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( inherited only from one parent) or, less commonly, appear to occur randomly for unknown reasons( sporadically). The disorder results from abnormally long sequences of information within a gene. 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.
Hypokinetic: Diminished movement and decreased motor function. Some movement disorders are hypokinetic, such as Parkinson’ s disease, PSP, and MSA.
Hyposmia: A decreased sense of smell.
Idiopathic: A disorder or condition of spontaneous origin; self-originated or of unknown cause. The term is derived from the prefix“ idio-” meaning one’ s own and“ pathos” indicating disease.
Inflammation: This is the body’ s first response to injury or irritation. The classic signs of inflammation are pain, heat, redness, swelling, activated immune response, and loss of function.
Inhibition: The restraint, suppression, or arrest of a process or the action of a cell or organ; the prevention or slowing of the rate of a chemical or an organic reaction. The term“ reciprocal inhibition” refers to the restraint or“ checking” of one group of muscles upon stimulation( excitation) and contraction of their opposing( antagonist) muscles.
Inhibitor: A substance that blocks, restricts, or interferes with a chemical reaction or other biologic activity.
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Insidious: Of subtle, gradual, or imperceptible development; referring to the development of symptoms that may not be recognized by an affected individual until the disorder in question is established.
Jejunostomy Tube: Similar to a gastrostomy tube, although this tube is longer and is inserted through the abdominal wall into the jejunum, the middle section of the small intestine.
Lateral: Sideways; of, on, from, or toward the side.
Levodopa: A drug used to treat Parkinson’ s disease. It is also called L-dopa and, in the United States, is sold as Sinemet. Levodopa is converted by the body to dopamine, a neurotransmitter that is reduced in Parkinson’ s disease and PSP brains. However, levodopa does not work well in PSP patients.
Lewy Body Disease: Also called diffuse Lewy body disease or Lewy body dementia. Lewy body disease is a common cause of dementia, accounting for approximately 15 – 20 % of all cases. The age of onset is typically in the late 50s through the 70s. Lewy body disease is characterized by more daily fluctuations in symptoms than Alzheimer’ s disease, as well as more prominent psychosis. Patients are prone to have adverse reactions to antipsychotics. Patients also have parkinsonian features early in the disease, including slowed movements and rigidity, though usually without tremor. In contrast to PSP and CBD, Lewy bodies are not made of accumulated and misfolded tau protein but consist of misfolded alpha-synuclein. In Lewy body disease, the Lewy bodies that cause neurodegeneration are most prominently found in the cortex, or surface of the brain, versus in the midbrain with Parkinson’ s disease.
Long-Term Care( LTC): An umbrella term referring to comprehensive healthcare delivered to people with functional impairments over an extended time period. An important goal of LTC is to provide care in the least restrictive environment( e. g., a person’ s home).