Glossary of Terms

Below you will find information to help you better understand some of the terminology you may hear when discussing Parkinson’s disease.

Medical Disclaimer

Surgical destruction or removal of any part of the body.

A chemical messenger released by cholinergic nerves. Normally found in many parts of the body, including the brain, and is necessary for normal body functioning. Medications that block the action of acetylcholine can help with the symptoms of Parkinson’s disease. There appears to be a reciprocal seesaw relationship between acetylcholine and dopamine and their respective nerve cell systems.

Action Tremor
Rhythmic, involuntary movement of a limb when movement is initiated, e.g., when writing or lifting a cup. Not usually seen in the earlier stages of Parkinson’s.

Adrenaline (Epinephrine)
The neurotransmitter of the adrenal gland that is secreted in moments of crisis. It stimulates the heart to beat faster and work harder, increases the flow of blood to the muscles, causes an increased alertness of mind, and produces other changes to prepare the body to meet an emergency. It is also a chemical messenger in the brain.

A chemical or drug that mimics neurotransmitter activity. For example, a dopamine agonist used in the treatment of Parkinson’s disease “fools” the brain into thinking that it is dopamine and the brain responses with improvement in symptoms.

Akinesia/freezing episodes
Difficulty starting or sudden cessation of movement.

Chemical name for biologically active form of Vitamin E.

Amantadine promotes the release of dopamine from nerve terminals, blocks its re-uptake and inhibits a glutamate receptor in the brain. It may decrease the activity of acetylcholine, which regulates movement and memory.

Anticholinergi Drugs
Anticholinergics do not act directly on the dopaminergic system. Instead, they decrease the activity of acetylcholine, a neurotransmitter that regulates movement and memory.

Drugs that oppose the actions of histamine; commonly used to treat allergies. Used in the past for Parkinson’s as they sometimes had beneficial effects on symptoms due to their anticholinergic properties.

A derivative of morphine and a dopamine agonist. Currently experimentally used as injectable treatment for severe Parkinson’s.

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.

Autonomic Nervous System
The branch of the nervous system that controls internal organs in the body, i.e., heart, lungs.

Basal Ganglia or Nuclei
A very complex anatomical region deep within the brain consisting of large clusters of neurons responsible for initiating and inhibiting movements, movement coordination and learning. There are thought to be two distinct pathways (direct and indirect pathway) and dopamine is thought to promote actions by “stimulating” the direct pathway while inhibiting the indeirect pathway. 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.

Benign Essential Tremor
A condition characterized by tremor of the hands, head, voice and sometimes other parts of the body. Essential tremor often runs in families and is sometimes called familial tremor. It is sometimes mistaken for a symptom of Parkinson’s. However, this is an action tremor and there is no rigidity or bradykinesia.

Beta-blockers (ß-blockers)
Drugs that block the action of epinephrine at certain sites. Usually used to treat hypertension and heart disease, they may be effective in the treatment of benign essential tremor.

Occurring on both sides of the body.

Spasmodic blinking or involuntary closing of the eyelids; a type of dystonia.

Botulinum Toxin (Botox)
Botulinum toxin is injected specifically into the overactive muscles that can cause foot cramps, eye twitching or drooling (salivary glands). The effect comes on gradually over several days, with the peak effect reached in approximately 2 weeks. The results last for about 3 months, so injections are repeated at 3 month intervals to maintain ongoing benefits.

Slow movements.

Levodopa is the gold standard medication for Parkinson’s with the broadest anti-parkinsonian effects of any treatment. In the brain, neurons typically convert levodopa to dopamine. Levodopa works by replacing the dopamine lost in Parkinson’s. It is combined with carbidopa to prevent nausea and ensure levodopa is not metabolized before it enters the brain.

Central Nervous System (CNS)
The brain and spinal cord.

The part of the brain that is involved in coordination.

Cerebral Cortex
The largest part of the brain; responsible for through, reasoning, memory, sensation, voluntary movement.

A naturally occurring substance which is a precursor of acetylcholine.

A type of dyskinesia (abnormal movement), characterized by continuing, rapid, dance-like movements. It may be a result of high doses of levodopa and/or long-term levodopa therapy. It can often be confused with Parkinson’s disease.

A dyskinesia characterized by choreic and athetoid movements.

Cognitive decline
The gradual 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. Results of recent research suggests that cognitive decline begins early in the course of PD. Aerobic exercise is thought to be beneficial in postponing cognitive deterioration or delaying the onset but there is still little evidence to support this. One study in PD showed that aerobic exercise had a beneficial effect on cognitive processes, termed executive functions. Executive function is a term used to describe cognitive processes including regulation and control of cognitive processes including planning, working memory, attention, problem solving and other mental areas.

