CEREBELLAR ATAXIA: SYMPTOMS, CAUSES, TREATMENT - NEUROPSYCHOLOGY - 2024

The cerebellar ataxia is a neurodegenerative disorder characterized by progressive atrophy of the cerebellum, resulting in a loss of neurons located in this area (Purkinje cells). Thus, a deterioration of motor function, balance, gait and speech is mainly generated.

Cerebellar ataxia is one of the most common motor disorders in neurological diseases. Scientists have described about 400 types of this ataxia. It is caused by damage that affects the cerebellum, as well as its reception and exit routes.

Figures 68 and 69 from the book «Cerebellar functions» by André Thomas, number 12 of the series of monographs on nervous and mental diseases, published by the Journal of Nervous and Mental Diseases (1912). The illustrations show the altered gait of a woman with cerebellar atrophy.

The cerebellum is one of the largest structures in our nervous system and can contain more than half of the brain's neurons. It is located in the back and lower part of the brain, at the level of the brain stem.

Studies have shown that neurons located in the cerebellum are related to movement patterns, participating in motor functions. Specifically, this structure is responsible for planning sequences of motor movements of the whole body, coordination, balance, the force used or the precision of movements.

Cerebellum (yellow)

In addition, it seems to exercise control over cognitive functions such as attention, memory, language, visuospatial functions or executive functions. That is, it regulates the capacity, speed and maintenance of these to achieve the objective of the task. It helps detect and correct errors in thinking and behavior. It seems to play an important role in procedural memory as well.

Therefore, a patient with cerebellar ataxia may have difficulties in regulating his own cognitive processes, as well as the movements of his body.

Generally this disease occurs in the same way in men and women. Regarding age, it can appear in both children and adults. Obviously, if it is due to degenerative processes in which the damage progresses over time, cerebellar ataxia affects older people more.

Causes

Cerebellar ataxia can occur from multiple causes. These can be broadly divided into hereditary and acquired. Next, we will see the most common:

-Hereditary

There are several diseases that are autosomal recessive. That is, they need the mutated gene to be transmitted from the mother and from the father in order for it to be inherited. Therefore, it is less frequent:

- Friedreich's ataxia: it is a hereditary neurodegenerative disease. It affects the nervous tissue of the spinal cord and the nerves that control muscles.

- Ataxia-Telangiectasia: also known as Louis-Barr syndrome, it is produced by the mutation in the ATM gene, located on chromosome 11. Its first symptom is an unstable gait, it is observed that the child leans to one side and staggers.

- Abetalipoproteinemia or Bassen-Kornzweig syndrome: caused by a defect in the gene that orders the body to produce lipoproteins. This makes it difficult to digest fat and certain vitamins, in addition to cerebellar ataxia.

- Mitochondrial disorders : disorders caused by protein deficiency in the mitochondria, which are related to metabolism.

Among the hereditary causes there are others that are autosomal dominant. That is, it is only necessary to receive an abnormal gene from one of the two parents to inherit the disease. Some are:

- Spinocerebral ataxia 1: it is a subtype of spinocerebellar ataxia. The affected gene is located on chromosome 6. It is characterized in that the cerebellum undergoes a process of degeneration and occurs commonly in patients older than 30 years.

- Episodic ataxia: it is a type of ataxia that is characterized by occurring sporadically and lasting a few minutes. The most common EA-1 and EA-2.

Acquired

The causes of cerebellar ataxia can also be acquired. Either by viruses or other diseases that affect the nervous system and that could compromise the cerebellum. Among the most common are:

- Congenital malformations: such as Dandy-Walker syndrome, Joubert syndrome and Gillespie syndrome. In all of them there are malformations in the cerebellum that cause cerebellar ataxia.

- Head injuries: they occur when physical damage occurs to the brain, affecting the cerebellum. It usually appears due to accidents, blows, falls, or other external agents.

