Glossary of Terms

A class of drugs used to treat mild to moderate dementia in Parkinson's disease. These drugs increase brain levels of a neurotransmitter called acetylcholine, which helps neurons communicate with each other and is involved in memory, learning and thinking.

See also: Dementia

Undifferentiated cells, found in a differentiated tissue, that can renew themselves and - with certain limitations - differentiate to yield all the specialized cell types of the tissue from which they originated. In addition, see what patients on our Patient Council have to share on the topic of stem cells.

See also: Embryonic stem cells, Stem cells, Umbilical cord-derived stem cells

A clumping of proteins inside cell bodies in the brain, which may be toxic. Aggregation of the protein alpha-synuclein is found in Lewy bodies, a pathological hallmark of Parkinson's disease.

See also: Alpha-synuclein, Lewy bodies

A chemical that binds to a receptor on a cell and triggers a response by that cell.

See also: Dopamine agonist

Inability to move ("freezing") or difficulty in initiating or maintaining a body motion. From the Greek a, without, and kinesia, movement.

See also: Freezing

A protein normally found in neurons, and present in high concentrations in Lewy bodies. A genetic mutation in this protein is the basis for a rare inherited form of Parkinson's disease. For more information see alpha-synuclein as a priority area.

See also: Aggregate

Normal animals modified mechanically, genetically or chemically, used to demonstrate all or part of the characteristics of a disease. With models, researchers can study the mechanisms of a disease and test therapies. Also known as preclinical models.

A class of drugs often effective in reducing the tremor of Parkinson's disease. They work by blocking the action of acetylcholine, a neurotransmitter in the brain. However, because acetylcholine is involved in memory, learning and thinking, anticholinergic drugs can bring about cognitive side effects including confusion or dementia.

See also: Dementia

A chemical compound or substance that inhibits oxidation - damage to cells' membranes, proteins or genetic material by free radicals (the same chemical reaction that causes iron to rust). Some studies have linked oxidative damage to Parkinson's disease.

A medicine used to treat Parkinson's disease. For more information see what patients on our Patient Council have to share on the topic of medication.

A movement disorder marked by loss of balance and decreased muscle coordination during voluntary movements.

A movement disorder sometimes confused with Parkinson's disease that manifests in low, repetitive, involuntary, writhing movements of the arms, legs, hands, and neck that are often especially severe in the fingers and hands.

Any problem with the functioning of the autonomic nervous system, which controls unconscious body functions that affect the bladder, bowels, sweating, sexual function and blood pressure.

A region deep within the brain consisting of large clusters of neurons responsible for voluntary movements such as walking and movement coordination. Many of the symptoms of Parkinson's disease are brought on by loss of or damage to dopamine neurons in this region, which encompasses the striatum, the subthalamic nucleus, and the substantia nigra.

See also: Dopamine, Neuron, Striatum, Subthalamic nucleus, Substantia nigra

Surgery performed on both sides of the brain.

Specific, measurable physical traits used to determine or indicate the effects or progress of a disease or condition. For example, high blood pressure is a biomarker of potential cardiovascular disease. No validated biomarker of Parkinson's disease currently exists.

A thin layer of tightly packed cells separating the central nervous system from the body's blood stream. This layer is crucial to protecting the brain from foreign substances, but also blocks some potentially therapeutic treatments from entering the brain via orally administered drugs.

One of the cardinal clinical features of Parkinson's disease, the slowing down and loss of spontaneous and voluntary movement. From the Greek brady, slow, and kinesia, movement.

A strategy aiming to replace cells damaged or lost by disease or injury with healthy new cells. Cell replacement in Parkinson's aims to replace with new cells the dopamine-producing cells in the brain that are progressively lost through Parkinsons's disease.

Central nervous system (CNS) is a term referring to the brain and spinal cord.

A general term for movement disorders that can be confused with Parkinson's disease, which are characterized by involuntary, random, jerking movements of muscles in the body, face, or extremities.

Organized medical studies that test the effectiveness of various treatments, such as drugs or surgery, in human beings.

