Tremor 101: Symptoms, Causes, Stages & Treatment

Tremor is the involuntary or uncontrollable shaky movement of any part of the body. Find out more about tremor, its symptoms, causes, stages, and treatment options.

by Pragalath Kumar


Tremor can occur sporadically or as a symptom of other disorders and it is most common among middle-aged to older adults of both sexes. Tremors are not a life-threatening disorder. Tremors can be differentiated from other involuntary movement disorders, such as chorea, athetosis, ballism, tics, and myoclonus based on the following unique characteristic – repetitive, stereotyped movements of a regular amplitude and frequency.

Tremors can be mistaken with rhythmic myoclonus (wrongly known as cortical tremor). Rhythmic myoclonus is characterised by brief muscle twitches, confined to one limb or to adjacent body regions, associated with spike-wave complexes on the electroencephalogram (EEG) or spinal lesions.

Clonus represents a rhythmic movement that is raised by muscle stretching. Asterixis are different from tremors on the basis of electromyographic (EMG) findings of prolonged absence of EMG activity during “flapping” or abduction of the upper extremities. Stereotypies may have rhythmic components, but it is dominated by complex movements. Epilepsia partialis continua (EPC) also known as Kojevnikov’s Epilepsia – is a form of a seizure happening every few minutes or seconds – would produce regular jerks of the arm or hand that are indistinguishable compared to tremor.

Hence it is most vital for tremors to be characterised. Tremors can be distinguished based on activation conditions, frequency, and topographical distribution.

Tremor Types

Tremor type has been classified according to the behaviour it occurs, that is rest and action tremor, which is further subdivided into a postural and kinetic tremor. Action tremor occurs during sustained extension of the arm and during voluntary movements. It is caused by voluntary muscle contraction. It is further divided into postural, isometric or kinetic tremors.

Postural tremor occurs when one maintains their position against gravity and increases with action. Kinetic tremor occurs during voluntary movement. Examples of postural and action tremors include essential tremors, metabolic disorders such as thyrotoxicosis, drug-induced parkinsonism such as lithium, toxins and neuropathic tremor. Both postural and kinetic tremors are also known as dystonic tremors. Dystonic tremor occurs in patients under 50 of age. The tremor is usually irregular and jerky, and certain hand or arm positions extinguish the tremor.

Rest tremor occurs with the patient sitting with his arms firmly supported without any voluntary activities that may increase due to mental stress and suppressed by voluntary movements. Examples of rest tremors include drug-induced parkinsonism such as neuroleptics, long-standing essential tremors, Parkinson’s disease, Parkinson’s plus syndrome and Wilson’s disease. Wilson’s disease is a rare, autosomal-recessive disorder that manifests in persons five to 40 years of age, sometimes with a wing-beating tremor.

Isometric tremors occur during the voluntary contraction of a muscle without other movements of the muscle.

Another way of classifying tremors is via clinical and etiologic basis. There are 10 types of tremors based on clinical and etiological studies. Common causes and symptoms of some of the tremors are also mentioned.

Physiologic Tremor

Physiologic tremor is a very low amplitude fine tremor at 6 Hz-12 Hz that is hardly visible to see. It is present in every normal person while maintaining a posture or movement. Neurological examination results of patients with physiologic tremors are usually normal.

Enhanced Physiologic Tremor

Enhanced physiologic tremor is a high-frequency, low-amplitude, visible tremor that occurs primarily when a specific posture is maintained. Drugs and toxins induce this form of tremor. It is triggered by a mechanical activation at the muscular level. This tremor can be enhanced by anxiety, stress, and certain medications and metabolic conditions. Signs and symptoms of drug toxicity or other side effects might or might not be present. Tremor symptoms can improve after the causative agents are discontinued.

Essential Tremor

Essential tremor is the most common form of all movement disorders. Patients with essential tremor have it in early adulthood (or sooner), but most patients do not seek help for it until they become senior citizens because of its progressive nature. It is also known as a “benign essential tremor” that causes people to retire early or modify their career path. It is predominantly a postural- or action-type tremor, and patients normally have a positive family history. Alcohol consumption helps reduce the tremor temporarily. Other associated symptoms can include mild gait difficulty and, as a group, patients with essential tremors have increased hearing disability compared with controls or patients with Parkinson’s disease.

