Device for investigation of muscular contraction

• US 5,012,820 A
• Filed: 08/11/1987
• Issued: 05/07/1991
• Est. Priority Date: 12/11/1985
• Status: Expired due to Term

• Current Assignee: Niels Meyer
• Original Assignee: Niels Meyer
• Inventors: Meyer, Niels
• Primary Examiner(s): Cannon, Alan
• Assistant Examiner(s): SHAY, RANDY CITRIN
• Application Number:
  US07/113,280
• Time in Patent Office: 1,365 Days
• Field of Search: 128/421, 128/423 W, 128/740, 128/741, 128/774, 128/782
• US Class Current: 600/595
• CPC Class Codes: A61B 5/224 Measuring muscular strength
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence

Abstract

The invention is directed to a device for the determination of the change in the mechanical magnitudes during muscular contraction and for the correlation with the change in the electrical magnitudes of nerve and muscle during muscular contraction. The body part with joint, which is to be investigated, is attached to a bolster (2) which rotates sagittally and is supported by means of axles (7, 8) on a line coinciding with the axis of rotation of the joint. An electromagnetically controlled functional coupling (10) and an electric motor (9) are connected to the axle (7) so as to be controllable, and horizontally extending flexure beams (27, 28), with stress measurement strips (29, 30), are fastened at the longitudinal sides of the electric motor (9). A potentiometer (11) and a torque measurement strip (31) are arranged on the axle (8). Electrodes (49, 50 and/or 51, 52) are arranged above the contracting muscle or its nerve and/or a stethoscope head (53), with a microphone (54) coupled thereto, is arranged above the muscle. Stress measurement strips (29, 30), potentiometer (11), electrodes (49, 50, 51, 52) and stethoscope/microphone (53, 54) are connected with an electric amplifier (40), and the latter is connected with a recording device (41). The muscle is excited by means of an electric stimulus current stimulator (39) and surface electrodes (42).

For the investigations of muscular contraction in smaller joints and muscles (e.g. in the hand), a rotatable frame is proposed as a further development, which consists of U-shaped structural component parts (69, 72), which are connected with one another and have shared axles (68), and is attached to the investigated body part (e.g. thumb) with the axles (68) on a horizontal line with the axis of articulation. The potentiometer (11) and the torque strips (31) are located on the axles (68). During the contraction of the muscle, the frame presses on the frame construction (80, 81, 82), which comprises a pressure plate (78), which is vertically movable in the latter, and a pressure spring (79), via a lever (75) with a double roller (77) which runs in defined cam guides (87).

Claims

1. A device for determining a change in mechanical magnitudes during muscular contraction and for correlating with a change in electrical magnitudes of nerve and muscle during muscular contraction in a body part having a joint with an axis of rotation, comprising:

a housing and within the housing, a member for supporting the body part;

two axles extending outward from said member and being supported for rotation in said housing so as to align horizontally with the axis of rotation of the joint;

means for exciting the muscle so that the muscle becomes contracted during a period of muscle contraction and thereby moves the body part rotatably about the axis of rotation of the axle joint to effect rotating movement, whereby said axles (7,

     8) rotate in response to the rotating movement of the body part;

counterforce means coupled to one of said axles for providing a counterforce against the force of the muscle during the period of muscle contraction as caused by said exciting means; and

measuring means for measuring muscular contraction and transmitting measured values indicative of said muscular contraction including potentiometer means attached to the other axle to measure angular positions of said axle in relation to the rotating movement of the body part during said period of muscle contraction;

means for measuring a total nerve potential and conductive speed of the nerve including a first pair of electrodes (49,

     50) attachable to the body part above a nerve of the contracted muscle;

means for measuring electric potential fluctuations and including a second pair of electrodes (51,

     52) attachable to the body part above the contracted muscle;

means for measuring muscular vibration and including a stethoscope head (3) and microphone (54) coupled to the stethoscope head (3), said stethoscope head (3) being attachable to the body part above the contracted muscle; and

means for simultaneously recording measured values delivered by said potentiometer means, said first and second pairs of electrodes and said microphone.

