Cervical dystonia (CD) is a neurological movement disorder causing involuntary, sustained muscle contractions in the neck. These contractions force the head and neck into abnormal, often uncomfortable, positions and movements. As the most common form of focal dystonia, this continuous muscle overactivity results in a visually distinct and often painful presentation.
The Defining Abnormal Postures
The most visible sign of cervical dystonia is the fixed or intermittent abnormal posture of the head, which can be categorized into four primary directions. The visual presentation is frequently a combination of these postures, reflecting complex patterns of muscle involvement. The resulting head position can be sustained (tonic) or involve abrupt, jerky movements (phasic).
Torticollis
The most frequent presentation is torticollis, where the head is rotated along its long axis, causing the chin to twist toward one shoulder. This twisting motion is caused by an imbalance in muscle activation, such as the sternocleidomastoid muscle and the ipsilateral splenius capitis muscle.
Laterocollis
Laterocollis appears as a tilt of the head, pulling the ear down toward the shoulder. This lateral flexion is often accompanied by an elevation of the shoulder on the side of the tilt.
Anterocollis
Anterocollis is characterized by the head pulling forward, forcing the chin down toward the chest. This forward flexion posture involves overactivity in the anterior neck muscles, such as the sternocleidomastoid and scalene muscles.
Retrocollis
Conversely, retrocollis presents as a backward tilt, with the head hyperextended and pulled back toward the spine. This posture is driven by the strong contractions of the neck extensor muscles.
Associated Symptoms Beyond Head Position
While the abnormal head posture is the hallmark of cervical dystonia, the physical experience is often dominated by chronic pain. Up to 75% of individuals report neck and shoulder pain, which can be more debilitating than the movement disorder itself. This pain can radiate from the neck into the shoulders and back of the head, sometimes manifesting as severe headaches.
The constant, involuntary muscle contractions lead to significant muscle stiffness and visible changes in the neck musculature. The affected muscles often become enlarged, or hypertrophied, from the relentless overwork, which can be palpated or seen as bulges on the neck. This muscle tightness contributes to the restricted range of motion experienced by the individual.
A non-dystonic head tremor is a common accompanying feature, affecting approximately half of all patients. This tremor is typically a jerky, shaking motion of the head seen in conjunction with the sustained posture. In some cases, contractions can spread to adjacent body regions, such as the face, jaw, or shoulder, causing additional localized spasms.
Variability and Sensory Tricks
The visual presentation is not static; it changes depending on the individual’s current state and activities. Symptoms commonly fluctuate throughout the day, often becoming worse with periods of stress, fatigue, or high concentration. The abnormal movements and postures typically diminish or disappear completely when the individual is at rest or asleep.
One characteristic feature of this condition is the phenomenon known as the “sensory trick,” or geste antagoniste. This refers to a simple physical maneuver that temporarily reduces or corrects the dystonic posture. The trick is often a light touch or application of counterpressure to the face, chin, or back of the head.
Visually, a person performing a sensory trick might place a finger on their cheek or chin, or rest their head against a high-backed chair. This non-forceful contact provides a sensory input that temporarily disrupts the abnormal motor signal, allowing the head to return closer to the midline. This temporary correction is a distinctive clue pointing toward a neurological basis for the dystonia.
How Symptoms Typically Develop
Cervical dystonia most commonly begins in adulthood, with onset peaking between 30 and 50 years, and it is observed more frequently in women than in men. The onset is usually gradual, with symptoms starting subtly and slowly increasing in severity over months or years. This slow progression allows the condition to reach a stable level, or plateau, after about one to five years.
The long-term course of the disorder is chronic, as spontaneous and complete remission is rare. Only about 10% to 15% of patients experience significant, sustained improvement without treatment. Even when remission occurs, the symptoms frequently return later.