UltraSound-Guided Versus Non-Ultrasound-Guided Botulinum Toxin Injections in Cervical Dystonia [CUSTODY]

Inclusion Criteria: * Minimum age 18 years old * Clinical diagnosis of Idiopathic Cervical Dystonia * On a stable dose of other medications (if any) used for focal dystonia treatment (e.g. anticholinergics and benzodiazepines) for at least 3 months prior to screening and expected to be maintained throughout the study * Treatment non-naïve to BoNT type A therapy for CD * At least 4 months have passed between the last BoNT injection at screening * Good clinical response to previous BoNT injections, on stable dosing and treatment scheme * Informed Consent as documented by signature. * Ability to perform study requirements (to attend assessment and treatments) Exclusion Criteria: * Diagnosis of other types of Cervical Dystonia (Inherited and Acquired) * Concomitant diagnosis of diseases that contraindicate the use of botulinum toxin, such as myasthenia gravis * Known hypersensitivity or allergy to Botulinum-A Toxin * Women who are pregnant or breast feeding * Intention to become pregnant during the study * Lack of safe contraception * Other clinically significant and unstable concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, etc.). * Inability to follow the procedures of the study, e.g., due to language problems, psychological disorders, dementia, etc. of the participant * Participation in another study with investigational drug within the 30 days preceding and during the present study * Previous enrolment into the current study