A tremor is an involuntary, rapid, rhythmic shaking of the body or part of the body.

Most people with Parkinson’s disease have tremors. When Parkinsonian tremors do appear, they’re usually seen during rest and at a slower frequency than tremors caused by essential tremor.

Often the pattern of tremors, along with other symptoms, helps distinguish Parkinson’s disease from essential tremor, but sometimes these conditions can be mistaken for each other.

Read on to learn about the similarities and differences between these two conditions that help medical professionals distinguish them.

Essential tremor is a fairly common neurological condition that causes uncontrollable tremors. These tremors may range from barely noticeable to causing more serious impacts on everyday activities.

About half of the cases of essential tremor are thought to be due to genetic factors. The exact cause hasn’t been identified.

Parkinson’s disease is a progressive condition that causes trouble with movement. It’s caused by the death of cells in a part of the brain called the substantia nigra. This part of your brain produces the neurotransmitter dopamine.

In some cases, specific genetic mutations are linked to the development of Parkinson’s. But more often, it seems to appear randomly. Environmental factors such as exposure to pesticides, herbicides, or air pollution may contribute, but more evidence is needed to understand the potential link.

According to the National Institute on Aging, Parkinson’s most commonly develops in people over the age of 60 and affects men about 50 percent more often than women.

Here are some key differences between essential tremor and Parkinson’s disease:

  • Development of tremor. Tremor is the key symptom of essential tremor. About 75 percent of people with Parkinson’s develop tremor.
  • Type of tremor. People with Parkinson’s usually have tremors when they’re at rest. People with essential tremor generally have tremors during movement.
  • Frequency of tremor. The movements of essential tremor generally occur at a higher frequency than Parkinsonian tremors. Parkinson’s usually causes higher magnitude tremors, but the magnitude of essential tremor movements is more variable.
  • Family history. Studies report a family history in about half of cases of essential tremor but only about 10 to 15 percent of Parkinson’s cases.
  • Other symptoms. Parkinson’s is more likely to cause trouble balancing and walking, stiff muscles, and slow movements.
  • Neurological pathway. Parkinson’s disease is associated with the loss of cells in a part of the brain called the substantia nigra that produces dopamine. Changes to the brain stem, and possibly the cerebellum, are thought to play a role in developing essential tremor.
  • Progression. Parkinsonian tremors generally affect one side of the body first and then spread to the other side, while essential tremors generally affect both sides in the beginning.

Finding care for essential tremor or Parkinson’s disease

Finding a neurologist with experience treating Parkinson’s disease and essential tremor can make managing your condition easier. Here’s how you can find a specialist:

  • Call the Parkinson’s Foundation Helpline at 800-4PD-INFO (800-473-4636).
  • Use the International Parkinson and Movement Disorder Society’s specialist directory.
  • Get a referral from your primary doctor.
  • Ask for a referral from another patient.
  • Contact your insurance provider for help.

There’s no known cure for Parkinson’s disease or essential tremor, but treatment in the early stages can improve your outlook and give you the best chance of slowing their progression.