WO2001010508A1

WO2001010508A1 - Rehabilitation device

Info

Publication number: WO2001010508A1
Application number: PCT/GB2000/002065
Authority: WO
Inventors: Nicholas William Granville; Neill Malcolm Pounder; Julian Anthony Webb
Original assignee: Smith & Nephew Plc
Priority date: 1999-05-27
Filing date: 2000-05-30
Publication date: 2001-02-15
Also published as: CA2375335A1; EP1187662A1; JP2003506165A; AU5089900A; GB9912269D0

Abstract

The invention relates to a position sensor device, which is attachable to a user and is able to indicate the position and/or motion of a body part of the user.

Description

REHABILITATION DEVICE

The invention relates to exercise devices used for the rehabilitation of patients following traumatic joint injury but also for sports physiotherapy and general exercise. The device may also be suitable for care of patients following wound injury, especially when patient compliance is required. More specifically, the invention relates to an intelligent device that allows a selection of exercise programs to be monitored.

It is well known that muscle, bones and joints should be exercised to maintain strength. It is also known that fractures exposed to permissible weight bearing stress often heal more predictably and more rapidly than fractures, which are not stressed at all. This is also believed true for connective tissue, such as ligaments and certain cartilage. Similarly the exercising of injured limbs has beneficial effects to the healing of the joint or muscle injury.

Currently the neuromuscular stage of rehabilitation is only addressed by one -to -one physiotherapy treatment, which can be costly and is time consuming. Current treatment systems and devices are concerned with enhancing proprioception via skin receptors or by training balance alone in the therapist's clinic, this could include the wobble board and KAT system.

Previously proprioception was thought of as just balance however surprisingly the devices of this invention show that the position and angle of the user's limbs, and / or the kinesthesia of the user's limbs may allow the therapists a better understanding of condition of the limb of the user. With regard to proprioceptive / neuromuscular rehabilitation this may allow the therapist a better understanding of the progression of a patient's rehabilitation, whether the patient is progressing at the desired rate and whether the exercise programme is suitable to the patient, or if it is not, to change the exercise program. Similarly this can offer benefits to the therapist working with sports men and women.

Previous physiotherapy equipment and treatment systems needed close supervision by the therapist to ensure that the exercises were being carried out correctly and indeed to ensure that the user was doing the exercises. The therapist, for the prior art rehabilitation systems had to be present when the user was being assessed. Usually the person using the physiotherapy equipment or treatment system, whether a patient or sports person would have to travel to the therapist at a clinic to use the equipment and to perform the exercises. Due to the time wasted between seeing one patient or client and the next this current system has the disadvantage of being a very ineffective use of the therapist's time.

It was previously thought that the current system, of the patient or client always travelling to the therapist for their rehabilitation treatment could not be improved upon as the treatment system required large, sometimes heavy, expensive equipment which was not easily transportable and that the therapist would have to be present to monitor the exercise programme.

It is an object of the present invention to address some of these before mentioned problems.

It is an object of the present invention to provide a device, which indicates the position and/or movement of a user's limb.

It is an object of the present invention to provide a proprioceptive and/ or neuromuscular device that may monitor and record the user's performance. It is an object of the present invention to provide a proprioceptive and/ or neuromuscular device, which is portable.

According to the present invention there is provided an exercise device comprising at least one position sensor that is attachable to a user and which can then indicate the position and/ or motion of a body part.

Also according to the present invention there is provided an exercise device comprising at least one position and/ or motion sensor that is attachable to a user and which indicates the position of the body part of the user to which the position and/ or motion sensor is attached.

Preferably the, or all, position sensors are in communication with a processor for processing data generated from the position sensor.

In preferred embodiments, the exercise device of the present invention will have a memory to store data generated from the position sensor, in order to download the data generated at a later time. However the exercise device of the present invention may also have a data transmitter that automatically transmits the data generated as it is generated. Whether the data generated by the sensor is downloaded as it is generated or at a later time, this information may be transmitted to the user or the therapist. If the data generated is stored by the exercise device of the present invention or by a separate memory database to which the exercise device has sent the data to, then the therapist, or user, can examine the data at a later, perhaps more convenient time, than when the actual exercise was performed.

Optionally the exercise device of the present invention may have a message conveyor, in order to instruct the user to perform a predetermined exercise programme. In simple embodiments of the present invention the instructions to the user may be written on a sheet of paper given to the user by the therapist. In more sophisticated embodiments of the present invention the instructions may be displayed on a separate monitor.

The device however may simply be worn by a user to indicate when a limb, or body part, of the user is moving too fast, or too far in a particular direction. This may therefore be used to help prevent, for example, overreaching by the user.

According to the present invention there is provided an exercise device having; a position sensing means that is attachable to a user whereby the position sensing means senses the position of the body part of the user where the position sensing means is attached; and a control means in communication with the position sensing means for receiving outputs from the position sensing means, the control means further including programmed processing means, for processing outputs from the position sensing means, and memory means for retaining the processed data outputs from the position sensing means, and the control means further having means to instruct a user to perform a predetermined exercise programme.

