A neurological movement disorder, it causes difficulty in speaking, and a voice that often breaks and sounds strained or strangled.
Robert F. Kennedy Jr., president-elect Donald Trump's choice to lead the Department of Health and Human Services, has said he has spasmodic dysphonia. It is a voice disorder characterized by involuntary spasms in the muscles that control the vocal cords, or folds. This causes difficulty in speaking, and a voice that often breaks and sounds strained or strangled.
It is known as a focal dystonia, a neurological movement disorder which affects one specific part of the body. Writer's cramp, where there are spasms in the hands or fingers, or persistent eye spasms or eye closure are others in the same category.
Spasmodic dysphonia most often develops at midlife -- in one's 30s or 40s -- and can be life altering, particularly for those whose careers may depend on speech.
"Most people take their voice for granted until they don't have it," said Pryor Brenner, a otolaryngologist in D.C. "It can be very discouraging. People don't feel comfortable speaking, or don't want to speak. They are embarrassed. It has a huge impact because they aren't able to express themselves."
Moreover, "it's an invisible condition, meaning others can't see it," said Michael M. Johns, professor of clinical otolaryngology at the Keck School of Medicine at the University of Southern California and director of the USC Voice Center. "It's not associated with any cognitive impairment, and these people look normal to the eye."
We asked laryngologists about spasmodic dysphonia, its causes and symptoms.
What to know
What causes spasmodic dysphonia?What are the types of spasmodic dysphonia?How is spasmodic dysphonia diagnosed?How is spasmodic dysphonia treated?