Device and method for automating treadmill therapy

[0002] The invention relates to an apparatus and a method for automating treadmill therapy for rehabilitating walking-disabled patients.

[0003] During treadmill therapy, patients (e.g., paraparetic patients or patients after a stroke) are trained on a treadmill. For this purpose, they are suspended on a special suspension device above the treadmill. On the one hand, this makes it possible to relieve part of their body weight and otherwise they need to be concerned only a small amount about maintaining their balance. Especially during the initial time after the injury, the patient is often not able at all to move his legs himself. As a result, physiotherapists must keg guide the patients' legs. If intensive training is performed on the patients as soon as possible after injury, special movement centers in the spinal chord of the patient are trained again, and the patient will learn to walk better than is possible with conventional forms of therapy. This guidance of the legs is very exhausting work for the therapists, and they tire relatively quickly when performing this training. Because of this, the training units often are too short, and the results of the therapy are less than optimal.

[0004] This training can be automated with the machine described here. This machine is an orthotic device driven at the knee and hip joints, which can be adapted to any patient. During training, the legs of the patient are guided by the orthotic device in a physiological sequence of movement. In contrast to the manually guided therapy, greater success can be achieved with the automated therapy because the training units can be performed as long as desired. It is possible to perform intensive training very soon after the patient is injured. Therapy with the driven orthotic device also requires only one therapist to caring for the patient, i.e., less personnel is needed.

[0005] Treadmill therapy is now commonly used in many areas when treating patients with neurological diseases. It is especially often used in paraplegic centers, and has been scientifically proven in this context. Therapy currently takes place on a treadmill where the patients are suspended with a belt, and their legs are guided by two physiotherapists (I. Wickelgren, Teaching the spinal cord to walk, Science, 1998, Vol. 279, 319-321). With the help of regular treadmill training, paraparetic patients and patients after a stroke are able to relearn walking much faster and better. Different orthotic devices are already being used in the rehabilitation of patients who have movement restrictions of the legs. Passive walking orthotic devices as described, for example, in U.S. 5,320,590 (1994), are already being used regularly in the rehabilitation of paraplegics. There are already several approaches for driven orthotic devices. U.S. Pat. No. 5,020,790 (1991) and GB 2260495 (1991) describe some of these, in which knee and hip joints are driven with hydraulic cylinders or electric motors. By using these orthotic devices, it is possible to move the legs of a patient for whom the respective orthotic device has been specifically manufactured in a movement pattern similar to walking.

[0006] Patent application EP 0782843 A2 (1996) describes an orthotic device that is also driven at the knee and hip joints. However, the patient undergoes his training on a treadmill. The leg movements are controlled via switches that the patient manually activates during walking and which bring about an extension or flexion of the leg.

[0007] It is the task of the invention at hand to automate the previously manual treadmill training for patients in rehabilitation.

[0008] According to the invention, this objective is realized with a driven orthotic device and an associated method for operating the orthotic device as described herein.

[0009] At issue is the guidance of the legs of a patient positioned above the treadmill in a walking pattern that as is as physiological as possible. This requires a control of the drives that regulate these drives according to a predetermined sequence of movement. The patient should be stabilized on the treadmill in such a way that he need not be concerned about his balance. This means he can concentrate on a dynamic, physiological walking pattern.

[0010] The orthotic device should be usable in the rehabilitation centers for training different patients and therefore must be adjustable in size and shape. The orthotic device must be designed so that no pressure points can be created on the patient's body since paraplegics, in particular, quickly develop pressure ulcers.

[0011] The invention is explained in more detail below in reference to the drawings.

