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essential tremor

What is essential tremor

Essential tremor also known as benign essential tremor, is a movement disorder that causes involuntary, rhythmic shaking (tremor), especially in the hands. Essential tremor is distinguished from tremor that results from other disorders or known causes, such as Parkinson’s disease or head trauma. Essential tremor is a nervous system (neurological) disorder that causes involuntary and rhythmic shaking. Essential tremor can affect almost any part of your body, but the trembling occurs most often in your hands — especially when you do simple tasks, such as drinking from a glass or tying shoelaces.

Essential tremor is a common disorder. Essential tremor is the most common neurological cause of postural or action tremor, affecting up to 10 million people in the United States. Estimates of its prevalence vary widely (estimated prevalence of up to 10% of the population in the US) because several other disorders, as well as other factors such as certain medications, can result in similar tremors. In addition, mild cases are often not brought to medical attention, or may not be detected in clinical exams that do not include the particular circumstances in which an individual’s tremor occurs. Severe cases are often misdiagnosed as Parkinson disease.

Essential tremor may appear at any age but is most common in people age 40 and older with an average age of onset of 35-45 years old. If a person were to have essential tremor, the disease would be prominent by 65 years of age, and virtually almost always present by 70 years old. Some studies have suggested that people with essential tremor have a higher than average risk of developing neurological conditions including Parkinson disease or sensory problems such as hearing loss, especially in individuals whose tremor appears after age 65.

Essential tremor affects both sexes equally. However, the site of involvement of the tremor is different depending on different gender. Head tremor may be more frequent in women while postural hand tremor is more frequent in men.

Sometimes essential tremor can be a familial disorder, in which a strong family history is seen. It is then called familial essential tremor or familial tremor.

Essential tremor can be passed through generations in families, but the inheritance pattern varies. In most affected families, essential tremor appears to be inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder, although no genes that cause essential tremor have been identified. In other families, the inheritance pattern is unclear. Essential tremor may also appear in people with no history of the disorder in their family.

In some families, some individuals have essential tremor while others have other movement disorders, such as involuntary muscle tensing (dystonia). The potential genetic connection between essential tremor and other movement disorders is an active area of research.

Essential tremor usually occurs alone, without other neurological signs or symptoms. However, some experts think that essential tremor can include additional features, such as mild balance problems.

Essential tremor usually occurs with movements and can occur during many different types of activities, such as eating, drinking, or writing. Essential tremor can also occur when the muscles are opposing gravity, such as when the hands are extended. It is usually not evident at rest.

In addition to the hands and arms, muscles of the trunk, face, head, and neck may also exhibit tremor in essential tremor; the legs and feet are less often involved. Head tremor may appear as a “yes-yes” or “no-no” movement while the affected individual is seated or standing. In some people with essential tremor, the tremor may affect the voice (vocal tremor).

The exact mechanism of essential tremor is unknown. It is thought that certain pathways in the brain are affected where the control of fine movement occurs. However, no pathology has been identified with essential tremor.

Essential tremor does not shorten the lifespan, but essential tremor typically worsens over time and can be severe in some people. However, essential tremor may interfere with fine motor skills such as using eating utensils, writing, shaving, or applying makeup, and in some cases these and other activities of daily living can be greatly impaired. Symptoms of essential tremor may be aggravated by emotional stress, anxiety, fatigue, hunger, caffeine, cigarette smoking, or temperature extremes.

Are there different kinds of tremor?

Yes, many things can cause tremor. Not all tremors are essential tremors. For example, Parkinson’s disease causes tremor that you might notice when your hands are resting in your lap or at the sides of your body. A stroke can cause tremor that gets worse when you reach for something. Thyroid problems or low blood sugar can cause mild tremor. Tremor can be caused by some medicines. These include heart medicines, decongestants, medicines for breathing problems, and tricyclic antidepressants. Drinks that contain caffeine also may cause a tremor.

Essential tremor is just one kind of tremor. Other things that can cause a tremor (non essential tremor) include:

  • Parkinson’s disease
  • Multiple sclerosis (MS)
  • Fatigue after exercise
  • Extreme emotional stress, brain tumors
  • Some prescription medicines
  • Alcohol or drug withdrawal.

