A tremor is a type of involuntary movement of the body, distinct from a muscle spasm or twitch. Causes can include lifestyle factors (like having too much caffeine) and medical conditions such as stroke or Parkinson’s disease.
Tremors are unintentional and uncontrollable rhythmic movements of one limb or part of your body.
Tremors can occur in any part of the body and at any time. They’re usually the result of a problem in the cerebellum, the part of your brain that controls muscular movement.
Most tremors can’t be easily treated, but they’ll often go away on their own.
It’s important to note that tremors are distinct from muscle spasms and muscle twitches.
A muscle spasm is the involuntary contraction of a muscle. A muscle twitch is an uncontrolled fine movement of a small portion of a larger muscle. This twitch may be visible under the skin.
Tremors can be caused by a variety of things.
General causes of tremors include:
- muscle fatigue
- ingesting too much caffeine
- low blood sugar levels
- prescription medications
Medical conditions that can cause tremors include:
Tremors are broadly classified as either resting tremors or action tremors.
Resting tremors occur when you’re sitting or lying still. Once you begin to move around, you’ll notice that the tremor goes away. Resting tremors often affect only the hands.
Action tremors occur during movement of the affected body part. Action tremors are further divided into these subclassifications:
- Postural tremor. A postural tremor occurs when holding a position against gravity, such as keeping your arm or leg outstretched.
- Intention tremor. An intention tremor occurs during targeted movements, such as touching your finger to your nose.
- Task-specific tremor. A task-specific tremor occurs while performing tasks that require skill, such as handwriting or playing an instrument.
- Kinetic tremor. A kinetic tremor occurs during voluntary movement of a body part, such as moving your wrist up and down.
- Isometric tremor. An isometric tremor occurs when you voluntarily contract a muscle but don’t otherwise move your muscle or limb, such as when you make a fist.
Tremors are also grouped by their appearance and cause.
An essential tremor is the most common type of movement disorder. Essential tremors are usually postural or intention tremors.
An essential tremor may be mild and not progress, or it may progress slowly over the course of a few years. It typically starts as a bilateral tremor, which means it affects both sides of the body.
Essential tremors weren’t traditionally thought to be associated with any disease processes.
However, recent research, such as a 2015 study and a 2018 textbook, has connected them to mild degeneration in the cerebellum.
A 2019 literature review also concluded that essential tremors were associated with Parkinson’s disease in some people. More studies are needed.
Essential tremors are sometimes associated with:
- a family history of the condition
- mild walking difficulty
- hearing disability
- mild cognitive impairment
The onset of Parkinson’s typically occurs
The tremor is caused by the depletion of dopamine in the basal ganglia. The basal ganglia are a group of nuclei in the brain.
While essential tremors usually begin as bilateral, Parkinsonian tremors typically begin in one limb or on one side of the body before progressing to the other side.
Functional tremor (psychogenic tremor)
A functional tremor, previously known as a psychogenic tremor, is characterized by:
- sudden onset and remission
- changes in the direction of your tremor and the affected body part
- greatly decreased activity when you’re distracted
It may present as a postural or an intention tremor.
People with functional tremors often have conversion disorder (a psychological condition that produces physical symptoms) or another psychiatric condition.
Dystonic tremors affect people who have dystonia, a movement disorder characterized by involuntary muscle contractions. The muscle contractions cause twisting and repetitive motions or abnormal postures, such as twisting of the neck. These can occur at any age.
Dystonic tremors occur irregularly. Complete rest can relieve these tremors.
The cerebellum controls balance as well as movement. Acerebellar tremor is a type of intention tremor caused by lesions or damage to the cerebellum from:
- a disease, such as MS
It may also be the result of alcohol use disorder or overuse of certain medications.
If you have alcohol use disorder or are having trouble managing medications, speak with a healthcare professional. They can help you create a treatment plan that works best for you. They can also connect you with other professional resources to help you manage your condition.
An orthostatic tremor usually occurs in the legs. It’s a rapid, rhythmic muscle contraction that occurs immediately after you stand.
This tremor is often perceived as unsteadiness. There are no other clinical signs or symptoms. The unsteadiness stops when you:
- are lifted
- start walking
A physiologic tremor affects the hands and fingers but isn’t typically noticeable to the naked eye. It’s a normal physical response that occurs in all individuals.
A more noticeable physiologic tremor is often caused by a reaction to:
- certain drugs
- alcohol withdrawal
- medical conditions, such as hypoglycemia, electrolyte imbalance, or an overactive thyroid
It will usually go away if you eliminate the cause.
Tremors aren’t always serious, but they may sometimes indicate a serious disorder. They’re often part of medical disorders that affect the brain, nervous system, or muscles.
Contact a doctor if you develop unexplained tremors.
During a physical exam, your doctor will observe the affected area. Tremors are apparent upon visual inspection. However, the cause of the tremor can’t be diagnosed until the doctor performs further tests.
Your doctor may also request that you write or hold an object to evaluate the severity of your tremor.
Your doctor may collect blood and urine samples to check for signs of thyroid disease or other medical conditions.
Your doctor may perform a neurological exam too. This exam will check the functioning of your nervous system. It will measure your:
- tendon reflexes
- muscle strength
- muscle tone
- ability to feel touch
During the exam, you may need to:
- touch your finger to your nose
- draw a spiral
- perform other tasks or exercises
Your doctor may also order an electromyogram (EMG). This test measures involuntary muscle activity and the muscle’s response to nerve stimulation.
If you get treatment for the underlying condition causing the tremor, that may be enough to cure the tremor.
Possible treatments include:
- physical therapy
- deep brain stimulation (DBS)
There are some prescription medications that are commonly used to treat the tremor itself. These medications may include:
- Beta-blockers. Beta-blockers are typically used to treat high blood pressure or heart disease. They’ve also been shown to reduce tremors in some people.
- Tranquilizers. Tranquilizers such as alprazolam (Xanax) may relieve tremors that are triggered by anxiety.
- Antiseizure medications. Antiseizure medications are sometimes prescribed for people who can’t take beta-blockers or who have tremors that aren’t helped by beta-blockers.
Botox injections may also relieve tremors.
These chemical injections are often given to people who have tremors that affect the face and head. However, Botox can be injected into virtually any muscle group that contributes to tremors, such as the neck, arms, or hands.
Physical therapy may help strengthen your muscles and improve your coordination. The use of wrist weights and adaptive devices, such as heavier utensils, may also help relieve tremors.
Deep brain stimulation (DBS)
Deep brain stimulation (DBS) may be the only option for those with debilitating tremors. During this operation, the surgeon inserts an electrical probe into the portion of your brain responsible for the tremors.
Once the probe is in place, a wire feeds from the probe into your chest, under your skin. The surgeon places a small device in your chest and attaches the wire to it. This device sends pulses to the probe to stop the brain from producing tremors.
Tremors can be normal. They don’t always interfere with your daily life or even require treatment.
They may occur when you’re under a lot of stress or experiencing anxiety or fear. Once the feeling subsides, the tremor usually stops. The chattering of your teeth when you’re cold is also considered a tremor.
If you suspect that your tremors are a sign of a more serious condition or are a side effect of medications you’re taking, speak with a doctor.