Ataxia: what does it mean?

Ataxia is a disorder in the coordination of movement sequences that is usually taken for granted in healthy people. It manifests itself in excessive movements in processes that require a relatively high level of coordination, such as running or writing. For example, if a person with ataxia tries to grab a glass, they often do not succeed but miss it or knock it over. On the one hand, ataxia is a symptom that can have different causes; on the other hand, the term describes a large group of neuronal diseases. Ataxia originates in the brain or spinal cord (central nervous system, CNS). Some forms of ataxia become more and more severe over time (progressive ataxia) or occur in attacks (episodic). We put symptoms

What is ataxia?

In the case of ataxia, the ability to coordinate movements is impaired, so those affected often find it challenging to carry out everyday movements such as gripping, walking or writing. There are many different forms of ataxia. Depending on whether the brain or the spinal cord is restricted, there can be different manifestations. It can also happen that only one-half of the body is affected by the disorder (hemiataxia). 

 

forms of ataxia

The following forms of ataxia are distinguished:

• Cerebellar ataxia (the cerebellum is affected)
• Spinal ataxia (the origin of the disease is in the spinal cord)
• Spinocerebellar ataxia (always hereditary causes)

What is Cerebellar Ataxia?

Cerebellar ataxia (also cerebellar ataxia) is a disorder in the cerebellum. The function of the cerebellum can be divided into three subgroups:

• Eye movements (oculomotor)
• Deliberate target movements (e.g. grasping objects or tongue movements when speaking)
• “Automatic” movements such as walking or standing (support and gait motor skills)

This also results in a wide-ranging combination of symptoms: If eye movements are disturbed, objects can no longer be reliably fixed in one’s gaze. The eyes overshoot when moving and must first be corrected to set the correct viewing window. If an object is then looked at, the fixation can often not be maintained and the eyes swing away again.

Target motor disorders affect all movements a person consciously performs, such as pouring water into a glass, grasping objects, writing, speaking, and more. Symptoms such as trembling during movements, wrong grasping (optic ataxia = disorder of hand-eye coordination), clumsy movements, misjudgment of strength and speed when performing movements or sluggish speech (dysarthria) appear. The best way to visualize the combination of symptoms is to observe someone who has been drinking alcohol, as the cerebellum is very sensitive to it. 

Disturbances of the supporting or gait motor function also present as a very wide-legged or short-step gait or like the staggering of a drunk person (gait ataxia). The most common form of cerebellar ataxia is, therefore, acute alcohol intoxication, which is triggered by too much alcohol but disappears entirely after sobering up. Difficulty standing or sitting upright is called trunk ataxia.

 

What is Spinal Ataxia?

In the case of spinal or sensory ataxia, the sensory pathways in the spinal cord that give the brain information about the body’s position are damaged. Thanks to them, you know, for example, that you are making a fist even if you are not looking at your hand.

The symptoms are similar to those of cerebellar ataxia. Spinal ataxia can be differentiated from cerebellar ataxia by closing your eyes, for example, while standing. If the cerebellum is damaged, the eye control is already damaged, so there is no worsening of the symptoms with the eyes closed. In the example, you could stand as securely or unsteadily as with your eyes open. With spinal ataxia, the body uses its eyes to compensate for the missing information that it usually processes unconsciously. Therefore, an affected person could stand with closed eyes worse than with open ones.

What is Spinocerebellar Ataxia?

Spinocerebellar ataxias are hereditary forms of ataxia – one then speaks of hereditary ataxia. The best-known form is Huntington’s chorea (Huntington’s disease). Spinocerebellar ataxia usually occurs between the ages of 30 and 50.

Unfortunately, with the current state of medicine, there is no cure for this type of ataxia. The focus of therapy is to alleviate or suppress the symptoms. In a study with those affected, the drug riluzole was able to lead to an improvement in symptoms, but further research on its effectiveness is still pending.

How does ataxia develop?

Ataxia occurs when structures necessary for planning and executing movements are damaged. These structures are specific nerve cells in the brain and spinal cord.

Such damage is caused, for example, by substances that are supplied to the body from outside (for example, toxins such as alcohol) or by-products that are produced during the body’s metabolism . In addition, so-called “focal diseases” (focal = originating from a focus of disease) can also trigger ataxia as a symptom. This term includes, for example, tumours or abscesses, cerebral haemorrhage, cerebral infarction or multiple sclerosis.

