Ataxia is a neurological symptom characterized by a lack of voluntary coordination of muscle movements, which can include aberrant walking, speech, and eye movements. Ataxia is a symptom that indicates a problem with the portions of the neurological system that control movement, such as the cerebellum. Hemiataxia is a kind of ataxia that affects only one side of the body. There are several plausible explanations for these neurological dysfunction patterns. Dystaxia is a kind of ataxia that is moderate. Gait abnormalities are the most prevalent sign of Friedreich's ataxia. The word comes from the Greek - [a negative prefix] + - [order], which means "lack of order."
Causes
The three types of ataxia have overlapping causes, so can either coexist or occur in isolation. Cerebellar ataxia can have many causes despite normal neuroimaging.
Lesions with a specific location
Any type of focal lesion of the central nervous system (stroke, brain tumor, multiple sclerosis, inflammatory [such as sarcoidosis], and "chronic lymphocytyc inflammation with pontine perivascular enhancement responsive to steroids syndrome") will result in the type of ataxia corresponding to the location of the lesion: cerebellar if in the cerebellum; sensory if in the dorsal spinal cord...to include cord compression by thickened ligamentum flavum or (including the vestibular areas of the cerebral cortex).
Exogenous substances (metabolic ataxia)
Exogenous chemicals that produce ataxia do so primarily because they impair central nervous system function. Ethanol (alcohol) is the most prominent example, which can cause reversible cerebellar and vestibular ataxia. Chronic ethanol use induces cerebellar shrinkage due to oxidative and endoplasmic reticulum stress caused by thiamine deficiency. Other examples include prescription medicines (most antiepileptic treatments include cerebellar ataxia as a side effect), lithium levels more than 1.5mEq/L, intake of synthetic cannabinoid HU-211, and a variety of other medicinal and recreational substances (e.g. ketamine, PCP or dextromethorphan, all of which are NMDA receptor antagonists that produce a dissociative state at high doses). Benzodiazepines are another type of medications that can produce short-term ataxia, especially in large dosages. Ataxia and other neurological problems are known to be caused by high amounts of methylmercury, which may be obtained by eating fish with high mercury contents.
Poisoning by radiation
Severe acute radiation poisoning resulting in an absorbed dosage of more than 30 grays can cause ataxia.
Deficiency of vitamin B12
Among various neurological problems, vitamin B12 insufficiency can result in overlapping cerebellar and sensory ataxia.
Hypothyroidism
Symptoms of neurological impairment may be the first sign of hypothyroidism in some persons. Reversible cerebellar ataxia, dementia, peripheral neuropathy, psychosis, and coma are among them. After thyroid hormone replacement treatment, the majority of neurological problems go entirely.
Isolated sensory ataxia causes
Depending on the amount of the neuropathic involvement, peripheral neuropathies can produce universal or localised sensory ataxia (e.g. a single limb). When the dorsal columns are involved, several forms of spinal diseases can elicit sensory ataxia from the lesioned level below.
Cerebellar degeneration that isn't passed down down the generations
Chronic alcohol use disorder, head injury, paraneoplastic and non-paraneoplastic autoimmune ataxia, high altitude cerebral oedema, celiac disease, normal pressure hydrocephalus, and infectious or post-infectious cerebellitis are all non-hereditary causes of cerebellar degeneration.
Hereditary ataxias
Ataxia can be caused by inherited illnesses involving degeneration of the cerebellum or the spine; most instances have both, and hence appear with overlapping cerebellar and sensory ataxia, even if one is more obvious than the other. Spinocerebellar ataxia, episodic ataxia, and dentatorubropallidoluysian atrophy are autosomal dominant disorders, while Friedreich's ataxia (sensory and cerebellar, with the former predominating) and Niemann Pick disease, ataxia-telangiectasia (sensory and cerebellar, with the latter predominating), and abetalipoproteinaemia are autosomal recessive disorders The uncommon fragile X-associated tremor/ataxia syndrome, or FXTAS, is an example of an X-linked ataxic disorder.
Malformation of Arnold–Chiari (congenital ataxia)
Arnold–Chiari malformation is a brain malformation. It is characterized by the downward displacement of the cerebellar tonsils and medulla via the foramen magnum, which can result in hydrocephalus due to a blockage of cerebrospinal fluid outflow.
Succinic semialdehyde dehydrogenase deficit is a kind of semialdehyde dehydrogenase deficiency.
Succinic semialdehyde dehydrogenase deficiency is an autosomal-recessive gene condition characterized by the buildup of gamma-Hydroxybutyric acid (GHB) in the body due to mutations in the ALDH5A1 gene. GHB builds up in the nervous system and can lead to ataxia and other neurological problems.
Wilson's disease
Wilson's illness is an autosomal-recessive gene condition characterized by an inability to adequately eliminate copper from the body due to a mutation in the ATP7B gene. Copper builds up in the brain system and liver, causing ataxia and other neurological and organ problems.
Gluten ataxia
Gluten ataxia is an autoimmune condition brought on by gluten use. Ataxia can be improved and prevented if diagnosed early and treated with a gluten-free diet. Because the death of neurons in the cerebellum as a result of gluten exposure is irreversible, the efficiency of treatment is dependent on the time between the beginning of ataxia and diagnosis. It is responsible for 40% of ataxias of unknown origin and 15% of all ataxias. Only approximately 40% of persons with gluten ataxia suffer intestinal damage, and less than 10% have any gastrointestinal symptoms. Primary auto-immune cerebellar ataxias are the most common kind of cerebellar ataxia (PACA).
