Glossary
H
Half life:
The half life of a drug is the time it takes for the blood level to decrease by half after a drug is stopped.
A slowly progressive hereditary disorder characterized by abnormal accumulations of iron pigments in certain regions of the basal ganglia (e.g., globus pallidus and substantia nigra). This autosomal recessive disorder typically becomes apparent during late childhood or adolescence. Associated symptoms may include progressive stiffness and resistance to movement (rigidity); increasing difficulties speaking and eating; sustained muscle contractions that result in repetitive twisting motions or unusual postures or positions (dystonia); the presence of multiple, irregular, jerky motions that may combine to appear flowing or writhing in nature (choreoathetosis); and/or other abnormalities.
Hallervorden-Spatz disease:
Hallucinations:
Perceptions that occur in the absence of external stimuli and while an individual is awake. Hallucinations may involve any of the senses, including hearing (auditory hallucinations), vision (visual hallucinations), smell (olfactory hallucinations), taste (gustatory hallucinations), and touch (tactile hallucinations). Hallucinations may occur with high-dose administration of certain medications or the abuse of particular drugs (hallucinogens) that cause increased stimulation or excitation of the central nervous system. They may also be caused by chronic alcohol abuse; sensory deprivation; certain types of seizures due to impairment or damage of a limited area of the brain (e.g., temporal lobe epilepsy); psychotic illnesses characterized by disturbances in thought, behavior, and emotional reactions (schizophrenia); or certain organic disorders, such as Huntington’s disease.
Hashimoto’s Thyroiditis:
Auto-immune disorder that is characterized by anti-body formation to thyroid tissue. Most commonly, anti-body production is toward the thyroid peroxidase antigen (TPA) and to a lesser degree, against Thyroglobulin. Commonly, TSH levels, T-3 and T-4 levels are measured to be ‘normal,’ but the patient suffers from the symptoms of hypothyroidism. Often associated with adrenal fatigue/failure, patients with Hashimoto’s Thyroiditis develop the clinical picture that may be labeled as “Chronic Fatigue Syndrome (CFS)” and Fibromyalgia (FMS). Treatment is best accomplished with treatment consisting of T-3 and T-4, combined, with adrenal replacement of DHEA, Pregnenolone, Cortisol, guided with sequential blood analysis and clinical monitoring.
Heat pain:
Heat pain arises from warm or hot temperatures.
Hemichorea:
: Irregular, abrupt, relatively rapid involuntary (i.e., choreic) movements that are unilateral or involve muscle groups on one side of the body.
Hemidystonia:
Hemidystonia is a form of dystonia that affects one side of the body or is characterized by unilateral involvement of the upper and lower limbs.
Hemizygote:
Refers to a cell, organism, or individual with only one of a pair of genes for a specific trait. This term is often used to describe males who inherit one copy of an X-linked disease trait. It may also refer to the state in which genetic material is deleted from one member of a chromosomal pair.
Hereditary:
Inherited; inborn; referring to the genetic transmission of a trait, condition, or disorder from parent to offspring. This is very different from “famililal,” which may infer a genetic condition, but it can also infer a shared-environmental factor or influence.
Heredodegenerative:
Pertaining to genetically transmitted (hereditary) neurologic disorders characterized by progressive neuronal loss and other neurodegenerative changes (e.g., associated gliosis). For example, the term “heredodegenerative dystonias” is used to refer to several, usually hereditary disorders in which neurodegenerative changes may lead to dystonia as a primary feature and other neurologic symptoms are typically present. However, in some patients with such disorders, dystonia may not always develop and other neurologic features may be primary findings. Disorders that have been categorized as heredodegenerative dystonias include ataxia-telangiectasia, Hallervorden-Spatz disease, Huntington’s disease, Parkinson’s disease, progressive supranuclear palsy, neuroacanthocytosis, and Wilson’s disease.
Hertz (Hz):
Cycles per second.
Heterogeneity:
The study of the electrical activity associated with a specific body function (e.g., EMG, EEG, etc.).
Heterozygous carriers:
The term “heterozygosity” refers to the state of having different genes that occupy the same position (locus) on one or more paired chromosomes. “Heterozygous carriers” describes individuals who carry a single copy of a mutated gene for a disease trait, such as females who have a copy of a disease gene for an X-linked disorder. Because females have two X chromosomes yet only one functioning copy is necessary, a percentage of X chromosomes with the mutated gene may not be expressed, typically in a random pattern (known as “random X chromosome inactivation”). Therefore, females who are heterozygous for an X-linked disease trait often have no disease manifestations or less severe symptoms than affected males. However, because males have one X chromosome from the mother and one Y chromosome from the father, males who carry an X-linked disease trait will typically fully express the mutated gene. Rarely, females who are heterozygous for an X-linked disease trait may manifest symptoms with about the same severity as affected males.
