The central nervous system, which is made up of the brain and spinal column, interacts with nerves and muscles to produce movement. When a disruption occurs in any of these places, movement disorders can result. There is a wide variety of diseases associated with movement disorders, and they range in severity from innocuous hiccups to Parkinson's disease.
Definition & Facts
A movement disorder results from damage or disruption to either the nervous system or the muscles supporting movement. Depending on the location and severity of the malfunction, movement disorders can be very severe and complex. Diseases affecting the brain or nerves cause many movement disorders such as Parkinson's or Huntington's disease, which are both caused by the degeneration of nerve cells in the brain.
Movement disorders may also be caused by autoimmune diseases or injuries to the brain or other neurological disorders. Some common movement disorders include dystonia, essential tremors, chorea, and progressive supranuclear palsy.
Symptoms & Complaints
Loss of balance or lack of coordination are also common symptoms. Depending on the disease causing the movement disorder, sometimes multiple parts of the body are affected, and other times symptoms are isolated. Tourette syndrome is a type of movement disorder that causes motor tics and phonic tics in which the individual vocalizes or verbalizes certain sounds or words.
Many movement disorders are caused by some type of nerve degeneration and are progressive. This means that symptoms will get worse over time and that new symptoms will emerge. Many of the better known movement disorders like Parkinson's, Huntington or dyskinesia tend to begin manifesting symptoms around or after the age of 40 while other diseases become symptomatic during childhood or following an injury occurring at any age.
Movement disorders have a wide variety of causes. The most common cause is degeneration of nerve cells in the brain, spinal cord, or brainstem. A lot of movement disorders are inherited genetic disorders or caused by genetic mutations, which are difficult to prevent.
Sometimes a medication like an antipsychotic, antihistamine, antidepressant, or anti-nausea drug that a person is on may cause a movement disorder like chorea or symptoms such as tremors. Tardive dyskinesia is typically caused by the use of antipsychotics. Other causes of movement disorders include metabolic disorders, strokes, endocrine disease or complications from another illness like rheumatic fever.
Diagnosis & Tests
Some movement disorders are easier to diagnose than others. For example, there is no definitive way to test for Parkinson's disease, so diagnoses are made when a doctor assesses symptoms and takes a patient's medical history. The same is true of symptoms like chronic motor tics or myoclonus.
A person with a physiologic tremor, which is a tremor that becomes more noticeable with psychological stress or caffeine, may be diagnosed based on the results of a patient's physical examination and neurological examination along with a thorough medical history. A person who presents with a resting tremor, which is a tremor that occurs when the body is at rest, may prompt a doctor to suspect a disease like Parkinson's.
Other disorders can be diagnosed based on the patient's symptoms, medical history, results of a physical and neurological exam and the results of genetic testing. Huntington's is a disease with genetic markers that have been identified, which makes it possible to confirm a diagnosis. Other types of movement disorders like Friedreich's ataxia or spinocerebellar ataxia can also be identified by genetic testing.
A person with any type of abnormal movement should consult with a doctor as soon as possible since movement disorders are not a normal part of aging and often are indicative of something more serious.
Treatment & Therapy
Some disorders can be treated with high rates of success while others are progressive and eventually fatal. There is no cure for disorders like Huntington, Parkinson's, or progressive supranuclear palsy. Sometimes, medication may be effective at treating symptoms of movement disorders.
Tremors, for example, can be treated effectively depending on the severity and cause of the tremor. Some tremors can be treated by minimizing triggers like stress of caffeine while others respond to drug therapy or deep brain stimulation where electrodes are placed deep within the brain to stimulate it. Drug therapies for tremors include beta blockers like propranolol or the anticonvulsant primidone.
Physical therapy can also help individuals minimize the effect that movement disorders may have. Physical therapists may work with patients to teach them how to move in ways that reduce certain involuntary motions such as pressing a limb against a firm surface when jerking or tremors begin.
Botulinim toxin, which is commonly used to reduce wrinkles or to relieve migraine headaches, has also been proven effective in treating some symptoms or disorders. Dystonia, which is characterized by painful muscle spasms, for example, will often respond to an injection of botulinim which inhibits the movement of the overactive muscles causing the spasms.
Some movement disorders are caused by illnesses or disorders that are curable. For example, a person with a coordination disorder caused by hypothyroidism or a vitamin E deficiency will often see improvement when the underlying cause is treated. Other disorders that occur as a side effect of medication can be treated by changing medications or lowering doses.
Prevention & Prophylaxis
Those who take medications known to cause abnormal motion should be on the lookout for signs and should speak with their doctor about changing medications or dosages if any symptoms occur.