What causes RFK Jr.’s strained and shaky voice? A neurologist explains this little-known disorder

Health and Human Services Secretary Robert F. Kennedy Jr. has attracted a lot of attention for his raspy voice, which results from a neurological voice disorder called spasmodic dysphonia.

Kennedy, 71, says that in his 40s he developed a neurological disease that “robbed him of his strong speaking voice.” Kennedy first publicly spoke of the quiver he had noticed in his voice in a 2004 interview with journalist Diane Rehm, who also had spasmodic dysphonia.

In 2005, Kennedy was…