Parkinson’s Tremor

Parkinson’s tremor is a low-frequency rest tremor typically defined as a pill-rolling tremor. Some patients may have postural and action tremors. It occurs in association with other symptoms, such as micrographia, slowness (bradykinesia), and rigidity. Patients usually do not have a family history. Alcohol consumption does not help in reducing the tremor. 

Cerebellar Tremor

A cerebellar tremor is a low-frequency (<4 Hz) intention tremor that occurs unilaterally. Common causes are multiple sclerosis, stroke, brainstem tumours and cerebellar injury. Signs and symptoms of cerebellar dysfunction that may be present include ataxia, dysmetria, dysdiadochokinesia, and dysarthria.

Holmes’ Tremor

Holmes’ tremor or rubral tremor is a combination of rest, postural, and action tremors that are triggered by midbrain lesions in the vicinity of the red nucleus. It is an irregular type of tremor with a low frequency (4.5 Hz). Signs of ataxia and weakness may be present. Common causes include cerebrovascular accidents and multiple sclerosis, with a possible delay of 2 weeks to 2 years in tremor onset and occurrence of lesions.

Drug-Induced Tremor

Types of tremors induced by drugs include enhanced physiologic tremor, rest tremor, and action tremor. Signs and symptoms of drug-induced tremors depend on the drug used and on a patient’s predisposition to its side effects. Some drugs cause extrapyramidal side effects manifesting as bradykinesia, rigidity, and tremor. Tremor reappears in Alzheimer’s disease patients treated with cholinesterase inhibitors. Anticholinergic agents are very effective in ameliorating the tremor of Parkinson’s disease.

Drug-induced Tremors and Corresponding Neurologic Signs

Drug or Drug Class Tremor Type Neurologic Signs
Amiodarone Postural Rarely parkinsonism
Bronchodilators Postural, action None
Lithium Rest, postural, action Extrapyramidal
Metoclopramide Rest, postural Extrapyramidal
Neuroleptics Rest, postural Extrapyramidal
Theophylline Postural None
Valproate Postural Rarely parkinsonism

Tremor Due to Systemic Disease

Tremor due to the systemic disease usually occurs when the patient is moving or assumes a specific position. Symptoms include asterixis, mental status changes, and other signs of systemic illness. Diseases such as thyrotoxicosis and hepatic failure as well as delirium tremens and drug withdrawal are among the common causes.

Psychogenic Tremor

Psychogenic tremor can involve any part of the body, but it most commonly affects the extremities. Usually, tremor onset is sudden and begins with an unusual combination of postural, action, and resting tremors. Psychogenic tremor decreases with distraction and is associated with multiple other psychosomatic complaints.

Orthostatic Tremor

Orthostatic tremor is considered to be a variant of essential tremor. This type of tremor occurs in the legs immediately on standing and is relieved by sitting down. Orthostatic tremor is usually high frequency (14 Hz-18 Hz), and no other clinical signs or symptoms are present.

Tremor Symptoms

The earliest symptoms for those having tremors are rhythmic shaking in the hands, arms, head or torso. One may experience a shaky voice and have difficulty in writing or drawing and have problems in holding and controlling utensils.

These symptoms would begin gradually and would be more prominent on one side of the body.  It worsens when with movement. The shaking mentioned above usually occurs on one of the hands first before affecting both hands. The shaking of the head is similar to “yes – yes” or “no-no” motions. The symptoms also are further worsened by emotional stress, fatigue, caffeine or extreme temperature.

Risk Factors

The risk factors differ according to the type of tremor one has. Having a family history and an age of 40 and above are factors that would increase the probability for one to get an essential tremor. An inherited variety of essential tremors (familial tremors) is an autosomal dominant disorder. A defective gene from just one parent is needed to inherit essential tremor. 