Cogwheel rigidity
Stiffness in the muscles, with a jerky quality when arm and leg joints are repeatedly moved.

COMT Inhibitors
A drug that blocks an enzyme (catchol-O-methyltransferase) that breaks down dopamine. These agents have no direct effect on symptoms, but instead are used to prolong the effect of levodopa by blocking its metabolism.

Diminished ability of intestinal muscles to move stool, often resulting in difficulty voiding or in very hard stool. Roughly 50 to 80% of patients with PD report constipation , the most common lower gastrointestinal symptom in PD.

Corticobasilar degeneration
Third most common atypical parkinsonism. Characterized by asymmetric motor impairment with both cerebrocortical and basal ganglionic dysfunction. Features include ideation and ideomotor apraxia, rapid irregular jerky action and postural tremor, predominantly an upper limb dystonia, numbness and paraethesia in the fingers, cortical myoclonus, oculomotor and eyelid abnormalities, dysarthria and dysphagia, and cognitive dysfunction.

CT scan
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.

Deep brain Stimulation (DBS)
Medtronic Deep Brain Stimulation (DBS) Therapy is a surgical treatment proven to reduce some of the symptoms associated with Parkinson’s disease. Medtronic DBS Therapy for Parkinson’s control helps reduce some of the symptoms of Parkinson’s disease and is used in conjunction with medication. Electrical stimulation is delivered to targeted areas on both sides of the brain to help relieve symptoms on both sides of the body. You may be a candidate for this therapy if your symptoms respond to levodopa, but levodopa and/or other medications have become less effective or ineffective.

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.

Dementia with Lewy bodies
DLB causes Parkinsonism and shares features of Alzheimer’s disease. The cognitive symptoms appear before or together with the movement symptoms and not afterwards, as with PD. Often starting with confusion, depression, or psychosis (hallucinations or delusions). Behavioral symptoms can vary greatly and can include period of unresponsiveness, elaborate delusions, and visual hallucinations, in addition to difficulty with memory or thinking. The hallucinations of DLB can occur without levodopa or other dopamine enhancing medications, which in PD, any hallucinations are a side effect of those medications. The parkinsonian DLB responds to levodopa/carbidopa.

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.

A chemical messenger (neurotransmitter) released by neurons in the midbrain. Neurons are the building blocks of the brain;The functions of dopamine are complex. Dopamine assists in the effective transmission of messages from one nerve cell to the next, movement initiation and inhibition.It also is associated with a reward-pleasure brain system, which is activated as a result of such behaviors as eating and sex, exploration, cognition and social interaction. It becomes deficient in the substantia nigra of a person with Parkinson’s.
Dopamine Agonists
Dopamine agonists are drugs that stimulate the parts of the human brain that are influenced by dopamine. In effect, the brain is tricked into thinking it is receiving the dopamine it needs.

Drug-induced Parkinsonism
Parkinson’s symptoms brought on most commonly by anti-psychotic medications. As many as 50% of patients referred for evaluation to a geriatric service have been reported to show parkinsonism associated with prescribed drugs. Although tremor and postural instability may be less prominent, this condition may be indistinguishable from Parkinson’s disease. Medications frequently associated with the development of parkinsonism include antipsychotics, metoclopramide, reserpine, tetrabenazine and some calcium-channel blockers (especially cinnarizine and flunarizine). The parkinsonism usually resolves within weeks to months after discontinuing the offending medication.

Speech difficulties caused by the disturbance of the muscles associated with speech.

Unsteadiness or balance problems.

Abnormal movement of voluntary muscles. May appear as a side effect of dopamine replacement medications. Involuntary movements or posturing involving particular muscle groups. Can be large or small in size or cause cramping (dystonias).

Difficulty in swallowing.

A movement disorder that commonly involves the head, neck and tongue. It can result in involuntary writing movements and unusual postures. It is often confused with Parkinson’s disease.

Essential Tremor (ET)
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.

Executive dysfunction
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.

Extrapyramidal Nervous System
Refers to the brain areas known as the caudate, putamen, subthalamic nucleus and substantia nigra.

Facial masking
A symptom experienced by some people with Parkinson’s, in which the face is immobile with reduced eye-lid blinking.

Fatigue is a non-motor symptoms of PD that occurs in 30-50% of patients with PD and is much more frequent in PD than in age-matched controls. The reasons for chronic fatigue in PD are poorly understood.

Walking in rapid, short, shuffling steps. Difficulty terminating a sequence or braking a movement

A bent, curved posture.

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.

Globus Pallidus
A structure made up of nerve cells located deep in the brain affecting movement, balance, and walking.

Small, incomplete movements

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.

