Hyperkinesia refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. Hyperkinesia is a state of excessive restlessness which is featured in a large variety of disorders that affect the ability to control motor movement, such as Huntington's disease. It is the opposite of hypokinesia, which refers to decreased bodily movement, as commonly manifested in Parkinson's disease. Many hyperkinetic movements are the result of improper regulation of the basal ganglia–thalamocortical circuitry. Overactivity of a direct pathway combined with decreased activity of indirect pathway results in activation of thalamic neurons and excitation of cortical neurons, resulting in increased motor output. Often, hyperkinesia is paired with hypotonia, a decrease in muscle tone. Many hyperkinetic disorders are psychological in nature and are typically prominent in childhood. Depending on the specific type of hyperkinetic movement, there are different treatment options available to minimize the symptoms, including different medical and surgical therapies. The word hyperkinesis comes from the Greek hyper, meaning "increased," and kinesis, meaning "movement."
Classification
Basic hyperkinetic movements can be defined as any unwanted, excess movement. Such abnormal movements can be distinguished from each other on the basis of whether or not, or to what degree they are, rhythmic, discrete, repeated, and random. In evaluating the individual with a suspected form of hyperkinesia, the physician will record a thorough medical history, including a clear description of the movements in question, medications prescribed in the past and present, family history of similar diseases, medical history, including past infections, and any past exposure to toxic chemicals. Hyperkinesia is a defining feature of many childhood movement disorders, yet distinctly differs from both hypertonia and negative signs, which are also typically involved in such disorders. Several prominent forms of hyperkinetic movements include:
Ataxia The term ataxia refers to a group of progressive neurological diseases that alter coordination and balance. Ataxias are often characterized by poor coordination of hand and eye movements, speech problems, and a wide-set, unsteady gait. Possible causes of ataxias may include stroke, tumor, infection, trauma, or degenerative changes in the cerebellum. These types of hyperkinetic movements can be further classified into two groups. The first group, hereditary ataxias, affect the cerebellum and spinal cord and are passed from one generation to the next through a defective gene. A common hereditary ataxia is Friedreich's ataxia. In contrast, sporadic ataxias occur spontaneously in individuals with no known family history of such movement disorders.
Athetosis Athetosis is defined as a slow, continuous, involuntary writhing movement that prevents the individual from maintaining a stable posture. These are smooth, nonrhythmic movements that appear random and are not composed of any recognizable sub-movements. They mainly involve the distal extremities, but can also involve the face, neck, and trunk. Athetosis can occur in the resting state, as well as in conjunction with chorea and dystonia. When combined with chorea, as in cerebral palsy, the term "choreoathetosis" is frequently used.
Chorea Chorea is a continuous, random-appearing sequence of one or more discrete involuntary movements or movement fragments. Although chorea consists of discrete movements, many are often strung together in time, thus making it difficult to identify each movement's start and end point. These movements can involve the face, trunk, neck, tongue, and extremities. Unlike dystonic movements, chorea-associated movements are often more rapid, random and unpredictable. Movements are repeated, but not rhythmic in nature. Children with chorea appear fidgety and will often try to disguise the random movements by voluntarily turning the involuntary, abnormal movement into a seemingly more normal, purposeful motion. Chorea may result specifically from disorders of the basal ganglia, cerebral cortex, thalamus, and cerebellum. It has also been associated with encephalitis, hyperthyroidism, anticholinergic toxicity, and other genetic and metabolic disorders. Chorea is also the prominent movement featured in Huntington's disease.
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