By Dr Ananya Mandal, MD
Ataxia is a form of movement disorder. There is loss of balance and physical co-ordination leading to difficulty in walking normally.
The Cerebellum of the brain is normally responsible for maintaining balance and co-ordination. Ataxia occurs when there is damage to the cerebellum. It may also result from damage to other parts of the nervous system.
Symptoms of ataxia
Ataxia leads to difficulty in balance, walking, speaking, vision, swallowing, performing tasks requiring high degree of motor control such as writing and eating etc.
The symptoms vary in intensity depending on the degree of damage to the parts of the brain regulating balance and co-ordination between motor movements.
What causes ataxia?
Ataxia is commonly caused by loss of function in the cerebellum. The cerebellum is located toward the back and lower part of the brain.
The central part of the cerebellum can control complex movements of walking, eye movements and stability of the head and trunk.
Other parts of the cerebellum help to coordinate smaller movements such as speech, eyes and swallowing.
Ataxia results when there is dysfunction in the pathways leading into and out of the cerebellum.
Types of ataxia
There are several types of ataxia which could be of over 100 types. Overall ataxia may be classified under three broad categories:-
Hereditary ataxia – one that runs in the families and is inherited genetically. The symptoms may develop slowly over many years
Acquired ataxia – the symptoms develop rapidly. This type of ataxia may occur due to injury to the brain or due to a stroke or other disease of the brain that affects movements and co-ordination.
Idiopathic late onset Cerebellar ataxia (ILOA) – in this type of ataxia the cerebellum is progressively damaged due to unexplained causes leading to ataxia.
Of the three types of ataxia, acquired ataxia is the commonest type and is associated with brain infections or encephalitis, stroke and multiple sclerosis. All ages may be similarly affected.
Both hereditary and ILOA types of ataxia are relatively rare. The commonest type of hereditary ataxia is Friedreich’s ataxia that makes up for almost half the cases of hereditary ataxias. It affects an estimated 1 in every 50,000 people in England annually.
Hereditary ataxias may begin in childhood and progress as the child grows. ILOA on the other hand affects middle aged adults first.
Diagnosis and treatment of ataxia
Ataxia is diagnosed clinically. It is a symptom of an underlying cause rather than a disease in itself. Diagnosis is made using clinical examination as well as laboratory testing and imaging studies.
At present there is no cure for ataxia. If the underlying cause can be found, the disease may be treated using medications or approaches that ease the symptoms. For example, if ataxia is the result of a vitamin deficiency, the deficiency may be corrected to achieve symptom relief.
There are no specific treatments available for hereditary ataxia and ILOA and these tend to worsen over time. Treatment usually revolves around rehabilitation of these patients and making them as self sufficient or independent as possible for as long as possible.
Outcome or prognosis of ataxia
The cause determines the prognosis or outcome of ataxias. Those with hereditary ataxias, show a progressive deterioration. Individuals with Friedreich’s ataxia die in their thirties and more severe cases have a shorter survival.
Hereditary ataxia and ILOA generally progressively worsen whereas acquired ataxias may be sudden in onset and may resolve with time and treatment.
Ataxias after a stroke for example may become better as the brain areas related to motor coordination and movement heals.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)