AT508091A1 - DEVICE AND METHOD FOR QUANTIFYING SPASTICITY AT LEAST EXTREMITY - Google Patents

Description

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The invention relates to a device for quantifying the spasticity of at least one limb with a moving part provided for movement of the limb, which is driven by a drive unit, wherein a device for detecting the resistance applied by the limb against the guided movement and a device for recording the detected resistance values are provided. Furthermore, the invention relates to a method for quantifying the spasticity of at least one limb, in which the limb is fastened to a part moved by means of a drive unit, wherein the resistance applied by the limb against the guided movement is recorded and recorded.

Spasticity basically refers to a speed-dependent increased residual stress of the skeletal musculature with elevated tendon reflexes. Spasticity is usually due to damage to the brain or spinal cord. The most common cause of spasticity is hypoxic damage to motor brain regions caused by cerebral infarction. Accidents involving craniocerebral trauma or spinal cord injury may also damage extrapyramidal tracts. Other triggers for spasms are disorders such as spastic spinal paralysis, multiple sclerosis and the like.

In clinical tests to quantify spasticity, a constant angular velocity joint is typically moved by a physician or physiotherapist and then subjectively assessed on a five-point scale of spasticity. Such clinical examinations, in which a lower leg is usually moved manually and the resistance to the constant rotational movement is subjectively detected, is known as the Ashworth method. On the one hand, such clinical examinations are extremely inaccurate because they are subject to a subjective component of the examining physician, and on the other hand they have the disadvantage that due to the limited joint mobility rapid acceleration phases at the beginning and at the end of the pivotal movement, i. Usually in the vicinity of the extended joint (= 0 °) and with a pivoting about 120 ° are necessary to achieve a constant angular velocity of the joint. • • • • • • • • • • - 2 -

Devices or methods are already known from the prior art with which a determination of the spasticity is modeled after the methodology used in the Ashworth scale.

WO 2008/121067 A already discloses a device and a method for quantifying the spasticity of a limb, in particular of the wrist. Here, a movable part is provided, on which the palm is placed, which is in a first pivoting range - if the limb is still no reflex - is constantly pivoted at a first speed and is pivoted in a further pivoting range at a second speed. In this case, the resistance of the limb is measured against the pivoting movement of the movable part. The disadvantage here is in particular that only the spasticity of a single joint is quantified and also with different speeds, depending on the tilt angle of the moving part, must be worked.

A similar device is known from US 2007/0027631 A. Again, a limb, here the lower leg, from a stretched position of the leg in a pivoted position moves mechanically and detects the resistance of the limb against the pivoting movement. A similar device, in which also a single joint is pivoted, is shown in connection with an arm in US 2008/0312549 A1.

In all of the Ashworth-method modeled, machine-assisted diagnostic procedures, the spasticity is disadvantageously diagnosed only by pivoting a single joint and thus a comparatively unnatural movement, since the spasticity of a human being is not specifically articulated, but rather affects the musculoskeletal system as such.

On the other hand, basically movement-training devices are known with a crank to which the feet or arms of a person exercising can be connected by means of pedals or the like. Such motion training devices can also be provided, as in EP 758 554 A1, with an electric motor which can drive or brake the crank. In order to allow a more flexible design of the training process, a computer is provided, which detects the angular position and the speed and torque. To avoid injury during passive training, it is known in such a training device that when a muscle cramping occurs a maximum drive torque is not exceeded. For this purpose, the limit value of the drive torque is automatically adjusted to the average drive torque required by the patient so that it is always greater by a certain percentage than this.

In principle, such motion exercise machines equipped with a crank handle are different types of devices with which the quantification of the spasticity is neither intended nor possible.

The aim of the present invention is therefore to provide a method and a device of the type mentioned, with which compared to known diagnostic devices or methods, a higher information about the influence of spasticity on the processes of daily life can be achieved. Furthermore, due to a comparatively small amount of time for the quantification of the spasticity, an improved applicability in examinations in clinics and rehabilitation centers is to be achieved.

The device of the initially mentioned type is characterized in that the movable part is designed as a peripheral crank. By providing a revolving crank, with which a limb of the person whose spasticity is to be quantified, is moved, a more natural movement of the limb is achieved compared to known diagnostic devices and methods, in which only a single joint is pivoted improved quantification of spasticity is made possible. In fact, during the orbital motion of the crank, at least two joints of the extremity, i. in case of e.g. a leg is moved by the crank, both the knee joint and the hip joint, so claimed • • • • • · · · · · · · · · • · · · · · · · · · · · · · · · · · · · · · · · · · It is not only the reaction of the muscles of a single joint that is used to quantify the spasticity. For example, if the spasticity in the area of the arm is measured, the elbow and shoulder joints would be moved and, in turn, an averaging of the resistance and / or moments of two-joint muscle to quantify the spasticity.

