Ataxia is defined as a lack of muscle control or coordination of voluntary movements caused by a dysfunction of the cerebellum in the brain. Dyskinesia is defined as abnormal, uncontrollable, involuntary movements, that includes movements similar to chorea or tics and diminished voluntary movements, that is caused by taking dopamine-depleting medications or degeneration of neurons in the brain system.
Ataxia can affect a lot of body movements, creating difficulties with swallowing, speech, and eye movement. Dyskinesia can be anything from a slight tremor of the hands to an uncontrollable movement of the upper body or lower extremities.
Ataxia can be a symptom of an underlying condition while dyskinesia can be a stand-alone condition.
Ataxia is caused by loss of nerve cells, degeneration, or damage to the cerebellum, the part of the brain that controls muscle coordination.
There are a lot of conditions that can cause ataxia, which includes alcohol abuse, multiple sclerosis, tumor, stroke, cerebral palsy, brain degeneration, and certain medications. Defective genes inherited from the parents, whether dominant or recessive, can also cause ataxia.
Ataxia can also be due to diseases that damage the peripheral nerves and spinal cord that connect the cerebellum to the muscles can cause ataxia. The following illnesses can cause ataxia:
- Autoimmune diseases
- Cerebral palsy
- Head trauma
- Paraneoplastic Syndromes
- Toxic reaction
- Vitamin E, vitamin B-12 or thiamine deficiency
There are no specific causes found for some adults who develop sporadic ataxia.
Sporadic ataxia can be in different forms, such as multiple system atrophy, a degenerative and progressive disorder.
Some forms of ataxia and some conditions that cause ataxia are genetic in nature.
Having one of the conditions mentioned above means that an individual is born with an abnormality or defect in a certain gene that makes abnormal proteins. The abnormal proteins prevent the normal function of nerve cells and cause degeneration primarily in the spinal cord and the cerebellum. As the disease progresses, coordination problems get worse.
A genetic ataxia can be inherited from either a dominant gene from a parent or a recessive gene from each parent. It is possible that neither parent carries the defective gene, so there might be no obvious family history.
Ataxia is caused by various gene defects that depend on the type of ataxia, many of which are progressive. Each type of ataxia causes poor coordination and additional signs and symptoms specific to the type of ataxia.
Dyskinesia usually occurs as a complication of the long-term use of levodopa and other antipsychotic drugs. Other factors that may contribute to dyskinesia include a diagnosis at a younger age and the intake of higher doses of levodopa and other antipsychotic drugs for extended periods of time.
Researchers believe that different brain chemicals like dopamine, glutamate, and serotonin play a significant role in developing dyskinesia. Fluctuating levels of dopamine may cause dyskinesia. The brain cells making dopamine are lost in Parkinson’s disease-causing dopamine levels to decrease. Levodopa temporarily restores dopamine, but the intake for several times in a day causes dopamine levels to rise and fall. A progressive loss of the dopamine-producing brain cells can also contribute to dyskinesia.
- Poor coordination
- Difficulty in speaking
- Unsteady walk and a tendency to stumble
- Involuntary back-and-forth eye movements (nystagmus)
- Difficulty swallowing
- Difficulty with fine motor tasks, such as eating, writing or buttoning a shirt
- the swaying of the body
- bobbing of the head
The major symptom of dyskinesia is involuntary movement. Symptoms get worse little by little over time but they can develop instantly or intensify the brain damage or injury.
There are different types of dyskinesia that produce specific and unique symptoms to differentiate one from the other types
Doctors usually look for treatable causes for individuals with ataxia. The doctor usually conducts a physical and neurological exam to check for the symptoms. The doctor might request laboratory tests, that include:
- MRI or CT scan Both of these scans may show shrinkage or damage to the cerebellum and other brain components in people with ataxia. Both of these may also show other findings like a benign tumor or blood clot, that could be affecting your cerebellum.
- Spinal TapA sample of cerebrospinal fluid is taken from the lower back between two lumbar bones through a needle injection and this sample is tested in the laboratory.
- Genetic testingGenetic testing may be recommended to determine whether a child has the gene mutation causing one of the hereditary ataxic disorders. There are gene tests available for most hereditary ataxias.
Dyskinesia is more difficult to diagnose. Symptoms might not appear until months or years after taking antipsychotic drugs or the movements may occur after stopping to take the drug. The timing can make it difficult to identify whether the medicine has caused the symptoms.
Doctors who prescribe taking of medicine to treat mental health conditions should check the patients at least once a year to ensure that he/she does not have dyskinesia.
The doctor can give a physical exam test called the Abnormal Involuntary Movement Scale.
The doctor can also do tests such as CT or MRI scan or blood tests to find out whether another disorder causes the abnormal movements, like:
There’s no known treatment specifically for ataxia. The treatment of ataxia is more on to alleviate symptoms or to treat the underlying cause of ataxia. Treating the underlying cause may resolve ataxia or in the case of bacterial or viral infections, may actually resolve on its own.
The doctor may recommend treatment, therapies, and adaptive devices to manage symptoms of ataxia.
Ataxia caused by conditions such as cerebral palsy or multiple sclerosis might not be treatable so adaptive devices may be recommended by a doctor to help a patient with his/her independence and to help him/her in doing his/her daily activities.
- Physical therapy – helps with coordination and enhances mobility
- Occupational therapy – helps with daily living activities
- Speech therapy – helps improve speech and helps in addressing swallowing problems
The specific treatment plan used for an affected individual depends on the type of dyskinesia and the severity of the symptoms. There are other courses of treatment available if reducing or completely stopping the intake of dyskinesia-causing medications do not alleviate the symptoms.
Some medicines can help control muscle spasms but one must be careful in choosing the medicines because some of them result in dyskinesia. Injecting botulinum toxin or Botox may also help limit or reduce involuntary movements.
For individuals with idiopathic or genetic dyskinesia, deep brain stimulator (DBS) is an effective treatment. This procedure puts electrodes in the brain in order to control posture and correct movement.