[0012] FIG. 1 shows a schematic portrayal of the principle of treadmill training with driven orthotic device, where the fixation is accomplished with a parallelogram;

[0013] FIG. 2 shows the parallelogram for fixing the driven orthotic device on the treadmill;

[0014] FIG. 3 shows a schematic portrayal of the principle of treadmill training with driven orthotic device, where the fixation is accomplished with a roller guide;

[0015] FIG. 4 shows the roller guide for fixing the driven orthotic device on the treadmill;

[0016] FIG. 5 shows an overall view of the driven orthotic device;

[0017] FIG. 6 shows a view of the adjustable hip orthotic device;

[0018] FIG. 7 shows an exemplary embodiment of a knee drive with ball screw spindle;

[0019] FIG. 8 shows an exemplary embodiment of a cuff for fixing the legs;

[0020] FIG. 9 shows an overview of the control of the therapy system; and

[0021] FIG. 10 shows the control unit.

[0022] FIG. 1 shows a schematic portrayal of the principle of the treadmill training system with driven orthotic device, in a variation with a parallelogram for stabilizing the patient. At each treadmill 1, one each rail 3 of a railing on supports 2 is mounted on each side of the walking surface, the rail being adjustable in height with a mechanism as is the case with a set of parallel hand rails. At the rear end of the rail 3, a parallelogram 5 that will be described in more detail later has been attached in a movable manner. The parallelogram 5 is used for stabilizing an orthotic device 6 that is designed to receive the patient and is located above the treadmill 1. The parallelogram 5 permits a movement of the orthotic device 6 only on a predetermined sector, whereby the movement is indicated by an arrow. This stabilizes both the orthotic device and the patient so that he is unable to tip either laterally, forward or backward. The patient's upper body is connected via a hip belt 7 and a chest belt 8 with the orthotic device 6 and is held in this way in a constant vertical position. The height adjustability of the rail 3 also makes it possible to adjust the height of the parallelogram 5. The parallelogram 5 also is automatically adjusted in height for patients of different heights when the rail 3 is adjusted.

[0023] Behind the treadmill 1, a suspension device comprising a support 9, cable hoist 10, jib 11, rollers 12a, 12b, and 12c, wire cables 13 and 14 and a variable counterweight 15 is also provided. From the cable hoist 10, the wire cable 13 is passed via rollers 12aand 12bto the patient. The latter is wearing a treadmill belt 16 to which the wire cable 11 is fastened. A second wire cable 14 that is fastened to the part of the wire cable 13 located between the rollers 12aand 12bis passed over the roller 12c, and a counter-weight 15 can be hung onto its end. When the therapy is started, the treadmill belt 16, which is used in the manner known from manual treadmill therapy, is put on the patient sitting in the wheel chair. The treadmill belt 16 is then hung with a spring hook onto the wire cable 13, and the patient is pulled up with the cable hoist 10. Once the patient is in an upright position, the counter weight 15 is attached, so that the patient is partially relieved of his own body weight during therapy. After this, the wire cable 13 can be slightly loosened again with the help of the cable hoist 10, after which the patient is able to walk on the treadmill under constant relief. The counter weight 15 is reduced during the course of the therapy, i.e., the load on the legs is gradually increased until the patient's legs are able to carry his entire weight.,

[0024] FIG. 2 shows the parallelogram 5 for fixing the driven orthotic device on the treadmill. The parallelogram consists of a frame-shaped base frame 20, an orthotic device part 21, two carriers 22aand 22bthat connect the base frame 20 with the orthotic device part 21, and an orthotic device holder 24. The two carriers 22aand 22bare positioned in bearings 23a-23din such a way that the orthotic part 21 can only move parallel to the base frame 20. On the orthotic device part 21, a U-shaped profile with guides 25aand 25b, which are constructed as L-shaped slits, is provided on the outside of the parallelogram of the orthotic device holders 24. The orthotic device is hung into these slits and fixed with a cam 26 (also see FIG. 6). By pulling out the cam 26, the orthotic device can be loosened and removed again.

