Robert F. Kennedy Jr.'s distinctive, raspy, and shaky voice is caused by a rare neurological disorder called spasmodic dysphonia. This condition causes involuntary spasms in the muscles that control the vocal cords, leading to breaks and a strained or strangled voice quality. Kennedy has had this condition for decades, first noticing symptoms in his 40s. He used to have a strong voice that could fill large halls without amplification but now experiences a trembling voice that he has said he "can't stand." Treatments such as botulinum toxin (Botox) injections and alternative therapies have been used, and he even underwent an experimental titanium bridge surgery to keep his vocal cords from pressing together, though the injury is neurological rather than structural in the voice box. The more he uses his voice, he says, the stronger it tends to get, even if it sounds terrible. The condition impacts roughly 50,000 people in North America and remains somewhat mysterious in its causes, involving abnormal brain signals affecting the vocal cord muscles.