Robert F. Kennedy Jr.'s distinctive, raspy, and sometimes shaky voice is caused by a rare neurological condition called spasmodic dysphonia. This disorder results from involuntary spasms in the muscles that control the vocal cords, causing the voice to have breaks, a strained or strangled quality, or sometimes a breathy sound. Kennedy developed this condition in his early 40s, which has progressively affected his voice over the decades. Despite the challenges, the more he uses his voice, the stronger it tends to get, but the injury is neurological and not due to any damage in the voice box itself. Treatments such as botulinum toxin injections have been used, and at one point he underwent a surgical procedure involving a titanium bridge implanted in his vocal cords, though this procedure is not approved in the U.S. The exact cause of spasmodic dysphonia is unknown but is related to abnormal nerve signaling in the brain.

Key Details of the Condition

• Spasmodic dysphonia causes involuntary muscle spasms in the vocal cords, leading to difficulty in speaking and a strained voice.
• About 50,000 people in North America are affected by this condition.
• The disorder is neurological, involving abnormal signaling in brain regions controlling muscle movements.
• It is chronic and currently without a cure but can be managed with treatments like Botox injections and experimental surgery.
• Kennedy's voice struggles are well-known publicly, and he has expressed frustration about the impact of the condition on his speech.

This explains the characteristic trembling and strained quality in Robert F. Kennedy Jr.'s voice.