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Published: May 17, 2010
Updated: May 17, 2010
Get definitions of a variety of movement disorders, including:
Ataxia is a neurological sign and symptom consisting of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of parts of the nervous system that coordinate movement, such as the cerebellum. Several possible causes exist for these patterns of neurological dysfunction.
The term "dystaxia" is rarely used as a synonym.
Choreia is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias. The term choreia is derived from a Greek word χορεία (a kind of dance), as the quick movements of the feet or hands are vaguely comparable to dancing or piano playing.
The term hemichoreia refers to choreia of one side of the body, such as choreia of one arm and not both (comparable to hemiballismus).
Hemiballismus is a condition of violent flinging of an arm or leg. It is most often associated with stroke, and usually improves without therapy. However, medications are often helpful in relieving symptoms.
Stereotypes in adults most often occur in people being treated with dopamine blocking drugs. Examples include anti-nausea medications, such as metoclopromide or promethazine. Major tranquilizers, such as haloperidol or respiridone, also are associated with this condition. Treatment is with medications.
Hemifacial spasm, or involuntary twitching on one side of the face, is treated with botulinum toxin, or occasionally, a neurosurgical procedure called facial nerve decompression.
Myoclonus is a brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease.
Myoclonic twitches are usually caused by sudden muscle contractions; they also can result from brief lapses of contraction. Contractions are called positive myoclonus; relaxations are called negative myoclonus. The most common time for people to encounter them is while falling asleep (hypnic jerk), but myoclonic jerks are also a sign of a number of neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a "provoked spasm."
Myoclonic jerks may occur alone or in sequence; in a pattern or without pattern. They may occur infrequently or many times each minute. Most often, myoclonus is one of several signs in a wide variety of nervous system disorders such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, subacute sclerosing panencephalitis, Creutzfeldt-Jakob disease (CJD), and some forms of epilepsy.
In almost all instances in which myoclonus is caused by central nervous system (CNS) disease it is preceded by other symptoms. For instance, in CJD it is generally a late-stage clinical feature that appears after the patient has already started to exhibit gross neurological deficits.
Anatomically, myoclonus may originate from lesions of the cortex, subcortex, or spinal cord. The presence of myoclonus above the foramen magnum effectively excludes spinal myoclonus, but further localization relies on further investigation with electromyography (EMG) and electroencephalography (EEG).
Tremor is an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements (oscillations) of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, head, face, vocal cords, trunk, and legs. Most tremors occur in the hands. In some people, tremor is a symptom of another neurological disorder.
Tremor can be a symptom associated with disorders in those parts of the brain that control muscles throughout the body or in particular areas, such as the hands. Neurological disorders or conditions that can produce tremor include multiple sclerosis, stroke, traumatic brain injury, and a number of neurodegenerative diseases that damage or destroy parts of the brainstem or the cerebellum, Parkinson's disease being the one most often associated with tremor.
Other causes include the use of drugs (such as amphetamines, caffeine, corticosteroids, SSRI), alcohol abuse or withdrawal, and mercury poisoning. This is also in infants with phenylketonuria (PKU), overactive thyroid, or liver failure. Tremors can be an indication of hypoglycemia, along with palpitations, sweating and anxiety. Tremor can also be caused from lack of sleep or vitamins, or stress. Deficiencies of magnesium and thiamine have also been known to cause tremor or shaking, which resolves when the deficiency is corrected. Some forms of tremor are inherited and run in families, while others have no known cause.
Characteristics may include a rhythmic shaking in the hands, arms, head, legs, or trunk; shaky voice; difficulty writing or drawing; or problems holding and controlling utensils, such as a fork. Some tremors may be triggered by or become exaggerated during times of stress or strong emotion, when the individual is physically exhausted, or during certain postures or movements.
Tremor may occur at any age but is most common in middle-aged and older persons. It may be occasional, temporary, or occur intermittently. Tremor affects men and women equally.
Restless leg syndrome is not really a disorder involving abnormal movements, but is a sensation associated with an urge to move, usually occurring at night, and disturbing sleep. It is treated with medications.
Tardive dyskinesia is a variety of dyskinesia (involuntary, repetitive movements) manifesting as a side effect of long-term or high-dose use of dopamine antagonists, usually antipsychotics.
Other dopamine antagonists that can cause tardive dyskinesia are drugs for gastrointestinal disorders (e.g. metoclopramide) and neurological disorders. While newer atypical antipsychotics such as olanzapine and risperidone appear to have less dystonic effects, only clozapine has been shown to have a lower risk of tardive dyskinesia than older antipsychotics.
The term tardive dyskinesia was introduced in 1964. Dyskinesia refers to an involuntary movement. The effect of these drugs can be tardive, meaning the dyskinesia sometimes continues or appears even after the drugs are no longer taken.
Tardive dyskinesia is characterized by repetitive, involuntary, purposeless movements. Features of the disorder may include grimacing, tongue protrusion, lip smacking, puckering and pursing of the lips, and rapid eye blinking. Rapid movements of the extremities or impaired movements of the fingers may also occur.
For comparison, patients with Parkinson's disease have difficulty moving, while patients with tardive dyskinesia have difficulty not moving.
Other closely related neurological disorders have been recognized as variants of tardive dyskinesia:
Tourette syndrome is a “tic disorder,” often first recognized in children, that is associated with sudden, fleeting movements that occur in the background of normal behaviors. Examples include frequent eye blinking, facial grimacing, hand jerking, sniffing, or grunting. Medications are the most common type of intervention for this condition.