Essential tremor is a nervous system (neurological) disorder that causes involuntary and rhythmic tremors. It can affect almost any part of the body, but tremors most often occur in the hands. You can find more information below.
What is essential tremor?
Essential tremor is a progressive, neurological disease characterized by tremors mostly in the hands or arms. Tremor is an involuntary, rhythmic movement of a body part. Tremor can be seen as involuntary movement of the affected area. Individuals with essential tremor may experience other motor symptoms, including an unsteady gait due to an inability to coordinate voluntary movements. In some cases, affected individuals may also develop a variety of non-motor symptoms, including cognitive impairment, depression or anxiety.
Essential tremor can also occur in childhood or adulthood. The exact, underlying cause of essential tremor is not fully understood. In some cases, the disorder runs in families, while in some individuals it can be seen without a genetic predisposition. Therefore, the causes of essential tremor are most likely multiple.
About essential tremor
Previously, essential tremor was viewed as a relatively benign disease characterized by tremor as a symptom. However, essential tremor can be associated with a variety of psychosocial problems and potentially significantly impair daily activities and social interactions. As a result, the term benign is no longer accepted.
Additionally, the researchers determined that additional motor and non-motor symptoms may be associated with the disorder. Some researchers now believe that essential tremor may actually represent a similar but distinct group of diseases that share the common feature of kinetic tremor.
What causes essential tremor?
In some affected individuals, it occurs spontaneously for unknown reasons (sporadically) and has no family history of the disease. However, in many cases, the disorder runs in families genetically. First-degree relatives of an individual with essential tremor are more likely to develop a tremor than the general population. The exact percentage of familial cases is not known, estimates range from 17% to more than 50% of cases.
In familial cases, essential tremor has traditionally been inherited as an autosomal dominant trait, although other modes of inheritance are increasingly being considered. Dominant genetic disorders occur when only a single copy of an abnormal gene is required for the disease to occur. The abnormal gene may be inherited from both parents or may be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene to the children of the affected parent is 50 percent for each pregnancy, regardless of the sex of the resulting child.
The exact underlying cause of essential tremor is not fully understood, but recent research suggests it may be a neurodegenerative disorder. Controlled postmortem studies have shown several degenerative changes in the cerebellum that affect the Purkinje cell population, and some patients also have other degenerative changes. Additional studies are required and further research is needed to identify the complex, underlying mechanisms that cause essential tremor.
What are the symptoms of essential tremor?
Essential tremor is a highly variable disease. The age of onset, progression, tremor distribution and severity can vary from person to person. The characteristic symptom of essential tremor is the condition that often presents as involuntary shaking or trembling of the hands or arms. In some cases, tremors of the hands or arms occur as an isolated finding. Usually, both hands or arms are affected, but one side of the body is usually more affected than the other. Tremors can also affect the head, voice, jaw, or tongue.
In many cases, the tremor that affects the hands or arms can progress slowly to affect other areas, mostly the head. Although generally progressive, the rate of progression is slow on average. Recent studies have shown that the average rate of progression of arm tremor severity is about 1.5 to 5% per year.
A tremor can be fast or slow, dramatically rapid, or almost imperceptibly slow. In individuals with essential tremor, the tremor usually worsens gradually with increasing age. The tremor is often exacerbated by movement. It can also be exacerbated by stress, fever, fatigue, high emotional state, low blood sugar and caffeine.
Doing certain daily activities can also trigger tremors. In most cases, tremors occur when individuals try to make voluntary movements. Such movements may include simple tasks such as drinking from a glass, using kitchen utensils, tying shoelaces, drawing or writing.
Postural tremors are also common in individuals with essential tremor. Postural tremor is the tremor of the arms outstretched in front of the body while the individual is trying to hold a fixed position against gravity, for example while holding a newspaper.
Some individuals with essential tremor have an “internal tremor”, which is described as a general tremor in the body. These tremors cannot be seen by other people.
In advanced cases, a resting tremor may occur. Resting tremors occur when the body relaxes and rests the arm against gravity, such as when sitting in a chair.
