Current Projects

Project 1: Shriner's Multi-Center Study: Comparison of Outcome Measurements

This study examines cross-sectional and longitudinal aspects of outcome instruments used in pediatric orthopaedics to assess children with different levels of severity of ambulatory cerebral palsy. The purpose of the study is to look at the ability of the outcome instruments to assess children with different levels of cerebral palsy at one instant in time and over a long period of time. The outcome instruments studied will be Functional Assessment Questionnaire (FAQ), Gross Motor Functional Measure (GMFM), Pediatric Quality of Life (PedsQL), Pediatric Outcomes Data Collection Instrument (PODCI), Pediatric Functional Independence Measure (WeeFIM), energy expenditure, and temporal spatial gait parameters. Subscores of each outcome instrument will be categorized as measures of impairment, functional limitation or disability.

Project 2: Quantifying Spasticity and its Biomechanical Influence on Function. (ERRIS)

The purpose of this study is to determine if and how spastic muscle behavior contributes to dysfunction and walking limitations. Information obtained will be used to improve treatment for disabilities associated with spasticity.  The project includes comparison of overground vs. treadmill walking in children with or without cerebral palsy in order to analyze strategies used to change walking velocity.

Project 3: Characterizing the Nature of Musculoskeletal Spastic Behavior

Spastic muscle behavior is a neuromuscular disturbance that can severely limit functional performance in tasks such as walking, eating, and basic hygene. Unfortunately, treatments for spastic dysfunction are not universally effective, outcomes are difficult to predict, and improvements are often minimal. A significant factor contributing to this clinical limitation is the inability to characterize the nature and severity of spastic behavior. Spasticity can be related to abnormal intrinsic muscle behavior, hyperactive reflex response, excessive muscle co-contraction, or any combination of these factors. The characteristic nature of spastic behavior may vary with pathology and between individuals. Existing clinical assays fail to characterize its nature or quantify its severity. Hence, "spasticity" as a diagnosis can be ambiguous and potentially inappropriate, making it difficult to tailor medical treatment to the specifics of the dysfunction. The characteristic nature of spasticity can be objectively quantified by measuring neuromuscular stiffness. Stiffness describes the spring-like mechanical and reflex force in a muscle due to a passive stretch perturbation. Despite evidence demonstrating the significance of musculoskeletal stiffness, this mechanical measure has not been applied to clinical assessment. Using mechanical stiffness to characterize spastic behavior will reduce the ambiguity and improve the objective quantification of clinical diagnoses. The goal of this research is to evaluate musculoskeletal stiffness as a objective method to characterize the nature and severity of spastic behavior. Successful results will improved our understanding of musculoskeletal spasticity and enhance clinical decision making, resulting in improved functional outcomes following treatment. This research project has just recently begun.

Project 4: Optimizing Orthotic Prescription in Cerebral Palsy

Approximately 70% of all children born with cerebral palsy will eventually become ambulatory and nearly all will receive at least one, and more likely several, ankle foot orthoses (AFO) during their lifespan. We have demonstrated in two previous reports that some orthotic designs can be effective in improving ankle position and hence gait in CP. However, indications of when to prescribe an orthosis, and if so, what type, are not still not clearly specified in the medical literature, as orthotic development has outpaced scientific study. In this project, we will use a within subjects design to study 20 children with spastic diplegia who will be assigned two different orthoses in random order: (1) a standard rigid ankle AFO that allows bending of the forefoot and toes as the body weight comes over the foot as it restricts plantar flexion at the ankle, and (2) a dynamic AFO with a rigid foot plate that allows restricted ankle motion while rigidly controlling the foot in a neutral position. We will utilize the plantar pressure measurement system for the analysis of the precise biomechanical effects of the orthoses, and we will correlate these effects with overall gait function as measured by the 3-D VICON system. In addition, families will complete a survey on reported functional ability and overall satisfaction with each brace, as compared to barefoot or shoes alone. To date, 7 families have enrolled in this protocol.

Project 5: Interface Design for a Shared Control Mobility Aid for the Elderly.    This study focuses upon the control of adult walkers to facilitate ambulation around obstacles and to assist in mobility for the elderly.  It is funded by the National Science Foundation.

Project 6: Ankle Force Recovery Following Muscle Tendon Lengthening Surgery.  This study uses an animal (rabbit) model to investigate the neuromuscular changes that result from mock-surgery where the muscle-tendon unit is lengthened.  Pre-operative vs. post-operative measures are taken of the muscle forces at various joint angles, and changes that occur during recuperation are documented.  This study is funder by the Zimmer Corporation.

Project 7: The Determinants of Gait & Center of Mass Moverment in Children with Cerebral Palsy.   In this study, normal children and children with cerebral palsy are analyzed.  The motion of the body-center-of-gravity is examined to assess energy efficiency during ambulation.  This study is funded by the Pediatric Orthopaedic Society of North America and Orthopaedic Research Education Foundation.

Project 8: An Adaptive Haptive Interface for Disabled Individuals. This study is an extension of the technology used in the Shared Control Mobility Aid for the Elderly, applied to adolescent children with cerebral palsy.  We are investigating current walker designs and formulating new designs that will assist patients in their walking and endurance.  This study is funded by the Department of Education and Barron Associates, Inc.

