Cervical dystonia (CD) is a neurological movement disorder characterized by involuntary, sustained muscle contractions in the neck. These spasms cause the head and neck to twist, tilt, or pull into abnormal and often painful positions. The condition is a type of focal dystonia, meaning it affects a specific area of the body, and it is also commonly referred to as spasmodic torticollis. The visual appearance of CD is defined by these sustained, unnatural postures, accompanying physical signs, and daily fluctuations in severity.
Defining the Abnormal Head Postures
The persistent, abnormal positioning of the head is caused by the overactivity of specific neck muscles. These postures are generally categorized into four primary types. However, most people experience a combination of these movements, often involving more than one axis of movement.
Torticollis is the most common presentation, involving the head rotating or twisting on the horizontal axis, pulling the chin toward one shoulder. Laterocollis involves the head tilting sideways, causing the ear to be pulled down toward the shoulder. This lateral tilt can sometimes make one shoulder appear visibly higher than the other.
The other two primary positions involve forward and backward movements. Anterocollis is the term for the head being involuntarily bent forward, pulling the chin down toward the chest. Conversely, Retrocollis involves the head being pulled backward, forcing the chin upward toward the spine.
These four types are rarely seen in isolation. The visual appearance is often a complex mixture of rotation, tilt, and flexion or extension, determining the unique look for each individual. For example, a person might present with a posture that is primarily torticollis but includes a noticeable laterocollis component.
Accompanying Physical Signs and Sensations
Cervical dystonia includes dynamic and physical signs that contribute to its overall appearance. A head tremor frequently accompanies the abnormal posture, affecting more than half of those with the condition.
This tremor is often jerky and irregular. Its intensity increases when the person attempts to move their head opposite to the dystonic pull.
Constant involuntary muscle strain results in muscle hypertrophy, which is an enlargement of the chronically overactive neck and shoulder muscles. The unrelenting tension can cause visible bulges or increased bulk on one side of the neck, making the asymmetry more pronounced.
A highly observable behavioral sign is the use of sensory tricks, also known as gestes antagonistes. This involves the patient lightly touching a specific area of the head or face, such as the chin, cheek, or the back of the head, to temporarily reduce muscle spasms. The simple, light touch provides sensory feedback that briefly interrupts the involuntary contraction, allowing the head to momentarily return closer to a neutral position.
Fluctuations in Appearance and Severity
The visual presentation of cervical dystonia can fluctuate significantly throughout the day and in response to external factors. Symptoms often subside completely during sleep, demonstrating the condition’s neurological basis. Conversely, emotional stress, anxiety, or physical fatigue can dramatically worsen the spasms.
Heightened stress causes involuntary contractions to become more intense, making the abnormal head posture and any accompanying tremor more pronounced. Some individuals report that symptoms are less severe in the morning and progressively worsen throughout the day.
Certain activities can also trigger or exacerbate the visual signs. For example, tasks like walking or writing may temporarily increase muscle contractions. Concentrating visually on a fixed object can help stabilize the head, while closing the eyes may cause the head to shift into its maximal abnormal posture.