An example of the second case, i.e. damage caused by products produced by the body, would include Huntington’s disease. In this disease, a defective protein is formed in the nerve cells due to genetic predisposition, which is deposited in the cells and permanently damages them.

 

Causes: where does ataxia come from?

Ataxia can be inherited (genetic ataxias) or develop throughout life. The second form is also known as acquired ataxia since it can be “acquired”. In addition, one speaks of sporadic degenerative ataxias when genetic and acquired causes can be ruled out.

Some underlying diseases can be acquired that can lead to ataxia or that can be a symptom of ataxia. These are primarily disorders of the cerebellum function. Possible acquired causes include but are not limited to:

• alcoholism
• other poisoning (e.g. from drugs or, in rare cases, from lead, mercury or pesticides)
• Underactive thyroid (hypothyroidism)
• Vitamin E deficiency ( vitamin E is an essential part of brain cell metabolism)
• Tumours (this is then referred to as paraneoplastic syndromes)
• Stroke (when relevant areas of the brain are damaged)
• Cerebral haemorrhage, cerebral infarction, inflammatory processes or abscess in the brain
• Infections such as syphilis, herpes zoster, Epstein-Barr virus, HIV or Lyme disease
• Wernicke encephalopathy (neurologic dysfunction caused by vitamin B1 deficiency; joint in alcoholism; also causes vitamin deficiency polyneuropathy, among other things)
• multiple sclerosis (an inflammatory disease of the central nervous system)

Ataxia with no known cause is called idiopathic ataxia.

Acquired forms of ataxia often have a better prognosis than hereditary ones. For example, if hypothyroidism is treated appropriately, the ataxia can disappear completely.

Diagnosis: How do you diagnose ataxia?

Ataxia is a symptom that can have many different causes. Therefore, a thorough diagnosis is required to determine the cause. This requires a thorough anamnesis (patient consultation, including clarifying a family history) and a clinical diagnosis. This means a specialist performs various physical and neurological examinations and combines the abnormalities into an overall picture. Such assessments include tests of the ability to coordinate or the function of the nervous system. Magnetic resonance imaging (MRI) of the brain also plays a crucial role in diagnosing.

Further examination methods must be used to distinguish the present type and predict the ataxia. Above all, it is essential to determine the causes of the ataxia. Hereditary ataxias are detected by molecular genetic tests, in which specific changes (mutations) in the DNA allow conclusions about the form of the ataxia. In the case of other causes of ataxia, blood tests or cerebrospinal fluid sampling (cerebrospinal fluid punctures), among other things, can provide information.

 

Distinguish ataxia from other diseases.

It is essential to distinguish the movement disorders caused by ataxia from other diseases – this is known as the differential diagnosis. Symptoms such as tremors, for example, can have a wide variety of reasons. A slight tremor at rest (resting tremor) occurs in most people without this being an indication of an illness.

To distinguish ataxia from other diseases, the time of onset is significant. In Parkinson’s disease, for example, there is increased tremor at rest (resting tremor), which improves as soon as a movement can be performed. In contrast, in ataxia caused by damage to the cerebellum, the tremors do not become apparent or worse until the movement is performed.

Apraxia can also be distinguished from ataxia. She also cannot perform targeted movements unrelated to a lack of coordination. Centres in the brain are often affected, which have to give the “command” to the muscles to move, but this no longer works.

Spasticity is also different from ataxia. Spasticity is characterized by involuntary movements with increased resting muscle tone, i.e. twitching movements and tremors at rest. Ataxia, on the other hand, is a coordination disorder, which is apparent when those affected try to perform complex movements such as running, waving or writing.

What helps with ataxia?

In the case of ataxia, which is not hereditary, the primary treatment is to treat the underlying disease. Depending on the severity of the nerve damage, the symptoms can disappear completely (e.g. in the case of cerebellar ataxia due to acute alcohol intoxication) or at least improve. Depending on the cause, therapy may require abstinence from alcohol, taking medication, or taking vitamins, for example.

Unfortunately, there is currently no causal therapy for the hereditary forms of ataxia. The focus is on physiotherapeutic treatments (physiotherapy) to alleviate the severity of the symptoms. Medication can also help with some forms of ataxia. 

