FocusNeuro Tremor Treatment
Tremor is a common and frequently undertreated condition that affects up to 4%, or around 800,000 Australians. The most common cause of tremor is “Essential Tremor”. “Dystonic tremor” is a related but less common cause of tremor.
Essential and dystonic tremor typically cause shaking of the hands, however it can also affect the voice, head and legs.
Essential and dystonic tremor sometimes runs in families, are often heightened by stress and with movement, and may be reduced by drinking alcohol. Essential tremor is typically regular and is particularly problematic with intentional movements, such as drinking a glass of water. Dystonic tremor is more irregular and jerky and is generally more severe with certain postures of the hands and arms. Dystonic tremor may be associated with dystonia, the abnormal pulling and posturing of other muscle groups.
Essential and dystonic tremor may worsen over time.
Tremor caused by Parkinson’s disease tends to be worst whilst resting, and decreases when actively moving the affected body part (the reverse is generally true with essential and dystonic tremor).
Other causes of tremor can include thyroid issues, some medications, brain injury, and multiple sclerosis.
Medications often help tremor, however only around 50% of people obtain a significant benefit.
The impact of tremor on quality of life is often very significant. Tremors can impact on the ability to eat, drink, dress and write. They can cause significant embarrassment and occasionally lead to social withdrawal and depression. Doctors often underestimate the impact of tremor on the affected person’s quality of life.
What is Essential Tremor?
Essential tremor (ET) is the most common adult movement disorder, affecting around 3-4% of the adult population.
Although essential tremor is generally viewed as a benign disease (it does not tend to cause death or a shortened life expectancy), its associated disabling aspects, particularly severe tremor of the hands, can have disastrous effects on the ability to feed oneself, dress, write, shave, perform the usual household activities, and function at work. It can also be embarrassing for the person affected, causing them to become socially withdrawn or anxious.
Essential tremor frequently runs in families, but in many there does not appear to be a genetic predisposition. It is thought that around half of all cases are due to a genetic mutation- in those cases the pattern of inheritance is suggestive of autosomal dominant transmission.
Focused ultrasound is increasingly used to treat essential tremor. Historically, essential tremor was treated with medications (some of which did not work, and some causing problematic side effects) or surgery. The surgical options in the past involved insertion of either a probe or electrode in the brain, with the aim being to destroy (thalamotomy) or deactivate (deep brain stimulation) a small volume of brain tissue containing nerve cells. The problem is that both of those older techniques are invasive and carry small but serious risks of bleeding, infection, stroke and mortality (death). The upside of Focused Ultrasound is that the serious risks are lower.
Treatment of Tremor
In very mild case of tremor, no treatment may be required. Medications are typically used in the first instance for more problematic tremor, and neurosurgical procedures may be considered in more severe cases where non-surgical treatment has failed.
Pharmacological options include beta-blockers, certain anti-seizure medications and also some anti-anxiety drugs. Around half of all patients will derive some reduction in tremor though the side effects, including fatigue or drowsiness, can be limiting.
2. Thalamotomy (traditional open procedure)
In this procedure, a small hole is drilled in the skull and a radiofrequency probe is inserted through the brain and into the thalamus. These cells are then destroyed with heat, sometimes leading to alleviation of the tremor. This procedure carries risks including bleeding, stroke, infection, seizures and death.
3. Deep brain stimulation
This involves drilling a hole in the skull and inserting an electrode into the thalamus or posterior subthalamic area. The electrode is then connected via a wires to a battery (implantable pulse generator) located in the chest region. It carries similar risks to thalamotomy, with the additional risk of hardware infection. The implantable pulse generator requires programming adjustments from time to time, and also requires replacement (every 10-15 years for rechargeable devices). Rechargeable devices often need recharging one or more times per week.
4. MRI-Guided Focussed Ultrasound (MRgFUS)
This is the modern day thalamotomy, with some key advantages over traditional thalamotomy and deep brain stimulation. It does not require incisions, holes are not drilled in the skull, and probes are not inserted into the brain. It is generally considered safer than the more traditional surgical approaches.