Returning Absent Abilities: Developmental Dystonia Research and Device Development

The first times I visited my advisor’s pediatric neurology clinic at Children’s Hospital Los Angeles as a new graduate student, I found the experience both beautiful and heartwrenching. My advisor, Dr. Terry Sanger, specializes in pediatric movement disorders. At that point in my life, I’d had limited exposure to people who live with any sort of motor or cognitive disability. The kindness and caring of the doctors and the parents was deeply moving, but developmental movement disorders are a difficult challenge to live with.

There are so many movement disorders, and in many cases, patients have more than one overlapping issue. Dr. Sanger and many other clinicians have assembled taskforces for creating clear formal definitions of various movement disorders so medical professionals will be able to properly distinguish, diagnose, and treat movement disorders. (See here for a list of the taskforce’s publications.)

Our lab is primarily focused on dystonia. Over 300,000 people in the US and Canada have this movement disorder, and according to Dr. Sanger, over 75% of patients with cerebral palsy have it. Dystonia is typically characterized by the existence of postures inserted involuntarily into voluntary movement. We know it is associated with the basal ganglia, but we don’t know the mechanism of developmental dystonia, per se.

We are, ultimately, an engineering lab. While that does mean we get involved with designing devices, it also shapes the way we study human physiology. Our projects can be loosely grouped as:


  • understanding how people without movement disorders and children with dystonia move, learn tasks, and compensate for risks and perurbations
  • attempting to understand the relationships between dystonia and abnormal neurophysiology

Device design:

  • attempting to use surface electromyography (sEMG) as a robotic interface for children with cerebral palsy
  • creating and testing biofeedback devices that vibrate in proportion to sEMG from muscle contractions
  • optimizing use of communication devices

Computational modeling of developmental dystonia

  • FPGA chips are used to run models at 365x, so 10 years of development can be modeled in 10 days

Nonlinear filtering algorithms for electrophysiological signals

  • Bayesian filtering of sEMG signals
  • Continuous-time non-linear filtering
  • Stochastic dynamic operators


I’m personally involved in developing the first stage of the sEMG robotic interface. I am working on the side of the interface that communicates with devices, while my labmate Cassie is working on the part of the interface that interprets the muscle activity of children with dystonia. I also think about how to improve use of Bayesian filtering.

We have high hopes for all of these projects, and are exciting about the fruit they are bearing!

Here is a list of the posters our lab is presenting at the conference this year. (If you’d like to see the abstracts, click the links below.)

Please feel free to contact me at if you would be interested in being featured in a blog post during the conference!


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