Many different things can cause ataxia, including multiple sclerosis, head trauma, alcohol abuse, stroke, cerebral palsy, genetics, or tumor. Ataxia may also be a symptom associated with certain infections.
There are many types of ataxia. In this article, we will discuss some of the more common types, causes, and available treatments.
Here are some key points about ataxia. More detail and supporting information is in the main article.
- Ataxia can be caused by a wide range of factors.
- Symptoms can include poor coordination, slurred speech, tremors, and hearing problems.
- Diagnosis of ataxia can be challenging and often involves a range of tests.
- Although ataxia is not always curable, symptoms can often be alleviated.
What is ataxia?
Ataxia refers to a group of disorders that can affect coordination, speech, and balance. It can also make it hard to swallow and walk.
Some people are born with ataxia, but others develop it slowly, over time. For some, it can result from another condition, such as a stoke, multiple sclerosis, or a brain tumor, or a head injury or excessive alcohol consumption.
Ataxia can get worse over time, or it can stabilize. This depends partly on the cause.
The following are some of the more common types of ataxia:
The cerebellum helps combine sensory perception, coordination, and motor control
This is ataxia caused by a dysfunction of the cerebellum - a region of the brain involved in the assimilation of sensory perception, coordination, and motor control.
Cerebellar ataxia can cause neurological problems such as:
- lack of coordination between organs, muscles, limbs, or joints
- impaired ability to control distance, power, and speed of an arm, hand, leg, or eye movement
- difficulty accurately estimating how much time has passed
- inability to perform rapid, alternating movements
The extent of symptoms depends on which parts of the cerebellum are damaged, and whether lesions occur on one side (unilateral) or both sides (bilateral).
If the vestibulocerebellum is affected, the person's balance and eye movement control will be affected. The person will typically stand with feet wide apart in order to gain better balance and avoid swaying backward and forward.
Even when the patient's eyes are open, balance may be difficult with feet together. If the spinocerebellum is affected, the patient will have an unusual gait with unequal steps, sideways steps, and stuttering starts and stops. The spinocerebellum regulates body and limb movements.
If the cerebrocerebellum is affected, the person will have problems with voluntary, planned movements. The head, eyes, limbs, and torso may tremble as voluntary moves are carried out. Speech may be slurred, with variations in rhythm and loudness.
This is ataxia due to loss of proprioception. Proprioception is the sense of the relative position of neighboring parts of the body. It is a sense that indicates whether the body is moving with the required effort and gives feedback on the position of body parts relative to each other.
A patient with sensory ataxia typically has an unsteady stomping gait, with the heel striking hard as it touches the ground with each step. Postural instability becomes worse in poorly lit environments. If a doctor asks the patient to stand with eyes closed and feet together, their instability will worsen. This is because loss of proprioception makes the patient much more reliant on visual data.
The patient may find it hard to perform smoothly coordinated voluntary movements with the limbs, trunk, pharynx, larynx, and eyes.
The vestibular system is affected. In acute (sudden) unilateral cases, the patient may experience vertigo, nausea, and vomiting. In slow-onset chronic bilateral cases, the patient may only experience unsteadiness.
Symptoms may vary depending on the severity and type of ataxia. If the ataxia is caused by an injury or another health condition, symptoms may emerge at any age, and may well improve and eventually disappear.
Initial ataxia symptoms usually include:
- Poor limb coordination.
- Dysarthria - slurred and slow speech that is difficult to produce. The patient may also have difficulties controlling volume, rhythm, and pitch.
If the ataxia progresses, other symptoms may also appear:
- difficulty swallowing, leading to choking or coughing
- facial expressions become less apparent
- tremors, shaking or trembling in parts of the body
- nystagmus, an involuntary, rapid, rhythmic, repetitive eye movement that may be vertical, horizontal, or circular
- cold feet, because of a lack of muscle activity
- problems with balance
- walking difficulties, so that some people may need a wheelchair
- vision and hearing problems
- depression, due to difficulty living with the symptoms
Early onset cerebellar ataxia usually emerges between the ages of 4 and 26. Late-onset ataxia generally appears after the patient is 20. Late-onset ataxia usually involves less severe symptoms, compared with early-onset ataxia.
