the use of specks in gait analysis
DESCRIPTION
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 gaitTRANSCRIPT
The Use of Specks in Gait Analysis
Smita Sasindran1, Jennifer Walsh2, Alison Richardson2, Jan Herman2, James Hollington2
1 School of Informatics, University of Edinburgh2 Anderson Gait Laboratory, SMART Centre, Astley Ainslie Hospital, Edinburgh
Gait Analysis • Brief observation to sophisticated measurement
• Patient population• 75% paediatric • Cerebral Palsy• Neurological Disorders• Prosthetics
• Treatment Planning
• Analysis of intervention
Clinical Gait Analysis• One of 2 centres in
Scotland providing clinical gait analysis
• Clinical Gait Analysis– 3D analysis
• Vicon 460
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
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
Phases of Gait
Clinical Gait Analysis
Three-dimensional gait analysis
• Track images from two or more cameras
• Points used to reconstruct original 3D trajectories
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)
Kinematics
Kinetics
Left Mean Barefoot (Mean Barefoot) Right Mean Barefoot (Mean Barefoot) Avg File 7 (Normals.gcd)
Hip Flexion Moment2.0
-1.0
Flex
Ext
Nm
Knee Flexion Moment2.0
-1.0
Flex
Ext
Nm
Ankle Flexion Moment3.0
-1.0
Dors
Plan
Nm
Fore/Aft Shear Force40
-40
N
Hip Ab/Adduction Moment1.0
-1.0
Add
Abd
Nm
Knee Ab/Adduction Moment1.0
-1.0
Var
Valg
Nm
Ankle Ab/Adduction Moment1.0
-1.0
Add
Abd
Nm
Medial/Lateral Shear Force30
-30
N
Hip Flexion/Extension Power3.0
-2.0
Gen
Abs
W
Knee Flexion/Extension Pow er2.0
-2.0
Gen
Abs
W
Ankle Flexion/Extension Pow er4.0
-2.0
Gen
Abs
W
Vertical Ground Reaction Force140
0
N
Limitations of current methods of Clinical Gait Analysis
• Modelling errors–Centre of knee rotation–Marker placement–Soft tissue movement–Foot modelling
Limitations of current methods of Clinical Gait Analysis
• Practical data collection constraints–Artificial capture environment–Snapshot analysis–Restricted activities–Specialist staff–Intrusive–Expensive
Specks
•
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
Comparative Results
• Normal Data Collection
• Patient Data Collection
Graph from Specks Graph from Vicon
Pelvic Tilt30
-10
Ant
Post
deg
Comparative Results – Pelvic Tilt
Graph from Specks Graph from Vicon
Comparative Results – Hip FlexionHip Flexion60
-15
Flex
Ext
deg
Graph from Specks Graph from Vicon
Knee Flexion90
-15
Flex
Ext
deg
Comparative Results – Knee Flexion
Graph from Specks Graph from Vicon
Ankle Flexion30
-30
Dors
Plan
deg
Comparative Results – Ankle Flexion
Graph from Specks Graph from Vicon
Pelvic Obliquity15
-15
Up
Dow n
deg
Comparative Results – Pelvic Obliquity
Graph from Specks Graph from Vicon
Hip Adduction20
-15
Add
Abd
deg
Comparative Results – Hip Abduction
Graph from Specks Graph from Vicon
Pelvic Rotation30
-30
Int
Ext
deg
Comparative Results – Pelvic Rotation
Pelvic Tilt30
-10
deg
Patient Data
Knee Flexion90
-15
deg
Patient Data
Pelvic Obliquity15
-15
deg
Patient Data
Hip Adduction20
-15
deg
Patient Data
Pelvic Rotation30
-30
deg
Patient Data
Pelvic Tilt30
-10
deg
Patient Data
Hip Flexion60
-15
deg
Patient Data
Original Curves Zero Mean Adjusted
Original Curves Zero Mean Adjusted
Original Curves Zero Mean Adjusted
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
Future work
• Anterior/Posterior pelvic tilt • “Root” of calculations
• Position of foot marker
• Orientation of markers
Future Work• Design
–Size
• Transmitting Wire / Internal memory
• Battery life
• Transmission problems
• Segmentation automated for pathological gait
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)
Thank you for your attention