Movement disorders are a group of pathologies characterized by the decrease, loss or excessive presence of body movements that seriously affect the quality of life of people who suffer from them.

In this article we explain what they are, what types of movement disorders there are and what their treatment is .

What are movement disorders?

Movement disorders include a group of disorders in which the regulation of motor activity is impaired and there are alterations in the form and speed of body movements , without force, sensation or cerebellar function being directly affected.

These types of disorders can be caused by diseases, genetic conditions, medications, or other factors. In addition, a movement disorder may be the only clinical expression of a specific disease or may be part of a set of neurological manifestations of more complex diseases .

The risk of developing a movement disorder increases with age. A previous history of stroke and the presence of cardiovascular risk factors, such as having high blood pressure or diabetes, may increase the risk of developing a movement disorder related to circulation.

Types of movement disorders

From a clinical perspective, two large groups of movement disorders can be differentiated : the hypokinetic ones, characterized by slow or decreased movements; and the hyperkinetic ones, characterized by an excess of movements or the presence of abnormal involuntary movements.

Hypokinetic movement disorders

Movement disorders or hypokinetic syndromes include all those pathologies of movement in which the movement is impoverished and slowed down, affecting the associated voluntary and spontaneous movements.

The most frequent hypokinetic disorder is the so-called parkinsonian syndrome , which consists of an alteration in the functioning of the cortical-subcortical motor circuit in charge of correctly generating body movements. This syndrome presents several common symptoms, such as: bradykinesia, tremors and rigidity.

In bradykinesia, at the beginning there is a slowing down of the motor ; then, in the performance and completion of the voluntary movement there are repetitive or alternating movements of the extremities, with a progressive reduction in speed and amplitude.

Three components can be distinguished in bradykinesia: motor slowing or bradykinesia itself, akinesia or poor spontaneous movement (with delayed initiation of movement or switching between fluid movements) and hypokinesia, which consists of a decrease in range of motion.

As for tremors, the most characteristic in hypokinetic movement disorders is the low frequency (between 3 and 6 hz) rest tremor. This tremor usually appears when the muscles have not been activated and decreases when a specific action is performed. An action tremor may also exist, but it is less frequent. However, a parkinsonian syndrome may exist without evidence of tremors.

Finally, is the name given to the resistance of a part of the body to passive mobilization . In parkinsonian syndromes it can present itself in the form of a cogwheel, where brief episodes of opposition alternate with episodes of relaxation.

It can also be manifested by a constant resistance, called a lead tube, in which the intensity of the resistance remains constant throughout the range of movement, whether extended or flexed (without it changing when the speed at which the body part moves varies, unlike spasticity).

Hyperkinetic movement disorders

Hyperkinetic movement disorders are those in which there is an excess of abnormal and involuntary movements. The main forms are: tics, chorea, ballism, athetosis, myoclonus and dystonia. Let’s see what each of them consists of.

1. Tics

Tics are stereotyped movements, without a specific purpose , that are repeated in an irregular way. They are characterised by the fact that they can be voluntarily suppressed and are increased by factors such as stress or anxiety. They can be classified into primary tics (sporadic or hereditary) and secondary tics, motor and vocal, simple and complex.

The most severe form of multiple tics is known as Gilles de la Tourette syndrome , an autosomal dominant inherited disorder associated with defects in chromosome 18. This disorder manifests itself with multiple motor tics and one or more phonic tics. These tics occur several times a day, virtually every day for more than a year. The severity and complexity of these tics may vary over time.

To treat this type of abnormal movements, such as tics, pharmacological treatment based on neuroleptics, clonidine and antidopaminergic drugs is usually necessary.

2. Koreas

Chorea is a movement disorder that refers to irregular, rapid, uncoordinated and continuous arrhythmic movements affecting any part of the body.

The causes of this movement disorder are multiple and rare: hereditary (Huntington’s disease, neuroacanthocytosis, Fahr’s syndrome, etc.), metabolic and endocrine (hyperparathyroidism, hyperthyroidism, etc.), vasculitis (e.g. systemic lupus erythematosus), due to basal ganglia stroke and pharmacological.

