A permanent solution for spasmodic dysphonia
Date: January 3, 2012
How well we communicate largely depends on a behind-the-scenes interaction between a branch of the laryngeal nerve and the two targets it activates: the thyroarotenoid and the lateral cricoarytenoid muscles. In most people, impulses from the nerve smoothly control these muscles, allowing us to speak clearly and easily. However, in an unlucky few who develop spasmodic dysphonia, the nerve’s action becomes uncontrollable and unpredictable, severely affecting these patients’ voices.
“They strain to talk with stammering voices,” says otolaryngologist Young Kim. “There’s no fluency to their speech no matter how hard they try.”
The occasional spasmodic dysphonia patient who rarely needs to speak could probably get by without treatment, Kim explains. However, many people who develop this condition rely heavily on their voices for their jobs—they’re teachers, real estate agents and others for whom spoken communication plays a pivotal, daily role in their success.
Currently, the most common treatment for spasmodic dysphonia is frequent botulinum toxin type A injections to chemically paralyze the affected muscles. It’s effective for the majority of patients, but it has significant drawbacks, Kim says. Patients need injections every three to four months, which can be painful and a nuisance, and a small subset of patients develops resistance to treatment, leaving them with few other options.
One way around this problem, Kim says, is an operation developed by Gerald Berke, Kim’s residency mentor at the University of California-Los Angeles. Only Kim and a handful of Berke’s protégés scattered around the country know how to perform the three-hour procedure.
With the patient under general anesthesia, Kim opens the larynx, separates the nerves innervating the thyroarotenoid and the lateral cricoarytenoid muscles, and then reinnervates those muscles with another nerve from the neck, the ansa cervicalis.
After surgery, patients’ voices sound soft and breathy. But as the newly placed nerve “learns” its new function, patients regain their ability to speak normally. The procedure completely resolves spasmodic dysphonia for about 80 percent of patients, Kim says. The remaining 20 percent can still be given botulinum toxin type A to treat their symptoms.
“For the vast majority of patients,” Kim says, “this operation offers a permanent fix to what might have been a lifelong disability.”
To refer a patient or learn more,