What is Ataxia?
Ataxia is a condition where a person lacks muscle control during voluntary movements, such as picking up objects or walking. Ataxia is a symptom of an underlying medical condition and may affect an individual's speech, movement, eye movement and even swallowing. Damage to the cerebellum causes persistent ataxia. Cerebellum is that part of the brain, which controls muscle coordination. There are various conditions, which can result in ataxia, such as stroke, alcohol abuse, cerebral palsy, tumor and multiple sclerosis. Ataxia can also be caused by an inherited defective gene.
Treatment depends on the cause of ataxia and comprises of adaptive devices like cane or walkers, which help in maintaining patient's independence. Other treatment options for Ataxia include physical therapy, speech therapy and occupational therapy.
Causes of Ataxia
Degeneration, damage or loss of nerve cells in the cerebellum, which is that part of the brain that controls muscle coordination, causes ataxia. The cerebellum comprises of two small ball-shaped folded tissues present at the base of the brain near the brainstem. Diseases which damage the spinal cord and peripheral nerves which connect the cerebellum to the muscles can also cause ataxia. Other causes of ataxia include:
- Stroke is a condition where the blood supply to a part of the brain gets severely diminished or interrupted, which deprives the brain tissue of oxygen and other nutrients resulting in death of brain cells.
- Trauma or injury to the head, which causes damage to the brain or spinal cord, can cause sudden-onset ataxia (acute cerebellar ataxia).
- Chickenpox can result in a complication in the form of Ataxia; although this is not common. Ataxia can appear during the healing stages of the infection and persist for days to weeks and gradually resolve over the time.
- Transient ischemic attack (TIA) is caused by a temporary reduction in blood supply to a part of the brain. Majority of the TIAs last only for a few minutes. Some of the symptoms of TIA include ataxia, which is temporary.
- Multiple sclerosis is a chronic, potentially debilitating medical condition, which affects the central nervous system.
- Cerebral palsy consists of a group of disorders, which occurs as a result of damage to a child's brain during its early development. It can be before, during or shortly after birth. It affects the ability to coordinate movements of the body.
- Paraneoplastic syndromes are rare, degenerative disorders, which are triggered by the response of the immune system to a tumor or neoplasm. This tumor is commonly in the lungs, ovaries, lymph nodes or breast. Patient can experience ataxia many months or years before cancer is actually diagnosed.
- Toxic reaction to some medications can also cause ataxia. Medicines, especially barbiturates and certain sedatives, like benzodiazepine, can cause ataxia as a side effect. Other things, which could cause toxic reactions, are heavy metal poisoning, alcohol and drug intoxication and solvent poisoning.
- Any type of growth on the brain, either cancerous or noncancerous, can damage cerebellum and cause ataxia.
- Deficiency of vitamin E or B-12 can also lead to ataxia.
No specific cause can be found for some adults who develop sporadic ataxia, also known as sporadic degenerative ataxia, which can be of many types, such as multiple system atrophy which is a progressive and degenerative disorder.
Types of Ataxia
There are some types of ataxia which are caused by some hereditary conditions and are known as hereditary ataxia. The cause behind this is defect in a specific gene which makes abnormal proteins. Patient is born with such a gene. These abnormal proteins disturb the nerve cells function, mainly in the cerebellum and spinal cord, and causes degeneration in them. Increase in progression of the disease worsens the problems with coordination.
The type of ataxia depends on the defective gene. Most of the ataxias are progressive. Each type causes poor coordination along with specific signs and symptoms.
Autosomal Dominant Ataxias
- Episodic Ataxia: There are seven known different types of ataxia which are episodic and not progressive. Of these, EA1 through EA7 and EA1 and EA2 are commonest. EA1 comprises of brief episodes of ataxia which can last for seconds or minutes. Some of the triggers of these episodes are stress, sudden movement or being startled along with muscle twitching. EA2 comprises of longer episodes, which commonly last from half-an-hour to six hours and are also triggered by stress. Patient also experiences fatigue, dizziness and muscle weakness during the ataxic episodes. Medication helps in resolving the symptoms. Symptoms can gradually resolve later on in life; however, this happens only in some cases of episodic ataxia. The life span of a patient is not affected by episodic ataxia.