[0025] The parallelogram 5 is fastened by means of a bearing 27 that is attached to the bottom part of the base frame 20 to a rail of the treadmill in such a way that it can be freely rotated horizontally. In this way the parallelogram can be rotated from the outside across the treadmill and can be fastened with a closure 28 that is attached on the side of the lower part of the base frame 20 facing the bearing 27 to the other side of the treadmill, again to the other rail. This makes it possible that the patient is able to drive or can be driven onto the treadmill with his wheel chair when the parallelogram is in the “opened” state. The parallelogram can be “closed” once the patient is lifted with the suspension device from his wheel chair and the wheel chair has been pushed off the treadmill. The it orthotic device, which has been fastened to the orthotic device holder 24, can be adapted and fixed to the patient. Between the base frame 20 and the top carrier 22a, a gas pressure nil spring 29 that compensates the weight of the orthotic device and the parallelogram is attached to bearings 30aand 30bby pushing the carrier 22aupward with a force necessary to move the orthotic device almost weightless along the parallelogram 5. Instead of the gas pressure spring 29, a mechanical spring can be attached at the same location in order to compensate the weight of the orthotic device.

[0026] Another option (not shown) for partially relieving the orthotic device of its weight consists of attaching a roller above the base frame 20, over which roller a wire cable is passed that is attached near the bearing 30aand is loaded on the other side of the parallelogram with a counter weight.

[0027] FIG. 3 shows a schematic of the principle of the treadmill training system with driven orthotic device in a variation with a roller guide for stabilizing the patient. This is an alternative to the stabilization described in reference to FIG. 1, whereby the solution for use with the driven orthotic device described in FIG. 1 should be preferred.

[0028] Another variation of the rail 40 that can be adjusted in height is mounted to the treadmill 1. As in the variation with the parallelogram, the suspension device consisting of support 9, cable hoist 10, jib 11, rollers 12a, 12b, and 12c, wire cables 13 and 14 and counter weight 15 is provided behind the treadmill 1.

[0029] A track 41 is attached with carriers 42 and 43 on the support 9 or the jib 11 above the treadmill 1. A cart 44 with two casters 45aand 45bis located on the track 41 and is able to move forward and backward on it. A guide tube 46 (rectangular tube) holding a spring 47 that is attached to the top end of the guide tube 46 is attached vertically downward on the cart 44. This spring pulls upward with a force that compensates the weight of the orthotic device. A rectangular tube 48 that fits into the guide tube 46 and in this way is guided by it is located at the lower end of the spring 47. The orthotic device holder 24 and a roller guide (see FIG. 4) are attached at the bottom end of the rectangular tube 48. A guide track 50aor 50bis attached to each side of the treadmill 1.

[0030] FIG. 4 shows the roller guide for stabilizing the driven orthotic device on the treadmill. At the bottom end of the rectangular tube 48 one is able to see the orthotic device holder 24, which again is provided on each side with a rectangular tube 51aor 51barranged vertically in relation to the orthotic device holder 24. Two further rectangular tubes 52aand 52bthat enclose tubes 51aand 51bcan be fixed with snap-in mechanisms 53aand 53bin two different positions on tubes 51aand 51b. FIG. 4 shows the left side in the ‘extended’ and the right side in the ‘retracted’ state. The outer ends of tubes 52aand 52bare provided with roller holders 54aand 54b, to which again rollers 55a-55dand 56a-56dare attached. The rollers 55cand 55dcannot be seen in the figure. In the extended state of tubes 52aand 52b, the rollers 55a-55das well as 56a-56drun in guide tracks 50aand 50b. Rollers 55a-55densure that the orthotic device, with the patient, is unable to tip forward or backward; rollers 56a-56densure lateral stability.

[0031] During therapy with the treadmill training system with driven orthotic device and a roller guide of this type for stabilizing the patient, the patient is suspended above the treadmill—as described in FIG. 2. The orthotic device is then moved towards the patient from the back, guided via the cart, and is adapted to him. Then tubes 52aand 52bare extended into the guide tracks 50aand 50bin order to stabilize the patient with rollers 55a-55dand rollers 56a-56d.