Hoehn and Yahr Scale:
The Hoehn and Yahr Scale is a commonly used physician-administered rating of the global severity of the motor symptoms of Parkinson’s disease. Scores range from 0, no signs of disease, to 5, wheelchair bound or bedridden without assistance.
Homeopathy:
Homeopathy is a system of medicine that is based on the Law of Similars, a belief in which substances that cause healthy people to exhibit symptoms can, conversely, be used to restore the body to health
Homeostasis:
Homeostasis exists when an organism’s internal state of being is in balance even when the external environment is changing.
Homocystinuria:
A metabolic abnormality characterized by excessive amounts of the amino acid homocystine in the urine. Homocystinuria, which may be transmitted as an autosomal recessive trait, may result from deficient activity of certain enzymes involved in the metabolic conversion of the amino acid methionine to cysteine. Associated symptoms and findings often include developmental delay; dislocated lens of the eyes (ectopia lentis); thin, weak muscles; progressive mental retardation; psychiatric abnormalities; skeletal defects; blockage of a blood vessel by a piece of a blood clot (thrombus) carried in the bloodstream (thromboembolism); and/or other abnormalities.
Huntington’s disease (HD):
A hereditary, progressive, neurodegenerative disorder primarily characterized by the development of emotional, behavioral, and psychiatric abnormalities; gradual deterioration of thought processing and acquired intellectual abilities (dementia); and movement abnormalities, including involuntary, rapid, irregular jerky movements (chorea) of the face, arms, legs, or trunk. HD may be inherited as an autosomal dominant trait or, less commonly, appear to occur randomly for unknown reasons (sporadically). The disorder results from abnormally long sequences or “repeats” of certain coded instructions (i.e., unstable expanded CAG repeats) within a gene (located on chromosome p16.3). Progressive nervous system dysfunction associated with HD results from loss of neurons in certain areas of the brain, including the basal ganglia and cerebral cortex.
Huntington’s Disease-like 2 (HDL2):
This rare disease strongly resembles Huntington’s disease in its inheritance and symptoms, which include abnormal movements, personality changes, and changes in the ability to think and process information. HDL2 is due to damage to the same parts of the brain as in HD; however, it is caused by mutation of a different gene, and also has an increased number of repeats. To date, almost all affected families have been of African ancestry. The other “Huntington’s disease-like” disorders (types 1, 3, and 4) are even rarer and have only been reported in one family each.
Hyperglycemia:
An abnormally high level of the simple sugar glucose in the blood.
Hyperkalemic:
Pertaining to hyperkalemia, a condition characterized by unusually high concentrations of potassium in the blood. Potassium, a positively charged ion, helps to regulate water balance, nerve conduction, and muscle contraction. Hyperkalemia may lead to various signs and symptoms, such as diarrhea, nausea, abdominal cramps, weakness, and, with increasing severity, abnormal heart rhythms and muscle paralysis.
Hyperkinetic:
Characterized by excessive movement because of abnormally increased motor activity or function. Certain movement disorders are termed “hyperkinetic” such as tics or essential tremor.
Hypertension:
Hypertension, also referred to as high blood pressure, is an abnormal increase in the pressure of blood against the walls of the arteries. Hypertension may be essential, meaning that it has no known cause, or may be related to another disease such as kidney disease or diabetes.
Hyperthyroidism:
a condition caused by the effects of too much thyroid hormone on tissues of the body.
Hyperventilation:
Abnormally rapid breathing usually accompanied by air swallowing. Hyperventilation results in excessive intake of oxygen and increased elimination of carbon dioxide, which may eventually lead to a disturbance in the body’s acid-base balance.
Hypokalemic:
Referring to hypokalemia, which is characterized by abnormally low potassium levels in the blood. Potassium, the primary positively charged ion (cation) of muscle, plays an important role in regulating muscle contraction, nerve conduction, and other bodily functions. Hypokalemia may result in confusion, fatigue, weakness, and, in severe cases, paralysis and heart rhythm abnormalities.
Hypokinetic:
Diminished movement and decreased motor function. Some movement disorders are hypokinetic, such as Parkinson’s disease.
Hypoparathyroidism:
An endocrine condition characterized by insufficient secretion of parathyroid hormone due to injury, disease, or congenital
abnormalities of the parathyroid glands. Parathyroid hormone plays an essential role in regulating calcium balance in the body. Hypoparathyroidism results in low calcium blood levels (hypocalcemia), leading to various symptoms and findings. For example, hypoparathyroidism may cause a condition known as tetany in which increased excitability of nerves and muscles results in uncontrollable, painful muscle spasms and cramping; abnormal involuntary movements resembling chorea; spasmodic closure of the larynx (laryngospasm); and other findings. Hypoparathyroidism may also lead to seizures; abnormal calcium deposits (calcifications) in the basal ganglia; loss of transparency of the lenses of the eyes (cataracts); dry, scaly skin; weakened tooth enamel; and/or other abnormalities.
Hypoxia:
abnormally low levels of oxygen.