Dystonic Tremor

Dystonic tremor is a specific type of shaking that occurs when muscles tense up involuntarily due to dystonia, a disorder that causes unwanted muscle contractions. This tremor can be irregular in rhythm and is often mistaken for other tremor conditions, making accurate diagnosis crucial for proper treatment.

Table of contents

• What is Dystonic Tremor?
• Types of Tremor in Dystonia
• Symptoms and Characteristics
• Diagnosis
• What Can Trigger Symptoms
• Treatment Options
• Living with Dystonic Tremor

What is Dystonic Tremor?

Dystonic tremor is a shaking that occurs in parts of the body affected by dystonia, which is a movement disorder that causes muscles to contract involuntarily. This happens because of faulty signals coming from the brain^[1][2]. Unlike the smooth, regular shaking seen in some conditions, dystonic tremor tends to be irregular in both rhythm and amplitude^[1].

The connection between tremor and dystonia has been recognized for more than 100 years^[1]. When doctors examined the muscle activity using special recording equipment, they found that rhythmic bursts of muscle contractions at 5-11 Hz were common during voluntary movements, while rhythmic and irregular bursts at 1-6.5 Hz occurred in the involuntary dystonic contractions^[1].

Rather than being a separate disease, dystonic tremor manifests most commonly as a shake in the hand, often occurring when performing specific tasks^[5]. This is a big distinction from conditions like Parkinson’s disease, where tremor typically occurs at rest. With dystonic tremor, people have difficulty when using their hands actively^[5].

Types of Tremor in Dystonia

Medical experts currently recognize two distinct forms of tremor that occur in people with dystonia^[1]:

• Dystonic tremor: This is tremor produced by dystonic muscle contraction. It occurs in the same body part where dystonia is present^[1].
• Tremor associated with dystonia: This is tremor in a body part that is not dystonic, but the person has dystonia elsewhere in their body^[1].

Both forms of tremor in dystonia frequently resemble essential tremor or other pure tremor conditions, such as isolated head and voice tremors and task-specific writing tremor^[1]. This similarity can make accurate diagnosis challenging, and misdiagnosis is common because mild dystonia is frequently overlooked in patients with tremor^[1].

Symptoms and Characteristics

The key symptom of dystonic tremor is uncontrollable shaking that occurs in muscles affected by dystonia. These movements are often uncomfortable or even painful, sometimes feeling like electric shocks^[3]. The tremor can be repetitive, especially when it presents as tremors, and the duration can vary widely—some tremors last only seconds or minutes while others can continue for months^[3].

The shaking typically becomes worse when using the affected muscles^[3]. For example, someone with dystonic tremor in the hand might notice increased shaking when writing or performing other fine motor tasks. The cause isn’t fully understood, but it appears to involve a situation where opposing muscle groups contract simultaneously, creating a “tug-of-war” effect that produces the visible tremor^[5].

As the autonomic nervous system becomes more balanced during recovery, both non-motor symptoms and motor symptoms can fluctuate. Spasms and tremors may change in duration, intensity, or even manifest in different areas of the body than the original dystonic muscle region^[17].

Diagnosis

To diagnose dystonic tremor, healthcare providers start with a detailed medical history and physical examination^[2]. A neurologist may ask about symptoms, other medical conditions, medications being taken, and whether anyone else in the family has dystonia, as it can sometimes be inherited^[6].

Several tests may be performed to look for conditions that could be causing the symptoms^[2]:

• Blood or urine tests: These can reveal signs of toxins or other conditions^[2].
• MRI or CT scan: These imaging tests look for changes in the brain, such as tumors or evidence of a stroke^[2].
• Electromyography (EMG): This test measures the electrical activity within muscles^[2].
• Genetic testing: Some forms of dystonia are associated with certain genes, and knowing if these genes are present can help guide treatment^[2].

A skilled neurologist can often diagnose dystonic tremor relatively quickly through careful observation and physical examination^[16]. In one patient’s case, a neurologist was able to identify cervical dystonia as the cause of a head tremor within ten minutes by asking questions, performing physical tests, and observing the tremor^[16].

What Can Trigger Symptoms

Several factors can trigger or worsen dystonic tremor symptoms^[6][17]:

• Tiredness
• Stress
• Drinking alcohol or caffeine
• Talking
• Eating or chewing
• Activities like writing, typing, or playing an instrument

Stress plays a particularly important role in the manifestation and aggravation of dystonia symptoms. For individuals already dealing with dystonia, stress can act as a catalyst, intensifying the challenges they face^[17]. Research suggests that stress-induced increases in serotonin, a brain chemical, may contribute to the onset of dystonia^[17].

Treatment Options

Treatment for dystonic tremor can help relieve symptoms, though there is no cure. The best treatment option depends on the type and severity of the dystonia^[6]. Healthcare providers typically recommend a combination of medicines, therapy, or surgery^[2].

Medications

Botulinum toxin injections (such as Botox or Dysport) are commonly used. These are injected directly into the affected muscles and can reduce or stop muscle spasms. The injections usually need to be repeated every 3 to 4 months. Side effects are generally mild and temporary, including weakness, dry mouth, or voice changes^[2][9]. In one patient’s experience, botulinum toxin treatment eliminated head tremors within two weeks^[16].

Other medicines target chemicals in the brain called neurotransmitters that affect muscle movement. Options include^[9]:

• Carbidopa-levodopa: This medicine can increase levels of the neurotransmitter dopamine
• Trihexyphenidyl and benztropine: These act on neurotransmitters other than dopamine, though side effects can include memory loss, blurred vision, drowsiness, and dry mouth

In cases where one or two connected body parts are affected (focal or segmental dystonia), botulinum toxin is commonly the most effective treatment and should be considered as the first approach^[10].

Surgery

Deep brain stimulation is the main type of surgery for dystonia and may be offered if other treatments don’t help^[6]. It involves inserting a small device, similar to a pacemaker, under the skin of the chest or abdomen. The device sends electrical signals along wires placed in the part of the brain that controls movement^[6][9].

Treatment Outcomes

In a study of people with upper limb dystonic tremors, approximately 39% of patients treated with oral medications, botulinum toxin, or surgery reported improvement on a patient-completed clinical scale^[7]. However, dropout rates with oral medications were high (74.2%) due to either lack of effectiveness or side effects. With botulinum toxin, 22.6% experienced mild weakness, though this caused only 2 patients to stop treatment^[7].

Living with Dystonic Tremor

Dystonic tremor is usually a lifelong condition. It may get worse for a few years but then remain steady, and occasionally it can improve over time^[6]. The severity of symptoms can vary from one day to another, and it can have a significant effect on daily life, making activities painful and difficult^[6].

Finding the right specialist is crucial. A competent doctor who understands the condition can make a big difference in the treatment regimen, helping to reduce symptoms faster^[13]. It’s important to find a therapist who specializes in treating dystonia and has experience in the field^[13].

Regular exercise tailored to individual needs can help reduce the severity of symptoms and improve quality of life. Exercise can prevent muscle stiffness, increase endurance, and provide greater comfort throughout the day^[13]. Not only is regular exercise beneficial for managing dystonia, but it’s also an essential tool for managing the condition over time^[13].

Some practical tips for daily living include^[12]:

• Planning ahead and working out what needs to be done and when
• Setting priorities so the most important things are comfortably achieved
• Taking frequent rests between tasks
• Avoiding multitasking and doing one thing at a time
• Not rushing or doing things at the last minute
• Using gadgets that save time and effort

Support is available. People living with dystonia don’t have to face it alone, and connecting with others who understand the condition can be invaluable^[13].