The most common form of Coenzyme Q, a vitamin-like antioxidant. Results of the first placebo-controlled, multicenter clinical trial of the compound, published in October 2002, suggested that it might slow disease progression in patients with early-stage Parkinson's disease. The results have yet to be confirmed in a larger study.

The loss of intellectual functions (such as thinking, remembering, and reasoning) of sufficient severity to interfere with daily functioning. The term cognitive dysfunction includes dementia and executive dysfunction, and may also encompass changes in personality, mood, and behavior. Cognitive dysfunction in Parkinson's disease typically does not respond to dopamine replacement therapy and ranges from mild impairment to dementia.

See also: Dementia, Executive dysfunction, Mild cognitive impairment

Irresistible impulses to act, regardless of the rationality of the motivation, or acts performed in response to such impulses. Some compulsive behaviors, such as compulsive gambling, hypersexuality, binge eating and shopping, have been associated with dopamine agonists used to treat Parkinson's disease, though this association has not been conclusively established.

A drug that blocks an enzyme (catchol-O-methyltransferase) that breaks down dopamine. COMT inhibitors include entacapone and tolcapone. Tolcapone has been known to cause serious liver problems and has been withdrawn from the Canadian and European markets.

See also: Enzyme, Dopamine

A naturally occurring amino acid that helps to supply energy to muscle cells. A preliminary clinical trial in 200 Parkinson's patients, published in February 2006, suggested that creatine may slow the progression of PD and may therefore merit additional study. A much larger study is underway to further evaluate the potential neuroprotective effects of creatine.

CT (Computed Tomography) scan is a technique that uses a series of X-rays to create image "slices" of the body from different orientations to create a two-dimensional cross sectional images of the body. Sometimes called CAT scan, for Cmputed Axial Tomography.

See also: Imaging

Deep Brain Stimulation (DBS) is a surgical procedure that uses a surgically implanted, battery-operated medical device called a neurostimulator - similar to a heart pacemaker and approximately the size of a stopwatch - to deliver electrical stimulation to targeted areas in the brain that control movement, blocking the abnormal nerve signals that cause tremor and PD symptoms. At present, the procedure is used primarily for patients whose symptoms cannot be satisfactorily controlled with medications. For more information see what patients on our Patient Council have to share on the topic of DBS and late stage treatments.

See also: Pallidotomy, Surgical therapies, Thalamotomy

A decline in memory and/or intellectual functioning severe enough to interfere with social or occupational functioning. Some Parkinson's patients experience dementia, generally at later stages of disease progression. This symptom does not typically respond to dopamine replacement therapy.

See also: Cognitive dysfunction, Executive dysfunction

A mental state, and non-dopamine-responsive symptom of Parkinson's disease, characterized by feelings of despondency and a lack of ability to initiate activity. For more information see what patients on our Patient Council have to share on the topic of emotion.

See also: Cognitive dysfunction

The study of the process by which organisms grow and develop. Developmental biology studies in Parkinson's disease hold potential to identify therapeutic targets and new cell replacement strategies.

Identification or naming of a disease by its signs and symptoms.

Unsteadiness or balance problems. A common problem in Parkinson's disease.

See also: Dopamine-non-responsive

A gene of unknown function implicated in rare inherited cases of Parkinson's disease.

A neurotransmitter chemical produced in the brain that helps control movement, balance, and walking. Lack of dopamine is the primary cause of Parkinson's motor symptoms.

A class of drugs commonly prescribed in Parkinson's disease that bind to dopamine receptors and mimic dopamine's actions in the brain. Dopamine agonists stimulate dopamine receptors and produce dopamine-like effects.

Refers to symptoms of Parkinson's disease characterized by a lack of improvement when treated with current dopamine-replacement therapies. These symptoms include cognitive dysfunction, postural instability and gait dysfunction, sleep disorders, speech disorders, depression, and others.

Slurred or otherwise impaired speech. A common problem in Parkinson's disease.

