Gait Analysis: Techniques and Recognition of Abnormal Gait Fabian E. Pollo, Ph.D. April 30, 2007.
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Transcript of Gait Analysis: Techniques and Recognition of Abnormal Gait Fabian E. Pollo, Ph.D. April 30, 2007.
Gait Analysis: Techniques and Recognition ofAbnormal GaitFabian E. Pollo, Ph.D.
April 30, 2007
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Gait analysis in modern terms implies that some type of quantification will take place.
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
1. Temporal / Spatial – velocity, cadence, step length, etc.
2. Kinematics - the movement of the body in space without any reference to forces.
3. Kinetics - the forces involved in producing these movements.
4. Dynamic Electromyography - the study of muscular activity patterns during walking.
Gait analysis involves the measurement of:
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Temporal-Spatial Parameters
1. Stop watch and marks on the floor
2. Gait Pressure Mat
Gait Pressure Mat
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Kinematics can be recorded using a variety of systems and methodologies
Passive Marker Systems use
reflective markers and multiple
cameras (typically 6 to 8 cameras
simultaneously). The cameras send
out infra red light signals and detect
the reflection from the markers
placed on the body. Based on the
reflected signals from at least 2
cameras - triangulation of the
marker in space is possible.
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Kinematics can be recorded using a variety of systems and methodologies
Active Marker Systems are similar
to the passive marker system but
use "active" markers. The markers
are triggered to illuminate. This
signal is used to triangulate the
location of the marker. The
advantage is that individual
markers work at predefined
frequencies and therefore, have
their own "identity".
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Kinematics can be recorded using a variety of systems and methodologies
Electromagnetic Systems track the
position (X, Y, and Z Cartesian
coordinates) and orientation
(azimuth, elevation, and roll) of
small sensors attached to various
segments of the body as they move
through space.
Z
Y X
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
• Vicon Motion Analysis System• Twelve MX-40 Cameras• 4 – Megapixel Resolution• 5 Hz – 2,000 Hz• Passive Marker System• Near Infra-Red Ring LEDs• Camera/Computer
Baylor Motion & Sports Performance Center
Force Platforms
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Camera Positioning (Think Volume)
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
X Y
Z
L- Frame – designates lab origin and orientation (Global Coordinate System) Calibration: L-Frame
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Wand – defines camera positions in relation to each other in 3D space and corrects for any lens distortion
Calibration: Wand
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Various Markers Sets and
Gait Models dependent on
application
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Direct Linear Transformation
Camera 1 Camera 2
Camera 3…………Camera 12
3D Image
DLTTake all 12 Raw Video Camera Views
Identified Markers3D Image
Virtual Hip Joint Centers
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Kinematics
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Force Platform
The reaction force produced by the ground is called the Ground Reaction Force (GRF), which is basically the reaction to the force the body exerts on the ground.
Kinetics
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Use Inverse Dynamics to compute Joint Forces, Joint Torques (Moments) and Joint Power.
Kinetics
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Electromyography
25 Gauge Needle0.051mm, insulated, hooked wires
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Raw EMG Signal
Rectified EMG Signal
Enveloped EMG Signal
Processing
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Recognition of Abnormal Gait
• Question is not whether a gait pattern is abnormal – what is primary cause.
• Requires formal gait analysis
• Many primary causes are fairly easy to diagnose (i.e. bunions and peroneal nerve dysfunction)
• Many secondary causes that are not so clear (chronic ligament tears and osteoarthritis)
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
1. Mild Cerebral Palsy
2. Traumatic Brain Injury
3. Medial Compartment Osteoarthritis
Examples
Recognition of Abnormal Gait
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Cerebral Palsy
• 9 year old girl with hemiplegia
• Equinovarus of her right foot (inverted hindfoot and plantarflexed)
• Caused by overpull of the tibialis posterior and/or anterior tibialis Tendons
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Surgical Options
Split anterior tibialis and transfertendon to cuboid.
Split posterior tibial tendon and transferred laterally to peroneus brevis tendon
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Use of Gait Analysis
• Determine if the anterior tibialis and/or posterior tibialis was contributing to her deformity.
• Document her movement pattern for comparison after surgery.
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Traumatic Brain Injury
• 45 year male suffered TBI in car accident in 1983
• Having Left Knee Pain
• Gait Evaluation
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Knee Osteoarthritis
• 51 year old women with medial compartment OA of left knee
• Evaluation for OA unloader brace prior to possible High Tibial Osteotomy
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Knee Osteoarthritis• Knee OA results from local
mechanical factors within the context of systemic susceptibility
• Hip-knee-ankle alignment significantly influences load distribution at the knee and disease progression
• Medial compartment more often affected
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
• Vertical GRF
• Muscular Forces
• Reaction force from external moment
Knee Loading
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Knee Osteoarthritis
• Unloader Bracing attempts to reduce that “Varus” load.
Gait Analysis: Techniques and Recognition of Abnormal Gait
April 30, 2007
Benefits of Gait Analysis• Aids in surgical planning
• Assessing the efficacy of surgical intervention
• Bracing issues and medication efficacy can be addressed using gait analysis techniques
• Evaluation of the rate of deterioration in progressive disorders that affect gait can also aid in understanding a patient's abilities and directing care
• Quantification for clinical and research
THANK YOUApril 30, 2007