Essential tremor

The author’s personal experience prompted her to delve into the causes, diagnosis and treatment of a common but often under-recognised neurologic condition

Two years ago I was asked to do a presentation on the development of primary care nursing in the UK. This is a subject I know well and I had a friendly audience, so I wasn’t unduly anxious. I instantly noticed, however, that I was having trouble hitting the right key on the computer to bring up the next PowerPoint slide because I was shaking, and had to resort to asking a colleague to do it for me. After the session we had snacks and an informal chat, mingling with our audience. I couldn’t hold my cup and saucer without shaking and spilling the contents and I certainly couldn’t hold a sandwich in one hand and cup and saucer in the other. Someone even asked me why I was so nervous!

This shaking had been becoming worse for some time, but I had tried to compensate. This was the first time in a public arena that the symptoms were so obvious. After this experience, I went to see my GP, who referred me to a neurologist who diagnosed Essential Tremor (ET).

SYMPTOMS OF TREMOR

The National Tremor Foundation describes ET as the most common neurologic movement disorder: it is 20 times more prevalent than Parkinson's disease. It is recognised as a chronic condition characterised by involuntary, rhythmic tremor of a body part, most typically the hands.¹ It’s considered to be a slowly progressive disorder and, in some people, may eventually involve the head, voice, tongue – with associated dysarthria (difficulty in speaking), legs, and trunk. However, in many people, the disorder may be relatively non-progressive. The tremor may be mild throughout life.

When I thought back, the condition probably started about 7 years ago, but I had put it down to clumsiness or imagination.

In ET, tremor may be most visible when the person is moving or performing a task.² It is not always obvious when the patient’s hands are still, for instance, in their lap or resting on a surface. In Parkinson’s disease, the opposite is generally true. However, even at rest patients with ET describe a feeling of general ‘shakiness’ or a vibrating sensation in the body. Hand tremor may cause difficulties with writing, drinking fluids from glass a or cup, eating, sewing, applying makeup, shaving, or dressing.

In individuals with ET the next most frequently affected area of the body is the head, followed by the voice, tongue, legs, or trunk. These tremors may occur in isolation or along with tremor of the hands or arms. Tremors usually disappear during sleep and the muscles will be perfectly relaxed even in rapid eye movement sleep (dream sleep). On waking, in my experience however, the tremors are severe and it is impossible, for instance, to clean my teeth. It takes some time for the tremors to settle and I am then able to perform my normal daily tasks and routine – but always with a tremor.

Many people with essential tremor only have symptoms in one hand; I have symptoms in both hands. For the diagnosis, the consultant asked me to draw a spiral, (with both hands) perform my normal signature and write a sentence. He then gave me a plastic cup half filled with water and an empty cup and asked me to pour the water from one cup into the other, back and forth. This is difficult for patients with essential tremor, as they will always hold a cup or glass with two hands to help prevent the tremor

PSYCHOLOGICAL AND SOCIAL EFFECTS

The psychosocial effects of ET may be embarrassing and debilitating.¹ It may eventually affect the patient's ability to perform certain work-related tasks, interfere with activities of daily living or lead to withdrawal from social activities and interactions due to embarrassment. For some people with ET other symptoms may also be present, such as unsteady, uncoordinated walking.

Two years ago, when my condition was diagnosed, I was finding it quite difficult to work. I ran a respiratory clinic in HMP Bedford and using the computer, performing spirometry and peak flow and showing patients how to use their inhalers was becoming more and more difficult and embarrassing. The more stressed a patient gets as adrenaline increases, the worse the symptoms become,3 so it is a vicious cycle. At this time, I decided to retire. My hobbies include water colour painting and playing the piano. I still paint but hold the brush with two hands to steady it. A year ago I took a piano exam and was able to blame failing the exam on my tremors!

Eating out in company can be the most stressful experience and I have found it difficult to be open and announce that I have a problem. The more stressed I get, the worse the symptoms. I can understand why patients withdraw from these social occasions, but I haven’t and hope never to do so. It has been suggested to me that having a couple of glasses of wine can help reduce the tremors, but even though I have enjoyed the wine, I haven’t found a major beneficial effect on the tremors. However, it does work for some people, although obviously alcohol can have its own problems.