See also: Dopamine-non-responsive, Speech disorders

Involuntary, uncontrollable, and often excessive movements that are a common side effect of levodopa treatment for Parkinson's disease. These movements can be lurching, dance-like or jerky, and are distinct from the rhythmic tremor commonly associated with Parkinson's disease. For more information see what patients on our Patient Council have to share on the topic of dyskinesia and dystonia.

Difficulty swallowing. A common problem in Parkinson's that increases the risk of inhaling food or liquids into the airways, which in its later stages can lead to a condition known as "aspiration pneumonia."

See also: Dopamine-non-responsive

A movement disorder that may be confused with Parkinson's disease. Dystonia is characterized by abnormal and awkward posture or sustained movements of a hand, foot, or other part of the body; may be accompanied by rigidity and twisting. For more information see what patients on our Patient Council have to share on the topic of dyskinesia and dystonia.

Primitive (undifferentiated) cells from the embryo that have the potential to become a wide variety of specialized cell types. Embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in an in vitro fertilization clinic and then donated for research purposes with informed consent of the donors. See what patients on our Patient Council have to share on the topic of stem cells.

See also: Adult stem cells, Stem cells, Umbilical cord-derived stem cells

The non-genetic surroundings, conditions or influences that affect an organism. These can be divided into physical, biological, social, cultural, and other factors and may play a role in the onset of various diseases, including Parkinson's disease. Environmental factors that have been inconclusively linked to Parkinson's disease risk include exposure to various pesticides and metals.

A protein that catalyzes or speeds up chemical reactions. Enzymes are critical to a wide range of healthy cell activities, and alterations in their function may play a role in Parkinson's disease.

The study of the patterns, causes, and control of disease in groups of people. Epidemiological studies can be used to better understand potential causes of Parkinson's disease.

A movement disorder that may be confused with Parkinson's disease. A fast tremor that is most pronounced when performing an action such as writing or bringing a hand to a target - as opposed to the resting tremor of Parkinson's disease, which is most pronounced when the limb is at rest.

Overstimulation of nerve cells by nerve impulses. Excitotoxicity often leads to cell damage or death, and may play a role in Parkinson's disease.

Difficulty sustaining "executive functions," higher-order processes that enable us to plan, sequence, initiate, and sustain our behavior toward a given goal, incorporating feedback and making adjustments along the way. Executive functions include aspects of memory, attention, problem solving, and multitasking. Some people with Parkinson's experience executive dysfunction or other forms of cognitive impairment, which do not respond to dopamine replacement therapy.

See also: Cognitive dysfunction, Dementia

Physical activity undertaken in order to maintain or improve health. A growing body of evidence suggests that exercise may play an important role in treatment regimens for Parkinson's disease, and may even slow or stop disease progression. Research is ongoing to understand whether and how exercise confers neuroprotection. Please see [add topic page] for more information on discussing an individualized exercise plan with your doctor.

See also: Physical therapy

A symptom experienced by some people with Parkinson's, in which the face is immobile with reduced blinking.

See also: Hypomimia

A rare form of Parkinson's disease that runs in families, in which genetics is believed to play an important role. This form of Parkinson's disease may account for less than five percent of Parkinson's cases worldwide.

See also: Sporadic Parkinson's disease

A common, poorly understood symptom of Parkinson's disease; a state in which one feels tired or exhausted, and the capacity for normal work or activity is reduced.

An involuntary quickening of steps and shuffling after starting to walk. Festination is a common feature of Parkinson's disease.

Abrupt and temporary inability of Parkinson's patients to move that frequently occurs when beginning to walk or at a boundary such as a door or when exiting a car.

See also: Akinesia

See: postural instability

Abbreviation for "Glial cell-derived neurotrophic factor." GDNF is part of a family of naturally occurring human growth factors (also known as trophic factors) known to nourish and foster the growth and development of dopamine-generating neurons. Several therapeutic approaches involving GDNF are currently under development.