Project 9: "Optimized Variable Stiffness Energy Returning Ankle Foot Orthosis"  This study addresses the need for new ankle-foot bracing designs.  Design parameters are defined and analyzed.  The end result may be a new brace design that serves to better assist the patients.  This project is funded by the National Science Foundation.

Project 10: Assessing the Gross Motor Function Classification System.  This study is querying retrospective analyses to determine if the GMFCS may be used to accurately define the general potential limits of a patients ambulatory skills.

Project 11: Determinants of Gait.  Individual and grouped parameters are assessed in both retrospective and prospective populations of patients.  Combinations will be optimized to determine what are the determinants of gait.

Student Projects

  • "Force of co-contraction in cerebral palsy", Dan Sullivan for Post-doctoral Fellowship in Physical Medicine and Rehabilitation, 1996.
  • "Strength profiles in spastic cerebral palsy", Mary Beth Wiley for MS in Motor Learning, 1996.
  • "Length tension relationship following muscle tendon lengthening in cerebral palsy", Jeff Bush for ME in Biomedical Engineering, 1996.
  • "The relationship between walking speed, energy efficiency index and endurance in children with spastic diplegic cerebral palsy", Tim Harris for MD Research Rotation, 1996.
  • "Effect of spastic cerebral palsy on gait patterns and joint function in adults", Tim Harris for MD Research Rotation, 1996.
  • "Change in maximum walking speed following surgical intervention in children with diplegic cerebral palsy", Tom McGovern for Post-doctoral Fellowship in Orthopaedic Surgery, 1995.
  • "Effect of ankle foot orthoses on the gait of children with cerebral palsy", Warren Carlson for MS in Biomedical Engineering, 1995.
  • "The natural history of gait in childhood and adolescent cerebral palsy", David Johnson for MD Research Rotation, 1995.
  • "A system to measure passive muscle tension intraoperatively" and "Surgical outcome from muscle-tendon lengthening surgery on gait and gross motor function in spastic cerebral palsy", Michael Pannunzio for Post-doctoral Fellowship in Rehabilitation Engineering, 1995.
  • "Functional and biomechanical effects of hamstring lengthening on the knee joint in spastic cerebral palsy", J.P. Romano for MS in Biomedical Engineering, 1995.
  • Three-dimensional kinematic and kinetic database of normal pediatric gait", Scott Colby for ME in Biomedical Engineering, 1995.
  • "Development of a biologically-based neural network architecture", Gary Brooking for Ph.D. in Electrical Engineering, 1995.
  • "Functional assessment of AFOs in cerebral palsy patients", Greg Juhl for Summer Research Project, 1995.
  • "An analysis of distributed loads experienced from ballet and gait", Simone Thompson for BS in Chemical Engineering, 1994.
  • "A biomedical application of real-time image processing", Thomas Lash for BS in Electrical Engineering, 1994.
  • "Strategies used by children with CP to increase gait speed", Jerome Watson as part of research rotation for MD degree, 1994.
  • "Stair climbing gait to evaluate anterior cruciate ligament reconstruction", Jeffrey Duncan for MS in Biomedical Engineering, 1994.
  • "Effect of total hip replacement on power requirements at the knee joints", Carlos Buitrago for MS in Biomedical Engineering, 1994.
  • "Total hip replacement and the influence of joint loading patterns", Kristen Bowsher for Ph.D. in Biomedical Engineering, 1994.
  • "Recognition of human gait patterns using artificial neural networks", Mark O'Malley for Fulbright Fellowship, 1994.
  • "Effective knee joint analysis through accurate calibration", Patricia Guido for BS in Mechanical Engineering, 1993.
  • "Design and implementation of a system for measuring spasticity in children with cerebral palsy", Jason Gerdeman for BS in Electrical Engineering, 1993.
  • "Factor analysis of bilateral electromyography in human gait", Kenneth Olree for MS in Biomedical Engineering, 1993.
  • "Pre-operative assessment of stair climbing in ACL deficient patients", Jody Smith as part of research rotation for MD degree, 1993.
  • "Post-operative assessment of stair climbing in ACL deficient patients", Christopher Hogan as part of research rotation for MD degree, 1993.
  • "Effects of quadriceps strengthening on functional gait in children with spastic diplegia", Diane Damiano for Ph.D. in Education, 1993.
  • "Three dimensional moments acting at the ankle in normal human gait", Jodi Nashman for MS in Biomedical Engineering, 1992.
  • "Analysis of gait, proprioception and response times in anterior cruciate deficient knees", David Kowalk for Post-doctoral Fellowship in Orthopaedic Surgery, 1992-93.
  • "Use of ankle foot orthoses in the management of cerebral palsy", Marcus Besser for Post-doctoral Fellowship in Rehabilitation Engineering, 1991-93.
  • "Quantifying the severity of spastic hypertonia using a dynamic locomotion approach, Kristen Bowsher for MS in Biomedical Engineering, 1991.