2. Device according to claim 1, wherein said housing (1) is formed with outer walls (12, 13);

said member for supporting the body part being in the form of a sagittally rotatable bolster (2); and

said axles (7,

     8) extending outward from said bolster (2) and passing through said outer walls (12,

     13), said axles (7,

     8) being formed to align horizontally with the axis of rotation of the joint.

3. Device according to claim 2, characterized in that a vertically arranged spiral spring (58) is attached to the outside of an outer wall (12), one end of the spiral spring (58) cooperating with a helical roller (57) attached on one of said axles (7) by means of a connection of material which is stable with respect to length, and its opposite end is attached to a flexure beam (59) attached at the outer wall (12), wherein the flexure beam is connected with an amplifier (40) and the means for recording (41).

4. Device according to claim 2, wherein said rotatable bolster has a U-shaped configuration defining a base portion and two vertical legs;

and further comprising;

a base plate (3) formed to accommodate the body part to be moved by means of the contracting muscle, said base plate (3) being attached on said base portion of said rotatable bolster (2); and

means for vertically adjusting the body part, said vertically adjusting means including rotational adjustment means (14) for adjusting said base plate relative to said rotatable bolster so as to change relative inclination of said base plate (3) and thereby vertically adjust the body part accommodated thereon, said rotational adjustment means including a spherical head.

5. Device according to claim 4, characterized in that a support (16) is provided below a base plate (3) as a lower stop for the base plate (3), which support (16) is attached in a recess (17) in the outer wall (13) of the housing (1) so as to be fixed, but detachable and vertically adjustable, the recess (17) extending in a curve-shaped manner.

6. Device according to claim 4, characterized in that the rotational adjustment means (14) includes three pairs of corresponding disks (32), (33), (34), said pairs of disks being securely connected with respect to each other and detachable again and being arranged vertically one above the other and being connected with one another by means of one of the disks in each instance, a first and a second pair of said disks (32) (34) being arranged in a vertical direction so as to be offset by 90°

relative to one another, and a third pair of said disks being arranged horizontally; and

further comprising;

scales (35), (36), (37) being arranged at each of said three pairs of disks.

7. Device according to claim 4, further comprising:

a heel holder (6), which is displaceable in the longitudinal direction of the base plate (3) along a detachable fixing device in order to fix the body part placed on it, is attached at a rear end of the base plate (3).

8. Device according to claim 4, characterized in that feelers (38) for the adjustment of the base plate (3) to the anatomical shapes of the respective body part to be investigated via the rotational adjustment (14) are attached at the respective inner ends of the axles (7) and (8), which ends penetrate a vertical leg of the rotatable bolster (2), which feelers (38) can be pulled out of the axles in a telescopic manner or pressed in the axles by means of inserted springs.

9. Device according to claim 2, wherein said means for exciting the muscle includes an electric current source (23), said counterforce means including an electric coupling (10) having discs (18, 19) adjoining each other, at least one of said discs (18, 19) having a friction brake lining (20), said coupling being formed to respond to electromagnetic means (21, 22), said counterforce means further including an electric motor (9) connected to said electric coupling (10), both said electric motor (9) and said electric coupling (10) being connected to one of said axles (7) on one of said outer walls (12) of said housing (1) and being fed in a controllable manner by said electric current source (23).

10. Device according to claim 9, wherein said means for exciting the muscle includes an electric current stimulator and electrodes (42) attachable to places on the body part relevant for muscular excitation and being responsive to said current stimulator (39) and to said electric current source (23) for exciting the muscle;

and further comprising;

an amplifier (40) connected to all of said electrodes (49, 59, 51,

     52), said microphone (54), said potentiometer means (11) and said electric motor (9), said amplifier being formed to amplify and transmit said measured values as amplified measured values; and

recording means responsive to said amplifier for receiving and recording said amplified measured values.

