Published online by Cambridge University Press: 05 February 2014
Cervical dystonia (CD), originally known as spasmodic torticollis and first described by Foltz in 1959, is a neurological syndrome characterized by abnormal head and neck posture caused by tonic involuntary contractions in a set of cervical muscles. However, CD and spasmodic torticollis are not interchangeable: CD is the preferred term when referring to idiopathic focal dystonia of the neck. Spasmodic torticollis is now considered to be one of four types of CD. Cervical dystonia is classified into four types based on the principal direction of head posture:
torticollis: abnormal rotation of the head to the right or to the left in the transverse plane
laterocollis: the head tilts toward the right or left shoulder
antecollis: the head pulls forward with neck flexion
retrocollis: the head pulls back with the neck hyperextended.
Cervical dystonia is slightly more common in females, with a male to female ratio of 1:1.2 (Kessler et al., 1999). Onset is usually insidious, although in some patients the onset has been reported as sudden. Cervical dystonia may develop in patients of all age groups, but the peak age of onset is 41 years (Kessler et al., 1999). Idiopathic CD usually progresses in severity over the first 5 years until it reaches a plateau, after which it remains fairly constant and becomes a lifelong condition. Although remission can occur, it is rare and the dystonia usually returns after a period of time. The cervical component may also exist as part of a more extensive form of dystonia, in which the dystonia can spread to involve adjacent structures such as the face or the arm(s). When dystonia involves several contiguous body parts, it is considered segmental dystonia. When it involves several parts of the body that are not contiguous, such as the neck and foot, it is called multifocal, and when it involves the majority of the body, it is referred to as generalized dystonia.