Essential tremor prognosis

Essential tremor is not a life-threatening condition. Although there is no associated death rate, it can cause significant inconvenience to the patients. This is due to the social and functional embarrassment that usually occur in activities of daily living. As much as 85% of the patients with essential tremor reported that this disease affected their lifestyle in certain ways.

Quality of life can be significantly impaired with essential tremor. This include employment, normal outing activities such as dining out, attending parties, shopping alone, etc.

Essential tremor complications

Essential tremor isn’t life-threatening, but symptoms often worsen over time. If the tremors become severe, you might find it difficult to:

  • Hold a cup or glass without spilling
  • Eat normally
  • Put on makeup or shave
  • Talk, if your voice box or tongue is affected
  • Write legibly

Essential tremor vs Parkinson’s disease

Many people associate essential tremor with Parkinson’s disease, but the two conditions differ in key ways:

  • Timing of tremors. Essential tremor of the hands usually occurs when you use your hands. Tremors from Parkinson’s disease are most prominent when your hands are at your sides or resting in your lap.
  • Associated conditions. Essential tremor doesn’t cause other health problems, but Parkinson’s disease is associated with stooped posture, slow movement and shuffling gait. However, people with essential tremor sometimes develop other neurological signs and symptoms, such as an unsteady gait (ataxia).
  • Parts of body affected. Essential tremor mainly involves your hands, head and voice. Parkinson’s disease tremors usually start in your hands, and can affect your legs, chin and other parts of your body.

The characteristics listed in the table below can help differentiate between Parkinson’s disease and essential tremor, but a medical professional should be consulted for proper diagnosis.

Many differences exist between essential tremor and Parkinson’s disease with, the essential tremor being at least eight times more common than Parkinson’s disease. Up to 20% of patients with essential tremor may develop Parkinson’s disease, and 10% report a family history of Parkinson’s disease. However, whether
essential tremor is a risk factor for Parkinson’s disease remains an unresolved and somewhat controversial issue 1.

Table 1. How Essential tremor differ from Parkinson’s disease

Parkinson’s disease tremor signs and symptoms

Essential tremor signs and symptoms

High amplitude. Lower, slower frequency.Low amplitude. Amplitude is more variable, ranging from barely perceptible tremor to a high amplitude tremor. Higher, faster frequency.
Mostly seen at rest.Mostly seen during action.
Generally involves slow movements (bradykinesia), rigidity (stiffness), and problems with walking or balance.Tremor is primary symptom – slowness, stiffness, walking and balance problems are not commonly seen.
Rarely a family history (<10%).Family history of tremor reported in the majority of patients (>50%).
Resting and postural (re-emergent); postural tremor observable after mean latency of 5 seconds; rarely kinetic.Postural, kinetic; postural tremor immediately observable; resting tremor less common.
Onset generally at ages between 55-65.Onset most common in middle age but can occur at any time in the lifespan.
Usually starts on one side of the body and progresses to the other side; usually remains asymmetrical.Usually affects both sides of the body initially (bilateral; symmetrical).
No effect from consumption of alcohol.Alcohol often improves tremor.
Usually improves with levodopa treatment.Improves with primidone and propranolol in some cases.
Hands affected more than legs, voice and head almost never affected.Hands predominantly affected, but tremor also present in the head and voice; rarely in the legs.
Worsens with emotional stress.Worsens with emotional stress.

As essential tremor progresses, tremor frequency (number of repetitions per second) may decrease; however, tremor amplitude (magnitude/strength) may increase. Increased amplitude is associated with a decreased ability to manage fine, discrete motor tasks.

In those with Parkinson’s disease the most disabling symptoms are generally slowness, stiffness and problems with walking and balance, although tremor can also cause some disability. In Parkinson’s disease, writing often becomes very small (micrographia) and therefore difficult to read.

The severity of essential tremor and level of disability can vary greatly among patients. Some patients have a very mild tremor and therefore minimal to no disability. Others who have a severe tremor often cannot perform the majority of their daily activities and require help.

The writing of a person with essential tremor tends to be large and tremulous rather than slow and small as in Parkinson’s disease.

Anxiety can increase both essential tremor and Parkinson’s disease.

