advertisement
Cores 1,2,&3 Circle of Life “Driving Biological Problem”: Neuromuscular Dynamics Neuromuscular Neuromuscular Dynamics Dynamics A A “Driving “Driving Biomedical Biomedical Problem” Problem” Scott ScottDelp Delp Bioengineering BioengineeringDepartment Department Stanford University Stanford University Digital Humans Digital Humans QuickTime™ and a Motion JPEG A decompressor are needed to see this picture. Digital Humans QuickTime™ and a Photo - JPEG decompressor are needed to see this picture. Digital T-Rex NIH Grant: simulation-based treatment planning Treatment of Gait Abnormalities is Complex Potential Causes: • impaired motor control • spasticity • weakness • muscle contractures • bone deformities Photos courtesy of S. Õunpuu, Connecticut Children’s Medical Center Treatment of Gait Abnormalities is Complex Possible Treatments: • orthopaedic surgery • physical therapy • orthotics, assistive devices • neurosurgery • tone-altering medications Photos courtesy of S. Õunpuu, Connecticut Children’s Medical Center Outcomes Are Frequently Good QuickTime™ and a Photo - JPEG decompressor are needed to see this picture. QuickTime™ and a Photo - JPEG decompressor are needed to see this picture. Outcomes Are Sometimes Poor QuickTime™ and a Photo - JPEG decompressor are needed to see this picture. QuickTime™ and a Photo - JPEG decompressor are needed to see this picture. Can Biomechanical Models Provide Insight? Photos courtesy of S. Õunpuu, Connecticut Children’s Medical Center Generation of Movement EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics premotor areas Musculoskeletal Geometry motor cortex sensory cortex cerebellum descending tracts Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces Generation of Movement EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics Musculoskeletal Geometry Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces activation dynamics contraction dynamics Generation of Movement EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics Musculoskeletal Geometry Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces muscle line of action muscle moment arm joint axis of rotation Generation of Movement EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics Musculoskeletal Geometry Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces force muscle moment arm moment Generation of Movement EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics Musculoskeletal Geometry Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces gravity Generation of Movement Proprioceptors EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics Musculoskeletal Geometry sensory neuron motor neuron Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces Many Factors Contribute to Gait Abnormalities EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Forces Abnormal Musculoskeletal Geometry Moments Abnormal Multi-Joint Dynamics Angles Velocities Observed Movement Accelerations Ground Reaction Forces Limitations of the Current Approach EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Forces Abnormal Musculoskeletal Geometry Moments Abnormal Multi-Joint Dynamics Angles Velocities Observed Movement Accelerations Ground Reaction Forces Limitations of the Current Approach Selective Dorsal Rhizotomy EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Forces Abnormal Musculoskeletal Geometry Muscle-Tendon Lengthenings, Tendon Transfers, Strengthening Exercises Osteotomies Moments Abnormal Multi-Joint Dynamics Orthotics Angles Velocities Observed Movement Accelerations Ground Reaction Forces Potential Contributions of Biomechanical Models Selective Dorsal Rhizotomy EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Forces Abnormal Musculoskeletal Geometry Muscle-Tendon Lengthenings, Tendon Transfers, Strengthening Exercises Osteotomies Moments Abnormal Multi-Joint Dynamics Orthotics Angles Velocities Observed Movement Accelerations Ground Reaction Forces Simulated Movement Potential Contributions of Biomechanical Models • Provide information that is difficult to obtain experimentally. • Answer “what if?” questions. • Elucidate “cause & effect” relationships. Outline • Example 1: Muscle-Tendon Model • Example 2: Musculoskeletal Model • Example 3: Dynamic Model • Challenges and Next Steps for SIMBIOS Outline 1: Analysis of Muscle Force-Generating Capacity After Tendon Surgery EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Muscle-Tendon Lengthenings Forces Abnormal Musculoskeletal Geometry Moments Abnormal Multi-Joint Dynamics Angles Velocities Observed Movement Accelerations Ground Reaction Forces How Much Should the Achilles Tendon be Lengthened to Treat Contracture of the Triceps Surae? gastrocnemius soleus Photos courtesy of E. Bleck How Much Should the Achilles Tendon be Lengthened to Treat Contracture of the Triceps Surae? gastrocnemius soleus Delp et al. (1995) J. Orthop. Research Example 2: Analysis of Hip Muscle Moment Arms During Internally-Rotated Gait EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Collaborators: Allison Arnold Deanna Asakawa Silvia Blemker Bill Hess Peter Loan Forces Abnormal Musculoskeletal Geometry Moments Abnormal Multi-Joint Dynamics Angles Velocities Observed Movement Accelerations Ground Reaction Forces Construction of MR-Based Kinematic Models Models of individuals with Cerebral Palsy QuickTime™ and Motion JPEG B decomp are needed to see this pi Subject 3 Age 14 Subject 1 Age 7 Subject 4 Age 27 Example 3: Identification of Factors that Cause Excessive Knee Flexion EMGs Impaired Motor Control Abnormal Muscle-Tendon Dynamics Forces Abnormal Musculoskeletal Geometry Moments Abnormal Multi-Joint Dynamics Angles Velocities Observed Movement Accelerations Ground Reaction Forces Simulated Movement Collaborators: Allison Arnold Clay Anderson Marcus Pandy Identify causes of excessive knee flexion QuickTime™ and a Motion JPEG A decompressor are needed to see this picture. Forward dynamic simulation of walking QuickTime™ and a Motion JPEG A decompressor are needed to see this picture. Contributions of soleus to knee motion QuickTime™ and a Motion JPEG A decompressor are needed to see this picture. Contributions of hamstrings to knee motion QuickTime™ and a Motion JPEG A decompressor are needed to see this picture. Simulation Challenges Challenge #1 Modeling muscles with complex geometry Gluteus Maximus Line-Segment Model Netter’s Atlas of Anatomy Many Muscles, High Speed Joey Teran, Ron Fedkiw, and others Challenge #2 Fast algorithms for creating subject-specific simulations . Dynamic Optimal Control Computed Muscle Control Stage 1: Desired Accelerations + Stage 2: Static Optimization - + Stage 3: Excitation Controller + + + Stage 4: Forward Dynamics + + - +- Thelen et al. (2003) J. Biomechanics 4+ months computer time 1 day Fast dynamics ….. Optimization …. Task Based Control … 1 min Challenge #3 Simulations that incorporate accurate representations of sensory-motor control. EMGs Forces Moments Angles Velocities Neural Command Muscle-Tendon Dynamics Musculoskeletal Geometry Multi-Joint Dynamics Observed Movement Accelerations Ground Reaction Forces Challenge #4: Multiscale modeling of muscle Adapted from Scientific American, 2000 Super useful components • Fast dynamics • Great integrators • Contact and proximity modeling • Controllers • Analysis tools SIM/TK as an Integrated Package
