Tremor in Parkinson’s

Tremor

A tremor is an involuntary quivering movement affecting 80% of people with Parkinson’s.

Understanding the basics of a Tremor and how it affects the body

Characteristically occurring at rest, the classic slow, rhythmic tremor of Parkinson’s disease typically starts in one hand, foot, or leg and can eventually affect both sides of the body.

The resting tremor of Parkinson’s disease can also occur in the jaw, chin, mouth, or tongue. In addition, some people with Parkinson’s disease can experience a feeling of internal tremor, which is not necessarily noticeable to others. Tremor is very common in Parkinson’s. It affects about 80% of people with Parkinson’s. Although many lay people, and even those with Parkinson’s disease themselves, think of tremor as being the main problem in Parkinson’s, it isn’t for most. For most people with Parkinson’s, tremor is not debilitating.

However, a tremor is annoying. It also attracts attention, so that people tend to keep their bad hand in a pocket, or to sit on it during conferences. Since it disappears with movement, it turns out that tremor does not interfere severely with activities of daily living.

What makes a Parkinson’s tremor different?

The tremor that occurs in Parkinson’s disease is different from almost all other tremors because it is a “resting tremor” since it presents primarily at rest. It goes away with movement, but often returns when the limb, usually a hand or fingers, are held in one position. While  holding a spoon or fork to the mouth, the tremor can reappear which is why those with Parkinson’s are known to spill things. Parkinson’s disease tremor may affect almost any part of the body, but most commonly involves the fingers, followed next most commonly by the hands, jaw, and feet.

Symptoms of Parkinson’s tremor

Like most symptoms of Parkinson’s disease, it is usually asymmetric. It starts generally on one side, which remains the more affected side forever. Having a tremor on one side does not mean that the other side will begin to shake as well. Many people have tremor on only one side throughout their illness.

Confusion with Essential Tremor

The tremor of Parkinson’s disease is often confused with the tremor of a condition called Essential Tremor, or Benign Familial Tremor. Katherine Hepburn had Essential Tremor, and was originally misdiagnosed with Parkinson’s. Ronald Reagan, also, had Essential Tremor. Both had a head tremor and a vocal tremor. With  Essential Tremor, the hands are most commonly involved, followed by the head and then the voice. Essential Tremor can cause the jaw to tremor, and it may be difficult to figure out if a jaw tremor is from Essential Tremor or Parkinson’s. Unfortunately, some people may have both disorders. Some authorities believe that there is, in fact, an increased association between the two conditions, so that more people with Parkinson’s disease have Essential Tremor than would be expected by chance alone, but this has not been established.

Types of Tremor

There are many different types of tremors. What are the differences?

Finger Twitching

The “pill rolling” tremor that is often described in medical texts refers to the tremors of the fingers, usually the thumb plus the other fingers, that makes it look as if the person is rolling a pill in the fingers. This is most often the part of the body where tremors will begin.

Jaw Tremors

Jaw tremor is common in Parkinson’s, whereas head tremor is not. The jaw tremor looks very much like shivering, although usually slower. It goes away with movement, so it is not present while chewing. It is extremely irritating  when it is severe enough to cause the teeth to click together. For people with dentures, it may keep the dentures from staying in place, in addition to attracting attention because of the clicking sounds. Chewing gum stops the tremor.

Foot Tremors

Many, if not most people, may have a leg tremor if they rest their leg in particular positions with the heel on the ground. This is not a Parkinson’s disease tremor. A foot tremor due to Parkinson’s isa resting tremor, so it is most evident when the feet are dangling or when the person is lying down. It always disappears when the person is standing, and does not interfere with walking. The tremor usually involves the feet, but the thighs may also be involved so that the whole leg moves.

Tongue Tremor

Sometimes the tongue has a tremor, and in about 1% of Parkinson’s disease cases the head shakes. Sometimes the head tremors because the arms are shaking and the tremor is simply transmitted. The voice, while frequently involved in Parkinson’s, is never involved by tremor.

Find out more about the vocal effects of Parkinson’s >>

Prognosis & Treatment

It appears that those with Parkinson’s disease whose major problem is tremor,relative to slowness, stiffness or walking problems, tend to have a much more benign course than others. They progress more slowly and probably live longer.

It also appears to be the case that tremor is the only symptom of Parkinson’s disease that may improve on its own — some who had severe tremors have seen them virtually disappear over the period of a decade. Tremors rarely continue to worsen beyond a certain point — at some point the tremor will plateau. 

Tremor can be hard to treat with medication

We use the usual Parkinson’s disease medications to treat tremor, but tremor is the least predictable of the four basic motor problems of Parkinson’s disease in its response to medication treatment. Typically when a person starts on Parkinson’s disease medications, it’s good to pay attention to mobility and stiffness, not just the tremor. This is because, while the hope is that the tremor will improve with L-Dopa (or another dopamine agonist), it may not.

If not warned about this, people will often think a drug isn’t working even though they are able to complete day to day tasks easier.  Knowing that tremor may not respond as well as the other symptoms of Parkinson’s Disease is extremely helpful for the person with Parkinson’s and their family.

Medications beyond Levodopa

When tremor is severe, or disabling in some way, and does not respond to the more commonly used Parkinson’s disease medications, other drugs that are not usually used as “first line” may be an option:

• The anti-cholinergic drugs (trihexyphenidyl/Artane, benztropine/Cogentin) or amantadine/Symmetrel are often used in this situation. Anti-cholinergic  drugs often have side effects which limit their usefulness.
• Propranolol, a drug used for hypertension, heart diseases, and migraine headaches are occasionally helpful.
• Clozapine, a drug used for treating refractory schizophrenia, may be enormously helpful for Parkinson’s disease tremor, but requires weekly blood tests for the first six months, due to a 1% chance of reducing the white blood count, causing immune problems. After the first six months the blood testing drops to once every 2 weeks for six months then once per month. It may cause weight gain, sleepiness and other problems.

What if medication fails?

Deep brain stimulation surgery is the single most reliable and effective treatment for Parkinson’s disease tremor when medications fail. Treatment is successful in about 90% of cases, and usually makes the tremor resolve completely or almost completely. It is not experimental and is approved by all insurance companies.

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