It is envisaged that the present invention can be small enough to be easily transportable and therefore the exercise routine need not necessarily be performed at the therapists clinic.

Even if the device is used in the therapist's clinic there are many advantages for using the present invention over the prior art devices. The therapist would be able to deal for users of the device more quickly than in the past and may have a reliable means of comparison to how the user is performing the exercises and how the improvement is progressing. There is an increasing demand for numerical records of patients' rehabilitation to be available for the following purposes.

To make therapists accountable for their actions, for instance, for performance reviews or litigation cases.

For feedback to the surgeon/physician, for example for justification for or against further intervention.

For feedback for reimburser, for example to please insurance companies requiring proof that patients are complying with treatment. For greater understanding of therapy and clinical research i.e. optimisation, of treatments and presentation of results.

For standardisation of treatment and common practices.

For overcoming prejudiced views in the art, by therapists, relating to rehabilitation.

Likewise, as the device may have means to convey instructions of the exercise programme to the user and has means to monitor and record the user's performance, it is again not necessary to use the device in the therapist's clinic only.

Not being restricted to performing the exercises at the therapist's clinic has many benefits to both the user and the therapist.

The user can save considerable time by not having to visit the therapist as often and can more easily fit the required exercise program into his or her daily routine. Being able to do the required exercises in private may also be a favourable consideration to some users and thus the user's compliance for doing the exercises may in fact increase when not in the presence of the therapist. This may be especially true when the device is for rehabilitation of elderly patients. The therapist also saves considerable time as data from the device can be collated some time after the exercises have been done and can be sent to the therapists for analysing or can be down loaded to a data collecting station at a mutually convenient time. The therapists will however still be able to closely monitor the user's compliance of carrying out the exercise and to determine if the exercises are having the desired effect. The therapist can alter the predetermined exercise programme of the device in order to ensure that the user does have an exercise programme suitable to their particular needs.

As individuals will perform the same exercise programme in very different ways with differing degrees of abilities, especially regarding speed, force and accuracy, it is hard for the therapist to compare the progress of one user with another. For example a young sports person may well be able to perform a programme of exercises faster than an elderly person that has been on the same programme of exercises for a longer period of time than the sports person. Consequently for the therapist to measure the progress of the user it is not only how well the user performs the exercise on the particular occasion but how much of an improvement there is in performing the exercises from before. The present invention provides an easy means to store and analyse the user's current and past exercise data to aid the therapist to monitor the progress of the user and therefore to be able to change the exercise programme accordingly. There is therefore an opportunity for the user to have a speedier recovery, saving time and money for the user and the therapist.

We hereby define the term position sensor to mean any sensor that can detect or compare its position, angle or motion and/ or its rate of change of position, angle or motion. Such position sensors are known in the art and include variable capacitance sensors, rotatory potentiometers, accelerometers, and angle sensors e.g. gyroscope and potentiometers.

Accelerometers are well known in the car industry for triggering car airbags. Accelerometers on the market that may be used with the present invention include accelerometers sold under the Trade Name IC sensors and those marketed by Analog Device Inc., for example the ADXL202 accelerometer. These are two-axis ± 2g micromachined sensors.

Typical gyroscopes suitable for use with the present invention are MG 100 supplied from Gyration Inc. This is a dual-axis gyroscope, originally designed for integration into pointers and remote controls, and computers and home entertainments systems.

The position sensor can be attached to the user by any suitable means. This could be simply by having a stick-on patch with the sensor or alternatively the sensor could be held on the user by a bandage or dressing. Likewise a strap with suitable hook and loop fastenings, for instance like those sold under the trade name of Velcro (Trade Mark), could be used to hold the position sensor in place.

Preferably the position sensor will be incorporated into a sleeve whereby the sleeve can be easily attached to the user at the desired position.

The sleeve may be any size or shape suitable to be attached to the user. Typically the sleeve will be in the shape of a glove, sock, armband, ring or bracelet, legband or anklet.

Likewise the sleeve may be made of any suitable material that would enable it to be safely attached to the user. The sleeve may be rigid like a conventional brace or may be of soft material. Preferably the sleeve will be substantially of soft material. When the sleeve is of substantially soft material, any soft material may be used to construct the sleeve for instance, textile fabrics. More preferably the sleeve will be small, soft and light in weight in order to be as comfortable to the user as possible.

The communication means by which the data from the position sensor means is conveyed to the control unit, in embodiments where there is a control unit, can be by any means suitable for such a purpose. Preferably the communication means will be by radio signalling or the like, so that the user is not hindered physically when doing the exercises. The communication means however could be by wire to the control unit provided that the exercises could be performed within the limited range of the wire.

The control unit could be attached to the user, for instance to a belt held around the user's waist, to allow freedom of movement of the device when the user is performing the exercises. This may be an important feature when the means of communicating the data from the position sensor to the control unit is by wire. This type of embodiment of the present invention may be especially important when the user is jogging and the control unit must be able to move with the user.