Hereditary ataxia: forms, symptoms and treatment

Hereditary forms of ataxia include:

• Friedreich’s ataxia (most common hereditary variant)
• Chorea Huntington
• all spinocerebellar ataxias

The rare Fragile X-associated tremor Ataxia Syndrome (FXTAS) is also an inherited form of ataxia.

 

What is Friedreich’s Ataxia?

Friedreich’s ataxia (also called Friedreich’s ataxia or Friedreich’s disease ) is the most common inherited form of ataxia. It is inherited in an autosomal recessive manner, meaning the disease only occurs if modified genes are inherited from the mother and father. The cause of ataxia is a progressive degradation of the nerve cells (neurons) in the spinal cord (progressive dorsal column degeneration).

Friedreich’s ataxia is suspected if the following symptoms are combined:

• unsteady gait with trips and falls, Beginning in adolescence
• general clumsiness, first of the legs, later also of the arms (stance and gait ataxia)
• disturbed perception of vibrations
• absent muscle reflexes
• combined speech and voice disorder (dysarthria)
• Eye movement disorder: Doctors speak of depending on the severity of the disorder
  • Gaze nystagmus (nystagmus = involuntary, rhythmic movements),
  • Fixation instability (so-called eye tremor; eye shaking) or
  • Reduced vestibular-ocular reflex (vestibular-ocular reflex = ability of the brainstem to maintain stable visual perception even with a sudden head movement by moving the eyes in the opposite direction to the head rotation)
• Heart failure (hypertrophic cardiomyopathy)
• curvature of the spine (kyphoscoliosis)
• Hohlfuß (Hollow foot)
• above-average frequency of diabetes mellitus

If those mentioned above have specific symptoms, the diagnosis is made via a molecular genetic test, i.e., a genetic test, in which the respective DNA mutations for Friedreich’s ataxia can be detected.

Friedreich’s ataxia can only be treated symptomatically. Treatment options include physical therapy, occupational therapy, and speech therapy. In particular, an existing cardiac insufficiency must also be treated with medication. In this form of ataxia, treatment with riluzole may also improve the symptoms.

As the disease progresses, a wheelchair usually becomes necessary. Most people with Friedreich’s ataxia die of heart failure, which is why the disease is associated with a reduced life expectancy. 15 to 30 years after diagnosis, affected people usually have a severe disability.

What is Huntington’s disease?

Huntington’s disease is also an inherited form of ataxia. Unlike Friedreich’s ataxia, it is inherited in an autosomal dominant manner, which means that children of an affected person have a 50 per cent risk of also developing Huntington’s disease. As with Friedreich’s ataxia, genetic predisposition produces a faulty protein that permanently damages the nerve cells in the brain. Most people become ill around the age of 40.

Depression, irritability, and obsessive-compulsive disorders are often present even before the actual typical symptoms appear. The usual physical symptoms consist of increasingly pronounced, unwanted movements of the facial muscles and the arms and legs, which look like throwing a ball or kicking, for example. Slow, twisting movements and unnaturally overstretched joints (athetosis) can be observed in some of those affected. Dementia usually occurs after a long illness.

Huntington’s disease cannot be cured with the current state of medicine. However, the accompanying symptoms can be alleviated with supportive therapy, for example with the help of medication that has a movement-inhibiting effect, antidepressants and physical and occupational therapy.

Other hereditary forms of hereditary ataxia: Episodic ataxia

Hereditary or Hereditary Ataxia is a form that can be passed from parents to their children. In addition to Friedreich’s ataxia, this also includes episodic ataxia. It is characterized above all by the fact that it occurs repeatedly, which is why it is also called episodic.

People with this form of ataxia experience attacks of balance disorders that are associated with dizziness and vomiting. An attack can last from a few minutes to several days. The frequency of seizures also differs between those affected, ranging from once or twice a year to several times a week. The disease most often first appears in childhood or early adulthood.

You cannot cure Episodic Ataxia, but you can influence how often attacks occur. This includes avoiding triggers like stress, caffeine, alcohol, heat, and fever. In addition, a so-called carbonic anhydrase inhibitor can be administered, influencing brain metabolism.