Glossary: Commonly Used Terms Found in Medical Literature — N-P

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Narcolepsy: A condition characterized by recurrent episodes of daytime sleepiness and lapses in consciousness.

Necrosis: Cell death. Loss of cells, tissues, or parts of a structure or organ due to the progressively degrading actions of certain enzymes, such as the degradation of DNA within the nucleus of dying cells. Necrosis may result from a loss of blood supply (ischemia), infection, excessive exposure to ionizing radiation, certain chemicals, or extreme temperatures.

Neoplastic: Relating to the formation of a neoplasm (tumor) or a new, abnormal growth characterized by uncontrolled, progressive multiplication of cells. Neoplasms may be benign or malignant.

Nerve conduction velocity (NCV) test: A diagnostic study during which both sensory and motor nerves are repeatedly stimulated in order to measure the speed at which nerve impulses are conducted. Unusually slow conduction velocities suggest damage to nerve fibers (e.g., loss of the protective covering surrounding certain nerve fibers [demyelination] or other disease process).

Neuroacanthocytosis: Also known as choreoacanthocytosis, this is a genetic disorder that most often becomes apparent between the ages of 25 to 45 years. The disorder is usually transmitted as an autosomal recessive trait. Associated symptoms may include generalized chorea; dystonia affecting muscles of the mouth and tongue; potentially mutilating lip- and tongue-biting; and sudden, involuntary, repetitive muscle movements (motor tics) and vocalizations (vocal tics). Patients may also develop personality changes and cognitive decline, seizures, parkinsonism, atrophy of muscle tissue (amyotrophy), and difficulties speaking and swallowing. Neuroimaging studies may reveal atrophy of certain regions of the basal ganglia (e.g., caudate nuclei and putamen [striatum]). The disorder may be confirmed by blood tests revealing the presence of abnormal circulating red blood cells that have spur-like or thorny projections (acanthocytosis).

Neurochemical: Referring to the chemistry or biochemical processes of the nervous system, such as activities involving naturally produced chemicals (i.e., neurotransmitters) that enable nerve cells (neurons) to communicate.

Neurodegenerative: Marked by or pertaining to neurologic degeneration; deterioration of the structure or function of tissue within the nervous system.

Neuroimaging: The production of detail, contrast, and clearness in images of the brain and spinal cord (central nervous system) through the use of computed tomography (CT) scanning, magnetic resonance imaging (MRI), positron emission tomography (PET) scanning, or other imaging techniques to assist in diagnosis, treatment decisions, or research.

Neuroleptic: Typically referring to an antipsychotic medication to treat hallucinations or psychosis.

Neuron: An individual nerve cell.

Neuronal: Pertaining to a neuron or neurons.

Neuropathic Pain: Pain due to a neuropathy (degeneration of nerves in the body).  This can occur in various portions of the body.

Neuroprotective effect: Having the ability to prevent or slow the death of neurons. The drug selegiline (Eldepryl®) may have a neuroprotective effect, possibly by preventing formation of free radicals.

Neuropsychologist: is a professional psychologist that studies and practices neuropsychology. Neuropsychology is the study of the relationship between the central nervous system (brain and spine) and behavior, from birth to old age. The assess cognitive domains such as attention and concentration, processing speed, memory, language functions, visuo-spatial ability, and executive functioning (initiation, cognitive flexibility, problem solving, self-montioring and inhibition). Psychology is the study and profession concerning behavior and the related functions and processes of both the mind and body, in human and non-human animals. Neuropsychologists have many different types of jobs and not every neuropsychologist does the same thing. Many neuropsychologists administer psychological tests and perform assessments to diagnose specific disorders of the brain. These brain disorders most often result in problems with thinking, emotions, and/or behavior. Neuropsychologists study ways to measure recovery from brain damage as well as strategies to rehabilitate (make better) people with brain damage and improve their care.

Neuroreceptor: Specific sites on the surface of a nerve cell to which certain special substances (neurotransmitters) bind, initiating the conduction of impulses (or signals) to other nerve cells.

Neurotransmitter: A specialized substance (such as norepinephrine or acetylcholine) that transfers nerve impulses across spaces between nerve cells (synapses). Neurotransmitters are naturally produced chemicals by which nerve cells communicate.

Nigrostriatal system: Referring to the substantia nigra, the striatum, and the connection between them.

Nocturia: Excessive urinating at night.

Nomenclature: System of names used in a particular scientific discipline to consistently and methodically designate certain classifications and avoid confusion or ambiguity.