- Spino-Cerebellar Ataxias: According to research, there are more than 20 autosomal dominant genes of ataxia, and this number is likely to increase. In all these types, cerebellar degeneration and cerebellar ataxia are common; however, depending on the specific gene mutation these types of ataxia have specific signs and symptoms, age of onset etc.
Autosomal Recessive Ataxias
- Friedreich's ataxia is commonest hereditary ataxia and is associated with damage to the cerebellum, peripheral nerves and spinal cord. The function of peripheral nerves is transmitting signals from the brain and spinal cord to the muscles. In majority of the cases, patient starts experiencing signs and symptoms before they have turned 25. The symptom which predominantly appears is difficulty in walking, which is the gait ataxia. Symptoms next start in arms and trunk. There is gradual weakening and wasting of the muscles resulting in deformities, especially in the hands, lower legs and feet. Patient also experiences other signs and symptoms and worsening of the symptoms, such as slow, slurry speech (dysarthria); rapid, involuntary eye movements (nystagmus); fatigue; hearing loss, spinal curvature (scoliosis); and heart diseases, such as cardiomyopathy and heart failure.
- Ataxia-Telangiectasia: This is a progressive and rare childhood disease, which causes degeneration in the brain and other systems of the body. This is an immune system disease which increases the susceptibility to other diseases and also affects other organs.
- Congenital Cerebellar Ataxia: Damage to the cerebellum, which is present at birth results in this type of ataxia.
- Wilson Disease: Individuals having this condition have a buildup of copper in their organs, including brain and liver, which results in neurological problems, including ataxia.
Signs & Symptoms of Ataxia
- Patient has an unsteady gait and tends to stumble and lose balance when walking.
- Patient has poor muscle coordination in the arm, hand or leg.
- Patient experiences difficulty with fine motor tasks, such as writing, eating, picking up objects or buttoning a shirt.
- Patient has nystagmus, i.e. involuntary back-and-forth movement of the eye.
- There are changes in the patient's speech, such as slow speech and slurring.
- Patient experiences difficulty in swallowing.
Investigations To Diagnose Ataxia
Doctor will conduct a physical exam and neurological exam, which will also consist of checking patient's concentration, memory, hearing, vision, balance, reflexes and coordination. Laboratory tests, which will be done include:
- Imaging studies, such as CT (Computerized Tomography) scan or MRI (Magnetic Resonance Imaging) of the brain helps in determining the cause of ataxia.
- Spinal tap (Lumbar Puncture) is a test where a needle is inserted into the lumbar region (lower back) to extract a sample of cerebrospinal fluid which is then sent for testing.
- Genetic testing is done to find out if the child has any gene mutation which causes any hereditary ataxia. However, gene tests are not available for all of the hereditary ataxias.
Treatment for Ataxia
There is no specific treatment for ataxia. Treatment comprises of treating the underlying cause which will help in resolving the ataxia. In cases where ataxia occurs as a result of chickenpox or some other viral infection, it will gradually resolve on its own. Adaptive devices or therapies are recommended by the doctor to help with ataxia, which include:
Ataxia is not treatable if it is caused by conditions like cerebral palsy or multiple sclerosis. In such cases the doctor will recommend adaptive devices like:
- Walkers or canes assist in walking and provide support and balance, which will help with the unsteady gait of ataxia.
- Utensils can be modified to help with eating.
- Communication aids help with speaking.
Therapies which can help with ataxia include:
- Occupational therapy helps with the daily living tasks like feeding.
- Physical therapy helps in building strength, flexibility and enhances mobility.
- Speech therapy helps in improving the speech and also swallowing.