- Brain tumors: a brain tumor is a mass of tissue that grows in the brain and can affect the cerebellum, pressing it.

- Hemorrhage in the cerebellum.

- Exposure to toxins such as mercury or lead.

- Deficiency acquired vitamin or metabolic disorders.

- Consumption of alcohol or antiepileptic drugs.

- Chickenpox: which is an infectious disease caused by the varicella-zoster virus. It usually occurs in children between 1 and 9 years of age.

Although it initially appears as a skin rash and is benign, it can have more serious complications such as cerebellar ataxia.

- Epstein-Barr virus: it is a virus of the herpes-virus family and one of its symptoms is inflammation of the lymphatic glands. Although it can present in childhood without symptoms, in adults it can be more serious. One of its complications is cerebellar ataxia.

- Coxsackie virus: it is a virus that lives in the digestive tract of humans. It thrives in tropical climates. It mainly affects children and its main symptom is fever, although in severe cases it can cause cerebellar ataxia.

- Paraneoplastic cerebellar degeneration: it is a very infrequent and difficult to diagnose disease where progressive cerebellar degeneration occurs. The most common cause of this disorder is lung cancer.

Symptoms

Cerebellar ataxia is characterized by the following symptoms:

- Tremors: that appear when the patient tries to carry out or maintain a posture.

- Dysynergia: inability to move the joints simultaneously.

- Dysmetria: the patient is not able to control the range of movement, and does not have enough balance to stand. He is unable to perform fine motor tasks such as writing or eating.

-Adiadochokinesia: that is, the inability to perform rapid alternating and successive movements. They may have trouble inhibiting one impulse and replacing it with an opposite one.

Thus, he has difficulty alternating supination (palm up) and pronation (palm down) movements of the hand.

- Asthenia : characterized by muscle weakness and physical exhaustion.

- Hypotonia: decreased muscle tone (degree of muscle contraction). This causes problems in standing (standing upright and on the legs). As well as to walk.

- Stumbling and unsteady gait.

- Nystagmus: uncontrollable or repetitive movements of the eyes.

- Dysarthria: speech disorders, there is a difficulty in articulating sounds and words. Slow production of the voice, excessive accentuations and pseudo-stuttering may occur.

- Alterations in executive functions such as planning, flexibility, abstract reasoning and working memory.

- Changes in behavior such as dullness, disinhibition or inappropriate behavior.

- Headaches.

- dizziness

Diagnosis

The doctor must perform a comprehensive examination that may include a physical exam, as well as specialized neurological tests.

The physical exam is necessary to check hearing, memory, balance, vision, coordination, and concentration. Specialized exams include:

- Electromyography and nerve conduction study: to check the electrical activity of the muscles.

- Lumbar puncture: to examine the cerebrospinal fluid.

- Imaging studies such as computed tomography or magnetic resonance imaging to look for damage to the brain.

- Complete blood count or hemogram: to observe if there are abnormalities in the number of blood cells and to check general health.

Treatment

When cerebellar ataxia appears due to an underlying disease, treatment will be aimed at alleviating the main cause. Measures are also advised to improve as much as possible the patient's quality of life, mobility and cognitive functions.

Virus as cause

When cerebellar ataxia is caused by a virus, there is usually no specific treatment. Full recovery is achieved in a few months.

If they are other causes, the treatment that will vary depending on the case. Thus, surgery may be necessary if the ataxia is due to a hemorrhage in the cerebellum. Instead, if you have an infection, antibiotic drugs can be prescribed.

Lack of vitamin E

Also, if it is an ataxia due to lack of vitamin E, high doses of supplements can be administered to alleviate this deficiency. This is an effective treatment, although recovery is slow and incomplete.

Anticoagulant drugs

Anticoagulant drugs may be indicated when there are strokes. There are also specific medications to treat inflammation of the cerebellum.