See also: Neurturin, Trophic factors

A novel approach to treat, cure or prevent disease by changing the expression of a person's genes. In Parkinson's disease, this research primarily seeks to repair or restore the function of dopaminergic neurons in the brain. As of February 2012, several gene therapy trials for Parkinson's disease are either ongoing or have been completed.

Any inherited genetic pattern that may make some individuals more prone than others to certain health conditions, disorders or diseases. For more information see genetics as a priority area.

The branch of biology that deals with heredity, especially the mechanisms of hereditary transmission via DNA and the variation of inherited characteristics (genes) among similar or related organisms. For more information see genetics as a priority area.

A structure made up of nerve cells located deep in the brain affecting movement, balance, and walking. It is often used as a target for surgical procedures in Parkinson's disease, including DBS and pallidotomy.

See also: Pallidotomy, Deep brain stimulation

The variable appearance of a condition; the heterogeneity of Parkinson's disease refers to the fact that its symptoms and appearance vary widely from patient to patient. From the Latin hetero, different, and genus, kind.

A clinical term for the slow or diminished movement associated with Parkinson's disease. From the Greek hypo, less, and kinesia, movement.

A clinical term for the Parkinson's symptom more commonly known as facial masking - an immobile face with reduced blinking. From the Greek hypo, less, and mimia, imitation or expression.

See also: Facial masking

Any method used to produce a picture of internal body structures.

Some imaging techniques commonly used in Parkinson's disease are: CT (Computed tomography) scan, MRI (Magnetic resonance imaging), and PET (Positron emission tomography) scan

Cells engineered from adult skin cells that share many of the physical, growth and genetic features typically found in embryonic stem cells. First engineered in 2007, these cells can differentiate to produce other tissue types, including what appear at first glance to be cells similar to dopamine neurons (the cells of interest to Parkinson's scientists). While a great deal more research is required, iPS cells are generating excitement in the scientific community because of their potential to achieve the same goals as human embryonic stem cells and therapeutic cloning without engendering political or ethical controversy.

The nonspecific immune response that occurs in reaction to any type of bodily injury. The reactions produced during inflammation and repair may be harmful or helpful. Work is ongoing to understand the role of inflammation in Parkinson's disease.

An area of cell damage or cell death.

Also called L-dopa, the most commonly administered drug to treat Parkinson's symptoms. Levodopa helps restore levels of dopamine, a chemical messenger in the brain responsible for smooth, coordinated movement and other motor and cognitive functions.

See also: Sinemet, Dopamine

Abnormal protein clumps that accumulate in dead or dying dopamine-producing cells of the substantia nigra in Parkinson's disease. At autopsy, the presence of Lewy bodies is used to confirm a Parkinson's diagnosis.

See also: Aggregate, Dopamine, Substantia nigra

A gene implicated in up to one percent of Parkinson's disease cases. LRRK2 functions as a kinase, an enzyme that modifies the function of proteins. For more information see LRRK2 as a priority area.

Abbreviation for "Mesencephalic Astrocyte-derived Neurotrophic Factor." MANF is a trophic factor that is still in the beginning stages of preclinical study. Early data suggests MANF is as effective as GDNF in reducing behavioral deficits in preclinical or animal Parkinson's disease models. However, there is still a lot of work to do before we can fully assess the potential of MANF to effectively treat Parkinson's in people with the disease.

See also: GDNF, Animal models

Thin metallic tubes inserted into the brain and guided by stereotactic methods. They are connected to the operating room computer and used to measure the electrical signal from brain cells during surgical procedures, such as pallidotomy.

See also: Stereotactic, Surgical therapies

Small, cramped handwriting that is a symptom for many Parkinson's patients.

Mild cognitive impairment, also known as MCI, ia a decline in memory and/or intellectual functioning that is not as severe as dementia. MCI occurs frequently in Parkinson's disease and may progress to dementia in some patients.

See also: Dementia

Mitochondria are the "power plants" of the cell, generating energy needed for cell activity. Reduced or incorrect mitochondrial function has been implicated in oxidative stress that may play a role in Parkinson's disease.