Alternatively the control unit and position sensor could be contained together within one unit provided the one unit could be small enough and sufficiently light in weight to be carried by the user.

The device of the present invention can be used by itself or with other exercise aids. Other exercise aids could be a mat that has markings on it to indicate positions on the mat that the user may be requested to move to or to move a particular body part or limb to. Preferably it is envisaged that the user will have an exercise programme that requires that the user to move either a hand or foot, or any other suitable part of the body, to a desired position on the mat. These programmes may specify whether it is the left or right, hand or foot or other body limb that is to be moved. For exercises requiring the user to move his foot or feet, to desired positions on the mat, the mat may preferably be positioned on the floor. Likewise for exercises designed to exercise mainly the lower body of the user the mat may preferably be positioned on the floor. Where the exercises require the user to move their hand, the mat may suitably be placed on a table or on a wall or other vertical surface to allow easy positioning of the user's hand on the mat. Likewise for exercises designed mainly for the upper body of the user the mat may be suitably placed on a table or held vertically. Suitable means of attaching the mat to a wall or vertical surface could be used to position the mat. The mat need not be restricted to substantially flat surfaces for it is envisaged that the mat could be used on uneven surfaces in order to test a users balance and/ or movement on an uneven surface. Typically the mat could be used on stairs or on a wobble board. This is especially important for rehabilitation exercises where a patient may feel quite stable when on surfaces that are substantially even but not when on stairs or when on surfaces that are uneven. Suitable attachment means to attach the mat securely to the stairs would be preferably used in conjunction with the mat in order to ensure safe usage of the mat by the user.

Likewise the mat may also be used on soft surfaces. For example the mat may be used on an exercise bouncer.

The mat may be of any size or shape however it is envisaged that a mat of approximately 1 m to 2 m by 1 m to 2 m would be preferable to allow for easy transportation of the device. It is envisaged that a smaller mat could be used for upper body exercises, for instance 1 m by 1 m, and a larger mat, for instance 2 m by 2 m, for exercises directed at lower body exercises. Typically the mat may be 1 m by 2 m for exercises directed solely for the upper body, and typically 2.5 m by 1.5 m for exercises directed solely for the lower body. The particular mat need not be limited for any particular program of exercise and it is envisaged that the one mat could be used for exercises directed at both the upper and lower body of the user. When not being used, the mat in some embodiments of the present invention may be easily rolled or folded to facilitate storage.

The mat can be made of any suitable material. Typically the mat will contain elastic material.

Preferably the mat will have markings to act as specific targets for the user to make contact with the mat when directed to do so for the particular exercise programme. This could be simply a series of labelled or indexed grids on the mat. The grids on the mat could be of different sizes and therefore suitable for a wider range of exercise programs. Typically when different size grids are used on the one mat the grids will be colour coded in order to allow easy visual differentiation between the grids. Typically the grid spacing will enable desired targets to be large enough for the user's hand or foot to be placed substantially over the target area.

Other markings could simply be shapes, numbers, letters or pictures on the surface of the mat.

Typically the grid spacing will enable desired target areas to be large enough for the user's hand or foot, or other body limb, to be placed substantially over the target area.

The mat may even contain lights on the surface of the mat in embodiments of the present invention where the lights themselves are the target for which the user should place their hand or foot, or other body limb, on to when that particular light lights up. The lights would suitably be protected from the physical contact of the user putting pressure on the surface of the mat. It would also be preferable with this embodiment of the present invention if the lights could be contained within the substantially flat surface of the mat or cover target so that the surface is still substantially flat. Having the surface substantially flat is important where the user is walking on the mat and may be tripped by the lights if the lights projected from the surface.

A common exercise programme presently used by therapists to monitor rehabilitation of a patient, which may be performed by a user with the present invention is the step up step down exercise.

This exercise can be used to address ankle, knee and even hip mobility and strength of the patient. Sensors may be attached to the user at various positions on the leg, e.g. front and/or back, to detect sideways and vertical accelerations, and sideways and vertical rotations. Typically the sensors may be positioned above or below the ankle or knee depending on the joint of interest. When the exercise is done correctly, the device will show that the sections of the limb above and below the joint are aligned throughout. When the exercise is done incorrectly there will be evidence of the joint being twisted and the angle achieved by the joint will be less than when the exercise is carried out correctly. Preferably both accelerometers and gyroscopes would be used with an embodiment of this invention to perform this type of exercise.

A particularly suitable exercise for performing with the present invention is the simple active/passive range of motion exercises. For these, during rehabilitation, the patient is asked to move their joint through certain angles. Either passively (moved by the therapist or a machine) or actively using the muscles. The range of motion should increase during rehabilitation. Typically the control means will be able to collect and store the data from the position sensor or any other sensors being used with the invention, in order to be able to later download the collected data. The downloading of the collected data, may be done by the therapist either at the clinic, or elsewhere, or the data could be downloaded by the user and sent to the therapist for analysing. It is possible, using suitable means that the collected data could be sent to the therapist by telephone, e.g. e- mail, or radio. It is even possible that the collected data could be sent to a collecting station near to the therapist or at the clinic to enable the therapist to analyse the data when required.

