Parkinson's Glossary

Acetylcholine: A chemical messenger (neurotransmitter) in the striatum area of the brain. It is involved in many brain functions, such as memory and control of motor activity. It is believed that acetylcholine and dopamine maintain a delicate balance in the brain. Lack of dopamine in people with Parkinson’s disrupts this balance. Anticholinergic medications block acetylcholine.

Acetylcholinesterase inhibitor: A medication that increases the level of acetylcholine in the brain and is commonly used to treat cognitive disorders.

Acupuncture: A complementary therapy in which a trained practitioner inserts small needles into the skin; has been proven to relieve pain.

Adjunctive: Supplemental or secondary. In the context of Parkinson’s, adjunctive medications are used to enhance the effects of levodopa.

Advance directives: Legal documents in which you spell out your end-of-life wishes. These often come in two parts. The first, sometimes called a living will, advises your doctor and healthcare team of your wishes for end-of-life care, such as whether you want to be resuscitated or placed on a respirator if your heart or breathing stop. This decision is referred to as DNR, Do Not Resuscitate, or AND, Allow Natural Death. The second part of an advance directive, often called a medical power of attorney, designates a person you want to make your healthcare or end-of-life decisions should you become unable to do so for yourself.

Akinesia: Loss of the ability to voluntarily move your muscles; in Parkinson’s, a common form is freezing.

Alpha-synuclein: A protein in the human brain that is associated with the development of Parkinson’s. It is the main component of Lewy bodies.

Alzheimer's disease: A neurodegenerative disorder that results in loss of memory, thinking and language skills and behavioral changes. It is the most common form of dementia.

Anticholinergic: A substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system; typically the main ingredient in over-the-counter sleep aids and many allergy medications (e.g., Benadryl). Trihexyphenidyl (formerly Artane), benztropine (Cogentin) and ethopropazine (Parsitan) are typical Parkinson’s medications in this class.

Anxiety: A feeling of nervousness, worried thoughts and physical distress.

Anxiety attack: A sudden, discrete period of intense anxiety, mounting physiological arousal, fear, stomach problems and discomfort that is associated with a variety of somatic and cognitive symptoms. The onset of this episode may have no obvious triggers.

Anxiolytic: Usually refers to a class of medications that reduce anxiety.

Apraxia: A neurological disorder in which you lose the ability to carry out common, purposeful movements when asked, even if you want to and are physically able to perform the movements. May affect speech or limb movement.

Ataxia: Loss of control of bodily movements.

Atypical antidepressant: A medication used to treat depression that works in a unique way and does not fit into one of the classes of antidepressants (selective serotonin reuptake inhibitor, SSRI; serotonin-norepinephrine reuptake inhibitor, SNRI; or tricyclic antidepressant).

Atypical parkinsonism: A group of brain disorders that initially look like Parkinson's disease, but differ in the course of the disease and response to antiparkinson medications. The term is used interchangeably with Parkinson-plus syndromes.

Auditory hallucination: A perceived voice or sound that is not real.

Basal ganglia: Area of the brain responsible for producing smooth, continuous muscular actions, including starting and stopping movements; also responsible for elements of thinking.

Benzodiazepine: A class of medication that causes sedation and muscle relaxation; used to treat anxiety; fast-acting but habit-forming.

Blepharospasm: Spasmodic winking caused by the involuntary contraction of an eyelid muscle.

Botox: The brand name for botulinum toxin A, a neurotoxin that weakens muscles. In Parkinson’s it is sometimes used to decrease saliva production for people who have issues with drooling.

Botulinum toxin: A neurotoxin that weakens muscles. It can take several injections to optimize benefit and may not always be effective, but when it works the benefit can last for several months before it wears off and re-injection is necessary. Botulinum toxin A (Botox) is sometimes used to decrease saliva production for people who have issues with drooling; botulinum toxin B (Myobloc) is used to treat dystonia.

Bowel impaction: When stool (feces) is firmly wedged in the bowel and has become so hard and dry that it cannot be removed from the body naturally. Laxatives, suppositories and measures must be tried to treat the impaction.

Bradykinesia: Slowness of movement.

Bradyphrenia: Slowness in thought processing.

Carbidopa: A medication used together with levodopa to enhance its effects. When carbidopa is added to levodopa, the dose of levodopa you take can be smaller while still getting the same benefits, with fewer side effects.

Cardinal symptom: A primary clinical symptom used to make a diagnosis. In Parkinson’s, the three cardinal symptoms are tremor, rigidity and bradykinesia.

Care Partner fatigue: Exhaustion and depression associated with taking care of a loved one with a chronic health condition.