Non-ergotoline medication: A dopamine agonist medication that has action similar to that of pergolide (Permax®) and bromocriptine (Parlodel®) but is not derived from an ergot. Examples of nonergotoline medications that are used to treat some neurologic movement disorders include pramipexole (Mirapex®) and ropinirole (Requip™.)

Non-kinesigenic: Not induced by movement; provoked by factors other than sudden motions. This term often refers to abrupt episodes of involuntary movement that occur spontaneously or may be worsened by fatigue, stress, alcohol or caffeine intake, heat or cold, fasting, or other factors.

No-on phenomenon: A phenomenon experienced by individuals that take levodopa. This phenomenon occurs when an individual takes levodopa but does not experience any typical benefit from the medication. This is not a common phenomenon and involves total failure of an “on” experience.

Noradrenaline (norepinephrine): A vasoconstrictor whose release triggers action within the sympathetic nervous system, the part of the nervous system that regulates certain involuntary responses during times of stress. Noradrenaline serves as a neurotransmitter that stimulates receptors (alpha- and beta-adrenergic receptors) at effector organs supplied or innervated by certain sympathetic nerve fibers (postganglionic adrenergic fibers). In addition to its production by neurons, noradrenaline is also secreted by the inner region of the adrenal glands (adrenal medulla). The release of noradrenaline serves to deepen breathing, raise blood pressure, and increase the heart rate. It also plays a role in regulating mood.

NREM sleep: Non-REM (nonrapid eye movement) sleep, which is the normal period of dreamless, lighter sleep as compared to the deeper REM sleep. NREM sleep accounts for the major portion of sleep.

Obfuscation: 1. To make dark or not clearly seen. 2. A purposeful attempt to cause confusion or prevent understanding.

Objective: Free from or independent of personal feelings, opinions, prejudice, etc.; detached; unbiased. 2. Pertaining to what is external to or independent of the mind; real. 3. Treating, stressing, or dealing with external or actual phenomena, as distinct from inner or imaginary feelings or thoughts. (As opposed to subjective).

Obsessive-compulsive behaviors: The performance of certain repetitive actions or rituals in response to persistent thoughts or impulses. For example, obsessions may consist of repeated doubts, such as wondering whether the stove was left on; a need for routine; or impulses to perform certain inappropriate actions. Compulsions frequently include repeated checking and rechecking, such as ensuring that the stove is indeed off; touching particular objects in a specific pattern or sequence; repetitive hand washing; or other repetitious behavior performed in an attempt to prevent or relieve anxiety, distress, or a feeling of dread.

Obstructive sleep apnea: A sleep disorder characterized by episodes of temporary cessation of breathing due to obstruction of the airway.

Oculomotor: Relating to or causing movement of the eyes.

“Off” period”: The period of time that an individual taking levodopa experiences a return of their motor symptoms. The return can be at unexpected times after the medication dosage has worn off and can be extreme bradykinesia, stiffness, tremor, or motoric freezing.

Olfactology: the study of the sense of smell.

Olfactory hyperesthesia: an abnormally increased sensitivity to odors or an abnormally increased sense of smell.

Olivopontocerebellar atrophy (OPCA): A group of rare hereditary disorders characterized by neurodegenerative changes of certain brain regions, including the cerebellum and specialized groups of nerve cells (nuclei) in the brainstem (e.g., olivary and pontine nuclei). With most forms of the disorder, initial symptoms become apparent from adolescence to mid-adulthood; however, a rare form has been identified that may be evident at birth. Depending upon the type of OPCA, symptoms may include progressively impaired coordination, postural instability, slurred speech (dysarthria), and other associated findings (i.e., cerebellar ataxia); parkinsonism; rapid, involuntary, rhythmic eye movements (nystagmus); and/or retinal degeneration. Some affected individuals may also have additional symptoms and findings, such as involuntary, rapid, jerky movements (chorea); relatively slow, writhing motions that appear to "flow" into one another (athetosis); increased muscle stiffness (rigidity) with associated twisting or distorted posturing of affected muscles (dystonia); and/or other abnormalities. Most forms of OPCA are inherited as autosomal dominant traits; however, autosomal recessive forms have also been identified.

“On” period: The period of time that an individual taking levodopa experiences resolution of their motor symptoms. Individuals are often better able to perform during this time.

“On-Off” phenomenon: This term has multiple meanings. In some contexts it refers to general motor fluctuations. In other contexts it refers to the abrupt stopping of the medication effectiveness and can have motor as well as other physical complications (e.g. heart, breathing, temperature, etc.).

