biomechatronics - lecture 9. clinical gait analysis
TRANSCRIPT
VU University Medical CenterAmsterdam The Netherlands
Clinical Gait Analysis
dr. ir. Jaap Harlaar
[email protected]/revalidatie
Human Movement Laboratory
Department of Rehabilitation Medicine
VU UniversityMedical Center
Amsterdam
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casus
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Goal setting vs. tools
• problems with specific activities• >> goal setting at this level• specific interventions might work• movement analysis: biomechanics
External Factors
Personal factors
Function / Anatomy
(Impairments)
Activities(Disabilities)
Participation(Handicaps)
Disease
International Classification of Functions(ICF)
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DecisionDisability assessment
General aim of treatment (disability level)no treatment
DecisionMovement analysis
Specific treatment
nestedComplete decision scheme
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casus
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GAIT
Gait and movement analysis in clinical practice of rehabilitation medicine
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Goal of walking
• To go from one place to another
• Walking speed, Energy & Safety
HOW ? By repeatedly placing one foot in front of the other
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Footsteps
Stridelength = StepRight + StepLeft
Left steplengthRight steplength
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Footsteps (asymmetric)
Stridelength = Right step + Left step
Left steplengthRight steplength
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www.gaitrite.com
Measure footsteps
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www.gaitrite.com
Measure footsteps
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Goal of walking
Walking speed [m/s]
3.6 km/h = 1 m/s
Cadence [ steps/min]
Stridelength [m]
x / 120 =
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Walking speed=stride length*cadence
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
0 20 40 60 80 100 120 140 160
Step rate (steps/min)
Strid
e le
ngth
(m)
0.25 m/s0.50 m/s0.75 m/s1.00 m/s1.25 m/s1.50 m/s1.75 m/s2.00 m/s
1.50 x 60 / 120 = .75
1.00 x 90 / 120 = .75
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Body length and stride length
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What is the optimal stridelength ?
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 20 40 60 80 100 120 140 160
Step rate (steps/min)
Stri
de le
ngth
/ Bo
dy L
engt
h 0.25 m/s0.50 m/s0.75 m/s1.00 m/s1.25 m/s1.50 m/s1.75 m/s2.00 m/s
StrideLengthBodyHeight =0.008 * StepRate
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Energy
Walking speed
Cadence
Stridelength
x Energy Cost
Statute
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Energy measurements during gait
• (ambulatory) oxygenrecording
• one ml O2 / min• = 5 cal / min • = 20 J/min
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Human gait is very efficient...
optimal:~3.4 J/kg.m
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How far can you walk on a pastry ?
250 kcalEnergy cost at optimal speed= 0.8 cal/kg.meter
250.000/(0.8*70)=4,5 km
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Metabolic Energy Measurement
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casus
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One stride lasts from initial foot contact until the next ipsilateral initial foot contact
the gaitcycle
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normalized time: 0 % - 100 %
the gaitcycle (2)
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Heelstrike & Toe-off
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the gaitcycle (3)
0 % -- stance -- 60 % -swing-100%
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the gaitcycle (4)
-- 50 % --
LEFT SWING LEFT STANCE
RIGHT SWINGRIGHT STANCE
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the gaitcycle (5)
LEFT SWING LEFT STANCE
RIGHT SWINGRIGHT STANCE
RIGHT SINGLE SUPPORT
LEFT SINGLE SUPPORT
DOUBLE SUPPO
RT
DOUBLE SUPPO
RT
DOUBLE SUPPO
RT
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Functional division of gait phases(after J. Perry)
Stride (gait cycle)
Stance Swingperiods
WeightAcceptance
Single LimbSupporttasks
LimbAdvancement
InitialContact
LoadingRespons
e
MidStance
Terminal Stance
PreSwing
InitialSwing
MidSwing
Terminal Swing
phases
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Initial Contact 0 %
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Loading Response 0-10 %
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Functional division of gait phases(after J. Perry)
Stride (gait cycle)
Stance Swingperiods
WeightAcceptance
Single LimbSupporttasks
LimbAdvancement
InitialContact
LoadingRespons
e
MidStance
Terminal Stance
PreSwing
InitialSwing
MidSwing
Terminal Swing
phases
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Midstance 10 - 30 %
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Terminal Stance 30 - 50 %
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Functional division of gait phases(after J. Perry)
Stride (gait cycle)
Stance Swingperiods
WeightAcceptance
Single LimbSupporttasks
LimbAdvancement
InitialContact
LoadingRespons
e
MidStance
Terminal Stance
PreSwing
InitialSwing
MidSwing
Terminal Swing
phases
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Pre-Swing 50 - 60 %
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Initial-Swing 60 - 73 %
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Functional division of gait phases(after J. Perry)
Stride (gait cycle)
Stance Swingperiods
WeightAcceptance
Single LimbSupporttasks
LimbAdvancement
InitialContact
LoadingRespons
e
MidStance
Terminal Stance
PreSwing
InitialSwing
MidSwing
Terminal Swing
phases
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Mid-Swing 73 - 87 %
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Terminal-Swing 87 - 100 %
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Functional division of gait phases(after J. Perry)
Stride (gait cycle)
Stance Swingperiods
WeightAcceptance
Single LimbSupporttasks
LimbAdvancement
InitialContact
LoadingRespons
e
MidStance
Terminal Stance
PreSwing
InitialSwing
MidSwing
Terminal Swing
phases
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The gait cycle
M.Whittle
8. terminal swing7. midswing6. initial swing5. preswing
4. terminal stance3. midstance2. load response1. initial contact
filenaam STUDY:
videorapport loopanalysedatum opname:
rechts links
/ /
xxxSYxxx.sty
BewegingsLaboratorium
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Observational GaitAnalysis formRancho Los Amigos Medical Centre
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Edinburgh GAIT Scoring Table
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Error sources in observational kinematic analysis
• Subjective
• estimation error
• out of plane (2D vs. 3D)
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Estimation of joint angles
How well do we perform ?