Cholinergic system: The system of cells that uses the neurotransmitter acetylcholine to send messages.

Clinical depression: Diagnosed depression that can be mild, moderate or severe based on the symptoms you have and how long you have them; classified as either major depressive disorder or dysthymia.

Clinical trial: A research study in humans that aims to test a new intervention – this could be a drug, surgery or therapy like exercise or diet guidelines – to make sure it is effective and safe.

Cognitive behavioral therapy (CBT): A type of psychotherapy that helps you recognize and change patterns of negative thinking and behavior.

Complementary therapy: A therapy that you use in addition to your medications (not to replace them); examples include nutritional supplements, acupuncture and massage.

COMT (catechol-o-methyl transferase): An enzyme that inactivates levodopa in the body before it gets to the brain. COMT inhibitors block the work of the enzyme, so more levodopa is available to the brain.

Continuous positive airway pressure (CPAP) machine: A machine that blows air into your airway (through a mask) at a pressure that is sufficient to keep the airway open during sleep; used to treat sleep apnea.

CT scan: A medical test that uses a computer linked to an x-ray machine to take pictures of the inside of the body.

Deep brain stimulation (DBS): A surgical treatment for Parkinson's disease. A special wire (lead) is inserted into a specific area of the brain responsible for movement. The lead is connected to a pacemaker-like device implanted in the chest region. This device creates electrical pulses, sent through the lead, which “stimulate” the brain and control abnormal brain cell activity.

Delirium: A state of altered awareness with agitation, hallucinations and confusion.

Delusion: A false, fixed, idiosyncratic belief, not substantiated by sensory or objective evidence; a delusion is not deliberate and cannot be controlled.

Dementia: A term used to describe a group of brain disorders that cause a broad complex of symptoms such as disorientation, confusion, memory loss, impaired judgment and alterations in mood and personality.

Dementia with Lewy bodies (DLB): A progressive, neurodegenerative disease that shares symptoms of both Alzheimer’s disease and Parkinson’s. Unlike Parkinson’s disease dementia, cognitive symptoms are present before or within one year of noticing movement symptoms. The central features of DLB include progressive cognitive decline, changes in alertness and attention, visual hallucinations and parkinsonian motor symptoms such as slowness of movement, difficulty walking or rigidity.

Depression: A mood disorder whose symptoms can include a persistent sad or empty mood, feelings of hopelessness or pessimism, irritability and loss of interest or pleasure in previously enjoyable activities.

DJ-1 gene: Provides instructions for making a protein called DJ-1 found in many tissues and organs. Mutations in this gene are associated with an early-onset form of Parkinson’s. This gene is also known as PARK7, denoting its link to Parkinson’s disease and the order in which it was found to have a connection to PD (7th).

Dopamine: A chemical messenger (neurotransmitter) that regulates movement and emotions.

Dopamine agonist: A class of medications used to treat Parkinson's disease. Agonists enhance the activity of a neurotransmitter – in this case, dopamine. Ropinirole (Requip), pramipexole (Mirapex), rotigotine (Neupro) and apomorphine (Apokyn) are common dopamine agonists.

Dopamine transporter: A protein that modulates how much of the neurotransmitter dopamine is available in the brain. It moves dopamine out of the space between nerve cells (synapse), which ends dopamine’s signaling.

Dopaminergic medication: A medication that increases the level of dopamine in the brain so can be used to treat Parkinson's disease. Carbidopa/levodopa and dopamine agonists are dopaminergic.

Double-blind study: A study in which neither the participants nor the investigators know which drug a patient is taking. This study design is to prevent observer bias in evaluating the effect of the drug.

Drug-induced psychosis: Certain drugs can lead to hallucinations and/or thought distortions. Should be considered before a diagnosis of Parkinson’s disease-associated psychosis is made.

Durable power of attorney (POA): Legal authorization for someone to act on your behalf (as your “agent”) in financial and business matters should you become physically or mentally unable to represent yourself. You may also name an alternate if your primary agent is unable or unwilling to serve. Once completed and notarized, the document should be registered in your county of residence. It is simple to revoke or change a POA if necessary.

Dysarthria: A speech disorder (slurred or unclear speech) caused by problems with the strength or coordination of muscles that produce speech, as a result of damage to the brain or nerves.

Dyskinesia: Abnormal, involuntary body movements that can appear as jerking, fidgeting, twisting and turning movements; frequently caused by dopaminergic medications to treat Parkinson’s.

Dysphagia: Difficulty swallowing.

