Untangling Dystonia

Muscles constantly contracting all over his body made Tyler McGuire into a human pretzel who could not even sit in a wheelchair. McGuire, 16, suffers from a rare movement disorder called dystonia. Racked by pain, he could not attend school or take part in other normal teenage activities. Because of an unusual treatment with deep brain stimulation at the University of Minnesota Children’s Hospital, Fairview, he now has more control over his body—and he has hope.

“[Dystonia] is not a muscle problem,” says his neurosurgeon  Aviva Abosch. “It’s a brain problem.” A member of University of Minnesota Physicians and a clinical researcher as well, she will analyze his response to the brain stimulation and use that knowledge to improve outcomes for others.

Dystonia can be compared to other, more familiar movement disorders. Essential tremor is the most common movement disorder, affecting 2 percent of Americans over the age of 60, including the late actress Katherine Hepburn. Medication can help many. Parkinson’s disease noticeably affects actor Michael J. Fox and up to 1 million other Americans. It also can be treated with medication, although side effects to the medications can become severe over time.

An alternative to medication is deep brain stimulation. Patients who have a medical device placed in their brains by a neurosurgeon often show immediate relief from symptoms of tremor or Parkinson’s.

Dystonia is the rarest movement disorder. While pianist Leon Fleisher lost the use of his right hand for decades because of focal dystonia in his hand, it influenced his choices of music and his career. (Fleisher has recovered with treatment.)

When dystonia affects the whole body, as it did for Tyler McGuire, it’s devastating. “You’re trapped in your body,” Abosch says. Although cases of generalized dystonia that are as severe as Tyler’s are rare, dystonia affects about 300,000 people in the United States.

Once McGuire became Abosch’s patient, she decided to try the deep brain stimulation device to see if she could relieve his distress. She had to obtain approval from the University of Minnesota Institutional Review Board, as deep brain stimulation for the treatment of dystonia is governed by a humanitarian device exemption (HDE) rather than formal FDA approval. After the device was placed in his brain, however, his relief was not immediate.

Yet he can now sit comfortably in his wheelchair and, with assistance, walk short distances. Also, he has resumed building plastic models, a hobby he was forced to abandon about a year earlier due to the disabling dystonia.

It took about three months to see improvement in his condition. “It suggests that a different mechanism is underlying the disease when you compare this to the immediate improvements seen in DBS for Parkinson’s disease or essential tremor,” Abosch says. “It’s fascinating.”

Was the targeted area of the brain the best place? This brain surgery using stereotactic MRI and a deep brain stimulation device for a rare disorder raises this and other questions, says Abosch, who has a scientific background in developmental neuroscience and also carries out clinical research.

By gathering data on how McGuire and other patients with dystonia respond to treatments and in which ways, Abosch ultimately expects to be able to recommend better approaches to her peer physicians.