Monoamine oxidase inhibitors (MAO) are drugs that enhance the effect of dopamine by preventing enzymes from breaking them down. Some studies suggest that MAO inhibitors may slow the progression of Parkinson's disease but this has not been proven in the clinic.

Conditions including Parkinson's disease, many neurodegenerative, that prevent normal movement. Some are characterized by lack (or "poverty") of movement, some by excessive movement. Besides Parkinson's, conditions categorized as movement disorders include essential tremor, multiple system atrophy, progressive supranuclear palsy, Huntington's disease, Tourette's syndrome and cerebral palsy.

A neurologist with specific training in the subspecialty of movement disorders. Movement disorders specialists typically follow a greater number of patients with movement disorders, and are thus more experienced in the use of the various medications (and their combinations) as compared to a general neurologist, internist or general practitioner.

See also: Movement disorders, Neurologist

Abbreviation for "Magnetic Resonance Imagin." MRI is a procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as CT (computed tomography) scan or x-ray. MRI is especially useful for imaging the brain, spine, the soft tissue of joints, and the inside of bones.

See also: Imaging

A movement disorder that may be confused with Parkinson's disease. It is a degenerative condition characterized by low blood pressure when standing. It may lead to parkinsonism, rigidity, ataxia, fainting, or incontinence. Also known as Shy-Drager Syndrome.

Having to do with the way the brain affects emotion, behavior, and learning. Parkinson's disease can include several neurobehavioral symptoms including depression and anxiety.

The slow and progressive death (degeneration) of certain brain systems in conditions such as Parkinson's disease, Alzheimer's disease and Lou Gehrig's disease (ALS).

A physician specializing in diseases and disorders of the brain, spinal cord, nerves, and muscles, including stroke, Parkinson's disease, epilepsy, Alzheimer's disease, and muscular dystrophy.

See also: Movement disorders specialist

A nerve cell used to transmit information within the central nervous system. Parkinson's disease involves death of and/or damage to dopamine neurons.

See also: Central nervous system, Dopamine

The branch of health science concerned with the study of the effects of drugs on the nervous system.

See also: Central nervous system

Providing protection to or stimulating the regrowth of any part of the body's nervous system. No currently available treatment for Parkinson's disease has been proven to provide a neuroprotective or neuroregenerative effect; all available Parkinson's disease treatments are symptomatic, meaning that they mask the symptoms while the underlying disease continues to progress.

See also: Neuroregenerative, Symptomatic

See: neuroprotective

A doctor who operates on the brain and central nervous system.

See also: Central nervous system

A specialized chemical messenger (e.g. dopamine, norepinephrine, serotonin) that sends messages from one nerve cell to another. Most neurotransmitters play different roles throughout the body, many of which are not yet known.

See also: Dopamine, Serotonin

A naturally occurring human growth factor (or trophic factor) in the same family as GDNF, known to nourish and foster the growth of dopamine-generating neurons.

See also: GDNF, MANF, Trophic factors, Dopamine, Neuron

An alkaloid (nitrogen-containing chemical) made by the tobacco plant or produced synthetically that is one of the major chemicals in cigarettes. Epidemiological data have linked cigarette smoking to protection against Parkinson's onset. However, because of the grave health risks associated with smoking, no responsible physician would recommend it as a means of preventing Parkinson's disease.

Poorly understood symptoms of Parkinson's that affect body systems other than movement. These include cognitive impairment, sleep problems and depression. These typically do not respond to dopamine replacement therapy. For more information see what patients on our Patient Council have to share on the topic of non-motor-symptoms.

See also: Cognitive dysfunction, Sleep disorders, Depression, Dopamine

A gene that plays an important role in the early development and maintenance of dopamine neurons.

See also: Dopamine, Neuron

A reduced or impaired ability to detect odors, which can be an early sign of Parkinson's disease. Researchers are studying olfactory dysfunction as a possible avenue toward a biomarker, or molecular fingerprint, of Parkinson's disease.