The predetermined exercise programme of the device may be preprogrammed into the device by the therapist. There is no limitation to what exercise programmes could be programmed into the device, in order for the user to carry out the exercise programme. The therapist would preferably choose an exercise programme that would be challenging to the user but still within their capabilities. The exercise programmes may consist entirely of simple commands, for instance to move the left foot to grid H or to move the right hand to square 5 when the present invention is used with such a particular target. The commands may be any number of different command including commands to ask the user to jump, hop, hit, kick, run or push.

The instructions or commands of what movement the user is required to do can be conveyed to the user by any suitable means. The means to convey instructions or commands to the user need not necessarily be attached to the control unit, or the device of the present invention, as the means to convey instructions or commands to the user as the means to convey instructions or commands to the user may be in wireless communication with it. This may be by instructions on a TV or LCD screen that the user can look at whilst performing the exercise programme. The display on the screen may be by any suitable means but would typically be written instructions or a graphic display of what the instructions are. The instructions may also be conveyed to the user by other visual means for example when lights are used within the mat to move to the light, which is switched on or off as the case may be.

Additionally the device may incorporate a light projecting means on to a mat where the user must move to where the light projection falls onto the mat. The instructions however could be by simple audio means, i.e. audiotape, or digitised voice. In the simplest of embodiments of the present invention the instructions to the user in order to perform the exercise programme may be written on a sheet of paper. Once the device has indicated to the user to start the exercises, for instance, this may be to show that the control means is ready to monitor and record the exercises, the user may perform the exercises as written on the sheet of paper.

Where the sleeve of the present invention covers the sole of the foot of the user the sleeve may contain a pressure sensor on the sole of the foot which is in communication with the control unit and is able to detect when the user places that particular foot on the ground. The pressure sensor may be able to distinguish when the user places the foot onto the ground and when the user actually puts weight on the foot. This information can be monitored and stored by the control unit to be later downloaded to a central data collecting unit at the therapist's clinic to be analysed.

This embodiment of the present invention may be easily adapted that the device may have pressure sensors positioned to monitor the pressure for hand, shoulder, arm exercises or the like. For instance, the amount of pressure by a user's hand may be monitor against a wall when performing a predetermined exercise. Devices of the present may be of various weights but preferably the device will be of a weight that can easily be portable and carried by the user with ease.

For small devices having few sensors the total weight of the device, being attached to the user may be less than 200 g. Preferably a device with few sensors would weigh less than 100 g, more preferably it would weigh less than 75 g.

Typical weights for a device with a single sensor may be 35 g, 38 g,

42 g and 45 g.

When more sensors are used this may increase the weight of the device used and therefore when a number of sensors are used the total weight of the device may be less than 2 kg. Preferably less than 1.5 kg and more preferably less than 1 kg, when low weight devices are required. The weight of the device attached to any one position on a user is unlikely to exceed 750 g, preferably it is unlikely to exceed 500 g when attached to any one position on a user, when low weight devices are required.

It may however be required that the device is of a substantial weight and therefore the device of the present invention may be any suitable weight which enables the user to perform the exercise programme. Typically the device will be less than 15 kg in weight.

According to the present invention there is also provided a method of manufacturing an exercise device comprising the steps of combining one or more position sensors, that are attachable to a user in which the position sensor, or sensors, indicate the position of the body part of the user where one or more of the position sensors are attached, to be in communication with a processor for processing data generated from one or more of the position sensors.

The invention further provides a method of manufacturing an exercise device comprising the step of connecting, a position sensitive means that is attachable to a user in which the position sensing means is for sensing the position of the body part of the user where the position sensing means is attached, and a control means in communication with the position sensor means for receiving outputs from the position sensor means, the control means further including programmed processing means for processing outputs from the position sensing means and memory means for retaining the processed data outputs from the position sensing means, the control means further having means to instruct a user to perform a predetermined exercise program.

The invention will now be further described by way of example only with reference to the drawings which are

Fig. 1 shows a device according to a first embodiment of the invention.

Fig. 2 shows a mat for use with an embodiment of the present invention.

Fig. 3 shows a Capacitance One Dimensional Angle sensor suitable for use with the present invention, the sensor having a position of low capacitance.

Fig. 4 shows a Capacitance sensor of Fig. 3, the sensor having a position of high capacitance. Fig. 5 shows a circuit diagram typical of an electrical circuit for use with the Capacitance sensor shown in Fig. 3.

Fig. 6 shows inductive Angle Sensors for use with the present invention.

Fig. 7 is a view of a user's leg with two positioned gyroscopes, positioned ready for a knee bend exercise programme.