The risk factors for Parkinsonian tremor are similar to Parkinson’s Disease – advancing age, male and Caucasian. Certain food and lifestyle issues contribute to raising risks of physiologic tremors. These include caffeine intake, stress, muscle fatigue, low blood sugar and anxiety

Diagnosing tremor

Tremor is diagnosed based on a physical and neurological examination and an individual’s medical history. The doctor would assess the following during the patient’s physical evaluation.

  • whether the tremor occurs when the muscles are at rest or inaction
  • the location of the tremor on the body (and if it occurs on one or both sides of the body)
  • the appearance of the tremor (tremor frequency and amplitude).

Other neurological findings such as impaired balance, speech abnormalities, or increased muscle stiffness are important to look at as well.  Blood or urine tests will discard metabolic causes such as thyroid malfunction and certain medications that can cause tremors.  These tests may also help to identify contributing causes such as drug interactions, chronic alcoholism, or other conditions or diseases.  Diagnostic imaging may help determine if the tremor is the result of damage in the brain.

Additional tests can be done to determine functional limitations such as difficulty with handwriting or the ability to hold a fork or cup.  Individuals may be asked to perform a series of tasks or exercises such as placing a finger on the tip of their nose or drawing a spiral.

The doctor may use an electromyogram to diagnose muscle or nerve problems to measure involuntary muscle activity and muscle response to nerve stimulation.

Tremor Treatment

There is no cure for tremors but there is medication to manage them.

Propranolol (up to 320 mg/day) and primidone (up to 250 mg three times daily) are the main treatments for essential tremors. It is also useful for patients with postural/kinetic syndromes. The combination of propranolol and primidone is more effective at suppressing essential tremors. Clonazepam can be useful for patients with kinetic predominant essential tremors. About 50% of patients with essential tremors respond to 2–4 units of alcohol. Moderate alcohol consumption would be beneficial during feeding, drinking, and other social engagements.

Propranolol reduces parkinsonian rest and postural tremors and is thus useful for Parkinson’s disease patients who present with tremor, or as an adjunctive treatment for those with tremor predominant Parkinson’s disease. Anticholinergic medications such as dopamine agonist drugs and levodopa preparations can decrease Parkinson’s disease tremor. Holmes’ tremor may respond to levodopa, but the patients may develop dyskinesias. Intramuscular botulinum toxin is the best option for treating isolated head tremors and head tremors associated with essential and dystonic tremors. Primary orthostatic tremor is usually treated with clonazepam.

Beta-blockers, anti-anxiety drugs, and anticonvulsant medications are among the treatment options for people with MS-related tremors. Tranquillizers are prescribed to patients having tremors with no obvious cause. Some doctors may prescribe Botox but that can cause weakness in the fingers. Deep brain stimulation (DBS) is used to treat tremors associated with Parkinson’s disease, essential tremors, or dystonia.

Other mitigation measures

Some patients benefit from using a “tripod” portable stool, which allows them to sit rather than stand for long periods. Patients with psychogenic tremors are required to undergo mental health counselling.

Tremor prevention

Tremor prevention can be done successfully if one changes his or her lifestyle. Avoid caffeine and other stimulants that can raise the tremor levels. Limit your alcohol intake as it is not a good solution to reduce tremors. Increasing the amount of alcohol would lead to alcoholism. Stress and anxiety would worsen tremors and the only way out is to relax. Relaxation techniques such as massage and meditation give patients a different perspective in reacting to stressful situations. Aside from that, one must learn to use the tremor affected hand lessor. For example, online banking options are better than issuing cheques. Those who are having tremors also can capitalise on technology as a preventive measure. Use voice-activated commands on the phone and speech recognition software on the computer.

Living with Essential Tremor

While there is no cure for patients with tremors, there are always medications and other methods of mitigating the symptoms. People living with essential tremor may require extra support for their day-to-day activities, Having a strong support system will help to alleviate the daily pressure faced by the individuals living with tremor and this can include help from dedicated caregivers

If you are living with essential tremor and need care support for activities of daily living, our Care Pros can help. Reach out to our Care Advisors at 016 299 2188 to learn more.

About the Writer
Pragalath Kumar
K Pragalath is an independent writer. He was a former journalist with a number of Malaysian news sites. He watches elections like how people watch football but dozes off over the matches.
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