Dysthymia: Persistent mild depression

Dystonia: A disorder in which muscles contract uncontrollably, causing abnormal movements and postures; can be very painful.

Electroconvulsive therapy (ECT): A treatment for severe depression that is usually used only when people do not respond to medications and psychotherapy. ECT involves passing a low-voltage electric current through the brain. The person is under anesthesia at the time of treatment.

Electroencephalogram (EEG): A test that detects electrical activity in your brain using small sensors attached to the outside of your head.

Endogenous: Caused by factors within the body or mind, rather than by external factors. For example, endogenous depression is caused by processes in the brain rather than external circumstances.

Essential tremor: A nervous system disorder that causes shaking of the hands or head and an unsteady quality of the voice. Shaking usually occurs on both sides of the body (compared to Parkinson’s, in which tremor typically begins on one side only) and is worse during movement (compared to Parkinson’s resting tremor). Essential tremor is more common than Parkinson’s.

Excessive daytime sleepiness: A chronic condition characterized by difficulty staying awake or paying attention; may be due to underlying sleep disorders, depression or some medications.

Freezing: Temporary, involuntary inability to take a step or initiate movement.

GABA: A chemical messenger (neurotransmitter) involved in muscle relaxation, sleep, diminished emotional reaction and sedation.

GBA gene: Provides instructions for making an enzyme called beta-glucocerebrosidase. Mutations in the

GBA gene can cause Gaucher disease and increase risk for Parkinson’s and parkinsonism. GBA-associated Parkinson’s often develops at a younger age and may cause more significant cognitive impairment.

Generalized anxiety disorder: The most common anxiety disorder in people with Parkinson’s. It is characterized by excessive, uncontrollable and often irrational worry about everyday things that is disproportionate to the actual source of worry.

Globus pallidus: A structure in the brain involved in the regulation of voluntary movement. It is a major part of the basal ganglia system, and the global pallidus internus (GPi) is one of three potential targets for some deep brain stimulation (DBS). DBS of the globus pallidus internus can reduce tremor, rigidity, bradykinesia, gait problems and dyskinesia.

Half-life: The time taken for the concentration of a drug in the bloodstream to decrease by one half. Drugs with a shorter half-life must be taken more frequently.

Hallucination: Something you see, hear, smell, taste or feel that is not actually there.

Homocysteine: An amino acid used normally by the body in cellular metabolism and the manufacture of proteins.

Hyperhidrosis: Excessive sweating. In Parkinson’s, this is because of problems with the part of the nervous system that controls sweating. It most often happens during “off” time.

Hypomimia: Decreased facial expression due to rigidity of facial muscles; also called “facial masking.”

Hypophonia: Low voice volume or muffled speech.

Idiopathic: Describes a disease or condition for which the cause is unknown.

Illusion: A distortion of sensory perception when you misinterpret real external stimuli, such as mistaking hats on a coat rack for heads.

Impulsive behavior: Performing an act persistently and repetitively without it necessarily leading to an actual reward or pleasure. In Parkinson’s, this can be a side effect of dopamine agonists and usually takes the form of uncontrolled shopping, gambling, eating or sexual urges. If you experience this symptom, tell your doctor immediately.

Incontinence: Involuntary urination or defecation.

Insight: In the context of hallucinations, when you recognize that what you are seeing or hearing is not real.

Intercourse-outercourse approach: A sexual therapy approach that emphasizes the value of different kinds of intimacy, including both intercourse and outercourse, defined as any erotic activity that does not involve the insertion of a penis into a vagina or anus.

Levodopa: The medication most commonly given to control the movement symptoms of Parkinson’s, usually with carbidopa. It is converted in the brain into dopamine.

Lewy body: Abnormal aggregation of proteins that develop inside nerve cells in people with Parkinson’s, named after Fritz Heinrich Lewy, the first person who noticed that some unusual proteins in the brain can make people act and think differently. Alpha-synuclein is the main component of Lewy bodies.

Livido reticularis: purplish or bluish mottling of the skin caused by certain medications taken by people with Parkinson's.

Living trust: A legal document that explains what you want to do with your assets. Like a will, but it allows heirs to avoid certain estate taxes and potentially lengthy and expensive probate procedures. Living trusts can be useful if you have complex financial circumstances or property in multiple states. Otherwise, many certified financial planners advise clients to avoid them.

LRRK2 (leucine-rich repeat kinase 2) gene: Mutations in this gene are the most common cause of inherited Parkinson’s. Researchers have identified more than 100 LRRK2 gene mutations that increase the risk of developing PD. It is particularly common in people of Ashkenazi Jewish, North African Arab Berber and Basque descent, and variants have also been found in Chinese and Japanese populations. This gene is also known as PARK8, denoting its link to Parkinson’s disease and the order in which it was found to have a connection to PD (8th).

