Your physician has confirmed it: You haven’t been imagining those shaking movements. They are actually a condition called “essential tremor.” Despite being the most common movement disorder, essential tremor is not very well-known by the general population. Essential tremor is a neurological condition causing involuntary shaking, meaning it starts and stops without your control. If you have just been diagnosed with essential tremor, there is reason not to lose hope: These tremors are not dangerous. And you are not alone.
However, that doesn’t mean they aren’t bothersome. So, what exactly causes essential tremor, and what can you do about it?
Questions and Answers with Dr. Deik
Andres F. Deik, MD, Assistant Professor of Clinical Neurology at Penn Medicine, explains what you need to know about essential tremor.
Q: What causes essential tremor? Can they be due to environmental toxins?
Dr. Deik: We don’t know the exact cause, but toxins don’t seem to play a part in developing essential tremor.
Q: What about a family connection?
Dr. Deik: Essential tremor does tend to run in families. That doesn’t mean that everyone in the family will definitely have it. But, they certainly can.
It also tends not to skip generations. If you have this type of tremor, chances are that one or more of your first-degree family members do, too.
Because it is a familial condition, we suspect essential tremor is a genetic disease. Unfortunately, a single genetic cause for all cases has not been identified.
Q: Why is it so difficult to discover the gene?
Dr. Deik: There are a few reasons. One is that it is likely that more than one gene can cause the tremor. It’s always easier to study a disease when there’s only a single gene that causes it. When there are multiple genes involved, the genes are much harder to find.
The other reason is that essential tremor is hard to study because the tremor may actually be due to something else. Misdiagnosis is not uncommon.
Q: What are some of the most common misdiagnoses?
Dr. Deik: A tremor can be a side effect of certain medications, so a neurologist needs to do a very thorough review of other medications before making a diagnosis. The tremor could also be due to another condition, like hyperthyroidism
Sometimes, a tremor is misdiagnosed as “essential,” when it’s actually an entirely different type of tremor. For example, the shaking could just be due to someone drinking too much caffeine. In other cases, someone may be diagnosed with essential tremor when they’re actually in the early stages of Parkinson's.
Q: What’s the difference between essential tremor, and the tremor caused by Parkinson’s?
Dr. Deik: Essential tremor features what we call an “action tremor.” Action tremors happen when someone does a certain activity, like moving their arm.
In Parkinson’s, the tremors are “at rest.” With an “at-rest tremor,” someone can just be sitting there, but their hands are shaking. However, as soon as they move their arms, the shaking goes away.
That’s the most obvious distinction, but there are many exceptions. People with severe essential tremor can notice the tremor at rest, and vice-versa with people with severe Parkinson’s.
Q: How do you diagnose the type of tremor?
Dr. Deik: In these cases, we diagnose based on which type of tremor—action or at-rest—is most prevalent. We also look for some of the other features of Parkinson’s in these patients.
If the person has stiffness, slowness, imbalance, or changes in walking, we lean toward Parkinson’s. Most people with essential tremor wouldn’t have those symptoms.
Q: How do you treat essential tremor?
Dr. Deik: The two most effective treatments are Primidone (an anti-seizure drug), and Propranolol (a beta blocker often used to treat heart conditions like high blood pressure).
There is also a surgical approach called deep brain stimulation. We place electrodes (small electricity conductors) on a patient’s brain, and connect them to a pacemaker-like device with wires. The wires send a current through the brain, stopping the tremor.
Q: Are there any recent developments in treatment?
Dr. Deik: Yes—Penn was one of the first centers in the US to offer a procedure called high-intensity focused ultrasound (also called “MR-guided Focused Ultrasound”). We use ultrasound beams to target the area of the brain where the tremor is coming from. This procedure can be very successful and is a great way to treat a tremor without surgery.
However, there are a few caveats. You can only do it on one side of the body, so you have to choose which side is most bothersome. Also, it’s not 100% risk-free. It can cause some tingling and imbalance. But overall, it has provided good results.
Q: What is the difference between essential tremor and dystonia?
Dr. Deik: Dystonia is another movement disorder that can cause tremor-like movements. In dystonia, the tremor causes a limb to seem to “want to pull” in a particular direction. An essential tremor is more of a fluctuation, with each side shaking like the other.
Tremor from dystonia is also more jerky, whereas essential tremor is more rhythmic. Dystonic tremor can also look like Parkinson’s tremors (at-rest tremors), and tends to be associated with other parts of the body (e.g., the head) more than essential tremor.