Opiate: Any preparation or derivative of opium.

Opioids: Means "like or similar to opium" and refers to medications with opium-like effects. This term is used to describe any synthetic drug that possesses the characteristic properties of opiate narcotics but is not derived from opium.

Organic: (1) Referring to or arising from an organ or organs. (2) Regarding substances that arise or are derived from living organisms. (3) Pertaining to chemicals that contain carbon.

Orthostatic hypotension: A sudden decrease in blood pressure that occurs when the affected individual sits up or stands. In some cases, it may occur as a side effect of certain medications.

Osteoarthritis: Arthritis related to the bones or to the joints.   Symptoms often include pain, limited mobility of the affected joint, and swelling of the affected area.

OT: an abbreviation for occupational therapy and occupational therapist.

Palate: The bony and muscular structure that forms the roof of the mouth and separates the oral and nasal cavities.

Pallidotomy: 1. A destructive operation on the globus pallidus (a structure deep within the brain), done to relive involuntary movement or muscular rigidity.

Parasympathetic nervous system: Part of the nervous system that, together with the sympathetic nervous system, forms the autonomic nervous system (ANS). The ANS controls the functioning of involuntary structures, including the heart, glands, and smooth muscle. The parasympathetic nervous system regulates nerve transmissions to certain effector organs under normal conditions, as opposed to times of stress. It serves to "steady" involuntary activities and conserve or restore energy. Parasympathetic responses may include slowing of the heart and breathing rates, contraction of the pupils, an increase in glandular activity, and an acceleration in the rate of peristalsis.

Parathyroid glands: Two pairs of endocrine glands located in the neck at the back of the thyroid gland. The parathyroid glands produce parathyroid hormone, which increases blood calcium levels by causing bones to release calcium into the blood, the kidneys to conserve calcium, and the intestines to increase calcium absorption from food. When blood calcium levels are high, the parathyroid glands reduce their production of parathyroid hormone, essentially reversing the process.

Paresthesias: Abnormal sensations occurring spontaneously or in response to stimulation. Paresthesias may include prickling, tingling, burning, or tickling feelings; numbness; "pins and needles"; or cramp-like sensations. Various neurologic movement disorders may be characterized by paresthesias, including restless legs syndrome (RLS), paroxysmal kinesigenic dyskinesia (PKD), and paroxysmal non-kinesigenic dyskinesia (PNKD).

Parkinson's disease (PD): PD is a disorder that affects nerve cells (neurons) in the part of the brain controlling muscle movement. It is a slowly progressive degenerative disorder of the central nervous system characterized by slowness or poverty of movement (bradykinesia), rigidity, postural instability, and tremor primarily while at rest. Additional characteristic findings include a shuffling, unbalanced manner of walking; forward bending or flexion of the trunk; a fixed or "mask-like" facial expression; weakness of the voice; abnormally small, cramped handwriting (micrographia); depression; or other symptoms and findings. Such abnormalities are thought to result from progressive loss of nerve cells within a certain region of the substantia nigra of the brain and the associated depletion of the neurotransmitter dopamine.

Parkinsonism: A constellation of the following symptoms: tremor, rigidity, bradykinesia (slow movements), and loss of postural reflexes. Although classically seen in Parkinson's disease, parkinsonism may have other causes. In the elderly, parkinsonism may be caused by dopamine-blocking drugs, multiple system atrophy, striatonigral degeneration, Shy-Drager syndrome, cortico basal degeneration, diffuse Lewy body disease, and Alzheimer's disease with parkinsonism. In younger people, parkinsonism may be caused by juvenile-onset dystonia/parkinsonism, Westphal variant of Huntington's disease, Wilson's disease, L-dopa-responsive dystonia, Hallervorden-Spatz disease, and progressive pallidal degeneration.

Paroxysmal: Pertaining to or occurring in paroxysms or sudden, recurrent episodes. The term paroxysms often describes transient episodes of abnormal involuntary movements (e.g., chorea, athetosis, dystonia, and/or ballismus) or ataxia, which is characterized by an impaired ability to coordinate voluntary movements.

