There are many types of movement disorders. Certain types are relatively common, such as Parkinson’s disease. However, many are considered rare with no accurate estimates of national prevalence.

Movement disorders can generally be classified as primarily hyperkinetic (causing an increase in movement) or primarily hypokinetic (causing a decrease in movement). Some movement disorders involve both hyperkinetic and hypokinetic symptoms.

For example, the motor symptoms associated with Huntington’s disease are primarily hyperkinetic. Huntington’s disease results in the degeneration of neurons in the basal ganglia, which causes characteristic involuntary, jerking movements. The movements associated with Huntington’s disease are called chorea and are often described as dance-like.

Conversely, Bell’s palsy is a movement disorder that is primarily hypokinetic. Bell’s palsy or facial palsy occurs when the nerve controlling facial muscles becomes compressed, inflamed or swollen. This leads to facial paralysis (or palsy) and weakness in the muscles controlling facial expressions and movement.

Parkinson’s disease is a common type of movement disorder that involves both hypokinetic and hyperkinetic movements. Parkinson’s disease is caused by the degeneration of cells that produce dopamine. This results in the various motor symptoms associated with the disease such as tremor, rigidity, bradykinesia and postural instability.

Some examples of primarily hyperkinetic movement disorders are:

• Essential tremor. One of the most common types of movement disorders. Most cases of essential tremor are associated with aging, though the symptoms can also begin in adolescence and early adulthood. Patients with this condition typically experience trembling when performing voluntary movements. The hands are most frequently affected, but shaking may also occur in the head, legs, tongue and arms. In some cases, the trembling may be severe enough to prevent patients from performing everyday tasks, such as dressing themselves.
  
  
• Dystonias. This group of disorders are marked by sustained muscle contractions that force the body into unusual postures, abnormal twisting or repetitive movements. It is caused by abnormalities in the basal ganglia.
  
  
• Tic disorders. There are many types of these disorders, which are characterized by uncontrollable and repetitive movements or vocalizations (tics). The tics may be simple movements that involve just one muscle group, such as head shaking, blinking, coughing or throat clearing. Alternatively, tics may also be more complex, such as self-hitting, jumping, twirling or repeating words.
  
  
• Tardive dyskinesia. Movement disorder associated with the long-term use of some medications for psychiatric, gastrointestinal and neurological disorders. Patients experience a wide-range of involuntary facial movements including grimacing, lip smacking and blinking. In some cases, the limbs may also become involved. Part of the treatment for tardive dyskinesia may require discontinuing or changing medications, but this should only be done under the guidance of a physician.
  
  
• Paroxysmal choreoathetosis. A disorder involving involuntary movements of the limbs, trunk and facial muscles. These movements may last for as long as an hour. Most patients with the disease exhibit the first symptoms during early adolescence and the severity of symptom attacks tend to lessen over time.
  
  
• Joubert syndrome. Disease characterized by a lack or underdevelopment of the cerebellar vermis, a part of the brain involved in balance and coordination. The disease causes abnormal breathing and jerky eye movements in infants and may also cause physical deformities. Most cases occur sporadically, though some are related to family history.
  
  
• Sydenham’s chorea. Unique among the movement disorders because it is known to result from bacterial infections. Female patients between 5 and 15 years of age seem most prone to this movement disorder. The disease causes rapid and irregular movements of muscles in the face, neck, trunk and limbs. The disease may be self-limiting and pass within three to six months, though recurrences have been recorded, especially during pregnancy.

Movement disorders that are primarily hypokinetic include:

• Amyotrophic lateral sclerosis (ALS). Also known as Lou Gehrig’s disease, this disease involves damage to the nervous system resulting in a gradual decrease in movement. Eventually, the disease causes paralysis.
  
  
• Multiple sclerosis. A common neurological disorder thought to be caused by the immune system attacking the body’s neurons. One third of patients eventually become paralyzed.
  
  
• Multiple system atrophy (MSA). In addition to movement, this group of slowly progressive disorders may also affect the patient’s blood pressure and excretory systems. The symptoms of each disease vary but all reflect damage to the patient’s nervous system.
  
  
• Angelman syndrome. Patients with Angelman syndrome tend to have movement and balance problems, in addition to developmental delays, seizures and skull malformations. Most cases of the disorder result from inherited genetic mutations, but some may also occur spontaneously.
  

  

• Cerebellar hypoplasia. Patients with cerebellar hypoplasia have a cerebellum that is not correctly formed. This part of the brain is involved in movement and balance. The deformation may occur sporadically or due to inherited genetic mutations. The disease causes symptoms that become progressively more severe with time and include developmental delays, ataxia, seizures, dizziness and imbalance.
  
  
• Corticobasal degeneration. Disease that causes the outer layer (cortex) and several other areas (including the basal ganglia) of the brain to degenerate. In most patients it begins after the age of 60. Symptoms typically include stiffness, shakiness, jerkiness or slowness of the extremities on the right or left side of the body. Over time, the symptoms spread to the other side and also become more severe.
  
  
• Progressive supranuclear palsy. A rare disorder that tends to develop in patients after age 40. The condition causes loss of control of gait, balance and eye movement in 20,000 Americans according to the National Institutes of Heath. Due to the balance problems that accompany the disease, progressive supranuclear palsy may initially be diagnosed as an inner ear condition. The disease progresses rapidly and patients typically die within 6 years of the onset of symptoms.
  
  
• Myotonia. Disorder characterized by a delay in muscle relaxation. This may affect many everyday activities, such as the patient being unable to release the grip following a hand shake. There are several types of myotonia and most result from inherited genetic conditions.
  
  
• Dyspraxia. A movement disorder that limits patients’ ability to perform motor tasks. It has many other names, including clumsy child syndrome and developmental coordination disorder. Children with dyspraxia demonstrate a delay in achieving developmental movement milestones, such as rolling over, sitting, standing and walking.
  
  
• Cerebellar degeneration. This group of non-specific conditions involves atrophy of the cerebellum, a part of the brain that is involved in balance and movement. When the spinal cord is also involved, it is termed spinocerebellar degeneration. Examples of cerebellar degeneration include Friedreich’s ataxia and Machado-Joseph disease. There are many possible causes of these conditions, though they are often hereditary. Cerebellar degeneration may also occur spontaneously or result from stroke, multiple sclerosis, cancer, alcohol abuse or vitamin deficiency.
  
  
• Neurodegeneration with brain iron accumulation. A rare, inherited movement disorder characterized by degradation of the nervous system. The disease typically starts in patients younger than age 10. They experience a great variety of symptoms, including jerky or slow writhing movements and distorting contractions of the muscles of the limbs, face and trunk. Eventually, the disease typically causes patients to require a wheelchair for mobility. This disease may also be referred to as Hallervorden-Spatz syndrome.

In addition, there are some disorders that have paralysis as the primary symptom. For example, locked-in syndrome involves the paralysis of all voluntary muscles other than those involved in eye movement. It is usually the result of damage to the pons, part of the brain stem that regulates communication between sections of the brain. The pons may be damaged by physical injuries to the brain, disease that destroys or degenerates the myelin sheath that protects nerve cells, diseases of circulatory or nervous system (e.g., Guillain-Barré syndrome) or medication overdose. Patients with locked-in syndrome remain conscious but are unable to speak or move.