patient on a predetermined walking surface, wherein by means of kick-on location sensing means which are associated to the walking surface actual kick-on locations are sensed, where the patient kicks his feet onto the walking surface,according to a predetermined training program a sequence of predetermined instructed kick-on locations of the feet of the patient on the walking surface is calculated andby means of a display apparatus images are displayed to the patient, which show instructed kick-on locations of his feet, wherein the display is continuously synchronized for showing instructed kick-on locations which are adapted to the sensed kick-on locations which have been detected by means of the kick-on location sensing means.

13. Method of claim 12, wherein, in timely resolved manner, a sequence of actual kick-on locations is being sequentially detected and the synchronization of the display for showing the adapted instructed kick-on locations is made in response to the sequence of actual kick-on locations.

14. Method of claim 12, wherein the synchronization of the displayed instructed kick-on locations to the sensed kick-on locations comprises movingly adapting a predetermined instructed step width to a sensed step width of the patient.

15. Method of claim 12, wherein the sensing of the actual kick-on locations of the feet of the patient onto the walking surface comprises an optical detection, in particular by means of a camera or light barrier, or is based on the detection of pressure distribution images of the feet of the patient on a matrix-type pressure sensor arrangement located underneath the walking surface.