Robert F. Kennedy Jr. has a rare neurological condition called spasmodic dysphonia, which affects the muscles controlling his vocal cords. This disorder causes involuntary spasms of the vocal cord muscles, resulting in a strained, raspy, tremulous, or sometimes breathy voice. The spasms affect his ability to control the voice, causing breaks, a strained or strangled sound, and a vocal tremble when he speaks. He was diagnosed with this condition in the 1990s, and it has impacted the sound of his voice for decades. Treatments like botulinum toxin (Botox) injections have been used but were not a perfect fit for him. The cause of spasmodic dysphonia is unknown, but it is thought to involve neurological dysfunction, particularly in brain areas controlling muscle coordination for speech. Kennedy has shared that he finds his voice sound problematic and has expressed regret over how it affects his speech.