In addition to medications and botulinum toxin, deep brain stimulation is a therapeutic option for those with severe disabling essential tremor or Parkinson’s disease.

Essential tremor is often associated with a strong family history (known as familial tremor), but no specific essential tremor-related gene has been identified.

Essential tremor causes

The causes of essential tremor are unknown. About half of essential tremor cases appear to result from a genetic mutation, although a specific gene hasn’t been identified. This form is referred to as familial tremor. It isn’t clear what causes essential tremor in people without a known genetic mutation.

Researchers are studying several areas (loci) on particular chromosomes that may be linked to essential tremor, but no specific genetic associations have been confirmed. Several genes as well as environmental factors likely help determine an individual’s risk of developing this complex condition. The specific changes in the nervous system that account for the signs and symptoms of essential tremor are unknown.

Figure 1. Familial tremor autosomal dominant inheritance pattern

Familial tremor autosomal dominant inheritance pattern

Risk factors for essential tremor

Known risk factors for essential tremor include:

  • Genetic mutation. The inherited variety of essential tremor (familial tremor) is an autosomal dominant disorder. A defective gene from just one parent is needed to pass on the condition. If you have a parent with a genetic mutation for essential tremor, you have a 50 percent chance of developing the disorder yourself.
  • Age. Essential tremor is more common in people age 40 and older.

Essential tremor prevention

Doctors don’t know exactly what causes essential tremor, so it can’t be prevented. If your doctor determines you tremor is caused by medicine or caffeine, you may be able to avoid essential tremor in the future by avoiding those substances.

Essential tremor symptoms

Essential tremor signs and symptoms:

  • Begin gradually, usually on one side of the body
  • Worsen with movement
  • Usually occur in the hands first, affecting one hand or both hands
  • Can include a “yes-yes” or “no-no” motion of the head
  • Quivering voice
  • Tremors worsen with purposeful movement
  • Rest helping to relieve tremors.
  • Tremors may be aggravated by emotional stress, fatigue, caffeine or temperature extremes

Often, tremors are the only symptom you have when you have essential tremor. Other conditions that cause tremors come with other symptoms.

Essential tremor diagnosis

Diagnosing essential tremor involves reviewing your medical history, family history and symptoms and conducting a physical examination.

There are no medical tests to diagnose essential tremor. Diagnosing it is often a matter of ruling out other conditions that could be causing your symptoms. To do this, your doctor may suggest the following tests:

Neurological examination

In a neurological examination, your doctor surveys your nervous system functioning, including checking your:

  • Tendon reflexes
  • Muscle strength and tone
  • Ability to feel certain sensations
  • Posture and coordination
  • Gait

Laboratory tests

Your blood and urine may be tested for several factors, including:

  • Thyroid disease
  • Metabolic problems
  • Drug side effects
  • Alcohol levels
  • Levels of chemicals that may cause tremor

Performance tests

To evaluate the tremor itself, your doctor may ask you to:

  • Drink from a glass
  • Hold your arms outstretched
  • Write
  • Draw a spiral

If your doctor is still unsure if your tremor is essential tremor or Parkinson’s disease, he or she might order a dopamine transporter scan (DaTscan). This can tell the difference between the two types of tremor. A special picture or scan of the brain that measures the uptake of dopamine, such as DaTscan, can help to differentiate between essential tremor and Parkinson’s disease tremor. Dopamine is depleted in patients with Parkinson’s disease but not in patients with essential tremor; therefore, scans showing depletion in dopamine are most likely Parkinson’s disease and normal scans would suggest a more likely diagnosis of essential tremor. These scans are used as a tool to help the physician make an accurate diagnosis in difficult cases.

Essential tremor treatment

Some people with essential tremor don’t require treatment if their symptoms are mild. But if your essential tremor is making it difficult to work or perform daily activities, discuss treatment options with your doctor.

