Essential tremor is a nervous system (neurological) disorder that causes involuntary and rhythmic shaking. It 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 usually not a dangerous condition, but it typically worsens over time and can be severe in some people. Other conditions don't cause essential tremor, although essential tremor is sometimes confused with Parkinson's disease.

Essential tremor can occur at any age but is most common in people age 40 and older.

Essential tremor signs and symptoms:

• Begin gradually, usually more prominently 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
• May be aggravated by emotional stress, fatigue, caffeine or temperature extremes

Essential tremor vs. Parkinson's disease

Many people associate tremors 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.

About half of essential tremor cases appear to result from a genetic mutation. This form is referred to as familial tremor. It isn't clear what causes essential tremor in people without a known genetic mutation.

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 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

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 tests 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
• 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. This scan can help your doctor tell the difference between the two types of tremor.

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.

Medications

• Beta blockers. Normally used to treat high blood pressure, beta blockers such as propranolol (Inderal) help relieve tremors in some people. 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. Other medications that might be prescribed include gabapentin (Gralise, Neurontin) and topiramate (Topamax, Qudexy XR). Side effects include drowsiness and nausea, which usually disappear within a short time.
• Tranquilizers. Doctors may use benzodiazepine drugs such as 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 Botox is used to treat voice tremors, it can cause a hoarse voice and difficulty swallowing.

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

Surgery might be an option if your tremors are severely disabling and you don't respond to medications.

• Deep brain stimulation. This is the most common type of surgery for essential tremor. It's generally the preferred procedure in medical centers with significant experience in performing this surgery. 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.

  Side effects of deep brain stimulation 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.

• Focused ultrasound thalamotomy. This noninvasive surgery involves using 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 to be sure the sound waves are generating the exact amount of heat needed for the procedure.

  Focused ultrasound thalamotomy creates a lesion that can result in permanent changes to brain function. Some people have experienced altered sensation, trouble with walking or difficulty with movement. However, most complications go away on their own or are mild enough that they don't interfere with quality of life.

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 commands on your smartphone and speech-recognition software on your computer.

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.

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.

You'll likely start by seeing your primary care provider. Or you might be referred immediately to a doctor trained in brain and nervous system conditions (neurologist).

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fasting before having a specific test. Make a list of:

• Your symptoms, including any that seem unrelated to the reason for your appointment
• Key personal information, including major stresses, recent life changes and family medical history
• All medications, vitamins or other supplements you take, including the doses
• Questions to ask your doctor

Take a family member or friend along, if possible, to help you remember the information you're given.

For essential tremor, some questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• Are there other possible causes?
• What tests do I need?
• How does essential tremor usually progress?
• What treatments are available, and which do you recommend?
• I have other health conditions. How can I best manage these conditions together?
• Are there restrictions I need to follow?
• Should I see a specialist? If so, whom do you recommend?
• Are there brochures or other printed materials I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

• When did your symptoms begin?
• Do you have a family history of tremor?
• Have you ever had a head injury?
• What parts of your body are affected?
• Does anything make your tremors better or worse?