Some affected individuals may also have trouble coordinating voluntary movements that affect their leg muscles. This can cause an uncoordinated or clumsy gait (abnormal gait).
In recent years, researchers have determined that individuals with essential tremor develop non-motor symptoms more frequently than individuals in the general population. These symptoms include cognitive disorders, personality changes, and depression. Hearing impairment and an altered sense of smell (mild smell disorder) have been reported in some studies. Cognitive dysfunction is more likely to occur in individuals with a higher age of onset of the disorder.
Essential tremor is often associated with a variety of social and psychological consequences. The disorder can cause difficulties in normal daily activities and potentially significantly affect an individual’s quality of life. Affected individuals may avoid social or stressful situations due to anxiety and frustration.
Recent epidemiological studies suggest that individuals with essential tremor have a slightly increased risk of developing dementia (especially Alzheimer’s disease) compared to their normal peers. Similar studies show that people with essential tremor have a more than four-fold increased risk of developing Parkinson’s disease .
How is essential tremor diagnosed?
Diagnosing essential tremor includes reviewing the medical history, family health history and symptoms, and performing a physical exam. There is no medical test to diagnose essential tremor. Diagnosing it is usually possible by ruling out other conditions that may be causing the symptoms. To do this, the following tests may be recommended:
In a neurological exam, the doctor tests the functioning of the nervous system, including checking:
- Tendon reflexes
- muscle strength and tone
- Ability to feel certain sensations
- Posture and coordination
Blood and urine can be tested for a variety of factors, including:
- Thyroid diseases
- metabolic problems
- drug side effects
- Hormone levels that can cause tremors
To evaluate the tremor itself, the doctor may order:
- holding a glass of water
- stretch your arms
- to write
- drawing a spiral
If the doctor is still unsure whether essential tremor or Parkinson’s disease is the cause of the tremor, they may order a Parkinson’s scan. This scan can help the doctor tell the difference between the two types of tremors.
How is essential tremor treated?
Some people with essential tremor do not need treatment if their symptoms are mild. However, if the tremor makes it difficult to perform daily activities, the patient should discuss treatment options with their doctor.
- Beta blockers: Normally used to treat high blood pressure , beta blockers like propranolol help relieve tremors in some people. Beta blockers may not be preferred if the patient has asthma or certain heart problems. Side effects may include fatigue, dizziness, or heart problems.
- Anti-seizure medications: Epilepsy medications such as primidone may be effective in people who do not respond to beta-blockers. Other medications that may be prescribed include gabapentin and topiramate. Side effects include drowsiness and nausea, which usually go away in a short time.
- Tranquilizers: Doctors may use benzodiazepine medications such as clonazepam to treat tension and anxiety that worsen tremors. Side effects may include feeling tired or mildly sedated. These drugs should be used with caution because they can be habit-forming.
- Botox injections: Botox injections can be helpful 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 the fingers. If Botox is used to treat tremors, it can cause hoarseness and difficulty swallowing.
Remember, your doctor will decide which medicine to take and how.
Doctors may recommend physical or occupational therapy. Physiotherapists can teach the patient exercises to improve muscle strength, control and coordination. Occupational therapists can help adjust to life. Therapists may also recommend some devices to reduce the effect of tremors on daily activities.
If the tremor is severe and does not respond to medications, surgery may be an option.
- Deep brain stimulation: This is the most common type of surgery for essential tremor. This surgery is often the procedure of choice in medical centers with significant experience. Doctors insert a long, thin electrical probe into the part of the brain that causes the tremor (thalamus). A wire from the probe flows into a pacemaker-like device (neurostimulator) that is placed in the chest under the skin. This device delivers painless electrical pulses to interrupt signals from the thalamus that can cause tremors.
- Focused ultrasound thalamotomy: This noninvasive surgery involves the use of focused sound waves that travel through the skin and skull. The waves generate heat to destroy brain tissue in a specific area of the thalamus to stop a tremor. A surgeon uses magnetic resonance imaging to target the correct area of the brain and make sure the sound waves produce the exact amount of heat needed for the procedure .