Essential tremor medications

  • Beta blockers. Normally used to treat high blood pressure, beta blockers such as propranolol (Inderal) help relieve tremors in some people. This is the most common medication used for treatment of essential tremor. Multiple studies have shown that propanolol improves the symptoms ranging from 50-70% of the patients. However, no long term study has been conducted regarding the effect of propanolol in essential tremor. Other beta-blockers include atenolol, metoprolol, sotalol and nadolol. Beta blockers may not be an option if you have asthma or certain heart problems. Side effects may include fatigue, lightheadedness or heart problems.
  • Anti-seizure medications. Epilepsy drugs, such as primidone (Mysoline), may be effective in people who don’t respond to beta blockers. The exact mechanism is unknown. Other medications that might be prescribed include gabapentin (Gralise, Neurontin) and topiramate (Topamax, Qudexy XR). However most of these anticonvulsants are not well studied – only small and short trials have been done to evaluate their effectiveness. Side effects include drowsiness and nausea, which usually disappear within a short time.
  • Tranquilizers. Doctors may use drugs such as alprazolam (Xanax) and clonazepam (Klonopin) to treat people for whom tension or anxiety worsens tremors. Side effects can include fatigue or mild sedation. These medications should be used with caution because they can be habit-forming.
  • OnabotulinumtoxinA (Botox) injections. Botox injections might be useful in treating some types of tremors, especially head and voice tremors. Botox injections can improve tremors for up to three months at a time. However, if Botox is used to treat hand tremors, it can cause weakness in your fingers. If it’s used to treat voice tremors, it can cause a hoarse voice and difficulty swallowing.

Essential tremor natural remedies

Lifestyle changes are often recommended to prevent the tremor from getting worse. Your doctor will ask you to avoid caffeine, cold medicines and certain other medicines if they seem to make your tremor worse. These medicines won’t make your tremor go away. However, the medicine may control the tremor enough to allow you to do normal activities without frustration or embarrassment.

To reduce or relieve tremors:

  • Avoid caffeine. Caffeine and other stimulants can increase tremors.
  • Use alcohol sparingly, if at all. Some people notice that their tremors improve slightly after they drink alcohol, but drinking isn’t a good solution. Tremors tend to worsen once the effects of alcohol wear off. Also, increasing amounts of alcohol eventually are needed to relieve tremors, which can lead to alcoholism.
  • Learn to relax. Stress and anxiety tend to make tremors worse, and being relaxed may improve tremors. Although you can’t eliminate all stress from your life, you can change how you react to stressful situations using a range of relaxation techniques, such as massage or meditation.
  • Make lifestyle changes. Use the hand less affected by tremor more often. Find ways to avoid writing with the hand affected by tremor, such as using online banking and debit cards instead of writing checks. Try voice-activated dialing on your cellphone and speech-recognition software on your computer.

Physical therapy

Doctors might suggest physical or occupational therapy. Physical therapists can teach you exercises to improve your muscle strength, control and coordination.

Occupational therapists can help you adapt to living with essential tremor. Therapists might suggest adaptive devices to reduce the effect of tremors on your daily activities, including:

  • Heavier glasses and utensils
  • Wrist weights
  • Wider, heavier writing tools, such as wide-grip pens

Surgery

Deep brain stimulation might be an option if your tremors are severely disabling and you don’t respond to medications. The surgical procedures are stereotactic thalamotomy or thalamic deep brain stimulation. Excellent results have been reported from these surgeries.

In deep brain stimulation, doctors insert a long, thin electrical probe into the portion of your brain that causes your tremors (thalamus). A wire from the probe runs under your skin to a pacemaker-like device (neurostimulator) implanted in your chest. This device transmits painless electrical pulses to interrupt signals from your thalamus that may be causing your tremors.

Figure 2. Deep brain stimulation

deep brain stimulation

Side effects of surgery can include equipment malfunction; problems with motor control, speech or balance; headaches; and weakness. Side effects often go away after some time or adjustment of the device.

Coping and support

For many people, essential tremor can have serious social and psychological consequences. If the effects of essential tremor make it difficult to live your life as fully as you once did, consider joining a support group like International Essential Tremor Foundation (https://www.essentialtremor.org/).

Support groups aren’t for everyone, but you might find it helpful to have the encouragement of people who understand what you’re going through. Or see a counselor or social worker who can help you meet the challenges of living with essential tremor.

References
  1. Fekete R, Jankovic J. Revisiting the relationship between essential tremor and Parkinson’s disease. Mov Disord 2011;26:391-8
Health Jade Team

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