Dystonia

Dystonia is a movement disorder in which muscles contract involuntarily, producing repetitive twisting movements, abnormal postures, or both. It can affect a single part of the body or, less commonly, the whole body. These contractions are not under the person’s control and cannot be stopped by effort or willpower.

Two aspects of dystonia are widely misunderstood. First, it is often painful; cervical dystonia (affecting the neck) in particular can be severely so, and pain is frequently what brings patients to seek care. Second, dystonia is not a psychological condition. Like most neurological symptoms, it tends to worsen with stress and fatigue, but this does not mean the underlying cause is psychological.

Many patients with dystonia notice a “sensory trick”; for example, lightly touching the chin or cheek can temporarily relieve a neck spasm. This is a recognized feature of dystonia and can be a useful clue during diagnosis.

Task-specific dystonia deserves particular mention: a musician, for example, may play scales without difficulty and then lose fine control of the same fingers the moment they play their instrument. Because everything else appears normal, these patients are sometimes among the last to be correctly diagnosed.

• Involuntary twisting or pulling of a body part
• Sustained abnormal posture; for example, the head turned, tilted or pulled forward
• Muscle cramps, frequently with significant pain
• A tremor that accompanies the abnormal posture
• Symptoms that worsen with stress, fatigue and sustained activity
• Temporary relief from a light touch to the affected area (a “sensory trick”)

Most patients with focal or segmental dystonia are managed well without surgery, using targeted botulinum toxin injections and, where relevant, oral medication and physical therapy. Surgical evaluation is generally considered for patients with:

• Generalized dystonia significantly affecting movement and daily function
• Severe focal or segmental dystonia where botulinum toxin injections have stopped providing adequate benefit or are no longer well tolerated

Botulinum toxin injections. Botulinum toxin is injected directly into the overactive muscles, in doses and patterns mapped to the individual patient. The effect is not immediate; it typically begins within a week and reaches its full effect at two to three weeks, and it is temporary rather than permanent, which is why injections are usually repeated every three to four months. Careful selection of the correct muscles is essential to a good result, and deeper muscle groups are often injected under EMG or ultrasound guidance. Patients who have had disappointing results elsewhere sometimes turn out to have received the right medication in the wrong muscles.

Deep brain stimulation. For generalized or severe dystonia, or when botulinum toxin no longer provides adequate benefit, DBS may be considered. Full details of the DBS procedure are provided on our Deep Brain Stimulation page.

• Detailed history and examination to classify the type and distribution of dystonia
• Assessment for an underlying cause where relevant
• Mapping of the specific muscles involved, using examination and, for deeper muscles, EMG or ultrasound guidance
• Neuropsychological assessment where DBS is being considered
• High-resolution brain MRI where surgery is being considered

Botulinum toxin injections aim to reduce muscle overactivity, improve posture, and, often the change patients notice first, relieve pain. Deep brain stimulation, in appropriately selected patients with generalized or severe dystonia, aims to reduce the severity of abnormal postures and improve function and comfort. As with all functional neurosurgery, treatment goals vary between patients, and individual results may differ.

Botulinum toxin side effects are usually mild, local and temporary (for example, neck weakness or swallowing difficulty after neck injections, or eyelid drooping after injections around the eye) and resolve as the effect wears off. A small number of patients develop reduced response over time; switching formulation sometimes helps. DBS carries the surgical risks described on our Deep Brain Stimulation page.

Botulinum toxin treatment is an outpatient procedure with same-day discharge; effects are reviewed at two to three weeks to refine the muscle map for future sessions if needed. Recovery and long-term follow-up after DBS are described on the Deep Brain Stimulation page.