Lumbar puncture: A procedure in which a needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Also called spinal tap.

MAO-B (monoamine oxidase B): An enzyme that breaks down several chemicals in our brain, including dopamine. MAO-B inhibitors work by blocking the effect of MAO-B, so more dopamine is available to be used by the brain.

Major depressive disorder: Severe clinical depression.

Meditation: A mental practice designed to enhance relaxation, gain insight and control over emotional and physical responses to daily experiences and improve compassion as well as mental or physical performance. Used as a complementary therapy to improve sleep, mental function and overall quality of life and decrease depression, anxiety, fatigue and pain.

Melatonin: A hormone made in the pineal gland that is tied to the sleep-wake cycle; levels rise toward the end of the day, signaling nighttime, and drop in the early morning, causing you to wake up.

Micrographia: Small, cramped handwriting.

Mild cognitive impairment (MCI): The intermediate stage between the cognitive decline of normal aging and dementia. It can involve problems with memory, language, thinking and judgement.

Mini-Mental State Examination (MMSE): A brief questionnaire that is used to measure cognitive impairment. It evaluates five areas of cognitive function: orientation, registration, attention and calculation, recall, and language. It takes less than 10 minutes and can be administered routinely as part of your PD check-up or at a primary care visit.

Monotherapy: Treatment that involves only one drug.

Montreal Cognitive Assessment (MOCA): Similar to the Mini-Mental State Examination, the MOCA is brief questionnaire that is used to measure cognitive impairment and can be administered routinely by a qualified health professional. It evaluates eight cognitive domains: memory, visuospatial ability, executive function, orientation, verbal fluency, attention, concentration, and working memory.

Motor fluctuations: Changes in the ability to move, often related to medication timing; also called “on-off” fluctuations.

Movement disorder specialist: A neurologist with extra training (usually a one- or two-year fellowship) in Parkinson’s and other movement disorders.

MRI (magnetic resonance imaging): A medical imaging technique that uses magnetic forces to obtain detailed images of the body. MRI is non-invasive and does not use radiation.

Muscle wasting: A decrease in the mass of the muscle, also known as muscle atrophy, that can be a partial or complete wasting away of muscle. When a muscle atrophies, it becomes weaker, since the ability to exert force is related to mass.

Myoclonus: Abrupt, jerking movements of the arms or legs, commonly occurring when you are falling sleep.

Neurodegenerative disorder: A disease characterized by the loss of cells of the brain or spinal cord, which over time leads to dysfunction and disability; Parkinson’s disease, Alzheimer’s disease and Lou Gehrig’s disease (ALS) are all examples.

Neuroleptics: Drugs that block dopamine receptors, usually prescribed to treat psychiatric symptoms. Because they block dopamine they cause Parkinson’s symptoms to worsen and should not be prescribed for someone with PD.

Neuron: Brain cell.

Neuroplasticity: The brain’s ability to reorganize itself by forming new connections. This allows the brain to compensate for injury and disease and to respond to new situations and changes in the environment.

Neuroprotective: Something that protects neurons against damage, degeneration or apoptosis (programmed cell death).

Neuropsychologist: A licensed psychologist with expertise in how behavior and skills are related to brain structures and systems. In clinical neuropsychology, brain function is evaluated by objectively testing memory and thinking skills. A physician who combines specialties of neurology and psychiatry to treat and manage the emotional (mental health) and cognitive symptoms of neurological diseases.

Neurostimulator: A battery-powered device that delivers electrical stimulation to the brain via a special wire (lead) inserted into a specific area of the brain responsible for movement. See deep brain stimulation (DBS).

Neurotransmitter: A chemical messenger that carries impulses from one nerve cell to another. Dopamine, acetylcholine and norepinephrine are examples.

Nocturia: Having to wake up frequently during the night to urinate.

Norepinephrine: A chemical messenger (neurotransmitter) that plays a role in mood disorders and is released in response to stress.

Obsessive-compulsive disorder: An anxiety disorder in which a person has an unreasonable thought, fear or worry that he or she tries to manage through a ritualized activity.

“Off” time: When medication is not working well. Symptoms become more noticeable and movement becomes more difficult.

“On-off” fluctuations: Changes in the ability to move, often related to medication timing. Also called motor fluctuations.

“On” time: When medications are working, and you experience good symptom control.

Orthostatic hypotension: A drop in blood pressure upon changing position from lying down or sitting to standing; can cause fainting. Also called postural hypotension.