DIAGNOSING TREMOR

Conclusive diagnosis is important for a number of reasons, including prognosis, optimising treatment and facilitating research. However, the exact course of ET is unknown, a cure has not been found, and medication only seems to reduce the tremors, not stop them completely. There are a number of other disorders that have shaking hands as one of the symptoms and drugs and chemicals can induce similar symptoms. The diagnosis of ET is therefore a process of elimination.⁴

To be diagnosed with tremor it is best for the patient to see either a doctor who understands tremor or a neurologist. There are a number of ways in which the tremor can be diagnosed:

1. The diagnosis will typically begin with the patient’s medical history

2. Looking for offending medications prescribed for other conditions which can cause tremor as a side effect

3. Family history of tremor

4. While the diagnosis of essential tremor remains a visual one, magnetic resonance imaging (MRI) and computerised tomography (CT) scans may be helpful in eliminating any other conditions which also produce tremor as a symptom

5. Blood samples may also be taken to rule out thyroid or copper metabolism problems

6. FP-CIT SPECT (also known as DATscan), a brain imaging technique using a radioactive iodine isotope, is a diagnostic test that can distinguish between essential tremor and tremors of Parkinson’s disease.

TYPES OF TREMOR5

Rest tremor found in Parkinson’s disease

• Tremor which occurs when the muscles are not being voluntarily moved
• Usually when the limb is moved, the tremor will weaken or disappear
• Like all tremors, it will get worse when stressed or anxious
• Rest tremor is quite separate from other tremors.

Tremors often found in Essential Tremor

• Action or kinetic tremor – tremor which occurs when the limb or body part is being moved.
• Postural tremor – found when maintaining a position, such as outstretching the hands.
• Intention tremor – tremor that becomes worse when the limb is guided to move towards an object (e.g. the patient’s finger towards the doctor’s finger).
• Task specific tremor – a tremor that occurs only with specific tasks or activities, e.g. writing.
• Idiopathic or dystonic tremor – this can affect multiple body parts. Most commonly affected are hands, head and occasionally the voice.

GENETICS AND ESSENTIAL TREMOR

In ET, when a single person has been affected, there is a wide range in the estimates of the risk to other family members. Generally people who have onset of essential tremor at an early age often have a family history of others affected with the same condition, whereas those who develop essential tremor later in life are less likely to have a familial disease.⁶

We know that in studies of twins with essential tremor, about 60% of identical twins will have both twins affected with tremor, as opposed to about 30% of non-identical twins.⁷ Although a lot of progress has been made in identifying potential genetic areas which might harbor genes that cause essential tremor, very little progress has been made in identifying the specific genes.

MEDICAL TREATMENT

The currently available medical treatments for essential tremor are symptomatic and not curative. This means that the severity of essential tremor can be decreased by medication but that the tremor will not be cured. There is no medication that will permanently remove essential tremor from a person who is affected by it. (Personal communication: Dr Huw Morris, National Tremor Foundation AGM [2009])

Initial treatment

Initially many patients prefer to receive treatment for essential tremor intermittently rather than regularly.

The occasional use of alcohol, propranalol, primidone or benzodiazepines (clonazepam) for high stress situations, such as social events or work engagements, is common.

