Method of and means for dynamic gait analysis

• US 3,894,437 A
• Filed: 01/10/1974
• Issued: 07/15/1975
• Est. Priority Date: 01/10/1974
• Status: Expired due to Term

• Current Assignee: Cecil W. Keller, John L. Hagy, John R. Hawthorn, Leonard M. Musil
• Original Assignee: Cecil W. Keller, John L. Hagy, John R. Hawthorn, Leonard M. Musil
• Inventors: Hagy, John L., Hawthorn, John R., Keller, Cecil W., Musil, Leonard M.
• Primary Examiner(s): Myracle, Jerry W.
• Assistant Examiner(s): Rasco, Marcus S.
• Application Number:
  US05/432,146
• Time in Patent Office: 551 Days
• Field of Search: 73/172,65,379,432R 128/2S,2N 340/279
• US Class Current: 73/865.4
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait

Abstract

A method of dynamically analyzing gait, particularly of a human being, is disclosed. The use of such method in diagnosing physical infirmities is described. A means for practicing such method, including a force plate coupled through appropriate piezoelectric quartz crystals to appropriate electronic processing equipment is disclosed and a specific embodiment of such means is described.

Claims

1. In the method of analyzing the gait of a subject walking a prescribed path by sensing the forces applied to a discrete area of said path by a foot of said walking subject, the steps of:

a. converting the varying vertical load forces imposed by said foot of said walking subject on said discrete area of said path during a given interval of time to correspondingly varying electrical signals;

b. converting the varying shear forces imposed by said foot of said walking subject on said discrete area longitudinally of said path during said given interval of time to correspondingly varying electrical signals;

c. converting the varying shear forces imposed by said foot of said walking subject on said discrete area laterally of said path during said given interval of time to correspondingly varying electrical signals;

d. recording all of said varying electrical signals with respect to time;

e. comparing the values of said recorded electrical signals at various instants of said given interval of time to each other;

f. photographing said walking subject at successive instants of said given interval of time in the plane of said prescribed path; and

g. correlating said photographs with said recorded electrical signals with respect to time.

2. In the method of claim 1, the additional steps of photographing said walking subject at successive instants of said given interval of time in planes which are lateral and longitudinal, respectively, of said prescribed path and correlating said photographs with said recorded electrical signals, with respect to time.

3. In the method of claim 1, the additional steps of obtaining data with respect to muscle activities of the lower extremities of said walking subject at successive instants of said given interval of time by electromyography and correlating said data with said recorded electrical signals with respect to time.

4. The method of claim 1, wherein said discrete area of said prescribed path is transparent and said step of photographing said walking subject in the plane of said path is performed from a point vertically below said discrete area of said path.

5. The method of claim 1 wherein said step of converting the varying vertical load forces imposed on said discrete area of said path to correspondingly varying electrical signals is performed simultaneously at three spaced points of said discrete area and the resulting signals are processed to provide information as to variations in the moment of said vertical forces with time.

6. The method of claim 1 wherein said step of converting the varying shear forces imposed on said discrete area of said path to correspondingly varying electrical signals is performed simultaneously at two spaced points on the periphery of said discrete area and the resulting signals are processed to provide information as to variations in the moment of said shear forces with time and variations with time of the torque resulting from said shear forces in the plane of said prescribed path.

7. The method of claim 5 wherein said steps of converting the varying shear forces imposed on said discrete area longitudinally and laterally of said path to correspondingly varying electrical signals is performed at three spaced points on the periphery of said discrete area and the resulting signals are processed to provide information as to variations with time of the moment of said shear forces and the torque resulting from said shear forces in the plane of said prescribed path.

8. The method of claim 7 including the steps of photographing said walking subject at successive instants of said given interval of time in the plane of said prescribed path and in planes which are longitudinal and lateral of said prescribed path;

obtaining data with respect to muscle activities of the lower extremities of said walking subject at successive instants of said given interval of time by electromyography; and

correlating in time said photographs and said data wiTh said recorded electrical signals and said information as to variations with time of the moments of said forces and torque resulting therefrom.

9. The method of claim 4 wherein said step of correlating said photographs taken from a point vertically below said discrete area of said path with said recorded electrical signals with respect to time includes the geometric analysis of the area of contact between said foot of said walking subject and said discrete area of said path.