In order to be able to control the rotational speed of the crank in a simple manner, it is advantageous if the drive unit is assigned a control unit. If an incremental encoder is assigned to a shaft of the drive unit, the angular position and angular speed of the revolving crank can be detected in a simple manner via the incremental encoder and thus a control of the angular velocity profile, i. e.g. a constant angular velocity of the revolving crank, done.

If two circumferential cranks are provided, the result is a device in the manner of a crank, in which at the same time two extremities can be moved and thus the total spasticity, which occurs in the range of four joints, can be detected as an average value; thus an even improved quantification of spasticity can be achieved.

In order to achieve a differentiation of the resistance, which is the movement of the respective crank, to achieve, it is advantageous if the cranks are designed as force measuring cranks. Here, the deformation of the connection between the respective crank and the crankshaft is preferably measured by means of strain gauges.

In order to achieve a guided movement of the limb, which is moved by the crank, it is advantageous if a receiving unit for attachment of the limb is connected to the movable part, so that the limb substantially rigid with respect to the connection between the receiving unit and the movable Part is arranged. In this case, orthoses are advantageously provided, in which a foot or hand contact surface in the manner of a pedal and one on the lower leg or.

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Forearm fitting guide are provided so that the leap resp. Wrist be immobilized.

To achieve a suitable angular speed of the crank, it is favorable if between the drive unit and the movable part at least one gear, preferably a reduction gear with a reduction ratio between 1:40 and 1:80, in particular 1:60, is provided. Here, it is advantageous if a planetary gear and a bevel gear are provided between the drive unit and the movable part, wherein the planetary gear is designed as a reduction gear and connects directly to the drive unit, with the bevel gear, however, a 90 ° deflection of the drive shaft to the cranks is achieved. Further, it is advantageous if a coupling is provided between the drive unit and the movable part. With regard to a good controllability and to easily detect the resistance that is applied by the extremity against the guided movement, it is advantageous if a preferably brushless servomotor is provided as the drive unit.

In order to attach the device in a simple manner in a variety of places, e.g. on a wheelchair, a tricycle or the like., It is advantageous if the drive unit together with the movable part and possibly the transmission and the clutch are combined in a modular mounting unit. In this case, for individual adaptation to the size of the person whose spasticity is to be quantified, it is advantageous if the fastening unit can be fastened in a length-adjustable manner to a seat arrangement.

The method of the initially mentioned type is characterized in that the moving part performs a cyclic movement. By providing a cyclic, i. circumferential, movement exporting part, the same advantages are achieved, as they have already been explained in connection with the device according to the invention, so that reference is made to avoid repetition of the above statements.

Since the power consumption of the drive unit is proportional to the applied torque, it can easily determine the resistance that the extremity of the guided movement opposes. Accordingly, it is advantageous if the power consumption of the drive unit is detected. In order to be able to regulate the speed of the moving part in a simple manner, it is advantageous if the angular position of the moving part is measured.

Since the spasticity is basically speed-dependent, it is advantageous to measure the resistance applied by the limb at different speeds. Accordingly, it is favorable if the moving part is moved at intervals with different angular velocity. It has proved to be advantageous here that the rotational speed of the moving part, preferably starting from essentially 10 revolutions / min, is increased to substantially 60 rpm / min. In order to simultaneously detect and record the resistance of the muscles acting on four joints and thus to be able to adjust the quantification of the spasticity to an improved average, it is advantageous if two cranks are provided as a moving part, wherein preferably the force application to each crank separately is measured.

The invention will be explained in more detail with reference to a preferred embodiment shown in the drawings, to which, however, it should by no means be limited. In detail, in the drawings:

1 shows schematically a view of a wheelchair with a device according to the invention for quantifying the spasticity, including a control and an evaluation unit;

Fig. 2 is a perspective view of the wheelchair of Figure 1 including moving parts in the manner of a crank.