Fig. 8 is a view of a user performing an embodiment of an active range of motion exercises.

Fig. 9 shows one embodiment of a sensor and attachment means of the present invention.

Fig. 10 is a flow diagram explaining a weight shift exercise.

Fig. 11 shows a typical neural network suitable for use with the present invention.

Fig. 1 shows a first embodiment of the invention in which a sleeve (1 ) is positioned on the right leg of a user (2), covering the knee and ankle joints of the right leg of the user (2). On the sleeve near to the knee position is attached an angle sensor (5), in order to measure the angle between the thigh and lower leg. Attached to the sleeve there are also two accelerometers (6,7) for measuring movement of the right leg of the user (2). One accelerometer (6) is attached to the thigh position of the sleeve, the other accelerometer (7) is positioned near to the ankle position of the sleeve. The accelerometers (6,7) and the angle sensor (5) are in wireless communication with a control unit (3). An aerial (4) attached to the control unit (3) aids reception of signals from the accelerometers (6,7) and the angle sensor (5). Attached to the control unit is a small television screen (8) whereby instructions from the control unit are conveyed to the user (2), to perform an exercise programme. The exercise programme is predetermined by a therapist. After performing the exercise programme the user (2) downloads the data via radio from the control unit to a central data-collecting unit at the therapists clinic for analysing. The therapist can also change the exercise programme by radio, without the need for seeing the user.

Fig 2 depicts a mat (21 ) for use in accordance with a second embodiment of the present invention. The mat (21 ) has a target grid on its upper surface.

Figures 3 and 4 show and example of a capacitance One Dimensional Angle Sensor suitable for use with the present invention. The angle sensor is based on the capacitance of a pair of parallel plates. The area of the plates overlapping is directly proportional to the capacitance. As the angle changes, the overlap of the plates change, as seen in Fig. 3 and Fig. 4, resulting in a change in capacitance.

The sensor may be attached to a hinged device and therefore would be capable of detecting angles in one plane (i.e. elbow motion). The sensor can be produced for a low cost and using a simple circuit, for instance as shown in figure 5. In order to remove the need for every sensor requiring calibration, incorporation of an absolute angle marker

(e.g. at 0°, 45° or 90°) is necessary, such as an L.E.D. or a photocell. The capacitance varies non-linearly with angle, hence the output voltage requires linearising by use of a look-up table, curve fit or spline.

As can be seen from the circuit diagram (figure 5), U1a is used to produce a free-running oscillator. The output from this circuit triggers U1 b, which is configured as a monostable mulitvibrator. The pulse period of this monostable is determined by the capacitance connected across terminals CN1 and CN2, which in this instance is a rotary vane capacitor whose capacitance is dependent on angular position. The output from IC 1 b is a pulse train of fixed frequency with a mark/space ratio, which varies according to the position of the variable capacitor. The DC component of the pulse train will vary with the mark/space of the pulse train. IC U2b is configured as a filter, which extracts the DC component from the pulse train. The DC component is level shifted and buffered by IC U2a and presented at connector CN4 for processing as required.

Inductive 3D angle sensors may also be used with the present invention in order to detect the angle of the body limb, which the present invention is attached to. These sensors may be suitable for sensing the angle of joints capable of moving in more than one dimension (i.e. shoulder, hip, ankle, wrist).

The device may be wireless and may be based on mutual inductance (as used to transmit heart rate data in sports heart monitor products). The sensor consists of a coil driven at a given frequency. The detector is a set of three coils, with iron cores, set orthogonally to each other (figure 6). As the sensor moves through the field, voltages are induced in the three coils, which can be detected and interpreted in response to the sensor position. When the coils are parallel the coupling is at a maximum and at a minimum when the coils are orthogonal. The coupling is dependent on the angle between the coils' axes, but also the distance between the coils.

To detect shoulder angle, it is anticipated that the transmitting coil would be on the patient's arm, whilst the three perpendicular receiving coils would be mounted on the chest. An exercise programme suitable for use with the present invention is the Knee Bend Exercise (figure 7). This exercise programme involves measuring the angle of the patient's limbs and is particularly suitable for movement in one plane. This exercise programme can work equally well for the elbow and other joints where the movement required is in one plane. Suitably therefore the One-dimensional Angle sensors such as the Capacitance Angle Sensor shown in Figure 3 may be used.

Typically the patient or user does the exercise sitting on a chair or on the edge of the bed. Two sensors e.g. gyroscopes are used, the first sensor (71) positioned above the knee and the second sensor (72) positioned below the knee. A larger number of sensors could be used, however for simplicity two is adequate.

The angle between the two parts of the limb, e.g. leg, is calculated from the orientation of the sensors.