[0032] FIG. 5 shows an overview of the driven orthotic device 6. It consists essentially of a hip orthotic device (see FIG. 6) and two leg parts 80aand 80b. The hip orthotic device is an orthotic device with adjustable width that can be adapted to the patient and in which the upper body of the patient is fixed with the hip belt 7 and the chest belt 8. The belts 7 and 8 are relatively wide hook-and-loop belts with a closure in both the back and the front. Each side of the hip orthotic device is provided at its bottom part with a ball bearing 62aor 62b. The two leg braces 63aand 63bare attached to the latter in a movable manner. These bearings guide the leg braces 80aand 80bduring walking on the treadmill in a plane parallel to the movement plane of the patient's legs. The hip orthotic device must be adapted to the patient in such a way that the hip joints of the patient are located directly below the bearing 62aor 62b.

[0033] The leg braces 63a, 63b, 64a, 64b, 65a, 65b, 66a, and 66bof leg parts 80aand 80bare constructed as rectangular tubes. The tubes 64a, 65a, and 64b, 65benclose tubes 63a, 66aand 63b, 66b, and are connected with each other via the knee joints 67aand 67b. The tubes 63a, 63band 64a, 64b, as well as 65a, 65band 66a, 66bcan be moved inside each other. The sliding surfaces between the tubes that have been pushed inside each other permit an easy adjustability of the leg lengths, that is, nevertheless, practically free from any play. At one end of each of the tubes 64a, 64band 65a, 65b, a snap-in mechanism 68a, 68b(not visible) and 69a, 69bis attached, which fixes these pipes with a bolt inside the rows of holes 70a, 70b, and 71a, 71bprovided in regular intervals in the tubes 63a, 63b, and 66a, 66b(neither of which is visible). In this way, the lengths of the leg parts 80aand 80beach are adapted to the leg lengths of the patient, and the position of the joints 67aand 67bcan be matched with the knee joints of the patient. The holes are continuously numbered so that the size setting can be read, which is important for a quick fitting when a patient is treated repeatedly.

[0034] Angle sensors (potentiometers) that are used to control the orthotic device are integrated in the hip and knee joints 62a, 62bor 67a, 67b. The leg braces 80aand 80bare fastened with cuffs 72a, 72b, 73a, 73band 74a, 74bto the patient's legs. The cuff pair 72a, 72bis attached on the track side to tubes 64a, 64b, the cuff pair 73a, 73bto tubes 65a, 65b, and the cuff pair 74a, 74bto tubes 66a, 66b.

[0035] Knee drives 75a, 75band hip drives 76a, 76bare provided for moving the hip or, respectively, knee joints.

[0036] The leg braces 64aand 64bcan be pulled completely out of leg braces 63aand 63b. The cables or electrical supply lines of the sensors and actuators below tracks 63aor 63bcan be unplugged via a connector. In this way, each leg part can be removed individually from the driven orthotic device 6. This makes it possible to guide only one leg of a patient with hemiparesis actively and to let an otherwise healthy leg walk by itself (one leg therapy).

[0037] FIG. 6 schematically shows a hip orthotic device with adjustable width. An orthotic device back support 81 is fitted on each side with two bolts 82, 82band 82c, 82dthat make it possible to suspend the hip orthotic device in the guides of the orthotic device holder. The backside of the orthotic device back support 81 is provided with a stop hole 83 into which the cam of the orthotic device bolder can be snapped in order to fix the hip orthotic device in the orthotic device holder. Two rectangular tubes 84 and 85 are provided on the front of the orthotic device back support 81. Rectangular tubes 87aand 87bas well as 88aand 88bare also provided on the top and bottom of two hip side parts 86aand 86band enclose the tubes 84 and 85 on one side each of the orthotic device back support and can be freely moved on the latter. The hip side parts 86aand 86bare fixed in the correct position with the snap-in mechanisms 89aand 89bas well as 90aand 90b, each of which can be snapped with a cam into the rows of holes 91aand 91bas well as 92aand 92b. In this way, the hip orthotic device can be adjusted to the individual requirements (hip width) of the patients by moving the hip side parts 86aand 86b. As a result of the rigid connection of the tubes 87aand 88aor, respectively, 87cand 88bthrough the hip side parts 86aand 86b, the snap-in mechanisms 89aand 90aor, respectively, 89band 90beach must be released simultaneously in order to move one hip side part. On the inside of the hip side parts 86aand 86b, the hip belt 7 is in each case attached on the top inside, and the chest fax belt 8 on the bottom inside. The figure also shows the two hip drives 76aand 76b.