Huntington’s disease is the most common type of hereditary chorea . It can start at any age, although it has a higher incidence in people between 40 and 50 years old, slowly evolving towards death over a period of 10 to 25 years. Survival is shorter among patients with juvenile onset of the disease.

Pneumonia and a series of other intercurrent infections are often the most common cause of death. There is a family history in almost all patients with Huntington’s disease. Huntington’s disease is an autosomal dominant inherited disorder with complete penetrance, and is the result of a genetic defect on chromosome 4.

3. Ballism

Ballism is a severe form of chorea that produces abrupt, involuntary and wide movements . It usually appears suddenly but can develop over days or even weeks. This movement disorder usually subsides during sleep.

The movements of ballism are so violent that they can lead to death by exhaustion or cause joint or skin injuries in the person suffering from it. It frequently affects a hemicorpse (hemibalism), although sometimes it may affect only one limb (monobalism), both lower limbs (parabolism) or, in more rare cases, all four limbs (bibalism or lateral balism).

4. Athetosis

Athetosis is a movement disorder that occurs in a quarter of all cases of cerebral palsy . This disorder is caused by lesions in the extrapyramidal system and manifests itself in slow, snaky, uncontrolled, involuntary and purposeless movements.

The muscles of the mouth are affected, which is why patients suffering from athetosis often have language disorders. It can also occur as an abnormal reaction to estrogen or some antidepressant drugs.

5. Myoclonus

Myoclonias consist of involuntary, sudden and brief movements caused by active muscle contraction or abrupt inhibitions of muscle tone . They can be classified, according to their origin, as: cortical, subcortical, spinal or peripheral.

Because of their distribution, they are classified as focal (involving a discrete muscle group), segmental or generalized (generally of progressive cause and associated with epileptic disorders). And because of their form of presentation, they can be spontaneous, action or reflex myoclonies.

6. Distonies

This type of movement disorder occurs in an involuntary and sustained manner, and produces a deviation or torsion of an area of the body . The person suffering from them cannot eliminate them voluntarily and they occur due to specific movements or actions.

They are usually suppressed during sleep. It is common for them to occur along with other movement disorders such as essential tremors. There is also a “dystonic tremor”, which arises when the patient tries to move a part of his body in the opposite direction to the force of the dystonia.

Treatment

Movement disorders should be treated according to their aetiology and severity. One of the treatments applied is deep brain stimulation , which significantly reduces involuntary movements. This is produced by generating electrical pulses in the brain, with the patient himself adjusting the intensity of the impulse to control his symptoms.

Another treatment that has been used in these cases is nuclear magnetic resonance-guided focused ultrasound (MRgFUS), a procedure that uses sound energy beams to remove a small volume of brain tissue without affecting adjacent areas.

Use of drugs in therapy

Sometimes drugs are also used to alleviate symptoms, including

1. Beta-blockers

Medications that lower blood pressure , so that shaking and other physical symptoms of many movement disorders are reduced.

2. Anti-epileptic drugs

These drugs are used to reduce tremors (for example, in parkinsonian syndromes), especially those produced in the hands.

3. Anticholinergics

These drugs are used to treat dystonias, by reducing the effects of acetylcholine, a neurotransmitter involved in muscle contractions, causing a decrease in tremors and stiffness.

4. Anxiolytics

Anti-anxiety drugs act on the central nervous system by causing muscle relaxation , which relieves, in the short term, the effects of shocks and spasms.

5. Botulinum toxin

This toxin acts by blocking the neurotransmitters responsible for muscle spasms, helping to stop them.

Bibliographic references:

  • Jankovic J. Treatment of hyperkinetic movement disorders. Lancet Neurol 2009; 8: 844 – 856.
  • Leon-Sarmiento FE, Bayonne-Prieto J, Chain Y. Neuronal plasticity, neurorehabilitation and movement disorders: the change is now Act Neurol Col 2008; 24: 40 – 42.