Figures 8a, 8b and 8c show an embodiment of an active range motion exercise that can be performed with the present invention. Sensors of the present invention may be positioned on the user's arm so that the vertical motion of the arm (Fig.8a), the horizontal motion of the arm (Fig. 8b) or the rotation of the arm (Fig. 8c) may be monitored. By using the present invention to monitor this type of exercise enables accurate results to be collected quickly and efficiently. By using the present invention to monitor this type of invention also enables complex movement of the arm to be performed and still accurate results can be collected which may be analysed to give useful data that can indicate how well the user can perform the exercises.

For this exercise the sensors of the present invention may be, suitably positioned on the user's arms by means of a bracelet, as shown in Figure 9. These are typically made of an elongated plastic material coiled to form an expanding bracelet shape (91 ) having one or more sensors (92) and optionally having a detachable cover (93). This bracelet may be positioned anywhere on the arms, the coiled mechanism acting to hold the bracelet without causing discomfort to the user and also not restricting movement by the user. The bracelet may be suitable for use on other limbs of the body, for instance on the leg.

The bracelets may be attached by any suitable means. A possible means to attach the bracelet around a user's limb is by VELCRO (Trade Mark) material.

The bracelets of Figure 9 may have a hard wire connection to a data processor for processing the data generated, however preferably the data generated would be conveyed to the processor by radio. This has the advantage that the user has good freedom of movement.

Examples of the manufacture and use of the invention are described below:-

Example 1

An exercise devise having four accelerometers, each accelerometer incorporated into a bracelet of soft material. The bracelet being substantially made of a woven cotton that provides some stretch in order to be easily attachable to a user's leg. The user wears the bracelets with the accelerometer/ position sensing means at each ankle and just below each knee such that the accelerometers are placed on the outside position of the user's leg.

The accelerometers detect limb motion and detect when the user is on one leg and how high the leg is held off the ground etc. The accelerometers are in wireless communication to a central unit which records information regarding the user's movements. The central unit has memory and processing means. The central unit was held by a belt to the user's waist. The central control unit has built into it a small audio microprocessor that conveys instructions to the user of what exercises to do. The exercise programme having been predetermined, and preprogrammed into the central control unit.

The user is instructed to hop on the left leg and then the right leg at various times throughout the exercise programme. After completion of the exercise programme the central unit was removed from the user and downloaded by telephone via a modem to a data collecting station at the therapist's clinic to be examined by the physiologist at a later time.

Example 2

An exercise device having four accelerometers as described in Example 1 , additionally also having a mat. The accelerometers are in wireless communication with a central control unit, which is placed on the floor near to the mat. The position of the accelerometers is monitored, thus indicating joint position and speed of joint response following instruction. The mat is positioned on the floor and the user is instructed audibly from a microprocessor that is attached to the central control unit, to perform particular exercises by placing the left foot or right foot on various positions on the mat.

The time that the microprocessor instructs the user to perform particular exercises is recorded in order to measure the response time to perform the exercise. The grid measures approximately from 1.5 m by 1.5 m and has two colour-coded grids. A solid line blue coloured grid whereby the grid forms squares with sides of 15 cm in length and these squares are evenly divided into four by a red coloured broken line grid. The blue coloured grid is labelled in the centre of the squares by blue numbering one to one hundred. The control device is pre-programmed to instruct the user to move his left foot or right foot to various positions by the audio microprocessor.

This information is collected and stored in the control means. After performance of the exercise programme the data collected is sent by telephone via a modem to a central data collecting station at the therapist's clinic for the therapist to analyse the data at a later time. The therapist can therefore monitor compliance by the user and the accuracy and speed of carrying out the programmed exercises. In this way the therapist saves considerable time in monitoring the user but can still monitor the benefits of performing the exercises.

Example 3

An exercise device having four accelerometers as described in Example 1 having also a rubber mat hanging from a door. The accelerometers are in wireless communication with a central control unit. The mat is hung from the door by a light plastic clip that attaches to the mat and hangs over the top of the door. The door is closed to firmly hold the mat in a stable position. The central control unit is able to collect data from the accelerometers of where the users ankles and knees are at a given time. The mat is approximately 1 m by 1 m with different coloured circles measuring 15 cm in diameter on the outer facing surface of the mat. The control unit is connected to a TV via the aerial socket of the TV. The TV is placed in view of the user when the user is positioned next to the mat. The control unit conveys instructions to the user via the TV screen as the TV screen displays the particular colour of circle which the user is instructed to move his hands to in accordance with the predetermined exercise programme, programmed by the therapist beforehand. The compliance of the user and the accuracy and speed at which the user completed the exercise program is monitored. This data is collected and stored by the control unit until downloaded by the therapist to a central data collecting station by telephone via a modem.

Example 4

An exercise device consisting of a sock with two accelerometers incorporated into the material in such a way that when the sock is positioned on the foot, one of the accelerometers is positioned at the ankle at the back of the ankle joint and the other accelerometer is positioned at the top of the toes of the foot. The user wears the sock on the right foot and is required to perform the exercise programme. The accelerometers are in wireless communication with a central control unit, which is placed in the same room where the exercises are to be performed. A mat is placed on the floor in front of the user and instructions from an audio microprocessor that is attached to the central control unit conveys instructions to the user of what exercises to do. These instructions will be to move the right foot to various positions on the mat while keeping the left foot still. The mat has a numbered grid on its upper surface, the different grid numbers being target positions for the user to move the right foot to. After the exercise programme has been completed the information that has been processed and stored in the central control unit is downloaded to a central data collecting at the therapist's clinic.