Ataxia telangiectasia symptoms generally include:
- Small veins appearing around the corner of the eyes, cheeks, and ears
- Delays in physical and sexual development
Friedreich's ataxia symptoms generally include:
If ataxia is caused by injury or illness, symptoms often improve over time and eventually go away completely.
Although ataxia is generally not curable, a great deal can be done to ease symptoms and improve the quality of life of the patient. Treatment for coordination and balance problems usually involves the use of adaptive devices that help the patient attain as much independence as possible. These may include the use of a cane (walking stick), crutches, walker, or a wheelchair.
Symptoms such as tremor, stiffness, spasticity, sleep disorders, muscle weakness, depression (or frustration, sadness, and anger) may be addressed with targeted physical therapy, speech therapy, medications, and counseling.
- Occupational therapy: This can help the person manage better around the house and at work. It may involve some home adaptations, wheelchair assessment, and making the kitchen more practical.
- Speech therapy: This can help with swallowing, coughing, choking, and speech problems. If speech becomes very difficult, the speech therapist can help the person learn how to use speech aids.
- Orthopedic care: This can help treat curvature of the spine.
- Physical therapy: This can help maintain strength and improve mobility.
- Counseling: Sessions can help the person manage frustration and depression that may arise when symptoms affect physical mobility and coordination.
- Supplements and nutrition: If levels of vitamin E are low, supplements, a special diet, or both may help. Sensitivity to gluten can occur with ataxia, so a gluten-free diet may help.
- Medication: Treatment for ataxia telangiectasia include gamma-globulin injections to boost the immune system. There are also drugs for muscle spasms and uncontrollable eye movements.
Vitamin B-12 deficiency is one potential cause of ataxia. It can produce overlapping cerebellar and sensory ataxia, as well as other neurological abnormalities.
Ataxia can also be a symptom of another health condition. It can also be defined as inherited or non-inherited:
This means the ataxia is caused by a genetic defect inherited either from the mother or father, or both.
A faulty gene that is passed down through generations can cause cerebellar ataxia. In some cases, its severity worsens from one generation to the next, and the age of onset gets younger.
The chance of inheriting ataxia from a parent depends on the type of ataxia the parent has. For a person to develop Friedreich's ataxia, the faulty gene would need to be carried by both the mother and the father (recessive inheritance).
Spinocerebellar ataxia, on the other hand, only requires one parent to carry the defective gene (dominant inheritance), and each of their offspring would have a 50 percent risk of developing the condition.
Even without a family history of ataxia, some people may still develop the condition. In some cases, doctors cannot identify the cause. The following can cause ataxia:
- brain surgery
- head injury
- alcohol or drug abuse
- infections, such as chicken pox (usually goes away after infection has cleared)
- brain tumor
- exposure to toxic chemicals
- multiple sclerosis (MS), cerebral palsy, and other neurological conditions
- malformation of the cerebellum before birth
A patient who shows signs of ataxia will probably see a neurologist, a specialist in conditions of the nervous system.
The specialist will check the patient's medical history for possible causes, such as brain injury, and their family history for indications of inheritance.
The following tests may also be ordered:
- MRI or CT scan, to see if there is any brain damage
- genetic tests, to assess for inherited ataxia
- Blood tests, as some types of ataxia can affect the make-up of blood
- Urine tests, to check for systemic abnormalities that are linked to some forms of ataxia. In Wilson's disease, a 24-hour urine collection may show unusual amounts of copper is in the system.
If, the specialist cannot determine the cause, this is known as sporadic or idiopathic ataxia.
It can take time to reach a conclusive diagnosis, because the symptoms could point to several other conditions.
There is no cure for ataxia, and the long-term outlook depends on the type.
People with hereditary ataxia are likely to have a shorter lifespan than those without it. Severe cases can be fatal in childhood or young adulthood, but many people live into their 50s or 60s.
If ataxia results from an accident, surgery, or illness during a person's life, the condition may stabilize or it may get worse over time.