Robert F. Kennedy Jr. started developing symptoms of the condition in 1996. Spasmodic dysphonia is a neurological condition that causes certain muscles in the “voice box,” or larynx, to spasm, often making the voice sound raspy, strained or breathy.

Kennedy's condition is called spasmodic dysphonia, which is a neurologic disorder that can affect the voice and speech by causing the muscles that generate a person’s voice to go into periods of spasm, according to Penn Medicine. It is a lifelong condition, but can be improved with treatment in some cases, according to Penn Medicine.

Robert F. Kennedy, Jr. has struggled for decades with a rare disorder affecting his speech, causing his voice to sound strained and raspy when he speaks.