Lewy Body Dementia
In Lewy body dementia, protein deposits, called Lewy bodies, develop in nerve cells in regions of your brain involved in thinking, memory and movement (motor control). Like Parkinson’s disease, Lewy body dementia can result in rigid muscles, slowed movement and tremors.

Levodopa (L-dopa)
Levodopais a chemical that is turned into dopamine after it crosses the blood brain barrier. Levodopa is a metabolic precursor to dopamine. After treatment with Levodopa the remaining dopaminergic cells produce more dopamine.

Levodopa-induced Dyskinesias
A side effect of medication that may occur with prolonged use. Reducing the amount of medication may alleviate these abnormal, involuntary movements. Modern approaches to medical therapy try to avoid or minimize the use of levodopa in order to reduce the risks of levodopa-induced dyskinesia.

Livido Reticularis
A purplish or bluish coloration of the skin seen usually below the knee and on the forearm in persons treated with amantadine (Symmetrel).

Monoamine Oxidase Inhibitors (MAO-B inhibitors)
MAO-B inhibitors block an enzyme in the brain that breaks down levodopa.

The tendency to have very small handwriting due to difficulty with fine motor movements .

Mitochondrial dysfunction
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.

Movement disorders specialist
A neurologist with specific training in the subspecialty of movement disorders. Although management of Parkinson’s disease is accomplished by a multi-disciplinary team for example neurologist, nurse PD specialist, primary care physician, geriatrician, dietician, speech, physical and occupation therapist, fitness professional, neuropsychologist, sexologist, social worker, pharmacist and psychiatrist, Mmovement disorders specialists typically follow a greater number of patients with Parkinson’s disease,

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.

Multiple System Atrophy
Second most common atypical parkinsonism. MSA is a group of disorders with parkinsonism (extrapyramidal dysfunction) and varying degrees and distribution of pyramidal, cerebellar, and autonomic dysfunction. The three best characterized are: striatonigral degeneration, Shy-Drager syndrome, and olivopontocerebellar atrophy.

Jerking, involuntary movement of arms and legs, usually occurring during sleep.

Vital part of the brain comprised of two basal ganglia (caudate and putamen). These are part of the basal ganglia.

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.

Neuroleptic Drugs (Also called major tranquilizers)
A class of drugs that act as dopamine antagonists (by blocking some dopamine receptors). These medications are used in the treatment of serious psychiatric disorders. They can produce or aggravate symptoms of Parkinsonism. This class includes Haloperidol (Haldol) and the phenothiazines, e.g., Compazine, Stelazine, Chlorpromazine, etc.

A nerve cell.

A specialized chemical produced in nerve cells that permits the transmission of information between nerve cells .

Nigrostriatal Degeneration
Degeneration of the nerve pathways from substantia nigra to the striatum.

Non-motor symptoms
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.

Chemical transmitter found mainly in two areas of the brain involved in governing the involuntary autonomic nervous system.

Obsessive compulsive behavior
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.

Olfactory dysfunction
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.

On-off Effect
Fluctuations that occur in response to levodopa therapy in which the person’s mobility changes suddenly and unpredictably from a good response (on) to a poor response (off).

Orthostatic Hypotension
A drop in blood pressure during rapid changes in body position (e.g., from sitting to standing). This can produce dizziness or light-headedness.

Individuals with PD have a lower bone mineral density than age matched healthy controls. Osteoporosis is high in patients with PD: up to 63% of women with PD and 20% of men with PD have this con¬dition. By comparison, in age-matched healthy populations the prevalence of osteoporosis is 29% in women and 12% in men. Patients with PD also have a high risk of falling which, in com¬bination with osteoporosis or osteopenia, increases the risk of fall-related injuries, hip fractures, and head traumas. Factors associated with osteoporosis in PD are multifactorial and include immobility, decreased muscle strength, low body weight, vitamin D deficiency, hyperhomcysteinaemia due to levodopa use, vitamin B12 and folic acid deficiency. Some research has shown that treatment with bisphosphonates, vitamin D, and calcium may increase bone mineral density and reduce fractures in people with PD.

A symptom of Parkinsonism, especially the postencephalitic form, in which a word or syllable is repeated and the flow of speech is interrupted.

Sensations, usually unpleasant, arising spontaneously in a limb or other part of the body, experienced as “pins and needles” or a fluctuations of warmth or coldness (thermal paresthesias).

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.

PET scan
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.

Postural Deformity
Stooped posture.

Postural Instability
Difficulty with balance.

Postural Tremor
Tremor that increases when hands are stretched out in front.