11. Device according to claim 9, characterized in that the electric motor (9) has no rigid connection with the housing (26), and said at least one axle (7) is supported in an outer wall of the housing (26) in a ball bearing;

and in that horizontally extending flexure beams (27), (28) are fastened to the housing (26) with stress measurement strips (29), (30) at both longitudinal sides of the electric motor (9).

12. Device according to claim 9, characterized in that a torque measuring strip (31) is attached to the other axle (8).

13. Device according to claim 4, characterized in that the base plate (3) comprises rotational adjustment means (14'"'"') with spherical head, wherein one or more measuring rods (55), which comprise resilient sleeves (56), are provided with scales and extend perpendicularly relative to the base plate (3), are attached at the underside of the base plate (3) and extend until a base piece of the rotating bolster (2).

14. Device according to claim 1, wherein said means for exciting the muscle includes an electric current source (23), a current stimulator (39) and additional electrodes (42) attachable to places on the body part relevant for muscular excitation and being responsive to said current stimulator (39) and to said electric current source (23) for exciting the muscle.

15. Device according to claim 14, further comprising;

an amplifier (40) connected to all of said electrodes (49, 50, 51,

     52), said microphone (54) and said potentiometer means (11), said amplifier being formed to amplify and to transmit said measured values as amplified measured values; and

said recording means being responsive to said amplifier for receiving and recording said amplified measured values.

16. Device according to claim 15, wherein said additional electrodes are formed as surface electrodes.

17. Device according to claim 15, characterized in that said additional electrodes are formed as needle electrodes (43).

18. Device according to claim 1, further comprising:

a limb holder (5) for the body part to be fixed is attached on the base plate (3) and consists of a cup of thermoflexible plastic in order to adapt to the shape of the respective body part.

19. Device according to claim 1, characterized in that said means for exciting the muscle includes a reflex hammer (44) with a hammer head (47) and includes a piezoelectric element (48) in said hammer head (77), said piezoelectric element (48) being formed to transmit an electric impulse to a tendon or muscle when said hammer (44) strikes the tendon or muscle;

and further comprising;

means for triggering said reflex hammer, said triggering means including spring means (45) and a catch (46), said spring means (45) biasing against said hammer head (47) and being formed to tension and relax in response to said catch (46) so as to trigger said reflex hammer.

20. Device according to claim 1 and further comprising:

a rear wall (24) of said housing;

an upper limb holder (4);

adjusting screw means for vertically and horizontally adapting said upper limb holder to the body part to be investigated; and

binding means for fixing said upper limb holder to the body part to be investigated;

said binding means being attached at the rear wall (24) of said housing.

21. Device according to claim 1, further comprising:

a housing (1) with a wall (12), one of said axles (7) extending outward from said wall (12), said counterforce means including a toothed rail (61) with one end, a toothed gear (60) meshing with said toothed rail (61) piston (63) at said one end of said toothed rail (61), a compressed air tank (65) with an output (64) into which is inserted said piston (63), said piston (63) being formed so as to be displaceable in said output at said axle (7) outside of said wall (12) of said housing (1) via said toothed gear (60) and said toothed rail (61).

22. Device according to patent claim 1, characterized in that, a U-shaped structural component part (72), with the axles (68) attached to its two opposite ends, and a strip (73) attached to the structural component part (72) by means of a fixing joint (74), is fastened to the body part to be investigated, wherein the axles (68) lie on a horizontal, imaginary line with the axles of rotation of the joint of the body part to be investigated and are supported at the end points of another U-shaped structural component part (69), which is fastened to an inherently rigid holder (70) for the body part to be investigaged by means of a adjusting device (71), on which a measurement scale is attached and which can be pulled out and can be rotated in a three-dimensional manner.

