Ataxia: causes, symptoms and treatments

Ataxia is a Greek term meaning “disorder”. We refer to the ataxia as a clinical sign characterized by a lack of coordination of movements: lack of stability of the gait; clumsiness or weakness of upper, lower limbs, body or eye movements, etc. following damage to the central nervous system (CNS).

In general, ataxia is usually secondary to damage to the cerebellum or its efferent or afferent nerve pathways, although other structures in the brain can cause this symptomatology. In this article, we will review the characteristics of this phenomenon.

Symptoms of ataxia

Although the main features of ataxia are incoordination of the limbs and jerky movements of the eyes, other types of symptoms can occur. However, all of the symptoms of ataxia are related to the ability to move parts of the body. These signs indicating that ataxia is affecting the normal functions of the body are described below.

  • Speech problems.
  • Difficulties in visuospatial perception due to oculomotor incoordination.
  • Visuoconstructive apraxia due to incoordination.
  • Dysphagia – swallowing problems -.
  • Difficulty walking, with a tendency to open the legs.
  • Total loss of walking ability.

As we said, at the clinic,
ataxia usually presents itself as a sign that can manifest itself in various acquired pathologies that is to say: cerebral infarctions, tumors, craniocerebral trauma, etc. – although it can also appear as an isolated disease in its hereditary forms.

Classifications (types of ataxias)

We could classify ataxia according to different criteria, although in this review
we will explain the main types of ataxia depending on whether the pathology is acquired or hereditary. Another possible classification method would be based on areas of the central nervous system that show lesions or abnormalities that could produce ataxia.

1. Acquired ataxias

The fact that ataxia is acquired implies that it occurs as a result of a major pathology from which the patient suffers. Thus, cerebral infarctions, cerebral anoxia – lack of oxygen in the brain -, brain tumors, trauma, demyelinating diseases – multiple sclerosis – are frequent causes of ataxia.

Among other less common causes, we might find birth defects, infections, other autoimmune diseases, human immunodeficiency virus, Creutzfeldt-Jakob disease, etc. In general,
For ataxia to occur, these conditions must damage the cerebellum or related structures such as the spinal cord., Thalamus or dorsal root ganglia. A very common cause of ataxia is cerebellar hemorrhage.

History, case study, and appropriate selection of diagnostic tests are necessary to find the correct etiology. Treatment will focus on the intervention of the acquired pathology and the prognosis will depend on the severity of the lesions.

2. Hereditary recessive ataxias

Unlike acquired ataxias, these types of ataxia usually start early, during childhood or between the ages of 20 and 30. The fact that the disease is recessive implies that we must have inherited two equal copies of the “defective” gene from our parents.

This implies that a large population is simply a carrier of the disease even if it does not manifest itself, because having a “healthy” gene is enough to prevent it from developing. In this group we find some of the most common types of ataxia such as Friederich’s ataxia or ataxia-telangiectasia.

2.1. Friederich’s ataxia

It is the most common type of inherited ataxia. Its prevalence in developed countries is estimated to be 1 person per 50,000 cases. Its onset usually occurs in childhood, with walking problems, clumsiness, sensory neuropathy, and abnormal eye movements. Other less common consequences can be skeletal deformities and hypertrophic myocardipathy.

As the disease progresses, dysarthria – alteration of the articulation of words -, dysphagia – difficulty swallowing -, weakness of the lower limbs, etc. they are more apparent. It is estimated that between 9 and 15 years of onset of symptoms, the person loses the ability to walk.

This clinical picture is a consequence of the neurodegeneration of the ganglion cells of the dorsal root, the spinocerebellar pathways, the cells of the dentate nucleus – a deep nucleus of the cerebellum – and the cortico-spinal pathways. Purkinge cells – the main cells of the cerebellum – are not affected. The neuroimaging study generally does not show any apparent involvement of the cerebellum.

There is currently no cure and the treatments given are usually symptomatic.. The risk due to dysphagia, cardiomyopathy, etc., means that patients need to be monitored regularly. Several clinical trials are underway to observe the potential of various drugs such as gamma interferon, among others.