148 º 24 º
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Estimation of joint angles
How well do we perform ?
148 º 24 º
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Projection error
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Projection error
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Projectionerror (2)
0 10 20 30 40 50 600
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40
60
80
100
120
140
160
180
angle of observation
obs
erve
d an
gle
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Earliest 3D movement analysisBraun & Fischer 1895
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Multiple 2D projections
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Calibrate the projectioncalibration frame
15 points are known in the real (3D) world
DirectLinear Transformation
Videobased systems: SYBAR, SIMI, PEAK, . . . .
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Automated marker tracking and 3D reconstruction of marker position
Multiple (2+) stroboscopic InfraRedcamera's using reflective markers on the body
Vicon, MotionAnalysis, Elite, Qualysis,. . .
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Automated marker tracking and 3D reconstruction of marker position (2)
Active InfraRed markers 3D camera ('s)
CODAmotion, OptoTrak, . . .
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markerrecording
segmentidentification
Body model anatomicalreference
clinicalconvention
kinematicsmarker-cluster n
kinematicsmarker-cluster 1
kinematics
kinematicsanatomical segm. #1
joint-kinematics
anatomical segm. #2
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3D Kinematics software
Matlabwww.bodymech.nl
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Clinical Feasibility
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Clinical Feasibility
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Clinical Feasibility
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INFORMATION
?
=
KNOWLEDGE
Observational analysis of pathological movement
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Muscle function during movement
Reprinted from: Inman et al. (1981)
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Electro Myo Gram (EMG)
Electrode mounted amplifier
differential lead-off
EMG is the summation of many asynchronous Motor Unit Action Potentials
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Relation EMG and Muscle Force
Raw EMG
Smoothed Rectified EMG @ 2 Hz
Isometric muscle force
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the SYBAR system
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the SYBAR system
display
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casus
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Groundreaction force
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Net joint moment
Moment =
F x r
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Estimated net joint momentversus inverse dynamics
Moment =
F x r
Boccardi et al. (1981)
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What therapeutic intervention is needed ?
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DecisionDisability assessment
General aim of treatment (disability level)no treatment
Decisionfunction analysis
Specific treatment
Evaluation of treatment at two (nested) levels
increased walking speed, decreased PCI
decreased ankle moment at heelstrike
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What therapeutic intervention is needed ?
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Complex Clinical Cases
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Dynamicsexternalmoments andforces
Kinematics- positions- angles- derivatives
Antropometrics:•mass•inertal moments•jointlocations•muscle attachments
Joint andmuscle function
- net moments- estimated
muscle forces
Inverse dynamics model
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Problem statement
Physical examination yields angles
The measure should address muscle length
The reference values are based on normal gait
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Method
• Application of a geometrical musculo-skeletalmodel SIMM (Delp et.al 1995)
• input 1: joint angles during physical examination
• input 2: joint angles during normal gait
• output: muscle length (origo-insertion)
• all lengths are normalized to anatomical position(=100 % )
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Results: m. Rectus Femoris (1)
•Figure 6.2
Figure 6.1
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Results: m. Rectus Femoris (2)
100,0%102,0%104,0%106,0%108,0%110,0%112,0%114,0%116,0%118,0%120,0%
0 12 24 36 48 60 72 84 96 108 120
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Length m. Rectus Femoris during gait
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Results: m. Rectus Femoris (3)
95%97%99%
101%103%105%107%109%111%113%
0 8 16 24 32 40 48 56 64 72 80 88 96 %gait
stance swing
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Discussion
• “Passive” muscle length is not the sole cause to contractures during gait
• Muscle length during movement and EMG should be considered
• Warning: validity of the model• Documentation of examination protocols
(standardisation) using modeling software animations creates awareness of muscle length testing
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Imaging•Clinical question
•Functional analysis
•Muscle-bone model•(invers)
•visualization
•function•structure
•load•(intended) therapeutical intervention
•musle-bone model•(forward)
•movement
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casus
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Models (1)
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Models (1)
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functional load and loading capability of the upper extremity
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Upper extremity
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Upper extremity (2)