Paroxysmal movement disorders: Certain neurologic movement disorders characterized by abrupt, transient episodes of abnormal involuntary movement, such as chorea, athetosis, dystonia, and/or ballismus (i.e., the paroxysmal dyskinesias) or impaired coordination of voluntary actions and other associated findings (i.e., paroxysmal ataxias). Depending upon the specific disorder present, episodes may be precipitated or worsened by different factors. As examples, in those with paroxysmal kinesigenic dyskinesia (PKD), episodes may be triggered by sudden voluntary movements. In non-kinesigenic dyskinesia (PNKD), episodes occur spontaneously and may be worsened by caffeine or alcohol consumption, stress, fatigue, or other factors. In patients with paroxysmal kinesigenic ataxias, episodes may be triggered by sudden voluntary movements or postural changes. These disorders may be familial, appear to occur randomly for unknown reasons (sporadically), or occur secondary to other underlying conditions or disorders (symptomatic).

Parvocellular layers: Part of the visual system that is involved with chromatic or color vision, specifically identifying the colors red-green. This visual system can be affected by age as well as multiple diseases, including PD. See also Magnocellular and Koniocellular.

Pathological: Caused by or altered by or manifesting disease or pathology. For example, “diseased tonsils”; “a morbid growth”; “pathologic tissue”; “pathological bodily processes”; “pathological sleep”.

Pathophysiology: The effects of disease on body functions; the physiology of altered function seen in disease. ("Patho-" is a combining form denoting any disease state, and "physiology" refers to the study of the processes and functioning of the human body.)

Penetrance: The regularity or frequency with which a specific gene yields its effect or "is expressed." For example, if a specific gene produces a disease in all individuals who carry the gene, it is termed 100% penetrant. If a gene produces the disease less than 100% of the time, it is not fully penetrant.

Pericardial fibrosis: mass or abnormal tissue in the heart and surrounding areas.

Periodic apnea: Episodes of the temporary cessation of spontaneous breathing. Periodic apnea may be characterized by absence of airflow, absence of chest wall movements, or airway obstruction that may result from poor control of tongue movements, impaired coordination of upper airway muscles, or other abnormalities.

Periodic limb movements in sleep (PLMS): Repeated stereotypic movements of the limbs (usually the legs) that occur during sleep. These movements typically consist of upward extension of the great toe and foot as well as flexion of the ankle, knee, or hip; they occur every 15 to 40 seconds and 0.5 to 6.0 seconds, usually during NREM sleep and have a duration of 0.5 to 6.0 seconds.

Peripheral edema: unusual fluid accumulation, resulting in swelling of the arms or legs.

Peripheral neuropathy: Inflammation, degeneration, or damage of nerves of the peripheral nervous system (PNS). The PNS includes nerves that extend from the brain and spinal cord (central nervous system) to various parts of the body. Peripheral neuropathy may involve motor nerves, causing muscle weakness, and/or sensory nerves, resulting in pain, abnormal sensations, such as numbness or tingling, or other findings.

Peripheral vision: A part of vision that occurs outside the very center of gaze.

Peristalsis: Rhythmic, wave-like contractions of smooth or involuntary muscle fibers that propel food through the digestive tract.

Periventricular: around or near a ventricle. A ventricle is an opening or chamber in the body.

Periventricular white matter: white matter that is immediately to the side of the two lateral (side) ventricles of the brain. The lateral ventricles are two curved openings (shaped like a horseshoe) located deep within the top section of the brain. White matter is a group of white nerve fibers that conduct nerve impulses quickly. White matter is important for muscle movements.

Pharyngeal: 1. Related to the pharynx. The pharynx is the upper expanded portion of the digestive tube, between the esophagus below and the mouth and nasal cavities above and in front. It is distinct from the rest of the digestive tube in that it is composed exclusively of voluntary muscle arranged in outer circular and inner longitudinal layers.

Phenotype: The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences. b. The expression of a specific trait, such as stature or blood type, based on genetic and environmental influences.

Phonation: The production of speech; utterance of sounds through use of the vocal cords.

Phonatory: relating to phonation – the production of vocal sounds by vibration of the vocal folds.

Physiologic tremor: A form of rapid tremor that may occasionally occur in any individual. Physiologic tremor is typically the result of fear, anxiety, or excitement. Physiologic tremor may affect the arms, legs, and, in some patients, the face or neck.

Pleuropulmonary fibrosis: mass or abnormal tissue in the lungs and surrounding area.

Polymerase chain reaction (PCR): A highly sophisticated technique during which a known sequence of DNA is copied rapidly over a short period, such as millions of copies over a few hours. PCR testing assists in diagnosing certain genetic disorders, helps identify individuals through analysis of a single cell or so-called "DNA fingerprinting," or characterizes certain strains of infectious microorganisms.

