Identifying and Managing Essential Tremor

Many people worry when they have a tremor that it may be a sign of Parkinson's disease (PD). However, there is another more common cause of tremor known as essential tremor (ET), and it doesn't have the serious implications of PD. In fact, ET is eight times as common as PD, and, unlike PD, does not cause worsening unsteadiness, rigidity, or dementia.

Although it might be a relief to hear that your tremor isn't caused by PD, it doesn't necessarily make the tremor less annoying. For some people, essential tremor comes and goes and hardly bothers them. For others, essential tremor is so bad that tying shoes or eating with utensils is nearly impossible.

Recognizing Essential Tremor

Unlike a Parkinsonian tremor, essential tremor is usually (but not always) bilateral—that is, it affects both sides at once. The hands and arms tend to be the most involved part of the body, although the head, face/jaw, tongue, voice, trunk, and lower limbs can also be involved. Another distinction from PD is that the tremor tends to be worse when the hands are being actively used (action tremor) instead of when they're at rest (resting tremor).

Other clues include a family history of tremor. Essential tremor is often inherited in an autosomal dominant fashion, meaning that if you have it, there's a good chance at least one of your parents did too. Another interesting hallmark of essential tremor is that it frequently improves after drinking a modest amount of alcohol.

How Common Is Essential Tremor?

About 10 million Americans have essential tremor, comprising about 3% of all people in the United States. Like many health changes, essential tremor tends to increase as we get older. The tremor increases in amplitude, becoming larger and more noticeable with time. It may also spread to other body regions.

Causes

The parts of the brain responsible for coordinating movement are something like different sections of an orchestra. Every section has its own rhythm, which is usually in synchrony with the other parts. Essential tremor involves the cerebellum, the thalamus, the frontal and parietal cortex, and the olivary nucleus of the brain stem, all of which work together in the planning, coordination, and rhythm of movement.

Despite there being a frequent family history of tremor in people with ET, no single gene has been clearly identified. Some people have suggested that some neurotoxic environmental factors, like β-Carboline alkaloids (e.g. harmane) found in well-cooked meat, might be involved. In addition, there is a possitive correlation of essential tremor with exposure to lead and agricultural chemicals, while there is no association found with pesticides or organic solvents.

What Makes It Worse?

In addition to getting older, essential tremor can be worsened by things that we might experience every day. Fatigue, changes in temperature, emotional stresses, and even normal changes in how sleepy you are can change the severity of the tremor.

There are also a wide number of different drugs that worsen tremor, such as those that act on the central nervous system, including certain antidepressants, antiepileptics, and alcohol abuse/withdrawal, as well as stimulants like bronchodilators, caffeine, Ritalin, or cocaine. Steroids can worsen tremor, as can thyroid hormones and antiemetic/prokinetic agents such as Reglan. In fact, there are so many different medications that can worsen tremor, it's probably best to just pay close attention to the timing of your tremor, and become familiar with the side effects of any medication that you're taking.

How Can the Neurologist Be Sure It Isn't Parkinson's Disease?

Usually, just talking to you and looking at your tremor will be enough for a neurologist to diagnose essential tremor. Sometimes it takes time to be sure. Essential tremor tends to change more slowly than PD.

In confusing cases, a test called a DaTscan can be done to look at the substantia nigra, which are parts of the brain that are worn down in PD. This scan uses a radioisotope to look at the activity of basal ganglia. In essential tremor, the scan will be normal.

Treatment

There are many different ways to manage essential tremor. Depending on how severe the tremor is, the best option may be no medical therapy at all. Since every treatment comes with some risk of side effects, if the tremor isn't particularly bothersome, then there's no need to be aggressive with medications or other therapies.

However, if the tremor is getting in the way of day-to-day living, then medications, such as propranolol or primidone, may be helpful. If these don't work, other medications may be tried, including Botox injections for head or voice tremor. In the most severe cases, surgical options, such as thalamic deep brain stimulation, may be considered.

While essential tremor can be a nuisance, it is not life-threatening. If the symptoms are preventing you from doing things that you want or need to do, however, you should speak with a qualified physician about the best way to manage your symptoms.