Neurodegenerative cerebellar ataxia

When it comes to neurodegenerative cerebellar ataxia, like other degenerative diseases of the nervous system, there is no cure or treatment that fixes the problem. Rather, steps are taken to slow the progression of damage. As well as improving the life of the patient as much as possible.

Exams

Scientists insist that thorough testing is necessary to determine the cause, as advances in knowledge of pathogenesis (causes) will aid in the design of new treatments.

Neurorehabilitation

Currently there are many studies that point to neurorehabilitation, which implies a great challenge. What is sought is to improve the functional capacity of the patient by compensating for their deficits, through techniques that improve their adaptation and recovery.

This is accomplished using neuropsychological rehabilitation, physical or occupational therapies, as well as others that aid speech and swallowing. The use of adaptive equipment to help the patient self-help, as well as nutritional counseling, can also be very helpful.

Drugs to treat symptoms

There are some medications that appear to be effective in improving balance, incoordination, or dysarthria. For example, amantine, buspirone, and acetazolamide.

Tremors can also be treated with clonazepam or propanonol. Gabapentin, baclofen, or clonazepam have also been prescribed for nystagmus.

Help with daily tasks

The person suffering from cerebellar ataxia may require help with their daily tasks due to impaired motor skills. You may need coping mechanisms for eating, moving around, and talking.

Clarifications

It should be clarified that some of the cerebellar syndromes are associated with other characteristics that involve other neurological systems. This can lead to motor weakness, vision problems, tremors, or dementia.

This can make ataxic symptoms difficult to treat or be made worse by the use of certain medications. For example, due to the side effects of medication.

Despite there is no cure for most cerebellar ataxias, treating symptoms can be very helpful in improving the quality of life of patients and preventing complications that could lead to death.

The supports that should be provided to the patient should be focused on education about the disease, as well as the support of groups and families. Also some families may seek genetic counseling.

Misinformation, fear, depression, hopelessness, as well as isolation, financial worry, and stress can often cause more harm to the patient and their caregiver than ataxia itself.

For this reason, psychological therapy must also help the family and be part of the patient's recovery, so that he can cope with his condition.

Forecast

If cerebellar ataxia is due to a stroke or an infection or bleeding in the cerebellum, the symptoms may become permanent.

Patients are at risk of developing depression and anxiety, due to the physical limitations that their condition implies.

Secondary complications can also occur which may include lack of physical condition, immobility, weight gain or loss, skin breakdown, as well as recurrent lung or urinary infections.

Respiratory problems and obstructive sleep apnea can also occur.

As mentioned above, the patient's quality of life can progressively improve if sufficient supports are provided.

References

1. Fernández Martínez, E., Rodríguez, J., Luis, J., Rodríguez Pérez, D., Crespo Moinelo, M., & Fernández Paz, J. (2013). Neurorehabilitation as an essential alternative in the therapeutic approach of cerebellar ataxias. Cuban Journal of Public Health, 39 (3), 489-500.
2. García, AV (2011). Cerebellar ataxia. REDUCA (Nursing, Physiotherapy and Podiatry), 3 (1).
3. Marsden, J., & Harris, C. (2011). Cerebellar ataxia: pathophysiology and rehabilitation. Clinical rehabilitation, 25 (3), 195-216.
4. Mitoma, H., & Manto, M. (2016). The physiological basis of therapies for cerebellar ataxias. Therapeutic advances in neurological disorders, 9 (5), 396-413.
5. Perlman, SL (2000) Cerebellar ataxia. Curr Treat Options Neurol, 2: 215.
6. Ramirez ‐ Zamora, A., Zeigler, W., Desai, N., & Biller, J. (2015). Treatable causes of cerebellar ataxia. Movement Disorders, 30 (5), 614-623.
7. Smeets, CJLM, & Verbeek, DS (2014). Cerebellar ataxia and functional genomics: identifying the routes to cerebellar neurodegeneration. Biochimica et Biophysica Acta (BBA) -Molecular Basis of Disease, 1842 (10), 2030-2038.