Tremor in Parkinson's disease (PD) results from the lack of dopamine in the brain. Dopamine is a chemical messenger (neurotransmitter) that helps coordinate movement in the body.1
In PD, the brain cells that make dopamine stop working or die. Muscle coordination and stability decrease when dopamine is unavailable. This can cause uncontrollable muscle tremoring.1
Who gets tremor?
In the early stages of PD, about 1 in 7 people have a slight tremor in one or both hands or feet.1
What does it look like?
The primary type of muscle tremor in PD is called a resting tremor. This type of tremor occurs when a person is not trying to move a limb or that limb is at rest. In PD rest tremors are common in the hands.1,2
A common type of rest tremor seen in PD is the "pill rolling" tremor. In this tremor it appears as if a person is rolling a pill (or other small object) between their thumb and index finger.1,2
Physical or emotional stress can make this tremor worse. Purposeful movement can make this tremor better. This tremor often starts on 1 side of the body, such as in just the right hand. The tremor may worsen over time and start affecting both sides of the body. Sometimes the chin, lips, face, or legs are affected.1,2
Why does it happen in PD?
In PD, the brain's nerve cells (neurons) are damaged and die. While PD affects several areas of the brain, the area that makes dopamine is one of the most heavily damaged. Dopamine is the chemical that relays the message to other parts of the brain to help regulate smooth, purposeful movement.3
When PD has damaged the nerve cells and connections across these circuits in the brain, motor (movement) symptoms occur, like tremor. Some research has shown that for motor signs of PD to appear, up to 80 percent of nerve cells that make dopamine have been damaged or destroyed.3
Tremor in other conditions
PD is not the only condition that can lead to tremor. Usually, tremor in the voice and head are not related to PD. This is usually an essential tremor, which is a type of tremor that can occur at rest or during movement. The exact cause of this type of tremor is generally unknown.1,2
There is not yet a cure for PD, but treatments help manage symptoms like tremor. There are many ways to treat PD symptoms, including medicines, surgery, and complementary or alternative medicine.
Most people with PD start taking medicine to manage their symptoms. Different types of therapy are used to treat PD. The most common treatments are:1-6
- Dopamine agonists
- MAO-B inhibitors
- COMT inhibitors
- Deep brain stimulation (DBS)
- Stress reduction
- Physical and occupational therapy
Managing tremor related to PD might look different for everyone. Many times, levodopa and carbidopa help, but not always. If medicine does not help, your doctor may suggest DBS therapy.1-3,6
Tremor can be a mild condition for some people, but it can be very disabling for others. People with tremor may find it challenging to do everyday activities like working, bathing, dressing, and eating. Tremor can also cause people to limit their physical activity, travel, and social engagements. This is done to avoid embarrassment or other consequences.
If you or your loved one has a tremor, there are options. Talk to your doctor about which treatments might be best.