Cervical Dystonia

Symptoms

Cervical dystonia, the most common form of focal dystonia, is characterized by abnormal squeezing and twisting muscle contractions in the head and neck area. Sustained muscle contractions result in abnormal positions or posturing. Almost all dystonic movements share a directional quality that is typically sustained. Movements may be prolonged or occur in an instant. In general, the dystonias may be classified based on: the age at which symptoms appear; the area or areas of the body that are affected (anatomical distribution); or the cause of the dystonia. CD is classified as a focal dystonia because it typically affects one area of the body (i.e., head and neck).

The dystonic muscle spasms associated with cervical dystonia (CD) may affect any combination of neck muscles. These sustained muscle contractions or spasms result in jerky head movements or periodic or sustained unnatural positioning the head (dystonic posturing). Sideways or lateral rotation of the head and twisting of the neck is likely the most common finding in CD. This is known as rotational cervical dystonia. In addition, tilting of the head is often present. The most common form of torticollis is characterized by turning, flexing, or extending of the neck to the side (laterocollis or lateral flexion). Less commonly, posturing to the front (anterocollis) or back (retrocollis) may also occur. One shoulder may be elevated and displaced forward on the side toward which the chin turns. In addition, there is often mild associated dystonia in the upper arm muscles on the same side (segmental dystonia). There does not seem to be an association between "handedness" and the direction of the tilt.

Symptoms of CD often worsen while walking or during period of stress. Symptoms typically improve with rest or sleep. In addition, CD is the most common focal dystonia that responds to a sensory trick or geste antagoniste. For example, patients with CD may find that placing a hand on the side of the face, chin, or the back of the head, temporarily alleviates the dystonic posture. Leaning the head back against a chair or placing a hand on the top of the head may also help to relieve CD symptoms. The reason that sensory tricks work for some patients is not fully understood.

Muscle hypertrophy is present in almost all CD patients. Over two-thirds or up to 80% of patients, particularly those with sustained head deviation, have associated neck pain. About 33% to 40% of these patients also experience head tremor (i.e., dystonic tremor), hand tremor, or both. Approximately 20% of patients with CD also have blepharospasm or dystonia in other muscles or in muscle groups of the arm or hand. In addition, about 15% of patients have hand tremor resembling essential tremor.

Evidence suggests that about 10% to 20% of patients with cervical dystonia may have brief, spontaneous remissions (Poewe W, 1992). Almost all affected individuals eventually experience a relapse of symptoms. An additional 10%, particularly patients with an earlier age at symptom onset, may have longer remissions of about two to three years, typically beginning during the first few years following disease onset.