23. A device for determining a change in mechanical magnitudes during muscular contraction and for correlating with a change in electrical magnitudes of nerve and muscle during muscular contraction in a body part having a joint with an axis of rotation, comprising:

a housing (11) with outer walls (12,

     13);

a sagittally rotatable bolster (2);

means for supporting said bolster (2) in said housing (11), said supporting means including two axles (7,

     8) extending outward from said rotatable bolster and leading through said outer walls (12,

     13), said axles (7,

     8) being formed to align horizontally with the axis of rotation of the joint;

an electric current source (23);

a current stimulator (39) connected to said electric current source (23);

means for exciting the muscle, said exciting means including surface electrodes (42) attachable to places on the body part relevant for muscular excitation and being responsive to said current stimulator (39);

an electric coupling (10) having discs (18,

     19) adjoining each other, at least one of said discs (18,

     19) having a friction brake lining (20), said coupling being formed to respond to electromagnetic means (21,

     22);

an electric motor (9) connected to said electric coupling (10), both said electric motor (9) and said electric coupling (10) being connected to one of said axles (7) on said outer wall (12) of said housing (1) and being red in a controllable manner by said electric current source (23);

first means for measuring muscular contraction, said first measuring means being formed to transmit measured values indicative of said muscular contraction and including a potentiometer means (11) attached to the other axle (8) at an outside of said outer wall (13) of said housing (1), second means for measuring a total nerve potential and for measuring a conductive speed of the nerve, said second measuring means including electrodes (49,

     50) attachable above the nerve of the contracted muscle, and third means for measuring electric potential fluctuations, said third measuring means including electrodes (51,

     52) attachable above the contracted muscle, a stethoscope head (53) attachable above the contracted muscle, and a microphone (54) coupled to the stethoscope head (53);

an amplifier (40) connected to the electrodes (49, 50, 51,

     52) of the second and third measuring means and the microphone (54) of the stethoscope head (53) and the potentiometer means (11) and the electric motor (9), said amplifier being formed to amplify said measured values so as to form and transmit amplified measured values; and

recording means for recording the amplified measured values, said recording means being connected to said amplifier for receiving and recording said amplified measured values.

24. A device for determining a change in mechanical and/or electrical magnitudes during muscular contraction and for correlating with a change in electrical magnitudes of nerve and muscle during muscular contraction in a body part having a joint with an axis of rotation, comprising:

a stationary member;

a supporting member for supporting the body part;

axles extending outward from the supporting member and being mounted for rotation on the stationary member;

means for fixing the body part on the stationary and supporting members;

means for adjusting the position of the body part on the supporting member so as to align the axis of rotation of the joint with the axles;

means for exciting the muscle so that the muscle becomes contracted during a period of muscle contraction and thereby moves the body part rotatably about the axis of rotation of the joint to effect rotating movement, whereby the supporting member and the axles rotate in response to the rotating movement of the body part;

counterforce means for providing a counterforce against the force of the muscle during the period of muscle contraction as caused by said excitation means;

means for measuring one or more of the rotation of the axles during the muscular contraction, electrical signals generated during the muscular contraction, and electrical magnitude of the nerve during the muscular contraction, the measuring means being formed to transmit values indicative of the muscular contraction; and

means for receiving the measured values and recording the same.

25. Device according to claim 24, characterized in that, said counterforce means includes a the frame construction (80, 81, 82) attached at one of said axles (7, 68) at an outer side (12) of a housing (1), and inner struts (83), which extend parallel to outer struts (82) through recesses in a base plate (80) and a cover plate of the frame construction (81) and are securely connected by means of a center plate (78), are displaceable in the frame construction (80, 81, 82);

and in that the center plate (78) cooperates with a lever (75) by means of a movable double roller (77) lying on top of it, wherein the lever (75) is connected with said one of said axles (7,

     68) at a right angle via a guide (76) and so as to be displaceable in the guide (76), and the lever (75) is guided at its opposite end in two elongated holes (87) of side walls (84) of the frame construction (80, 81,

     82) in the area of the double roller (77) via axial elongations (86), the side walls (84) being located opposite one another;

the two elongated holes (87) describing a mathematically determined curve; and

in that a compressible pressure spring (79) is tensioned between the base plate (80) and the center plate (78).

