In this article:

• What is essential tremor?
• What are the symptoms of essential tremor?
• What causes essential tremor?
• How is essential tremor different from other types of tremor?
• How is essential tremor diagnosed?
• What can patients do to help their essential tremor?
• What can be done to treat essential tremor?
• Further information on ultrasound treatment of essential tremor

WHAT IS ESSENTIAL TREMOR?

The term essential tremor has been around for almost 150 years and refers to a common neurological condition that will typically be referred to a neurologist. A neurologist has appropriate training and experience to diagnose essential tremor against other types of tremor condition or movement disorder.

Essential tremor (also sometimes known as benign essential tremor or familial tremor) is a chronic condition, and one of the most common neurological movement disorders. The condition is between 8 and 10 times more common than Parkinson’s disease.

WHAT ARE THE SYMPTOMS OF ESSENTIAL TREMOR

Essential tremor presents as an involuntary rhythmic trembling or shaking of the hands or arms. This shaking is usually present on both sides and may be mild to severe. Whilst essential tremor is not life threatening, its effect on quality of life can be debilitating.

Sometimes, people feel that the tremor is worse on one side. That may be the dominant hand or the non-dominant hand. Most typically, the tremor or the shake is fairly symmetrical. Essential tremor can also present as shaking of the head, legs, trunk and even the voice.

Essential tremor symptoms can start at different ages and tends to persist through life. Whilst some patients will continue to have a mild tremor throughout their life, we also know that essential tremor can be a slow progressive disorder, meaning that it sometimes gets a worse with age.

Essential tremor is what we call an isolated Tremor syndrome. This means that whilst we sometimes see tremor elsewhere (for example in the head or another body part), we don’t typically see other neurological systems involved. For example, people with essential tremor don’t typically have significant problems with walking or memory. Sometimes, we see a family history but that’s not a requisite for a diagnosis of essential tremor.

WHAT CAUSES ESSENTIAL TREMOR?

Despite essential tremor being a common movement disorder, the exact cause is unknown. We are really not sure why one person develops essential tremor and not another. In fact, there have been many studies and lots of research performed over the decades looking at this question.

Essential tremor can run in families, and there have been studies looking at a potential genetic cause. However, apart from one or two genes in very small and specific populations around the world, a specific cause for essential tremor in an individual patient has not yet been identified.

It’s important to remember that in today’s world, we now think of essential tremor more as a syndrome. This means that it is probably a collection of different types of condition that drive the tremor.

HOW IS ESSENTIAL TREMOR DIFFERENT FROM OTHER TYPES OF TREMOR?

In general, tremor is a very common symptom. Essential tremor is different to other tremor syndromes (such as Parkinson’s disease tremors) in that it is an ‘action tremor’. This means that the tremors occur when you move that body part or when you’re activating the muscles in that body part. This is as opposed to a ‘rest tremor’, where tremors occur when the body part is resting.

As well as being an action tremor predominantly, an essential tremor is also fairly symmetrical.

Essential tremor vs Dystonic Tremor

A common question we see is whether essential tremor is the same at dystonic tremor. Dystonic Tremor is similar to essential tremor in that it causes shaking. However, the prerequisite of dystonic tremor is that there is an additional movement disorder associated with the tremor that we describe as dystonia. Dystonia is a twisting, turning or abnormal posturing of a body part. This could involve the head, the neck, parts of the face or the hand.

Dystonic Tremor also has a tendency to be less symmetrical than essential tremor. This, combined with the dystonia, differentiates dystonic tremor from essential tremor.

So, for a diagnosis of essential tremor, we’re looking for symmetry (looking for both arms or hands to be involved as well as possibly other body parts) and we are looking for the absence of involvement of other neurological systems.

HOW IS ESSENTIAL TREMOR DIAGNOSED?

Essential tremor is diagnosed through a combination of three things.

The first is the patient’s story. This is always one of the most important things for a neurologist to make a diagnosis. The story involves hearing about the symptoms and the onset of tremor, how it’s evolved, what body parts it involves and how it has affected the patient.

The patient’s story is then triangulated with an examination of the patient, where a neurologist will examine the patient objectively to assess what the patient’s movements look like, what the tremor looks like and thinking about the frequency or the rapidity of the tremor. This will allow an experienced neurologist to identify essential tremor and differentiate it from other movement disorders.

The neurologist will also look at whether any other neurological systems are involved. This may involve looking at the power in the limbs and looking at the patient walking.

Sometimes (though not always for tremor syndromes) other investigations or specialist tests are required. This might include blood tests looking at thyroid function or other minerals or electrolytes.

A neurologist might also include diagnostic imaging. For example, a Magnetic Resonance Imaging (MRI) scan of the brain may be used to rule out any structural causes for the tremor. A specialist nuclear medicine scan called a DaTscan may be also be useful to look at dopamine levels in the brain and can help rule out a diagnosis of Parkinson’s disease. In general, diagnostic tests will only be used if they might be useful to rule out other conditions.

WHAT CAN PATIENTS DO TO HELP THEIR ESSENTIAL TREMOR?

There are certain factors in one’s life that can influence the severity of the tremor, and sometimes make tremors worse. For example, the amount of caffeine consumed, the medications that one is taking for other medical conditions and sometimes emotional state can all have an influence on the severity of tremor at any one time.

Finding an experienced neurologist to obtain an accurate and up-to-date diagnosis, and who can discuss the full range of treatment options with you is highly recommended. They will also be able to refer you to specialist therapists who will be able to help with adaptive devices and strategies for managing your tremor in your day to day life.

WHAT CAN BE DONE TO TREAT ESSENTIAL TREMOR?

The treatment of Tremor is multimodal.

Medications are sometimes helpful for patients and there are several medications we use including beta blockers. Most medications can suppress the tremor, but don’t often completely get rid of it. In fact, this would be unusual. Injections are also being used increasingly often to provide tremor control e.g. botulinum toxin. These can have limitations, including the possibility of weakness.

Other therapists may also be engaged for the management of essential tremor symptoms. For example, occupational therapists can help patients with essential tremor to adapt their environment to accommodate for the tremor. There are also devices and wearables that can help. For example, weighting of the limb to make it heavier can dampen the tremor, and prove successful in some situations.

The role of surgery in essential tremor

We have known for a long time that surgical approaches are also very effective for moderate to severe tremors that have not responded to medication or other therapies. Deep brain stimulation has been used for many years to interrupt the abnormal signals responsible for tremor. However, another form of surgery called ‘thalamotomy’ involves deliberately making a small lesion deep in the area of the deep brain which controls movement, to block the abnormal electrical signals and reduce tremors.

Very excitingly over the last 10 years or so, a new technique called MR Guided Focused Ultrasound has been used to perform lesions in brain tissue without any need for a stimulating device, or any incisions in the scalp or skull. The procedure involves ‘shining’ many ultrasound beams through the skull and onto that same area in the brain to create a small lesion, which is proving very successful in ablating the tremor.

Whilst there is no known cure for essential tremor, it is very exciting that all forms of treatment, both non-surgical and surgical, are now available for our patients in Queen Square.

WHERE CAN I FIND INFORMATION ABOUT FOCUSED ULTRASOUND TREATMENT OF ESSENTIAL TREMOR?

MR-guided focused ultrasound treatment for medication-refractory essential tremor is now available in Queen Square to private patients. If you are interested in treatment and would like to find out more, please contact our treatment coordinators at treatment@queensquare.com.

Additional information is also available at https://queensquare.com/services/focused-ultrasound-essential-tremor-treatment/

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