See also: Biomarkers

Sudden loss of activity of levodopa lasting minutes to hours after a brief period of effectiveness. The term also sometimes refers to a cyclical response to medication where the patient can function adequately at times but is too stiff and immobile to function at other times.

See also: Levodopa

A surgical procedure in which lesions are produced in the globus pallidus region of the brain in an effort to lessen Parkinson's symptoms such as tremors, rigidity, and bradykinesia. Pallidotomy has become less commonly performed with the establishment of deep brain stimulation (DBS) surgery as a safe and effective surgical intervention for Parkinson's disease.

See also: Deep brain stimulation, Surgical therapies, Thalamotomy, Tremor, Bradykinesia

Antiquated term for paralysis or an uncontrollable shaking of the body. When he discovered Parkinson's disease, Dr. James Parkinson named it "the shaking palsy."

A gene, mutations in which have been associated with a familial form of Parkinson's disease. How loss of function of parkin leads to dopaminergic cell death is unclear. The current prevailing hypothesis is that the normal function of parkin is to help degrade one or more proteins that are toxic to dopaminergic neurons.

See also: Dopamine

Parkinson's disease is a chronic, degenerative neurological disorder that affects one in 100 people over age 60. While the average age at onset is 60, people have been diagnosed as young as 18. There is no objective test, or biomarker, for Parkinson's disease, so the rate of misdiagnosis can be relatively high, especially when the diagnosis is made by a non-specialist. Estimates of the number of people living with the disease therefore vary, but recent research indicates that at least one million people in the United States, and more than five million worldwide, have Parkinson's disease.

See also: Biomarkers

Generic term referring to slowness and mobility problems that result from or look like Parkinson's disease. Several conditions that are not actually Parkinson's disease, including multiple system atrophy and progressive supranuclear palsy, as well as a number of medications, can result in parkinsonism and a misdiagnosis of Parkinson's disease.

See also: Multiple System Atrophy

A database used to record cases of diseases of public health importance. Registries are a valuable epidemiological resource that can be used to calculate and monitor incidence rates and risk, as well as trends in incidence and mortality.

Peripheral nervous system (PNS) is a term referring to the nerves that lie outside of the central nervous system (brain and spinal cord). The PNS connects the central nervous system to organs, limbs, and skin.

PET (Positron Emission Tomography) scan is a procedure in which a small amount of a radioactive drug is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the drug is used. This technique can be used to monitor and produce pictures of metabolic or biochemical activity in the brain. A variety of radioactive drugs are used to produce pictures that provide information about different biological systems.

See also: Imaging

The use of exercises and physical activities to help condition muscles and restore strength and movement. Similar to exercise, certain forms of physical therapy may be useful to maintain balance and flexibility as part of an overall Parkinson's disease treatment regimen.

See also: Exercise

Alternating movements of the thumb and forefinger that give the appearance of rolling a small object between the fingers; a characteristic slow tremor in the fingers of Parkinson's patients.

See also: Tremor

A gene of unknown function implicated in rare cases of Parkinson's disease.

A Parkinson's-like illness, cases of which followed the worldwide flu epidemic of 1918; also called von Economo encephalitis.

Uncontrollable problems with standing or walking, or impaired balance and coordination, which are symptoms of Parkinson's disease for some patients and do not respond to dopamine replacement therapy.

See also: Gait dysfunction

See: animal models.

The expected future course of an illness.

Progressive Supranuclear Palsy (PSP) is a movement disorder that can be mistaken for Parkinson's disease. PSP is a degenerative disease of unknown cause characterized by problems looking up and down, frequent falls and parkinsonism. It does not consistently respond to dopamine replacement therapy.

See also: Parkinsonism, Dopamine

Process by which cells regulate the expression, localization and degradation of proteins. Mishandling of proteins is of interest to Parkinson's researchers because it has been inconclusively linked to Parkinson's disease.

Abbreviation for "People with Parkinson's" or "Person with Parkinson's."