[0038] FIG. 7 shows an exemplary embodiment of a drive with a ball screw spindle for the right knee joint. A holder 100 is attached to the leg brace 64a. A bolt 101 is located on this holder 100. A guide cylinder 102 of the spindle drive is positioned via a roller bearing on this bolt 101. A ball screw spindle 103, which in this drawing is almost completely retracted, moves inside this guide cylinder 102. Located in the screw nut housing 104 is the ball screw spindle nut (not visible) that is positioned inside the housing so that it can be driven via a toothed V-belt 105 by an electric motor 106. The part of the ball screw spindle 103 extended from the guide cylinder 102 is positioned via a roller bearing on a bolt 107 that is fastened in a holder 108. The holder 108 is again connected tightly to the leg brace 65a.

[0039] The leg brace 64ais connected via ball bearing 67ain an articulated manner with the leg brace 65a. If the electric motor 106 rotates the spindle nut via the toothed V-belt 105, the ball screw spindle 103 (“stationary spindle”) is rotated into or, respectively, out of the guide cylinder 102. This results in an extension or flexion of the leg orthotic device around bearing 67a.

[0040] At the top end of the leg brace 64aor at the bottom end of the leg brace 65a, the snap-in mechanisms 68aor 69acan be seen, as well as the numbered rows of holes 70aor, respectively, 71aarranged in tubes 63aor 66a, which are used for quickly fitting the length of the leg parts to the patient. The rows of holes 70aand 71aare provided with marks (numbers) so that the settings can be read off them. The settings are necessary for configuring a regulator. However, they also can be stored in order to correctly set the orthotic device for the patient at a later training session.

[0041] The same ball screw spindle drive is used in principle in the same manner to drive the left knee and both hip joints.

[0042] FIGS. 8aand 8bshow a cuff for fixing the legs: FIG. 8ais a perspective view; FIG. 8ba frontal view. A holding mechanism 120, one of which is attached to each of the leg braces, is provided with a round opening into which a metal pipe 121 is passed. The metal pipe 121 can be freely moved inside the holding mechanism 120 and can be attached in the correct position with a quick-screw mechanism 122. On the other leg of the metal pipe 121, that is bent at a right angle, a second holding mechanism 123, that is identical with holding mechanism 120, is provided and can be moved, like the latter, freely on the pipe and be fixed in the correct position. In this way, the patient's legs can be positioned optimally in the orthotic device so that the movement planes as well as joint positions of the orthotic device and legs of the patients match. The positions in which the holders 120 and 123 are fixed on the pipe are marked with marks 124 and 125 so that the settings can be reconstructed at any time.

[0043] A rigid, half-round hoop 126 is screwed onto the holding mechanism 123. At each of the ends of this hoop 126, a bearing 127 and 128 is fixed. A small metal plate 129 and 130 is able to rotate freely in each of these bearings. At the inside of the small metal plates, a hook-and-loop tape 131 has been attached so that the rear part of the tape is closed on the hoop side, and front part is open. The length of the rear part has been selected so that the leg of a patient finds enough space inside the cuff, yet the tape does not touch the hoop 126 in the stretched state (when the leg is fixed in it). At the front, open part of the tape 131, a metal hoop 132 is attached on one end, through which the other end of the tape can be looped. In this way, the tape can be pulled tightly around the patient's leg and fixed with a hook-and-loop closure 133. These tapes, which are positioned in a rotatable manner, make it possible to distribute any forces that occur as uniformly as possible over the patient's skin when the leg orthotic device moves the patient's legs. The patient's leg does not come into contact with rigid parts of the orthotic device. This is important in order to prevent pressure ulcers.

