James Sulzer, Ph.D.

Assistant Professor, Department of Mechanical Engineering

University of Texas at Austin

Research Summary

Rehabilitation after neurological damage such as stroke or spinal cord injury works... sometimes. And that's the problem. It is notoriously difficult to understand why some people recover and others do not. "We're just learning how the brain works.  Now add to that the complex challenge of understanding neural recovery after brain damage. So with all these unknowns, how can we expect to understand why therapy works and how to improve it?" says James Sulzer, Assistant Professor in Mechanical Engineering at UT Austin. 

One way to understand recovery is to develop quantitative measures of therapy. "There is very little information on exactly what happens during therapy. We're recording as much quantitative data during training as we can to figure out how quantity and quality of training affect recovery". Dr. Sulzer is using inertial measurement units, similar to what's used in a smart phone, to portably track motions during gait therapy with Drs. Patrick Spicer at Dell Medical School and Robert Lee at St. David's Medical Center.  

Camus stated, "good intentions may do as much harm as malevolence if they lack understanding". A case in point is how people with stroke react to exoskeletal assistance.  Using a knee exoskeleton, Dr. Sulzer showed that despite improving knee flexion, stroke patients actually walked worse with the assistance. "Even though we improved their ability to clear the foot during walking, they swung their leg out even more, which was a new and surprising finding. We realized that we just didn't understand what was wrong with them. It wasn't a weakness issue, it was a coordination problem". Dr. Sulzer believes that the future of wearable robotics in neurological injury depends on our ability to understand patients' problems. "We're now trying to figure out exactly how different impairments affect walking, and then devising interventions that specifically address these impairments." On this research, Dr. Sulzer is collaborating with Drs. Richard Neptune and Ashish Deshpande at UT Austin, Dr. Kathleen Manella at University of St. Augustine, and Dr. Lee at St. David's.

Despite that recovery happens in the brain, conventional therapy focuses on the limbs. Dr. Sulzer's research is looking for ways to incorporate online measurement of brain activity into therapy paradigms. "If we can monitor brain activity during therapy, we can guide training to activate the brain in a way that we believe is beneficial for recovery". This procedure is called neurofeedback, a type of biofeedback of the brain. Dr. Sulzer plans to use neurofeedback to control activation all over the brain, from circuits that correspond to greater finger individuation in stroke patients with Drs. Jarrod Lewis-Peacock and Steven Warach at UT Austin, to control of spasticity with Drs. David Ress at Baylor College of Medicine and Sheng Li at TIRR, to fine motor control with Drs. Paul Ferrari, Larry Abraham and David Schnyer at UT Austin. "If you can observe it, it's likely you can control it," says Dr. Sulzer regarding brain activation.

Figure: Illustration of how neurofeedback can drive therapy. If brain activity is not activating in a way conducive to recovery (left), we can use a neural controller guide therapy accordingly (right).


Dr. Sulzer has expertise (or is gaining expertise) in functional neuroimaging (fMRI, fNIRS and MEG), especially towards its application to neurofeedback, human motor control and rehabilitation. He also has expertise in exoskeletal design, robotics and gait biomechanics. He hosts a gait laboratory with a split-belt force treadmill and optical motion capture system. He has two full body inertial measurement unit systems that act as portable motion capture systems. Dr. Sulzer teaches graduate courses in Robot Modeling and Control and a signature course in Rehabilitation Engineering. 

Collaborative Interests

Dr. Sulzer is open to collaborating with anyone sharing similar goals and bringing in new perspectives. Particularly helpful are clinical experience, neuro- and neuromuscular physiology, and advanced computational methods. 

Please visit his website to learn more about Dr. Sulzer's research and the tireless graduate students that power it.

  • picture1.png
  • sulzer_james-200x300.jpg