Example 5

An exercise device as described in Example 4 where the accelerometers are replaced by angle sensors. The angle sensors used were gyroscopes, MG 100, supplied from Gyration Inc.

Example 6 An exercise device as described in Example 4 where the sleeve also contains a pressure sensor on the sole of the foot region of the sleeve in order to measure additionally when the user places the right foot onto the ground and when the user places weight onto the right foot.

Example 7

An exercise device as described in Example 5 where the sleeve also contains a pressure sensor on the sole of the foot region of the sleeve in order to measure pressure on the sleeve when the user places the right foot onto the ground and when the user places weight onto the right foot.

Example 8

An exercise device having two accelerometers contained within a sleeve such that when the sleeve is placed on the arm of the user one accelerometer is positioned near to the wrist and the other near to the elbow. The accelerometers are in wireless communication with a central control unit. The central control unit has attached to it an audio microprocessor for conveying instructions to the user regarding the exercise programme, which the user is requested to do. Before starting the exercise programme the user is sitting down. The exercise programme starts with the microprocessor delivering an ascending audio note and the user moves the arm with the device attached in time to the audio note. The movements of the arm are processed and recorded by the central control unit to be downloaded later to a data collecting station at the therapist's clinic by telephone via a modem. The therapist can therefore examine the data at a later time in order to assess how the user is progressing with the exercise programme.

Example 9 An exercise device as described in Example 8 where the accelerometers are replaced by angle sensors, which are positioned adjacent to the elbow joint. The angle sensors used were gyroscopes,

MG 100, supplied from Gyration Inc.

Example 10

For this example the patient was asked to perform a weight shift exercise. The patient was asked to rock from side to side putting their full weight on each leg in turn. A common occurrence is for a patient to rock their shoulders or hips. When this occurs the patient may believe their weight is being fully transferred to each limb, but this is not the case. Sensors, e.g. accelerometers in this example, are placed on the sternum and the waist for detecting abnormal shoulder or hip movement.

The data collected was analysed rather like what the therapist would do in practice. When the exercise was done correctly the upper body moves from side to side while remaining in a vertical plane. When the exercise is done correctly sensors at the waist and chest will indicate approximately equal movements. However, when the exercise is done incorrectly the shoulders (upper body) or hips are likely to move significantly more than the other or there will simply be insufficient movement. Commonly when the exercise is done incorrectly there will be shoulder wobble (when the shoulders move significantly more than the hips) or hips wobble (when the hips move significantly more than the shoulders) or insufficient movement (when the patient does not move his body enough due to, for example, tiredness or injury).

The ranges of the horizontal axis of each of the two accelerometers are compared and advice is given to the patient. The flow chart of Figure 10 explains the analysis, with range-waist representing the range of acceleration at the waist and range-chest representing the range of acceleration at the chest.

Example 11

Weight shift exercises similar to the exercise explained in Example 10 apart from that the user also has accelerometers to detect sideways movement of their waist and shoulders.

The data collected was analysed using neural network. The neural networks are very good at identifying non-linear relationships between a set of inputs and one or more outputs. The advantage of using neural networks is that they find the best relationship without the user having to specify a choice of possible relationships. Neural networks find a relationship but do not determine if this relationship is a good or bad one, meaningful or meaningless, it is up to the user or therapist to determine this.

Neural networks train using a set of data (the training set). Users assess the quality of the network output using another set of data (the validation set). Because the networks train on one set and are assessed using another, it is possible, if the two data sets are too similar, for the network to be of low quality even though the validation set suggests otherwise. Therefore, cautious users have another set of data (the test set) to reduce the chance of this happening.

Figure 11 shows a typical neural network. There is one input node (111 ) for each feature; there is one output node (112) for each class of movement. The number of hidden nodes (113) can vary. The lines (114) represent weights between pairs of nodes. Hidden nodes, e.g. hi , will be the sum of input nodes i1 to i5 multiplied by their respective weights w1 to w5. The other hidden nodes (113) are the sum of the same input nodes (111) but multiplied by a different set of weights. Similarly, each of the output nodes (112) are the sum of the hidden node multiplied by a set of weights. Ideally. In a classifying network like this one, the output will be close to unity while all the other outputs will be close to zero. This is because the volunteer's movement can only be put into one class at a time. In order to help the network find the optimum set of weights, each sum of inputs to a node can also be scaled to fall within a desired range of values.

The movement of the user performing the exercises is classified into one of four classes:

1. Correct movement

2. Move hips less 3. Move hips and shoulders more

4. Move hips and shoulders less

Accelerometers were placed in front of the user at the waist and at the chest. The outputs from the accelerometers in the horizontal and vertical planes were used (please note that in Example 10 only side-to- side movement was considered).