[0044] It was found to be particularly advantageous that during the first adaptation of the orthotic device to a patient, all settings at the marks are read, that the values measured in this way are stored, and that during a later therapy session with the same patient the orthotic device is again set according to these values.

[0045] FIG. 9 shows an overview of the control of the therapy system. The control consists of an input device 140, a control unit 141, the treadmill 1 and the driven orthotic device. The control unit 141 can be configured with the user data 142 via the input device 140. The control unit 141 is used to generate and control natural, i.e., physiological walking patterns in the orthotic device 6 and to control the treadmill 1. The orthotic device contains the desired position values for the knee and hip drives as control signals 143a. The measuring values of the angle sensors integrated in the knee and hip joints are returned as measuring values 144 to the control unit 141, creating a control circuit (141143a6144141) through which the leg position of the orthotic device 6 can be precisely controlled and synchronized with the treadmill speed. A control signal 143bis fed to the treadmill 1 and permits control of the treadmill speed that can be predetermined at the input device 140.

[0046] A central task of the control unit 141 is the synchronization of the sequence of movements of the orthotic device 6 with the treadmill speed: because of the orthotic device 6 driven at the knees and hip and the speed-controlled treadmill 1, a coupling 145 between the orthotic device 6 and the treadmill 1 is created during each standing phase and results in an overdetermination of the system that is eliminated by a synchronization of the leg movement with the treadmill speed.

[0047] FIG. 10 shows the control unit 141 in detail. The interfaces of the control unit 141 consist of the user data 142, control signals 143aand 143b, and measuring values 144. The user data 142 include a predetermined setting for the step length 142a, a predetermined setting for the treadmill speed 142b, as well as all patient-specific settings 142c, in particular the leg length set in the orthotic device. The user data 142 also include the desired movement curves 142dthrough which a walking pattern 150 to be created can be adapted optimally to the patient. The control signals 143aare connected to the knee and is, hip drives of the orthotic device and preset the desired position of the knee and hip joints. The control signal 143bpermits the speed control of the treadmill. The measuring values 144 are divided into signals 144aof angle sensors that are integrated into the knee and hip joints of the orthotic device, and into signals 144bof foot switches that are often used in walking analysis and are integrated on or in the patient's shoes.

[0048] The user data 142 must be entered at the beginning of the therapy session or must be loaded from data storage into the control unit 141. For safety reasons, a change of the patient-specific settings 142cand desired movement curves 142dcan only be performed when the orthotic device is standing still. In contrast, step length 142aand treadmill speed 142balso can be changed during operation of the driven orthotic device.

[0049] The central processes of the control unit 141 consist of a position regulator 146, a phase regulator 147, and a trigger unit 148. The position regulator 146 generates the control signals 143athat are fed as desired values for the leg position to the knee and hip drives of the orthotic device. The control circuit of the position regulator 146 is closed by feeding the measuring values 144aof the angle sensors of the orthotic device back, so that the leg position of the orthotic device can be precisely controlled. The phase regulator 147 is located together with the trigger unit 148 in a control circuit that is higher than the position regulator 146 and which, because of the predetermined treadmill speed 142band mechanical settings of the orthotic device (patient-specific settings 142c) scales the desired movement curves 142din such a way with respect to time that the predetermined step length 142ais on average reached as closely as possible, and the sequence of movement of the orthotic device is synchronized with the treadmill speed 142b: with a predetermined step length 142a, the swinging leg of the patient, i.e., the leg that is not standing on the treadmill, should always be set down at the same position on the treadmill. The change from the swinging to the standing leg and vice versa is reported to the phase regulator 147 by the trigger signal 149 that originates in the trigger unit 148. The trigger unit 148 receives the information necessary for this from the measuring values 144, i.e., from signals 144aof the leg position of the orthotic device (knee and hip angle) as well as from signals 144bof the foot switches. The walking pattern 150 calculated in this way in the phase regulator 147 is made available to the position regulator 146, and is used as a predetermined value for the leg position, and is further supplied via control signals 143ato the orthotic device.