One of the cardinal clinical features of Parkinson's disease, an unwanted and uncontrollable movement that affects a limb when it is at rest and stops for the duration of a voluntary movement.

See also: Tremor

Abnormal stiffness in a limb or other body part. One of the cardinal clinical features of Parkinson's disease, rigidity is often most apparent when an examiner moves a patient's limb.

Ribonucleic acid, the chemical responsible for carrying instructions from DNA for the synthesis of proteins enabling various life-enabling functions in body cells.

RNA interference (RNAi) is a mechanism in which certain genes in an organism are "silenced" (turned off, so that their normal effects do not occur) by the introduction of small fragments of RNA whose sequence matches that of the gene in question. Researchers can use RNAi to test the functions of genes they are studying, and it may also form the basis of novel therapies to treat disease.

A brain neurotransmitter that may be deficient in some cases of depression and whose potential role in Parkinson's disease is under investigation.

See also: Neurotransmitter, Depression

The brand name of the most commonly prescribed version of the drug levodopa, consisting of a combination of levodopa and carbidopa. For more information see what patients on our Patient Council have to share on the topic of medication.

See also: Levodopa

Chronic troubles with the amount, duration or quality of sleep an individual experiences. Some people with Parkinson's experience sleep disorders as a symptom. This symptom typically does not respond to dopamine replacement therapy.

See also: Dopamine

Somatic cell nuclear transfer (SCNT) is a technique in which a nucleus from a patient's body cell, such as a skin cell, is introduced into an unfertilized egg from which the original genetic material has been removed. The egg is then used to produce a blastocyst whose stem cells could be used to create tissue that would be compatible with that of the patient. This is called "therapeutic cloning."

See also: Adult stem cells, Embryonic stem cells, Stem cells, Umbilical cord-derived stem cells

Symptoms that affect up to 90 percent of individuals with Parkinson's disease at some time in the course of their disease, and that commonly include reduced volume, monopitch, hoarseness, a breathy voice quality and/or imprecise articulation. Parkinson's disease-associated speech disorders often can be alleviated by a specialized physical therapy regimen.

See also: Physical therapy

The most common form of Parkinson's disease, accounting for upwards of 95 percent of cases, and arising from causes likely to include a combination of genetic and environmental factors. Sporadic Parkinson's disease is sometimes called idiopathic, meaning that the cause is unknown. Sporadic Parkinson's disease does not run in families, unlike other (much rarer) forms of Parkinson's disease.

See also: Familial Parkinson's disease

Very immature cells with potential to differentiate into a wide variety of cells, including neurons. In addition, see what patients on our Patient Council have to share on the topic of stem cells.

See also: Adult stem cells, Embryonic stem cells, Umbilical cord-derived stem cells

Refers to use of precise coordinates to identify deep structures of the brain. The coordinates may be obtained by fitting a patient's head with a special frame and conducting a CT scan or MRI. The position of the brain structures relative to the frame permits precise, three-dimensional localization of the deep brain structures. Stereotactic techniques are often used for surgical interventions such as DBS and gene therapy.

See also: Imaging, CT scan, MRI, Surgical therapies, Deep brain stimulation, Gene therapy

The largest component of the basal ganglia, the striatum controls movement, balance, and walking. It is sometimes called the corpus striatum. Loss of dopamine in the striatum is responsible for many of the symptoms of Parkinson's disease.

See also: Basal ganglia, Substantia nigra, Dopamine

From the Latin for "black substance," the substantia nigra is a part of the basal ganglia that is rich in dopamine-producing nerve cells and the black pigment neuromelanin. In Parkinson's disease the loss of nerve cells from this region leads to a dopamine deficit and subsequently to Parkinson's symptoms.

See also: Basal ganglia, Striatum, Dopamine

Subthalamic nucleus (STN) is a nerve center near the substantia nigra. The STN may be targeted for deep brain stimulation (DBS) to reduce Parkinson's symptoms.

