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What are the three most common movement disorders?

Movement disorders are neurological conditions that affect a person’s ability to control their voluntary and involuntary movements. They can significantly impact quality of life and ability to perform daily activities. The three most common movement disorders are:

Parkinson’s Disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by tremors, slowness of movement, limb rigidity, gait abnormalities, and balance problems. It is caused by the death of dopamine-producing neurons in the substantia nigra region of the brain. The main motor symptoms of PD are:

  • Tremor – Involuntary shaking, most commonly at rest
  • Bradykinesia – Slowness of movement
  • Rigidity – Stiffness of the limbs and trunk
  • Postural instability – Impaired balance and coordination

PD is the second most common neurodegenerative disorder after Alzheimer’s disease. It affects about 1% of people over 60 years old. Men are 1.5 times more likely to develop PD than women. While the exact causes are unknown, factors like genetics, environmental toxins, and decreased dopamine levels are thought to contribute to PD development.

Essential Tremor

Essential tremor (ET) involves uncontrollable shaking or trembling of parts of the body, such as the hands, head, voice, legs, or trunk. It typically affects the hands and arms first. ET is caused by abnormalities in the parts of the brain that control muscles throughout the body. Symptoms of ET include:

  • Tremor – Most noticeable when using the affected body part
  • Head titubating – Rhythmic bobbing of the head
  • Shaky voice – Tremulous speech
  • Handwriting changes – Difficulty writing

ET is one of the most common movement disorders, affecting up to 5% of people over 65 years old. It often runs in families and worsens with age. Emotional stress, fatigue, low blood sugar, and certain medications can exacerbate tremors. While not fatal, ET can interfere with daily activities and cause embarrassment or social isolation.


Dystonia involves involuntary muscle contractions that lead to abnormal movements and postures. There are many different types of dystonia that affect various parts of the body:

  • Cervical dystonia – Neck muscles contract causing head to twist or tilt
  • Blepharospasm – Eyelid muscles contract causing excessive blinking or squinting
  • Oromandibular dystonia – Jaw and tongue muscle contractions
  • Writer’s cramp – Hand cramps and contortions when writing

Dystonia can occur at any age but often first appears in middle age. It may be inherited or caused by other factors like physical trauma, infections, or reactions to certain medications. Dystonia symptoms may come and go over time and can be managed with medications, botulinum toxin injections, therapy, and sometimes surgery.

Similarities and Differences

While Parkinson’s disease, essential tremor, and dystonia have some overlapping symptoms like tremors and movement problems, there are key differences:

Disorder Main Symptoms Age of Onset Causes
Parkinson’s Disease Tremor, slow movements, rigidity, balance problems Middle age and older (over 60) Loss of dopamine-producing brain cells
Essential Tremor Tremors during voluntary movements Middle age and older (over 65) Abnormalities in the cerebellum
Dystonia Involuntary muscle contractions, abnormal postures Can occur at any age Genetics, brain abnormalities, trauma, medications


Since movement disorders share some similar signs and symptoms, a detailed medical history and neurological exam are needed for accurate diagnosis. Doctors may order tests to help determine the specific condition:

  • Blood tests – To check medication levels or look for other disease indicators
  • Brain imaging – CT or MRI scans to visualize brain structure
  • Genetic testing – Identify gene mutations linked to movement disorders

Observing the characteristics of tremors, onset, triggers, and body distribution helps distinguish between PD, ET, and dystonia. Response to medications can also confirm diagnoses.


While there are no cures for these common movement disorders, various treatments can help manage symptoms:

  • Medications – Levodopa for PD; beta blockers or anticonvulsants for ET; muscle relaxants for dystonia
  • Therapy – Physical, occupational, and speech therapy
  • Surgery – Deep brain stimulation for PD or dystonia
  • Botulinum toxin injections – Used for dystonia and tremors

Lifestyle changes like avoiding triggers, exercising, reducing stress, physical/occupational therapy, and support groups can also improve quality of life.


Parkinson’s disease, essential tremor, and dystonia are the three most prevalent movement disorders. They have some overlapping symptoms but key differences in terms of age of onset, body distribution, triggers, and causes. Proper diagnosis is important to determine the appropriate medications, botulinum toxin injections, surgery, and lifestyle changes to manage disruptive symptoms.

With further research into the mechanisms behind these disorders, scientists hope to develop better treatments to minimize symptoms and improve daily functioning for people living with movement disorders.