Feasibility Study for evaluating the effectiveness of Orient inertial 3D motion capture wireless devices (developed by the Speckled Computing research group at the University of Edinburgh) for human gait analysis and for identifying deviations from normal gait

1. The Use of Specks in Gait
Analysis
Smita Sasindran1, Jennifer Walsh2, Alison
Richardson2, Jan Herman2, James Hollington2
1 School of Informatics, University of Edinburgh
2 Anderson Gait Laboratory, SMART Centre, Astley Ainslie
Hospital, Edinburgh

2. Gait Analysis
• Brief observation to sophisticated measurement
• Patient population
• 75% paediatric
• Cerebral Palsy
• Neurological Disorders
• Prosthetics
• Treatment Planning
• Analysis of intervention

3. Clinical Gait Analysis
• One of 2 centres in
Scotland providing
clinical gait analysis
• Clinical Gait Analysis
– 3D analysis
• Vicon 460

4. Biomechanical model
• Three markers per body
segment
• Markers on joints define two
adjacent segments
• Marker placement conducted
by physiotherapist
• Markers placed on bony
prominences and anatomical
markers

5. Biomechanical model
• Modified Helen Hayes model 3D
axis system for each segment
• Sagittal plane angles -
Flexion/extension
• Coronal plane angles
Abduction/adduction
• Transverse plane angles
Internal/external rotation

6. Phases of Gait

7. Clinical Gait Analysis

8. Three-dimensional gait analysis
• Track images from
two or more cameras
• Points used to
reconstruct original 3D
trajectories

11. Clinical Gait Analysis
• Kinematics
• Angular displacements in 3 planes
• Kinetics
• Forces, moments, powers
• Temporal Parameters
• Walking speed (m/s)
• Cadence (steps/min)
• Double/Single support time (s)
• Stride length (m)
• Step length (m)
• Step time (s)

12. Kinematics

13. Kinetics
2.0
Hip Flexion Moment 1.0
Hip Ab/Adduction Moment 3.0
Hip Flexion/Extens ion Power
Flex Add Gen
Nm Nm W
Ext Abd Abs
-1.0 -1.0 -2.0
2.0
Knee Flexion Moment 1.0
Knee Ab/Adduction Moment
2.0
Knee Flexion/Extension Pow er
Flex Var Gen
Nm Nm W
Ext Valg Abs
-1.0 -1.0 -2.0
3.0
Ankle Flexion Moment 1.0
Ankle Ab/Adduction Mom ent
4.0
Ankle Flexion/Extension Pow er
Dors Add Gen
Nm Nm W
Plan Abd Abs
-1.0 -1.0 -2.0
40
Fore/Aft Shear Force 30
Medial/Lateral Shear Force
140
Vertical Ground Reaction Force
N N N
-40 -30 0
Left Mean Barefoot (Mean Barefoot) Right Mean Barefoot (Mean Barefoot) Avg File 7 (Normals.gcd)

14. Limitations of current methods of Clinical
Gait Analysis
• Modelling errors
–Centre of knee rotation
–Marker placement
–Soft tissue movement
–Foot modelling

15. Limitations of current methods of Clinical
Gait Analysis
• Practical data collection constraints
–Artificial capture environment
–Snapshot analysis
–Restricted activities
–Specialist staff
–Intrusive
–Expensive

16. Specks
•

17. Potential benefits of Specks for CGA
• Address limitations of current optical motion
capture methods
• Provide objective measure of functional ability in
every day environments
• Provide ongoing monitoring
• Increase national service capacity
• Reduce assessment costs

18. Comparative Results
• Normal Data Collection
• Patient Data Collection

19. Comparative Results – Pelvic Tilt
Pelvic Tilt
30
Ant
deg
Post
-10
Graph from Specks Graph from Vicon

20. Comparative Results – Hip Flexion
Hip Flexion
60
Flex
deg
Ext
-15
Graph from Specks Graph from Vicon

21. Comparative Results – Knee Flexion
Knee Flexion
90
Flex
deg
Ext
-15
Graph from Specks Graph from Vicon

22. Comparative Results – Ankle Flexion
Ankle Flexion
30
Dors
deg
Plan
-30
Graph from Specks Graph from Vicon

23. Comparative Results – Pelvic
Obliquity
Pelvic Obliquity
15
Up
deg
Dow n
-15
Graph from Specks Graph from Vicon

24. Comparative Results – Hip Abduction
Hip Adduction
20
Add
deg
Abd
-15
Graph from Specks Graph from Vicon

25. Comparative Results – Pelvic
Rotation
Pelvic Rotation
30
Int
deg
Ext
-30
Graph from Specks Graph from Vicon

26. Patient Data
30
Pelvic Tilt
deg
-10

27. Patient Data
90
Knee Flexion
deg
-15

28. Patient Data
15
Pelvic Obliquity
deg
-15

29. Patient Data
20
Hip Adduction
deg
-15

30. Patient Data
30
Pelvic Rotation
deg
-30

31. Patient Data
30
Pelvic Tilt
deg
-10

32. Patient Data
60
Hip Flexion
deg
-15

33. Original Curves Zero Mean Adjusted

34. Original Curves Zero Mean Adjusted

35. Original Curves Zero Mean Adjusted

36. Analysis of The Use of Specks in Clinical
Gait Analysis
• Format of result in line with Gait Analysis
reports
• Integration cumulative error, reset at mid-
stance
• Reset orientation of markers
• Zero centred magnitudes

37. Future work
• Anterior/Posterior pelvic tilt
• “Root” of calculations
• Position of foot marker
• Orientation of markers

38. Future Work
• Design
– Size
• Transmitting Wire / Internal memory
• Battery life
• Transmission problems
• Segmentation automated for pathological gait

39. Summary of The Use of Specks in Gait
Analysis
Kinematics
• Angular displacements in 3 planes
• Kinetics
• Forces, moments, powers
• Force Transducers
• Temporal Parameters
• Walking speed (m/s)
• Cadence (steps/min)
• Double/Single support time (s)
• Stride length (m)
• Step length (m)
• Step time (s)

40. Thank you for your attention