Ataxia is the defect in normal movements like walking, speaking, eating swallowing etc. It is caused most commonly by damage to the brain stem or cerebellum that regulates movements.
Symptoms of ataxia
One of the earliest symptoms noticed in ataxia is loss of balance and co-ordination in the limbs. The limbs may feel numb or may lose strength altogether.
Walking becomes difficult as the sufferers may have to keep their feet apart to prevent falling over. A wheelchair may be required for transportation in most patients with ataxia sooner or later.
There is loss of co-ordination of fine motor activities such as writing, eating etc. the hands may shake when the person tries to use them.
As the condition progresses there is difficulty in speaking and the condition affects the mouth and the tongue. Speech starts to slur and becomes unclear. Slowly the capacity to swallow food becomes difficult with the person often choking on food.
There may be unusual and involuntary eye movements. The eyes roll upwards and below or sideways rapidly of their own accord. This is called oscillopsia.
Some ataxias also result in disturbance of bladder and bowel movements as well.
There may be cognitive or memory loss accompanied by depression and/or anxiety.
Three main types of ataxia
There are over 50 to 100 types of ataxia. Ataxias are classified under three broad headings:-
Hereditary ataxia – one that runs in the families and is inherited genetically. The symptoms may develop slowly over many years.
Idiopathic late onset Cerebellar ataxia (ILOA) – in this type of ataxia the cerebellum is progressively damaged due to unexplained causes leading to ataxia.
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.
Friedreich’s ataxia – this is the commonest type of hereditary ataxia and makes up for almost half of the cases of hereditary ataxias.
Symptoms usually first begin to appear in childhood between the ages of eight and 15 years. There is definitive deformity of the feet, such as high arches or abnormal curvature of the toes called hammer toes. In addition the spine may be curved to one side called scoliosis.
There is damage to the optic nerve resulting in blindness, and there may be hearing loss as well. Patients are often diabetic and may suffer from hypertrophic cardiomyopathy resulting in abnormal thickening of the muscles of the heart.
Ataxias due to vitamin A deficiency – this is a rare form of ataxia that begins in childhood. Lack of vitamin E leads to nerve damage. The symptoms are similar to Friedreich’s ataxia but the symptoms may be relieved by providing Vitamin E as supplements in the body.
Ataxia-telangiectasia – this is a rare type of hereditary ataxia and is seen in 1 in 100,000 babies. Symptoms usually begin in early childhood and progressively worsen with age.
The name of the condition is derived from the small, spider-like clusters of red blood vessels in the corner of their eyes and on their cheeks called telangiectases. This condition usually co-exists with a weak immune system making the children more vulnerable to infections.
By the age of 10 there is need for a wheelchair to move the child around. Many children with the condition also develop cancers like acute lymphoblastic leukaemia or lymphomas.
Spinocerebellar ataxias – are a variety of ataxias. These affect around one in every 100,000 persons. The symptoms usually manifest once the person reaches adulthood. The symptoms may be first seen when the person is in his or her 30’s or may begin when he or she is in their 70’s. Occasionally some types of spinocerebellar ataxias may begin in childhood as well.
The condition is manifested by muscle cramps and stiffness, lowered sensation of hands and feet, memory loss or difficulties in language, urinary incontinence, slow eye movements, restless legs syndrome, migraine, vertigo and progressive loss of vision.
Episodic ataxia – this is another rare type of hereditary ataxia. There are bouts or episodes of ataxia interspersed with normal periods with no ataxia. Bouts may last for minutes to hours.
Bouts come after specific triggers such as stress, exercise or excitement. The symptoms begin in adolescence and may disappear completely after the person reaches middle age.
The symptoms are similar to hereditary ataxias but they are rapid in onset. In addition they may result after certain diseases or conditions such as strokes, multiple scleroses etc.
Idiopathic late onset cerebellar ataxia (ILOA)
These ataxias are rare and generally begin around the age of 50 and then progressively worsen with time. There are symptoms affecting walking, balance, disturbed sleep, double vision, cognitive changes, memory loss, and urinary incontinence. etc.