Motor disorder

Motor disorder
Specialty	Neurology

Motor disorders are disorders of the nervous system that cause abnormal and involuntary movements. They can result from damage to the motor system.^[1]

Motor disorders are defined in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) – published in 2013 to replace the fourth text revision (DSM-IV-TR) – as a new sub-category of neurodevelopmental disorders. The DSM-5 motor disorders include developmental coordination disorder (dyspraxia), stereotypic movement disorder, and tic disorders including Tourette syndrome.^[2]

Signs and symptoms

Motor disorders are malfunctions of the nervous system that cause involuntary or uncontrollable movements or actions of the body.^[3] These disorders can cause lack of intended movement or an excess of involuntary movement.^[4] Symptoms of motor disorders include tremors, jerks, twitches, spasms, contractions, or gait problems.^{[citation needed]}

Tremor is the uncontrollable shaking of an arm or a leg. Twitches or jerks of body parts may occur due to a startling sound or unexpected, sudden pain. Spasms and contractions are temporary abnormal resting positions of hands or feet. Spasms are temporary while contractions could be permanent. Gait problems are problems with the way one walks or runs. This can mean an unsteady pace or dragging of the feet along with other possible irregularities.^[3]

Through the process of several healthcare professionals can help in diagnosing motor disorders. Neurological examinations can be made to identify motor disorders. This can be done through MRI or CT or electromyography, which are tests done to evaluate the function of muscles and nerves. ^[5]

Common Types of Motor Disorders

Ataxia is a common type of movement disorder that affects an individual's balance through uncoordinated movement of the arms and legs, as well as affecting their speech.^[6]

Chorea is another common type of movement disorder that causes rapid and involuntary movements that occur irregularly. Huntington's disease is the most common type of genetic chorea. ^[7]

Dystonia is caused by intermittent muscle contractions and head tremors. This leads to abnormal or repetitive movements or posture ^[8]

Functional Movement Disorder (FMD) is a condition characterized by abnormal and involuntary movements; however FMD is not caused by an underlying neurological disease. Functional movement disorder is not chronic and can be treated.^[9]

Multiple system atrophy (MSA) is a neurodegenerative disorder that has no known cause. MSA affects an individual's movement, sense of balance, and the regulation of body functions. Low blood pressure, irregular bowel and bladder control, and breathing issues.^[1]

Causes

Pathological changes of certain areas of the brain are the main causes of most motor disorders.^[4] Causes of motor disorders by genetic mutation usually affect the cerebrum.^[10] The way humans move requires many parts of the brain to work together to perform a complex process. The brain must send signals to the muscles instructing them to perform a certain action. There are constant signals being sent to and from the brain and the muscles that regulate the details of the movement such as speed and direction, so when a certain part of the brain malfunctions, the signals can be incorrect or uncontrollable causing involuntary or uncontrollable actions or movements.^[4]

Risk Factors

The irregularity of body movements, such as tremors and jerking movements in the hands, arms, legs, and the head, including the face, can cause issues with coordination and balance. Issues with coordination and balance may cause stability problems that can lead to falls and injuries. Movement disorders can cause a decrease in pace within the body which can be exhausting and much harder for individuals to get by in their daily living. ^[11]

References

1. Knierim J. "Chapter 6: Disorders of the Motor System". The University of Texas Health Science Center at Houston. Archived from the original on November 17, 2017. Retrieved October 5, 2013.
2. American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (Fifth ed.). Arlington, VA: American Psychiatric Publishing. pp. 74–85. ISBN 978-0-89042-555-8.
3. Stone, Jon. "Functional Tremor/ Spasms / Walking Problems and Other Functional Movement Disorders." Movement Disorders. Neurology Research Fund of the Department of Clinical Neurosciences, 2015. Web.
4. Mandal, Ananya, MD. "What Are Movement Disorders?" News-Medical.net. AZO Network, 14 Oct. 2014. Web. 10 Nov. 2016.
5. "Movement disorders: Causes, Risk Factors, Symptoms, Treatment". continentalhospitals.com. Retrieved 2025-11-28.
6. "Movement disorders - Symptoms and causes". Mayo Clinic. Retrieved 2025-11-28.
7. "Movement disorders - Symptoms and causes". Mayo Clinic. Retrieved 2025-11-28.
8. "Movement disorders - Symptoms and causes". Mayo Clinic. Retrieved 2025-11-28.
9. "Movement disorders - Symptoms and causes". Mayo Clinic. Retrieved 2025-11-28.
10. Esra, Tara, and Khodakhah, Kamran. Pathophysiology of Cerebellar-induced Motor Disorders (2012): ProQuest Dissertations and Theses. Web.
11. "Movement disorders: Causes, Risk Factors, Symptoms, Treatment". continentalhospitals.com. Retrieved 2025-11-28.