Continuous treatment

There are a number of option available for continuous treatment, including:⁸

• Propranolol – beta blockers and propanalol in particular, are effective in reducing the tremor in ET but no one is sure how. There are a small number of adrenergic receptors neurons in the brain itself, so the effects of propanalol could be either through the autonomic nervous system or directly in the brain, or both. Beta blockers (and particularly the non-selective propranolol) are contraindicated in a number of conditions, including asthma and peripheral vascular disease, so are not suitable for all patients with ET.
• Primidone is a barbiturate precurser. Primidone was first used as an anti-epileptic drug and found to be effective with tremors. However, about 20% patients react badly to their first dose, particularly with nausea and vomiting. However, some patients respond very well and the beneficial effects in those patients appear to be long lasting.
• Topiramate is widely used as an anti- epileptic drug. An important side effect is that it can effect the eye, causing acute myopia with secondary glaucoma.
• Gabapentin is usually reasonably well tolerated, however its effectiveness in ET is still at the probable rather than the proven efficacy stage and better clinical trials are required.
• Benzodiazepines have evidence to support their use for treating ET. They are anti-anxiety agents and muscle relaxants. Their prolonged use risks addiction and severe withdrawal symptoms if treatment is suddenly stopped.
• Botulinum toxin treatment is sometimes considered for head or voice tremor.

Alcohol

Alcohol will temporarily improve the tremor in 50% of people.⁵ Typically 2 units of alcohol (roughly one pint or one small glass of wine) will suppress essential tremor for about 4 hours. However, there is often a rebound that worsens the tremor the next morning.

BRAIN SURGERY – DEEP BRAIN STIMULATION

Surgical intervention has been used in ET for over 50 years, and is used for those patients who have particularly severe/disabling tremor that does not respond to medication.

About 50% of severely affected ET patients have medication-resistant symptoms or are intolerant of medication and brain surgery is an option. In order to alleviate tremor in a patient’s right arm, surgery is performed on the left side of the brain and vice versa for the left arm. Consequently, in order to relieve tremor in both arms, surgery is required on both sides of the brain.⁹

Risks

The main risks of this type of surgery, when performed in a neurosurgical centre by a specialist functional neurosurgeon, are:

• 1/1000 risk of death
• 3% risk of a bleed within the skull
• 1% risk of a stroke.

Success of surgery

• Long-term studies have shown that tremor control can be maintained for up to six years after deep brain stimulation.
• The effects of deep brain stimulation on the patient’s thought processes, mood state and quality of life after up to 6 years are mainly positive.

ROLE OF THE PRIMARY CARE NURSE

I have been unable to find published papers about the role of the nurse in ET, but obviously the nurse can and should have a major role if he or she looks out for it. ET can start at any age but it is more common in the older age group. If a patient comes to see you for any treatment you see that their hands, voice or head shakes, perhaps ask them if they have ever been treated for their symptoms. Do their symptoms interfere with their quality of life? Are there things they used to be able to do, but now find difficult or impossible because of their tremor? Many of these patients will avoid the social situations that they used to enjoy because of the embarrassment of their tremor. We human beings are very quick to put deterioration down to ageing without realising that we can live a full and active life whatever our age.

If the patient is referred for accurate diagnosis, treatment and management, with appropriate intervention, tremor (if the diagnosis is ET) can be reduced to a manageable level, and this can improve the patient’s life considerably.

REFERENCES

1. Bain PG. Tremor assessment and quality of life measurements. Neurology 2000;54:S26-S29

2. Bain PG, Findley LJ, Atchison P, et al Assessing tremor severity. J Neurol Neurosurg Psychiatry 1993;56:868-873

3. Chatterjee A, Juewicz EC, Applegate LM et al. Personality in essential tremor: further evidence of non-motor manifestations of the disease. J Neurol Neurosurg Psychiatry 2004;75:958-961

4. Plumb M, Bain PG. Essential tremor, the facts. Oxford University Press; 2007

5. Pahwa R, Lyons KE Essential tremor: differential diagnosis and current therapy. Am J Med 2003;115:134-142

6. Bain PG, Findley LJ, Thompson PD, et al. A study of hereditary essential tremor. Brain 1994; 117:805-824

7. Tanner CM, Goldman SM, Lyons KE et al Essential Tremor in Twins - an assessment of genetic vs environmental determinants of etiology. Neurology 2001 57, 1389-1391

8. Bain PG The effectiveness of treatment for essential tremor. Neurologist 1997 3, 305-321

9. Benabid AL, Benazzous A, Pollak P. Mechanisms of deep brain stimulation. Movement Disorders 2002: 17:S73-S74