Research

Current experiments involve three-dimensional kinematic and kinetic analysis and EMG recording during treadmill and overground gait. State-of-the-art modeling and optimization techniques are used to develop simulations based on experimental data. Ongoing research projects are related to:

1) Muscle deficits and subject-specific interventions for post-stroke hemiparetic gait

fastfesOver the last decade, we have investigated the relationship between altered muscle morphology, muscle activation and muscle coordination during walking after stroke.  To achieve these goals, we have implemented a robust Research Core to facilitate and track subject recruitment and eligibility, developed novel imaging tools using MRI and ultrasound to compare paretic and non-paretic muscle atrophy, (3) implemented new methods to estimate central activation ratio and maximal force generating ability, (4) applied custom-designed hardware and software in post-stroke  intervention studies involving FES, treadmill training and robotics, (7) integrated  OpenSim with EMG-driven modeling to enhance subject-specific simulation capabilities, (8) used subject-specific simulations to identify muscle coordination and compensatory strategies, (9) established a database of subject-specific muscle, gait and clinical data, and (10) established an effective and productive team of collaborators engaged in stroke-related studies. 

 

2) Cartilage contact and compressive forces in progressive knee osteoarthritis

COBRE

We utilize an interdisciplinary approach to study osteoarthritis initiation and progression which spans the continuum from tissue engineering to clinical evaluation.  My projects investigate the risk factors for progression of knee osteoarthritis and couples motion analysis with novel imaging techniques.  Specifically we are exploring changes in cartilage contact area using innovative weight-bearing MRI techniques for comparison with knee contact forces estimated from subject-specific musculoskeletal models.  As part of this effort, the Patient-Specific Modeling core has been established in the Delaware Rehabilitation Institute to

  • Enhance functionality and compatibility of existing and novel tools (motion capture, imaging, modeling) to streamline data collection and processing to extract clinically useful measures.
  • Develop and apply musculoskeletal modeling and simulation tools for COBRE projects that provide insight to muscle coordination, task-specific function and tissue loading.
  • Share modeling approaches to OA and clinical outcomes with the local and global community through workshops and Web-based resources.

 

3) Simulation-based analysis of muscle coordination in healthy and pathological gait

MSThe goal of this work is to develop subject-specific musculoskeletal modeling and simulation techniques to understand available compensatory strategies for altered muscle morphology and function following stroke, and identify which stroke survivors are likely to benefit from specific types of intervention.   Experimental measures are used to deduce information about muscle activation impairment, atrophy, neural control, strength and movement patterns and incorporated into subject-specific models.  These models are used to understand available compensatory strategies for altered muscle morphology and function following stroke, and can be related to clinically relevant outcomes.  Because forward dynamic models offer a deterministic framework to explore relationships between muscle function and resultant movements, we wish to identify changes underlying effective responses to intervention and ultimately predict which stroke survivors are likely to benefit from functional electrical stimulation of key muscles or other interventions.

 

4) Interactions between cognitive function and gait performance

Although historically considered an automatic process, gait control has been shown to consume attentional demands, supported by the concept of dual-tasking with a motor and cognitive challenge. Identifying the impact of cognitive challenges on motor tasks in healthy younger and older adults could detect increased fall risk and lead to prevention strategies for at risk populations, such as the elderly or cognitively impaired.  Cognitive function during motor tasks also has important implications for rehabilitation where information about performance must be relayed and interpreted by the user.  The objective of this work is to (1) quantify the interaction between motor and cognitive performance and (2) use this information to design optimal biofeedback systems.

 

Recent publications