Idiopathic Cervical Dystonia

Cervical dystonia is a condition that causes the neck muscles to tighten or spasm, leading to abnormal head positions and pain. The main questions it aims to answer are: * Do ultrasound-guided BoNT injections improve quality of life more than injections without ultrasound? * Are ultrasound-guided injections as safe as injections without ultrasound? Researchers will compare: * BoNT injections with ultrasound guidance * BoNT injections without ultrasound guidance (based only on body landmarks) Participants will: * Receive both types of injections during the study (one first, then the other) * Complete questionnaires about quality of life, movement, pain, and mood * Attend follow-up visits over about 8 months About 37 adults with cervical dystonia will take part. The study will take place at the Fondazione IRCCS Istituto Neurologico Carlo Besta in Milan, Italy.