Progressive Supranuclear Palsy (PSP)
Most common atypical form of Parkinsonism. A degenerative brain disorder sometimes difficult to distinguish from Parkinson’s disease especially in the early stages. Progressive onset of symmetric symptoms, lack of tremor, rigidity in the trunk and lower extremities, gait disturbances with extended trunk and knees and a broad base, early falls, pseudobulbar features (problems swallowing, emotional lability), a “surprised” facial expression and difficulty moving the eyes up and down, and early dementia. Other symptoms include fainting spells, an erect or backwardly arched neck posture.

Propulsive Gait
Disturbance of gait typical of Parkinsonism in which, during walking, steps become faster and faster with progressively shorter steps that passes from a walking to a running pace and may precipitate falling forward.

Pseudobulbar Palsy
A disorder that occurs in patients with arteriosclerosis that is often mistaken for Parkinson’s disease.

Range of Motion
The extent that a joint will move from being fully straightened to completely bent.

A sensory nerve ending that responds to stimulus.

Resting tremor
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.

Retropulsive Gait
Walking that is propelled backwards.

Increased resistance to passive movement that occurs in the limb and trunk muscles.

Rivastigmine tartrate
Rivastigmine tartrate inhibits enzymes that break down acetylcholine.

Increased oily discharge from the sebaceous glands of the skin in those with Parkinson’s disease.

Seborrheic Dermatitis
Inflammation of the skin sometimes associated with seborrhea.

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

Shaking Palsy
An older, popular term that was used to designate early Parkinson’s diagnosis. The early Latin form of this term was Paralysis Agitans.

Shy-Drager Syndrome
A rare condition in which the symptoms are the result of abnormalities in motor function and problems in the autonomic nervous system. A person with Shy-Drager Syndrome has Parkinsonism, extremely low blood pressure that worsens upon standing, bladder problems, severe constipation and decreased sweating.


Sleep dysfunction
Sleep dysfunction occurs in about two-thirds of patients with PD, with frequent problems being night-time awakening, difficulty falling asleep and sleep duration.

Sporadic Parkinson’s disease
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.

Stereotactic Surgery
Surgical technique that involves placing a small electrode in an area of the brain to destroy a tiny amount of brain tissue (see Deep Brain Stimulation).

Striatonigral Degeneration
A degenerative disorder similar to idiopathic Parkinson’s disease in which there is a degeneration of the nerve pathways traveling from the striatum to the substantia nigra. People with this degeneration also appear to have Parkinsonism but respond differently to drug 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.

Substantia Niagra
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 contributes to the symptoms of Parkinson’s disease.

Sustention or Postural Tremor
Tremor that increases when hands are stretched out in front.

Tardive Dyskinesia
A movement disorder associated with long-term use of certain medications, such as the neuroleptic drugs Chlorpromazine, Haloperidol, Loxapine, etc. Movements of a person with tardive dyskinesia are similar in appearance to those of a person with levodopa-induced dyskinesias, but the causes of the two conditions are different.

Neurosurgical operation, in which a small region of the thalamus is destroyed. Tremor and rigidity in Parkinsonism and other conditions may be relieved by thalamotomy. This surgery is rarely indicated and has been replaced by other neurosurgical approaches including deep brain stimulation.

A mass of gray matter centrally placed deep in the brain near its base and serving as a major relay station for impulses traveling from the spinal cord and cerebellum to the cerebral cortex.

A poisonous substance.

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 motor features of idiopathic Parkinson’s disease

Trigger event
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.

Occurring on one side of the body. Parkinson’s motor symptoms (e.g., tremor, rigidity) may begin unilaterally.

Vascular Parkinsonism
Multiple small strokes can cause parkinsonism. Patients with this disorder are more likely to present with gait difficulty than tremor and are more likely to have symptoms that are worse in the lower than in the upper limbs. Some will also report the abrupt onset of symptoms or give a history of step-wise deterioration (symptoms

“Wearing-off” effect
The tendency, following long-term levodopa treatment, for each dose of the drug to be effective for shorter periods of time.

Medical Disclaimer

The information above has been modified from the glossary published by The Michael J. Fox Foundation and the Parkinson’s Society of Southern Alberta: Farley B. Developing Parkinson specific exercise programs. Journal of Active Aging. 2004;22-28; Speelman et al., How might physical activity benefit patients with Parkinson disease? Nat. Rev. Neurol. Advance online publication 12 July 2011;doi: 10.1038/nrneurol.2011.107; Farley, B. Table 2 Clinical features that help distinguish commonly seen forms of parkinsonism due to other causes from primary PD, workshop Charlotte, North Carolina, April 2012; Bos F et al., Parkinson’s disease and osteoporosis. Age and Ageing. 2012:1-7. doi: 10.1093/ageing/afs161.