Polysomnography: A diagnostic test during which a number of physiologic variables are measured and recorded during sleep (e.g. brain electrical activity, muscle movement, breathing/air flow, etc.).

Positron emission tomography (PET): An advanced, computerized imaging technique that uses radioactively-labels substances (e.g., glucose) to demonstrate chemical and metabolic activities in the brain as well as track other brain functions. Brain structures are also visualized on PET scans.

Positron emission tomography (PET) scanning: A noninvasive, diagnostic procedure used to record the uptake and distribution of certain substances in the tissues and organs of the body. Thus, PET assists in evaluating various metabolic and physiological activities in the body. During this procedure, three-dimensional, color-coded images are created based upon the detection of positively charged particles (positrons). The positrons are produced by certain biochemicals (e.g., glucose) carrying radioactive substances that have been introduced into the body (via intravenous injection). PET scanning may help to detect abnormal biochemical patterns associated with certain neurologic conditions, such as Parkinson’s disease, brain tumors, seizure disorders, and psychiatric abnormalities.

Postural tremor: Any tremor that is present while an individual voluntarily maintains a position against gravity, such as holding the arms outstretched.

Precursor: Literally a "forerunner," such as a substance that precedes another in a biochemical reaction.

Prefrontal Cortex: Behind your forehead is the prefrontal cortex of the brain. It is the very first area in the front of the brain. The prefrontal cortex is responsible for the planning and initiating (starting) of voluntary movement. Damage to this area will impair these motor activities. The prefrontal cortex has connections with the premotor cortex and the supplemental motor cortex. The premotor cortex and supplemental motor cortex are areas near the middle of the brain important for movement..

Progressive supranuclear palsy (PSP): A progressive neurological disorder characterized by neurodegenerative changes of certain brain regions, including particular areas of the basal ganglia and the brainstem. Symptom onset most often occurs in the sixth decade of life. Associated findings may include balance difficulties, sudden falls, stiffness (rigidity), slowness of movement (bradykinesia), an impaired ability to perform certain voluntary eye movements, and visual disturbances. Affected individuals may also develop slurred speech; swallowing difficulties; personality changes; dystonia; sudden, involuntary, "shock-like" muscle contractions (myoclonus); or other abnormalities. The disorder usually appears to occur randomly for unknown reasons (sporadically); however, there are some reports of families with multiple affected members, suggesting a possible hereditary component to the disease.

Prophylactic: Referring to preventive treatment (i.e., prophylaxis); a medication, procedure, or device that serves as a preventive against disease.

Prophylaxis: Protection from or the prevention of disease; preventive (i.e., prophylactic) therapy; often refers to the use of a drug, mechanical agent, or procedure to prevent infection with certain microorganisms (e.g. bacteria).

Proprioception: One’s awareness of posture, movement, and changes in balance and the knowledge of position, weight, and resistance of objects in relation to the body.

Prosody: 1. The rhythmic and intonational aspect of language. 2. The varying rhythm, stress, and frequency of speech that aids meaning transmission.

Psychogenic: Of mental or emotional origin; referring to a symptom, condition, or disorder that is caused by mental, psychological, or emotional factors rather than physical illness.

Psychosis: Refers to any mental disorder characterized by severe distortion of thinking, comprehension, and judgment (i.e., mental capacity); impaired contact with reality; and abnormal emotional responses and disorganized behaviors. Symptoms may include false beliefs despite evidence to the contrary (delusions), such as fears of persecution; the perception of sounds, sights, or other sensations in the absence of external stimuli (hallucinations); apparent lack of emotion (affect); abnormal thought patterns; disorganized, incoherent speech; and/or agitated, aggressive behaviors. Psychosis may be of physical (i.e., organic) origin, such as due to brain damage, neurological diseases, underlying metabolic disorders, etc., or "functional," meaning that it is produced or caused by factors other than organic disease.

Pulmonary: Referring to the lungs.

Pulmonary embolus: Obstruction from a blood clot in the pulmonary artery or one of its branches.

Putamen: One of the 3 major brain regions that, together with the caudate nuclei and the globus pallidus, comprise the basal ganglia. Relatively similar in function and structure, the putamen and the caudate nuclei are collectively referred to as the striatum. Specialized groups of nerve cells within the putamen receive input from various regions of the cerebral cortex. The messages are processed and relayed by way of the thalamus to the motor cortex, influencing voluntary movement.

PWP: Person With Parkinson’s