Essential tremor (ET) is a neurological condition that typically causes a rhythmic tremor of the hands, head, or voice. Parkinson’s tremor (PT) is a symptom of Parkinson’s disease (PD).
The two types of tremors have different causes, characteristics, and outlooks.
Tremor is a neurological condition that involves trembling or shaking movements in one or more body parts, most commonly in the hands.
This article outlines the differences between ET and PT and considers the outlook for people with each type of tremor.
Parkinson’s tremor (PT) and essential tremor (ET) are different types of tremor with different causes, presentations, and treatments.
According to the International Essential Tremor Foundation (IETF), ET is 8 times more common than PT and affects an estimated 7–10 million Americans.
According to the Parkinson’s Foundation, the main difference between PT and other types of tremor is that PT typically presents as a “resting tremor.”
A resting tremor is a trembling or shaking movement that occurs while a person is resting or staying still.
Other types of tremors typically present as “action tremors,” generally occurring when the person actively uses the affected body part.
Below are some additional differences between PT and ET.
Tremor presentation: Parkinson’s tremor
Tremor is typically the first motor symptom of Parkinson’s disease (PD). Around 70–90% of people with PD experience tremor at some stage of the disease.
Parkinson’s tremor most often affects the hands, causing interference with day-to-day activities. The affected hand will often produce a pill-rolling action, as if the person is continually rolling a pill between their thumb and forefinger.
Tremors can also affect the following parts of the body:
- the lower lip
- the jaw
- the leg
In the early stages of PD, tremors typically affect only one side of the body. As the disease progresses, the tremors may occur on both sides.
Tremor presentation: Essential tremor
Essential tremor is an “action tremor” that occurs when a person actively moves the affected body part.
According to the Parkinson’s Foundation, ET typically affects the hands and forearms but can also affect the head. Some people with ET will also have a noticeable tremor in their voice.
ET typically affects both sides of the body.
Although ET is not the same as PT, individuals with ET may be at increased risk of developing PD compared with the general population.
The IETF outlines some of the similarities and differences between ET and PT. This information is presented in the table below.
| Characteristics | Essential tremor | Parkinson’s tremor |
|---|---|---|
| Occurrence | occurs during movement | is most noticeable at rest |
| Severity (amplitude and frequency) | • variable amplitude ranging from low amplitude (barely perceptible) to high amplitude (highly perceptible) • higher, faster frequency | • high amplitude • lower, slower frequency |
| Distribution | typically affects both sides of the body | typically starts on one side of the body and progresses to the other side |
| Body parts affected | • most often occurs in the hands or forearms but also affects the head and voice • rarely affects the legs | • most often occurs in the hands but can also occur in the legs • rarely affects the head and voice |
| Response to stress | worsens with emotional stress | worsens with emotional stress |
| Response to alcohol consumption | alcohol often reduces tremor | alcohol has no effect on tremor |
| Typical age at onset | incidence increases with age, but it can occur in childhood or early adulthood | generally occurs between the ages of 55 and 65 years |
| Disease course | stable or slowly progressive | progressive |
| Treatment | can improve with the drugs primidone and propranolol | typically improves with the drug levodopa |
Another key difference between ET and PD is that ET is not usually associated with other symptoms besides tremor. Contrastingly, PD may cause additional symptoms,
- slow movements, or “bradykinesia”
- muscle rigidity, which may result in:
- difficulty moving
- difficulty making facial expressions
- painful muscle cramps
- problems with walking or balance, which may result in a slow, shuffling walk with very small steps
According to the United Kingdom’s National Health Service (NHS), other potential symptoms of PD include:
- anosmia, which is a loss of sense of smell
- nerve pain, which may cause burning, coldness, or numbness
- frequent urination, or urinary incontinence
- constipation
- erectile dysfunction in men
- difficulties with sexual arousal and orgasm in women
- dizziness or fainting when standing up
- excessive sweating
- difficulty swallowing
- excessive saliva production
- sleep problems, such as insomnia and excessive daytime sleepiness
Essential tremor and PD have different disease outlooks. These differences are outlined below.
Essential tremor
There is no cure for ET, but medications such as primidone and propranolol can alleviate the tremor.
Even though there are no cures for ET and PD, some treatments may help. For example, deep brain stimulation (DBS) is a surgical procedure that can
DBS involves surgically implanting an electrical medical device in the brain. It delivers electrical stimulation to parts of the brain involved in movement to alleviate tremors.
The Parkinson’s Foundation states that individuals with ET may be at increased risk of developing PD. However, a
Parkinson’s disease
The
Initially, drug treatments may offer significant improvement, but motor symptoms may eventually reappear as the drugs become less effective. At this stage, doctors may recommend surgical treatment such as DBS.
According to the NINDS, PD usually progresses slowly, and the average life expectancy for people with this disease is typically the same as that for people without the disease.
Below are some answers to frequently asked questions about ET and PT.
Can essential tremor turn into Parkinson’s?
Research into whether ET can develop into PD offers conflicting results. As a
The review notes that these differences may be due to difficulties differentiating ET from other types of tremor disorders.
What causes tremors if it’s not Parkinson’s?
As the
Some other common forms of tremor
- Dystonic tremor: occurs in people with the movement disorder “dystonia”
- Cerebellar tremor: occurs in people with damage to the brain’s cerebellum or the pathways that connect it to other brain areas
- Enhanced physiologic tremor: a potentially reversible tremor that can occur due to the following:
- reactions to certain drugs
- alcohol withdrawal
- medical conditions, such as an overactive thyroid and hypoglycemia
- Orthostatic tremor: a tremor of unknown cause that produces rapid muscle contractions in the legs when a person stands up
What is the finger test for Parkinson’s?
The finger tap test for PD evaluates bradykinesia, or slowed movements.
For this test, a person must tap their index finger onto their thumb as fast as possible, ensuring that the finger and thumb separate as far as possible between each tap. They should repeat the exercise with each hand.
The test can help doctors identify bradykinesia.
Essential tremor (ET) and Parkinson’s tremor (PT) are two different types of tremors.
While ET is usually an isolated condition, PT is a symptom of Parkinson’s disease (PD). As such, PT can occur alongside other symptoms of PD, such as bradykinesia, muscle rigidity, and problems with walking and balance.
One key difference between ET and PT is that ET is an action tremor, while PT is a resting tremor. Both types of tremor can affect both sides of the body, although PT typically starts on one side and progresses to the opposite side over time.
There are many different types of tremors. Anyone who experiences tremors should consult a doctor to determine the cause.
Different types of tremors may require different treatment approaches, so it is vital a person receives a correct diagnosis.