We reviewed the evidence about the effect of botulinum toxin type A (BtA) in people with involuntary positioning of the head, or cervical dystonia. This is an update of a previous Cochrane Review and we assessed the effectiveness (reduction in severity, disability and pain) and safety of BtA versus placebo (a pretend medicine) in cervical dystonia.


Cervical dystonia, also called spasmodic torticollis, is a disease that causes undesired, uncontrollable, often painful, abnormal placement of the head. It is a relatively uncommon condition (affecting 57 to 280 people per million) that can be very disabling and can affect a person’s quality of life negatively. In most cases the cause is unknown and no cure exists. Since cervical dystonia is normally a long-term disease it requires long-term treatment.