10. Apparatus for use in analyzing the gait of a subject walking a prescribed path by sensing the forces applied to a discrete area of said path by a foot of said walking subject comprising:

a. a force plate of sufficient thickness to be rigid when subjected to the full weight of said walking subject, said plate having parallel opposed major surfaces of substantially larger area than the contact area of said foot of said walking subject and a peripheral edge normal to said major surfaces;

b. means mounting said plate with one of said major surfaces thereof forming said discrete area of said prescribed path, said means including a plurality of piezoelectric load cell assemblies and a plurality of compression spring assemblies in operative contact with said plate, a first one of said plurality of load cell assemblies and a first one of said plurality of compression spring assemblies contacting said edge of said plate on opposite sides of said plate at points lying on a first line, a second one of said plurality of load cell assemblies and a second one of said plurality of compression spring assemblies contacting said edge of said plate on opposite sides of said plate at points lying on a second line transverse to said first line, and a third one of said plurality of load cell assemblies contacting the other one of said major surfaces of said plate; and

c. means for recording the electrical output of said plurality of piezoelectric load cell assemblies with respect to time.

11. Apparatus as claimed in claim 10 wherein each of said plurality of load cell assemblies includes a load cell mounted between a pair of pivot means and an elongated swivel means in contact with one of said pivot means.

12. Apparatus as claimed in claim 11 wherein each of said plurality of compression spring assemblies includes a pair of spaced pivot means and an elongated swivel means in contact with one of said pivot means.

13. Apparatus as claimed in claim 10 wherein said means mounting said plate with one of said major surfaces thereof forming said discrete area of said path comprises a pit in said path and a frame mounted in said pit and supporting said plurality of piezoelectric load cell assemblies and said plurality of compression spring assemblies for operative contact with said plate whereby said plate is positioned for use with said one major surface thereof flush with said prescribed path.

14. Apparatus as claimed in claim 13 wherein a fourth one and a fifth one of said plurality of piezoelectric load cell assemblies are supported by said frame in operative contact with said other one of said major surfaces of said plate at points spaced from the point of contact therewith by said third one of said plurality of load cell assemblies.

15. Apparatus as claimed in claim 13 wherein said edge of said plate includes a first rectilinear portion extending in a direction substantially perpendicular to the longitudinal axis of said path, said first one of said plurality of piezoelectric load cell assemblies being supported by said frame in operative contact with said first rectilinear portion of said edge and a sixth one of said plurality of piezoelectric load cell assemblies supported by said frame in operative contact with said first rectilinear portion of said edge at a point spaced from said first one of said plurality of load cell assemblies.

16. Apparatus as claimed in claim 15 wherein said second line including said points of contact between said edge of said plate and said second one of said plurality of load cell assemblies and said second one of said plurality of compression spring assemblies is substantially perpendicular to said longitudinal axis of said path.

17. Apparatus as claimed in claim 15 wherein said edge of said plate includes a second rectilinear portion on the opposite side of said plate from said first rectilinear portion and substantially parallel thereto, said first one of said plurality of compression spring assemblies is supported by said frame in operative contact with said second rectilinear portion at a point such that said first line is substantially parallel to the longitudinal axis of said path and a third one of said plurality of compression spring assemblies is supported by said frame in operative contact with said second rectilinear portion at a point spaced from said first compression spring assembly, said points of contact of said third one of said plurality of compression spring assemblies and said sixth one of said plurality of load cell assemblies lying on a third line spaced from and substantially parallel to said first line.

18. Apparatus as claimed in claim 13 wherein said plate is made of transparent material and a camera is mounted in said pit and oriented to photograph the foot of said walking subject in contact with said one major surface of said plate.

19. Apparatus as claimed in claim 10 wherein said means for recording said electrical output of said piezoelectric load cell assemblies with respect to time includes means for the visual display thereof.

20. Apparatus as claimed in claim 10 wherein said means for recording said electrical output of said piezoelectric load cell assemblies with respect to time includes means for processing said signals with respect to each other.

21. Apparatus as claimed in claim 10 wherein camera means are included for photographing said walking subject at said discrete area of said path in the plane of said path and in planes extending longitudinally and laterally, respectively, of said path.

22. Apparatus as claimed in claim 10 including electromyography means for obtaining data in the form of electrical signals with respect to muscle activities in the lower extremities of the walking subject and recording means for recording said data with respect to time.