See also: Basal ganglia, Substantia nigra, Deep brain stimulation

Many people find that support groups are tremendously effective in helping them cope with the day-to-day realities of having Parkinson's disease. Support groups come in different formats - from large, formal meetings to smaller "living-room" get-togethers - and you may not be equally comfortable or get the same benefit from all. If you don't like the first group you find, look for another that will suit you better. If you can't find any you like in your area, consider starting one. If you are unsatisfied with the available options, it is likely that you're not the only one feeling that way. For more information see what patients on our Patient Council have to share on the topic of support groups.

Brain surgery that can supplant or supplement drug therapies for Parkinson's disease in some patients. Deep brain stimulation (DBS) is currently the most common surgery for Parkinson's disease. Other less frequently performed procedures include surgical lesion of the subthalamic nucleus and of the internal segment of the globus pallidus, a procedure known as pallidotomy. Gene therapy is another approach that involves brain surgery. As in all aspects of their treatment regimen, patients considering surgery should work closely with their individual physicians to assess the risks and potential benefits of surgical intervention.

See also: Deep brain stimulation, Pallidotomy, Thalamotomy, Gene therapy, Subthalamic nucleus, Globus pallidus

The reflexive muscular contraction that causes substances to pass from the mouth through the esophagus and into the body. Some people with advanced Parkinson's disease develop difficulty swallowing (also called dysphagia), which may become severe enough to require a change in diet.

See also: Dysphagia

1. Of or pertaining to the symptoms of a disease.
2. A term used by people with Parkinson's to describe the state in which they are strongly affected by the symptoms of their Parkinson's disease, and in which their medication or treatment regimen is providing little relief.
3. Pertaining to treatments that affect the symptoms of a disease, but not the underlying actions that cause the disease to progress. All currently available treatments for Parkinson's disease are symptomatic, meaning that they mask symptoms while the disease continues to progress.

See also: Neuroprotective

Any of a variety of changes in the body or its functions that indicate disease or phases of disease.

A surgical procedure, now less commonly performed than it once was, in which cells in the thalamus are destroyed in an effort to eradicate debilitating tremors.

See also: Thalamus, Tremor, Deep brain stimulation, Pallidotomy, Surgical therapies

A mass of gray matter (nerve cells) located deep in the brain that is responsible for motor control and serves as a relay center for sensory signals.

See Somatic Cell Nuclear Transfer

Involuntary, uncontrollable, rhythmic movements (fast or slow) that may affect the hands, head, voice or other body parts. Resting tremor is one of the cardinal clinical features of Parkinson's disease.

See also: Resting tremor

An external or environmental factor such as head trauma, stress or exposure to a toxin that may contribute to the development of a condition or disease.

Naturally occurring molecules that contribute to cell growth and survival. Neurotrophic factors, such as GDNF, neurturin, and MANF are trophic factors that affect nerve cells. For more information please see the Neurotrophic Factors Priority Area page.

See also: GDNF, Neurturin, MANF

A gene that provides instructions for making an enzyme called ubiquitin carboxyl-terminal esterase L1. This enzyme is found in nerve cells throughout the brain and is probably involved in the cell machinery that breaks down unwanted proteins. In rare familial instances of Parkinson's disease, mutations in UCH-L1 may increase risk of Parkinson's onset.

See also: Protein handling, Enzyme

Undifferentiated cells taken from umbilical cord blood. These cells can be used in some research toward cell replacement therapies for regenerative medicine and tissue replacement after injury or disease. In addition, see what patients on our Patient Council have to share on the topic of stem cells.

See also: Adult stem cells, Embryonic stem cells, Stem cells

Surgery performed on one side of the brain.

See also: Bilateral surgery

Various substances found in plants and animals that are required for life-sustaining processes. While anecdotal evidence suggests that taking certain vitamins may prevent or improve some symptoms of Parkinson's disease, no clinical trial to date has proved this.

Loss of effectiveness of Parkinson's medications between doses. If the effectiveness of a medication does not last until the next dose is due, it "wears off."

A rare form of Parkinson's disease characterized by onset of symptoms before age 40.