Essential tremor is a nervous system (neurological) disorder that causes involuntary and rhythmic shaking that can resemble the symptoms associated with Parkinson’s disease. There is much debate about whether essential tremor is related to Parkinson’s disease and whether one can lead to or is a sign of the other.
Essential tremor and Parkinson’s disease (PD) both share many of the same symptoms, including:
- Tremor that begins gradually, normally on one side of the body
- The tremor can worsen with movement (although normally in PD the tremor improves with movement)
- The tremor often occurs in the hands first
- The tremor may be aggravated (becomes worse) by emotional stress, fatigue and/or caffeine/stimulants
However, essential tremor and Parkinson’s disease also differ in many important ways:
- Tremor timing: Essential tremor usually worsens with movement (i.e., tremor of the hand worsens when you use your hands). Tremors from Parkinson’s disease are often most apparent when at rest.
- Parts of the body affected: Essential tremor mainly involves the hands, although the head and even one’s voice can also be affected. The tremor associated with Parkinson’s disease can and usually does involve more body parts, including the hands, legs, face/chin and/or feet.
- Associated symptoms: Normally, essential tremor is limited to the hands and/or head; a person with essential tremor may also develop an unsteady gait (known as ataxia). People with Parkinson’s disease may have many more symptoms, including a stooped posture, shuffling gate, slurred speech, difficulty swallowing, muscle stiffness and rigidity as well as balance issues and an unsteady gait.
How do you know if you have Essential Tremor or Parkinson’s disease?
Only a trained neurologist can help you determine if your symptoms indicate your have essential tremor or Parkinson’s disease. The difficulty is that there is no definitive diagnostic testing to determine the difference. Often, the most telling features are only distinguishable over time.
In looking at the peer-reviewed literature on the subject, the question of whether essential tremor correlates with Parkinson’s disease has not been definitively decided. Some literature suggests that there is no correlation between essential tremors and Parkinson’s disease while other literature suggests that Parkinson’s disease is thirty-five times more common is some populations among those with essential tremor.
However, you may not need a definitive diagnosis to help you figure out how to correct the underling cause of your tremor. A dopamine challenge can be a very useful tool to help distinguish those that have a dopamine-dominant condition (like Parkinson’s disease) versus those that do not. If a person does not tolerate a dopamine challenge, they should not be considered at risk for Parkinson’s disease. If they do tolerate the dopamine challenge, it is very likely that they will require ongoing dopamine support and they should be managed accordingly. Keep in mind that this is not a definitive diagnosis for Parkinson’s disease, but it does suggest the need for additional support that is especially useful if the tremor (or associated symptoms) are interfering with day-to-day activities.