Twenty years ago, while studying classical guitar at the University of Minnesota, Dean Harrington lost the fine motor control in the “plucking” fingers of his right hand. Soon he also found that he could no longer type efficiently on a computer and that his right forefinger would spontaneously click the mouse at inappropriate times.
He had developed focal dystonia, a neurological movement disorder that causes muscles to involuntarily contract and twist into unnatural positions. It typically affects a single group of muscles, usually those that a person repeatedly uses for a specific purpose—the muscles, for example, in a pianist’s hand, a trumpeter’s lips, a golfer’s forearm, a surgeon’s wrist, or a football placekicker’s leg. Many people in a variety of professions, including well-known musicians, athletes, writers, and illustrators, have been forced to forsake their careers after developing the condition.
Harrington found the computer problem was annoying, but easy to fix: He resorted to one-finger typing. But the effect of the focal dystonia on his guitar playing was devastating. Harrington had to give up classical guitar. Fortunately, he could still play with a flat pick, a technique that uses a different set of muscles. He switched to performing jazz.
In the ensuing years, Harrington tried all sorts of treatments for his hand dystonia, including acupuncture and various behavioral and massage therapies. Nothing worked. Harrington has enjoyed a full and busy career as a jazz musician (he performs with the popular gypsy jazz band Mill City Hot Club—see video above right), but he never completely gave up on returning to classical guitar. So when he heard about the focal dystonia research being conducted at the University of Minnesota’s Brain Plasticity Laboratory, he volunteered. So far, he has participated in three of the lab’s brain-stimulation studies, including one last year that involved a combination of repetitive transcranial magnetic stimulation (rTMS) and physical therapy.
Neuroplasticity ‘gone bad’
The aim of the lab’s focal dystonia research is to alter brain-cell excitability in a way that helps the brain “rewire” itself to regain lost function. “Focal dystonia is thought to be the result of neuroplasticity gone bad,” explains Teresa Kimberley, P.T., Ph.D., codirector of the Brain Plasticity Laboratory. “People who develop focal dystonia seem to have lost the inhibitory mechanisms in their brain that come in and stop the neuroplastic response.”
Individuals with focal dystonia “literally wake up one morning to discover that their muscles are doing weird things,” she says. And the problem is usually very task-specific. An illustrator may discover, for example, that the muscles in his drawing hand no longer let him hold a pencil. But he can do just about anything else with the fingers of that hand— button a shirt, for example, or eat with chopsticks.
“There’s nothing really wrong with their muscular-skeletal system,” explains Kimberley. “Their muscle biopsies are normal. Their nerve conduction velocities are normal. Their strength is normal. Their range of motion is normal.”
For that reason, focal dystonia is often mistakenly diagnosed as a psychological disorder. “Many people have dreadful stories of being told that they were just crazy,” says Kimberley. “Others were told they had Parkinson’s disease or [multiple sclerosis] or even carpal tunnel syndrome, and then they would have surgery, which would make it worse. Often it takes years to get a correct diagnosis.”
Focal dystonia may be “all in the head,” but not in a psychological way. Brain imaging has shown that the condition arises from faulty, over-excited neural connections in the sensorimotor area of the cerebral cortex, the thin layer of neurons that cover the cerebrum. Because of those over-excited neurons, the brain tells the wrong muscles to contract.
Current treatments for focal dystonia include botulinum toxin (Botox) injections and sensorimotor retraining therapy, a somewhat tedious process in which the brain is retrained to pick up the correct sensory cues from the affected muscles. But neither is a cure, and many people with the condition who undergo these treatments fail to see their symptoms improve.
At the Brain Plasticity Laboratory, Kimberley and her colleagues are exploring a promising new avenue of treatment. In experimental studies, they have found that priming the affected cells in the brain with rTMS can inhibit their excitability, making the brain more receptive to retraining.
“rTMS alone is not going to be a magic bullet that somehow miraculously changes people,” says Kimberley. “But it could be that the technology could be harnessed as an adjunct, enhancing the rehabilitation.”
Harrington knew the Brain Plasticity Laboratory’s studies were in their earliest stages and that there was no guarantee that they would have any impact on his focal dystonia. Still, he’s noticed some subtle changes in his symptoms, particularly since his participation in the latest study last summer.
“My typing has improved,” he says. “It’s not fast, but I’m not typing any more with one finger.”
He has even returned, if only tentatively, to playing classical guitar. “I’m approaching it like a beginner,” he stresses. “I’m going in really, really slow.” It’s too soon, he says, to know if he will be able to perform that style of guitar with any regularity. But for the first time in 20 years, he feels hopeful.
By Susan Perry