26. Device according to claim 25, characterized in that a lower end of the pressure spring (79) is inserted in an area of the base plate (80) in a cup-shaped supporting cylinder (85), which is detachably attached to the base plate (80) by means of a bayonet lock, known per se, the pressure spring (79) extending through a corresponding opening of the base plate (80) until the center plate (78), and pressure springs having different spring constants can be used interchangeably.

27. Device according to claim 25, characterized in that stress measurement strips (88) are attached to the lever (75).

28. Device according to claim 24 for the investigation of muscular contraction in smaller joints and muscles, characterized in that the body part to be investigated, with its portion which is moved by means of the contraction of the muscle, e.g. the thumb, is placed in a cup 94 and fastened in the latter, while the portion of the body part which is not moved, e.g. the rest of the hand, is inserted and fixed in a holder 97, 98, 99, 100, wherein the holder consists of a base 97, a rigid outer wall 98, which is attached to the latter at a right angle, and outer walls 99, 100, which are displaceable in a direction of the outer wall 98 by means of lockable rail guides 101 and 102 and are likewise arranged at a right angle to the base 97 is adapted to the shape and attitude of the body part by means of the outer walls 99, 100 and a support bar 105, which is fastened on the base plate 106 by means of the graduated and fixable ball joint 104, 104'"'"' and is likewise graduated and longitudinally displaceable within the ball joint 103, 103'"'"', and which is arranged so as to be attached at the base 97 and with graduated and fixable ball joint 103, 103'"'"' and, further, in that the cup 94 is securely connected with a known fastening joint via a holder 95 and with the axle 90 via a stirrup 93, and there are measuring rods 96 at the two ends of the stirrup 93 for fixing the joint of the investigated body part on the imaginary line of the axis of articulation with one of said axles 90;

in that a translating gear wheel 113, which comprises a thread arranged on its circumference, and, following this, the potentiometer 11 for measuring the force of the rotational movement during the rotation of the axle 90, are attached on said one of said axles 90 at the longitudinal side opposite the stirrup 93;

further, in that the translating gear wheel 113 cooperates with the rod 117, which is arranged at a right angle to said one of said axles 90, but is not connected with the latter or with the translating gear wheel 113 so as to be fixed, which rod 117 is movable in its longitudinal direction in linear guides 118;

119, 120 and comprises two cord/wire holders 115, 116 with a pretensioning device at least one of the holders in the area assigned to the translating gear wheel;

both ends of the cord/wire 114 inserted in the thread of the translating gear wheel 113 being fastened in the holders;

further, in that the rod 117 has an electric winding 123 with a coil holder 122 at its end downstream of the linear guide 119, 120, the electric winding 123 penetrating a magnet core 124, which is attached separately at the base plate 106, and being fed in a controllable manner by means of an electric current source 23 and the current regulator 121 and being pulled in or pressed out of the magnet core 124 with the rod 117 according to the intensity of the magnetic field;

moreover, in that the force which acts on the rod 117, is generated by the contracting muscle, and is transmitted via the stirrup 93, said one of said axles 90 and the translating gear wheel 113, as well as the determined counterforce exerted by the solenoid coil 122, 123, 124, are recorded by means of a tension/compression recorder 126, wherein the recorded data is amplified in the amplifier 40, and is recorded in the recording device 41; and

in that the lock 125 is provided for the secure adjustment of the rod 117 in predetermined positions of its longitudinal direction, preferably as a coil/magnet core switch, which is likewise controllable via the current regulator 121; and

in that said one of said axles 90 is supported in two ball bearings 91 arranged within the bearing support pipe 92, and the bearing support pipe 92 is in turn rigidly connected with the housing wall 108 which extends vertically relative to the base plate 106.

29. A device according to claim 24 wherein said measuring means include electrodes attachable above a nerve of the body part to measure a nerve potential and/or the conductive speed of the nerve, electrodes attachable above or in the muscle to measure electric potential fluctuations thereof, a microphone attachable above the muscle to measure vibrations thereof, means for measuring the contraction force of the muscle, and a potentiometer attached to at least one of the axles to measure the mechanical magnitude and/or the velocity of the muscle contraction.