The following features were extracted from each of the four accelerometers: 1. The standard deviation of the accelerometer output over the 30 readings (about 1.8 seconds)

2. The range of accelerometer output over the last 30 readings (i.e. accelmax- accelmin)

3. The absolute sum of the accelerometer change over the last 30 readings (i.e. the sum of abs ( reading n - reading n-1 ) Twelve features (the above three from each of four accelerometers) are input to the network. The network used Bayesian regularisation to limit the magnitude of each network weight.

Matlab version 5.3.1 with the neural network toolbox 3.0.1 was used to do the analysis.

Other training regimes could be used. Not all features need be input into the network, thus simplifying its use but probably reducing its accuracy. The number of hidden nodes could be varied. Finally, the output classification could be altered, but only if the assessors are watching the patient, changes the classification of the exercises.

The therapist can examine the data at a later time in order to assess the user's performance.

Example 12

In this example the patient was asked to perform a knee bend exercise.

One gyroscope is placed on each part of the leg, above and below the knee. The gyroscopes are oriented to detect a forwards/backwards and up/down change in position, i.e. it would detect a change in knee angle, but not a side-to-side movement of the leg. Typically 100 or more readings are taken without the sensors moving to determine the mean stationary output of each gyroscope. Typically, these might be, as in this example, 1125 for the upper leg and 1767 for the lower leg (arbitrary units). Previous experiments have indicated that each sensor changes output by 10.7 for a 1 degree change in orientation. Thus for the upper leg, the angle is: Angle Upper Leg = (sensor output - 1125)/ 10.7

The angle for the lower leg is:

Angle Lower Leg = (sensor output - 1767)/ 10.7

The knee angle is:

Knee angle = Angle upper leg - Angle lower leg

Interpretation of the quality of the exercise can be made using any of the terms in the final equation.

Again the therapist or user can examine the data generated at a later time to assess the results of the exercise programme.

Example 13

Forward Step-up/down

A device of the invention having one accelerometer above the knee and one accelerometer below the knee was positioned on a user. The user was asked to stand facing a single step. The step was 17 cm high and wide enough for the user to stand on comfortably. The user would step up, onto the step, ending with both feet on the step. Then the patient steps down onto the floor, ending with both feet on the floor.

The exercise was repeated several times. The results i.e. data from the accelerometers was collected, downloaded via a modem to a computer at the therapist's clinic to be analysed later.

Example 14 Lateral Step-up/down

Using a similar step as described in Example 13, the user initially stands to the side of the step. The device of the invention, which the user is wearing, is similar to the one described in Example 13, except that, the accelerometers are replaced by gyroscopes, MG 100.

Standing feet together to the side of the step, the user steps up onto the step, leading with the leg nearer the step, ending with both feet on the step. Then the user steps down onto the floor, ending with both feet on the floor. (The step down can be done on either side of the step, depending which leg the exercise is aimed at. The user leads with the foot closer to the direction of travel.)

The exercise was repeated several times. The results from the accelerometers were collected, downloaded via a modem to a computer at the therapist's clinic to be analysed later.

Example 15

An exercise device as described in Example 4 in which at the accelerometer positions there is also an angle sensor. The angle sensors used were gyroscopes, MG 100, supplied from Gyration Inc.

Claims

1. An exercise device comprising at least one position sensor that is attachable to a user and which can then indicate the position and/or motion of a body part of the user.

2. An exercise device as claimed in claim 1 in which the position sensor is in communication with a processor for processing data generated by the position sensor.

3. An exercise device as claimed in claim 2 in which the processor and sensor are attached.

4. An exercise device as claimed in claim 2 in which the sensor communicates with the processor by radio signals.

5. An exercise device as claimed in any preceding claim in which the processor can store data.

6. An exercise device as claimed in any preceding claim in which the device has means to convey information to the user.

7. An exercise device as claimed in claim 6 in which the device is able to convey information the user of the position data.

8. An exercise device as claimed in claim 6 in which the device is able to convey information of an exercise programme.

9. An exercise device as claimed in any preceding claim in which one or more of the sensors are selected from the group; capacitance sensor, accelerometer, rotary potentiometer, angle sensors, potentiometers, or mixtures thereof.

10. An exercise device as claimed in any one claim 1 to 9 in which one or more of the sensors are gyroscope.

11. An exercise device as claimed in any preceding claim in which one or more of the sensors are attached to an arm of the user.

12. An exercise device as claimed in any one of claims 1 to 10 in which one or more of the sensors are attached to a leg of the user.

13. An exercise device as claimed in any preceding claim in which one or more of the sensors are attached to a user by a soft sleeve.

14. An exercise device as claimed in any one of claims 1 to 13 in which the processor communicates with a computer.

15. A rehabilitation device comprising an exercise device as described in any one of the preceding claims.