2.2. Ataxia telangiectasia

With an estimated prevalence of 1 case between 20,000 and 100,000 cases, ataxia-telanigectasia (AT) is the most common cause of recessive ataxia in patients under 5 years of age. As the disease develops, one can find hypotonia – a decrease in muscle tone -, polyneuropathy – damage to the peripheral nervous system -, oculomotor apraxia – problems changing the gaze to a stimulus to be fixed -, etc. Patients with AT usually have immune deficiencies that cause recurrent lung infections.

In the neuroimaging study, atrophy of the cerebellum can be observed, unlike Friedrich’s ataxia.. As in the previous case, treatment is aimed at the symptoms and there is no cure.

2.3. Other hereditary recessive ataxias

We find many more types of hereditary ataxias such as ataxia with oculomotor apraxia, Cayman ataxia, ataxia with vitamin E deficiency, infantile spinocerebral ataxia, etc.

3. Dominant hereditary ataxias

Dominant hereditary ataxias
they occur in every generation of a family with a 50% risk of contracting the disease from one of the parents. In this case, only one copy of the affected gene is enough to develop the disease. Depending on the course of the disease, it can be divided into episodic or progressive. There are different genetic tests for the diagnosis of these pathologies. As in the previous cases, there is no cure.

Ataxia and apraxia: they are not the same

From a neuropsychological point of view,
the biggest differential diagnosis to make is to distinguish ataxia from apraxia. Although they can lead to similar cognitive deficits, especially in acquired forms, they are clinically significantly different. Apraxia is defined as an impairment in the performance of certain movements learned in response to a command and out of context that is not attributable to sensory or motor impairments, lack of coordination or deficits in attention.

Ataxia, on the other hand, is a motor coordination deficit as such. Even if a patient is unable to perform the required action on a command, it will be due to a motor impairment. In apraxia, the problem arises because “verbal input” – that is, command – cannot be associated with motor response or “motor output”.

On another sideIn apraxia, we should not find other problems such as unsteadiness of walking, Swallowing problems, etc. Thus, in these cases, neurological evaluation is mandatory if one observes signs incompatible with apraxia. However, it should also be noted that the two manifestations clinics may present concomitantly.

The incidence of ataxia nationwide

With the prevalences that we have mentioned in the case of ataxia in its hereditary form, we can consider these diseases as rare – being in Europe a rare disease which occurs one case every 2000 people.
When diseases are classified as rare, it is usually more difficult to advance their research to find effective treatments.

Moreover, as we have seen, the hereditary forms of the disease would mainly affect children and young people. This has led to the emergence of various non-profit associations that promote the treatment, dissemination and improvement of the quality of life of these patients. Among them are the Catalan Association of Hereditary Ataxia, the Sevillian Association of Ataxia and the Madrid Association of Ataxia.

conclusions

Ataxia, although not widespread in its hereditary manifestation,
it is a disorder that affects the activities of daily living and independence in the lives of many people, Especially among youth. In addition, pharmaceutical and commercial priorities are slowly advancing research in this area, so treatment proposals focus on palliative care.

That is why its existence must be revealed and its effects known. Each step, no matter how small, can represent an improvement in the quality of life of these patients, with the relief of the healthcare system that this implies. The study and development of early detection and automation of treatment systems will benefit patients, relatives, caregivers and healthcare professionals. When we move forward in these areas, we all come out ahead, and for this reason, we need to raise awareness and support these social causes.

Bibliographical references:

books:

  • Arnedo A, Bembire J, Tiviño M (2012). Neuropsychology through clinical cases. Madrid: Editorial Mèdica Panamericana.
  • Junqué C (2014). Textbook of Neuropsychology. Barcelona: Synthesis

articles:

  • Akbar U, Ashizawa T (2015). Ataxia. Neurol Clin 33: 225-248.
  • Delatycki MB, Williamson R, Forrest SM (2000). Friedreich’s ataxia: an overview. Journal of Medical Genetics 37: 1-8.
  • Manto M, Marmolino D (2009). Cerebellar ataxias. Current Opinion in Neurology 22: 419-429.
  • Matthews BR, Jones LK, Saad DA, Aksamit AJ, Josephs KA (2005). Cerebellar ataxia and Whipple’s disease of the central nervous system. Neurology Archives 62: 618-620.
  • Pandolfo M (2009). Friedreich’s ataxia: the clinical picture. J Neurol 256 (Suppl 1): 3-8.

Leave a Comment