Spasmodic dysphonia is a neurological disorder that affects the voice. Its exact cause is unknown, but it is believed to be triggered by issues in the brain and nervous system. While there is no cure, treatment can help manage symptoms, such as injections of botulinum toxin into the affected muscles. It may be genetic or caused by factors like stress or voice injury. Rose Kennedy's voice sounded similar to individuals with this condition, although she was not officially diagnosed.