Pump for potassium
Some ataxias may be caused by a malfunction of the sodium-potassium pump. Cerebellar Purkinje neurons' intrinsic activity mode has been found to be controlled and set by the Na+-K+ pump. This shows that the pump is more than just a "housekeeping" molecule for ionic gradients; it might also be a computational component in the cerebellum and brain. Indeed, in the cerebellum of a live mouse, an ouabain block of Na+-K+ pumps causes ataxia and dystonia. Lower ouabain concentrations cause ataxia, whereas greater ouabain concentrations cause dystonia.
Anti-GAD antibodies are linked to cerebellar ataxia
Cerebellar impairments are caused by antibodies against the enzyme glutamic acid decarboxylase (GAD: enzyme that converts glutamate to GABA). Antibodies hinder motor learning and lead to behavioral problems. Immune-mediated cerebellar ataxias are a type of ataxias that are caused by antibodies against GAD. Synaptopathy is caused by the antibodies. Autoimmune illnesses are especially dangerous to the cerebellum. Cerebellar circuitry, because to cerebellar reserve and many kinds of plasticity, has the ability to compensate and recover function. LTDpathies are a group of immunological illnesses that target long-term depression (LTD), which is a type of plasticity.
Diagnosis
A CT scan or an MRI of the brain may be used to detect probable reasons. In persons with ataxia, an MRI may reveal shrinking of the cerebellum and other brain areas. Other treatable abnormalities, such as a blood clot or benign tumor pushing on the cerebellum, may also be shown.
Lumbar puncture (spinal tap) - A needle is placed between two lumbar vertebrae in the lower back (lumbar region) to collect a sample of cerebrospinal fluid for examination.
Genetic testing is used to see if a mutation that causes one of the hereditary ataxic disorders is present. Many, but not all, genetic ataxias have tests available.
Treatment
The success of ataxia therapy is determined by the underlying cause. Treatment may help to restrict or lessen the consequences of ataxia, but it is unlikely to completely remove them. Individuals who have a single focused damage (such as a stroke or a benign tumor) recover faster than those who have a neurological degenerative disorder. In 2009, a review of the treatment of degenerative ataxia was published. A small number of uncommon illnesses that manifest with pronounced cerebellar ataxia are treatable, and early detection of these disorders is crucial. Vitamin E insufficiency, abetalipoproteinemia, cerebrotendinous xanthomatosis, Niemann–Pick type C illness, Refsum's disease, glucose transporter type 1 deficiency, episodic ataxia type 2, gluten ataxia, and glutamic acid decarboxylase ataxia are some of the diseases that might occur.
Anti-sense oligonucleotides are being used in particular to target the RNA abnormalities associated with cerebellar diseases. To lessen impairment, pharmaceutical therapies as well as physical therapy and occupational therapy can be used to control the movement problems associated with ataxia. 5-hydroxytryptophan (5-HTP), idebenone, amantadine, physostigmine, L-carnitine or derivatives, trimethoprim/sulfamethoxazole, vigabatrin, phosphatidylcholine, acetazolamide, 4-aminopyridine, buspirone, and a combination of coenzyme Q10 and vitamin E have all been used to treat ataxia.
In order to retrain particular functional motor patterns, physical therapy must focus on adjusting activity and supporting motor learning. Physical therapy appears to be useful, according to a new systematic review, although there is only minimal evidence to back this up. Vestibular habituation, Frenkel exercises, proprioceptive neuromuscular facilitation (PNF), and balance training are the most commonly used physical therapy interventions for cerebellar ataxia; however, therapy is often highly individualized, and gait and coordination training are large components of therapy.
If a person can walk with or without a mobility assistance, current research recommends that physical therapy should include an exercise program that addresses five components: static balance, dynamic balance, trunk-limb coordination, stairs, and contracture avoidance. Once the physical therapist has determined that the client can safely do elements of the program on their own, it is critical that they be prescribed and routinely engage in a supplemental home exercise program that integrates these components to enhance long-term outcomes. Balance tasks, gait, and individual activities of daily life are among the results. While the benefits are mostly ascribed to changes in the brain rather than the hip or ankle joints, it is still unclear whether the gains are due to cerebellar adaptations or compensation by other brain regions.
Decomposition, simplicity, or slowing of multijoint movement may also be a helpful method that therapists can adopt to help people with ataxia improve their function. According to one study including stroke patients with limb ataxia who received comprehensive upper limb retraining, training must be vigorous and targeted. Constraint-induced movement therapy was used in their treatment, which improved their arm function. Treatment will very certainly include ways for dealing with challenges with regular tasks like walking. Gait aids (such as a cane or walker) can be used to reduce the risk of falls caused by a loss of balance or coordination. Severe ataxia may necessitate the use of a wheelchair in the future.
In order to get better outcomes, potential concurrent motor impairments, in addition to those caused by ataxia, must be addressed. Muscle weakness and diminished endurance, for example, may result in increased tiredness and inferior movement patterns.
Therapists and health care professionals dealing with ataxia patients can use a variety of evaluation techniques. The International Cooperative Ataxia Rating Scale (ICARS) is one of the most frequently used, with excellent reliability and validity. Other instruments that measure motor function, balance, and coordination are also very useful in assisting the therapist in tracking their patient's improvement and quantifying their functioning. These tests may include, but are not limited to, the following:
- The Berg Balance Scale is a scale that measures how well a person can
- Walking in a Pair (to test for Tandem gaitability)
- Taping tests based on the Scale for the Assessment and Rating of Ataxia (SARA). – While the therapist monitors the level of dysdiadochokinesia, the subject must tap their arm or leg swiftly and frequently.
- Finger-to-finger, therapist's finger-to-finger, and alternative nose-to-finger are some of the variants of the finger-nose test.