3 is a perspective view of the drive train of the device; and

4 shows a block diagram of the method according to the invention for quantifying the spasticity. • · · · · · · · · · · «· · · · · · · · · · · · · ··········································

In Fig. 1, a wheelchair 1 is shown, to which a drive train 2 via a clamping mechanism 1 'is fixed, so that the legs of a person sitting on the wheelchair 1 person with powered via the drive train 2 moving parts 3', namely cranks 3, passive be led circumferentially.

For connection between the cranks 3 and the legs, whose spasticity is to be quantified, in each case an orthosis 4 is pivotally connected to a crank 3.

As can be seen in particular in FIG. 2, each orthosis 4 has a tread surface 5 in the manner of a pedal, on which a rail 5 'extending at the back of the lower leg is provided substantially perpendicular thereto. In order to achieve a guided predetermined movement in the hip and knee joint when the cranks 3 are rotating, the foot of the person to be tested is connected via a belt (not shown) in the region of the tread surface 4 and the lower leg via a belt (not shown) to the rail 5 'connected so that the ankle is fixed. Thus, a defined movement in the hip and knee joint is mandatory.

In order to be able to adapt the position of the tread surface 5 of the orthosis 4 and thus the range of motion of the hip and knee joint to the body size of the person to be tested, a pull-out, preferably rectangular cross-section tube 6 is provided so that an adaptation to different leg lengths can. At the front end of the extendable tube 6, a stand 7 is provided, on the underside of a cross member 7 'is mounted, at the ends of each of which a roller 8 is rotatably mounted, so -that the wheelchair 1 together with the drive train 2 and the cranks 3 in a simple manner remains mobile. As can be seen in particular in FIG. 2, the stand 7 has a vertical sliding guide 9, so that adaptation in the vertical direction is also possible. Basically, the extendable tube 6 is attached via the clamping mechanism 1 'by means of two cross members to frame struts 1' 'of the wheelchair 1. Of course, therefore, a mounting to other frame struts as those of a wheelchair in a simple manner possible. • ♦ · ♦ ············· · ···· - 8th -

As further shown in Fig. 1, the drive train 2 is controlled by a controller 10, which in turn is connected to a data processing system 11. In addition, the controller 10 is connected to an energy source 10 '.

In Fig. 3, the drive train 2 is shown in detail. It can be seen that a servo motor 12 is provided as a drive unit. This is preferably a brushless motor (BLDC motor - Brushless Direct Current Motor, often referred to as EC motor - Electronic Commutated Motor - called). The operating principle of such a motor is fundamentally the same as that of a conventional DC motor, i. An electromagnet (rotor) rotates in the field of a permanent magnet (stator). The current in the rotor is controlled according to its position in the stator field. This usually happens via the brushes on the commutator and is subject to wear and loss. When brushless motor 12, however, the place of electric and permanent magnet is reversed. Control electronics detect the rotor position via non-contact sensors and control the electromagnet in the stator accordingly. The stator carries here a three-phase winding, which is connected in star connection. The position of the rotor is detected in particular by means of an incremental encoder 13. Furthermore, an absolute encoder is provided. As an incremental encoder 13, an optoelectronic encoder is usually used. The absolute position is usually detected with three staggered Hall sensors.

In order to be able to achieve rotary movements of the cranks 3 with appropriate angular speeds via the servomotor 12, the servomotor 12 is adjoined by a planetary gear 14, with which a reduction of approximately 1:60 is usually achieved. Furthermore, a bevel gear 15 with a ratio of 1: 1 is provided for the purpose of deflecting the rotational movement. Between the planetary gear 14 and the bevel gear 15, a play-free elastic coupling 16 is also provided. At the two output shafts 15 'of the bevel gear 15 then directly the cranks 3 can be attached to achieve the circumferential movement. ······················································································· · ···· - 9 -

In the block diagram of FIG. 4, the method for quantifying the spasticity is shown in detail. It can be seen here that the data processing unit 11 specifies a spasticity measuring routine 17, by means of which the servomotor 12 is controlled with the aid of the motor control 10. In addition, the consumed motor current for moving the cranks 3 is continuously measured via the motor control with the angular velocity predetermined by the spasticity measuring routine 17 and stored in a data record 18. Since the motor current is proportional to the consumed torque, this results in the resistance, which oppose the legs of the guided movement. In addition to the consumed motor current is measured by the incremental or angle encoder 13 of the crank angle, which is also the data recording 18 is supplied. The recorded data are evaluated in an evaluation unit 19 and fed to a control or display unit 20, wherein the crank angle or the crank angle speed of the spasticity measuring routine is again supplied, so that the desired angular velocity s-course is controlled , It has proved to be advantageous here that the angular-velocity profile is kept constant at intervals, wherein - since the spasticity is speed-dependent - tests are carried out or recorded at different speed intervals. Advantageously, the limbs of the person under test are guided at six different speeds, starting at a speed of 10 revolutions / min, the speed is increased to 60 revolutions / min in a total of six stages, wherein the extremities are passively moved in each case in 15 revolutions , Thus, it follows that advantageously the total time required to quantify the spasticity is no more than about 5 minutes. This results in a significantly improved applicability of the method in clinics and rehabilitation centers.

