What Causes Motor Fluctuations in Parkinson’s Disease?

Medically Reviewed on 10/25/2021
Parkinson's Motor Fluctuations
Motor fluctuations in Parkinson’s disease are caused by drops in dopamine brain levels since your nerve cells can no longer make enough of the chemical.

Motor fluctuations are common occurrences in many people with Parkinson’s disease as the disease progresses. Researchers think they are caused by two reasons.

Wearing off effect

  • As time passes, Parkinson’s disease worsens. The ability of brain cells (neurons) to store dopamine further decreases. When the blood level of levodopa (the drug administered to treat Parkinsonism) decreases, the dopamine levels plummet and result in the worsening of Parkinson’s symptoms. This period is called “off-times.”
  • Parkinson’s medications, such as levodopa and dopamine agonists, lose their effect with time, resulting in a “wearing-off” effect. The wearing-off effect causes the symptoms of Parkinson’s to return or become more noticeable.

Increased sensitivity of neurons

  • As Parkinson’s disease progresses, the neurons become more sensitive to both higher and lower blood concentrations of levodopa. So, at lower concentrations of levodopa, the affected person is more likely to experience the off-times. Likewise, at higher concentrations of levodopa, the affected person may experience abnormal, involuntary movements called dyskinesia.

What are the different motor fluctuations?

Doctors have given names for different motor fluctuations, such as:

  • Wearing off: The most common type of motor fluctuation. This happens when the symptoms of Parkinson’s increase until the next scheduled dose of levodopa is taken.
  • Morning off: Parkinson’s symptoms occurs first thing in the morning before the first dose of levodopa starts working.
  • Partial on: When a dose of levodopa does not take effect completely.
  • Delayed on: When symptoms stay for a longer time even after taking a dose of levodopa.
  • Dose failure: When the dose of levodopa fails to show the desired effect on the symptoms.
  • Unpredictable off: When symptoms return out of the blue, and this cannot be linked rationally to the dosing schedule.

What is dystonia and freezing in Parkinson’s disease?

Along with motor fluctuations and dyskinesia, some people with Parkinson’s disease experience problems with muscle contractions called dystonia and freezing.

Dystonia is the involuntary, continuous contractions of muscles that result in repetitive movements, such as twisting or curling of one or more body parts.

Dystonia may occur at various times, including:

  • When the medication is working at its full potential
  • When dopamine levels are the lowest
  • When the medication has just begun to exert its effect

Freezing is the temporary and involuntary inability to move. People feel as if their feet are stuck to the ground. This can happen for several seconds to minutes. The phenomenon results from decreased levels of dopamine.


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How are motor fluctuations treated?

Motor fluctuations affect the quality of life of people with Parkinson’s significantly by limiting their activities of daily living, mobility, and social interaction. The treatment aims to keep the person moving and make them carry their daily activities independently.

Doctors can use any of the following strategies to help the affected people to minimize or avoid motor fluctuations:

  • Adjusting the dose of levodopa: The doctor can either increase the dose or change the number of times the drug is taken in a day.
  • Introducing different medications: Adding different medications to the current medication (levodopa) can help maintain consistent levels of dopamine and thus, prevent off-times.
    • These medications include
      • Catechol-O-methyltransferase inhibitors
      • Dopamine agonists
      • Monoamine oxidase-B inhibitors
  • Using a different form of the medication: A controlled-release or extended-release formulation of the medication can help provide effects for a longer time. This decreases the need for frequent dosing.
  • Surgery: Deep brain stimulation and duopa therapy.
    • Deep brain stimulation involves implanting electrodes into certain areas of the brain and providing electrical stimulation.
    • Duopa therapy involves administering carbidopa or levodopa in gel form called enteral suspension. For enteral suspension, patients will need to undergo surgery that involves making a small hole in the jejunal wall to place a tube in the intestine.
Medically Reviewed on 10/25/2021
Liang T-W, Tarsy D. Medical management of motor fluctuations and dyskinesia in Parkinson disease. UpToDate. https://www.uptodate.com/contents/medical-management-of-motor-fluctuations-and-dyskinesia-in-parkinson-disease