The data can hereby be fed, as shown in FIG. 1, via telemetry 21 to the data processing system 11.

Furthermore, it can be seen in FIG. 4 that, optionally, provided that the cranks 3 are designed as force measuring cranks 22, the resistance which the legs individually satisfy for the given movement is also given. [001] ···· ·· ··

10, can be measured and thus the individual force values can also be evaluated in the data processing system 11. From the measured data can thus be given in a simple manner compared to known devices and methods improved quantitative statement about the spasticity.

Of course, the method and, accordingly, the device can also be used for other joints than those shown here in the preferred embodiment, e.g. for the elbow and shoulder joint or the like., Are used.

Claims (19)

• • • • • • • · ·· 1. A device for quantifying the spasticity of at least one limb with a movable part (3 ') provided for movement of the limb, which is driven by a drive unit (12), wherein a device for detecting the resistance applied by the limb against the guided movement and a device for recording the detected resistance values (11), characterized in that the movable part (3 ') is designed as a revolving crank (3). 2. Apparatus according to claim 1, characterized in that the drive unit (12) is associated with a control unit (10). 3. Apparatus according to claim 1 or 2, characterized in that a shaft of the drive unit (12) is associated with an incremental encoder (13). 4. Device according to one of claims 1 to 3, characterized in that two circumferential cranks (3) are provided. 5. Apparatus according to claim 4, characterized in that the cranks (3) are designed as force measuring cranks. 6. Device according to one of claims 1 to 5, characterized in that with the movable part (3 '), a receiving unit (4) for attachment of the limb is connected, so that the limb substantially rigid with respect to the connection between the receiving unit and the movable part is arranged. 7. Device according to one of claims 1 to 6, characterized in that between the drive unit (12) and the movable part (3 ') at least one gear (14), preferably a reduction gear with a reduction ratio between 1:40 and 1:80 , in particular of 1:60, is provided. • · · · · · · · · ·············· 8. Apparatus according to claim 7, characterized in that between the drive unit (12) and the movable part (3 '), a planetary gear (14) and a bevel gear (15) are provided. 9. Device according to one of claims 1 to 8, characterized in that between the drive unit (12) and the movable part (3 ') a coupling (16) is provided. 10. Device according to one claims 1 to 9, characterized in that a preferably brushless servomotor is provided as drive unit (12). 11. Device according to one of claims 1 to 10, characterized in that the drive unit (12) together with the movable part (3 ') and optionally the transmission (14, 15) and the coupling (16) are combined in a modular fastening unit. 12. The device according to claim 11, characterized in that the fastening unit in length-adjustable manner to a seat assembly (1) can be fastened. Method for quantifying the spasticity of at least one extremity, in which the extremity is attached to a part (3 ') moving by means of a drive unit (12), whereby the resistance applied by the extremity against the guided movement is recorded and recorded, characterized in that the moving part (3 ') performs a cyclical movement. 14. The method according to claim 13, characterized in that the energy consumption of the drive unit (12) is detected. 15. The method according to claim 13 or 14, characterized in that the angular position of the moving part (3 ') is measured. • · · · · · · · · · · · · · · · · · · · · ··················································································· · ···· - 13 - 16. The method according to any one of claims 13 to 15, characterized in that the moving part (3 ') is moved at a substantially constant angular velocity. 17. The method according to any one of claims 13 to 16, characterized in that the moving part (3 ') is moved at intervals with different angular velocity. 18. The method according to claim 17, characterized in that the rotational speed of the moving part (3 '), preferably from substantially 10 revolutions / min to substantially 60 revolutions / min, is increased. 19. The method according to any one of claims 13 to 18, characterized in that as a moving part (3 ') two cranks (3) are provided, wherein preferably the force application to each crank (3) is measured separately. / RB