Palsy: Paralysis of a muscle group.

Paranoia: A common type of delusion resulting in extreme distrust or suspicion.

Parasomnia: A group of conditions that involve abnormal or unusual movements, behaviors, emotions, perceptions and dreams that happen when you are falling asleep, during sleep or as you are waking up. REM sleep behavior disorder (RBD) is an example.

Parkinson’s disease dementia: A type of dementia that affects attention, recent memory, executive function and visuospatial relations. It usually develops years after the PD diagnosis.

Parkinson’s disease-associated psychosis: A non-motor symptom of Parkinson’s disease that causes you to experience hallucinations and/or delusions.

Parkinson’s-plus syndrome: A group of brain disorders that initially look like Parkinson's disease but differ in the course of the disease and response to antiparkinson medications. The term is used interchangeably with atypical parkinsonism.

Perimenopausal: The years leading up to menopause, during which levels of female hormones fluctuate more widely than normal from month to month as hormone production gradually decreases and menstrual periods become irregular. Perimenopause lasts an average of five years.

Periodic limb movements of sleep (PLMS): A parasomnia that involves involuntary, twitching movements during sleep that occur every 15-40 seconds and last for part of the night or even the entire night.

PINK1 gene: Provides instructions for making a protein located in the mitochondria of many cells throughout the body. More than 70 mutations of this gene have been found to cause Parkinson’s and most are associated with an early-onset form of PD. This gene is also known as PARK6, denoting its link to Parkinson’s disease and the order in which it was found to have a connection to PD (6th).

Positron emission tomography (PET) scan: A type of medical imaging that uses small amounts of radioactive material to diagnose and determine the most appropriate treatments for a variety of diseases.

Postural hypotension: A drop in blood pressure (hypotension) due to a change in body position (posture) when a person moves from sitting to standing or from lying down to sitting or standing. Postural hypotension is more common in older people and is also called orthostatic hypotension.

Postural instability: Impaired balance and the tendency to fall without explanation, usually when pivoting; a common symptom in the later stages of Parkinson’s.

PRKN gene: One of the largest human genes, PRKN provides instructions for making a protein called parkin. Researchers have identified more than 200 PRKN gene mutations that cause Parkinson’s. Many are associated with juvenile Parkinson’s (before age 20). This gene is also known as PARK2, denoting its link to Parkinson’s disease and the order in which it was found to have a connection to PD (2nd).

Prodromal symptom: In Parkinson’s, a symptom that appears before the onset of move symptoms.

Psychosis: A broad medical term used to describe a loss of contact with reality that involves hallucinations and/or delusions.

Psychotherapy: The treatment of a mental or emotional disorder by talking and a variety of communication techniques, rather than taking medication.

Qigong: Combines the breath with subtle, flowing movement along with focused attention to release energy (chi) and reach a calm state of mind. Has been shown to improve symptoms of PD.

Randomization: A method used in clinical trials whereby study participants are assigned to a treatment group based on chance.

Rapid eye movement (REM) sleep: A normal stage of sleep characterized by rapid movement of the eyes. During a normal night of sleep, we usually experience about four or five periods of REM sleep, totaling 20-25% of total sleep time. REM sleep stages are short at the beginning of the night and longer toward the end.

Rapid eye movement (REM) sleep behavior disorder (RBD): A sleep disorder in which people physically act out vivid, unpleasant dreams. RBD is a type of parasomnia.

Restless legs syndrome (RLS): A sleep disorder in which an uncomfortable or creepy-crawly feeling occurs in the legs while at rest, primarily at night, and causes an irresistible urge to move the legs.

Retropulsion: The tendency to fall backwards.

Rigidity: In Parkinson’s, stiffness of the arms or legs beyond what would result from normal aging or arthritis. Some people call it “tightness” in their limbs.

Schizophrenia: A psychiatric illness that can involve hallucinations and delusions.

Seborrhea: Oily skin.

Selective serotonin inverse agonist, SSIA: A type of drug that specifically targets serotonin receptors and makes them do the opposite of their normal function. Pimavanserin (Nuplazid) is an SSIA FDA-approved to treat Parkinson’s disease-associated psychosis.

Selective serotonin reuptake inhibitor, SSRI: A class of antidepressant medication that blocks the reuptake of the neurotransmitter serotonin so that more serotonin is available in the brain.

Sensate focus: A term usually associated with a set of specific sexual exercises for couples or for individuals. The term was introduced by Masters and Johnson, and was aimed at increasing personal and interpersonal awareness of the self and the other's needs.

Serotonin: a neurotransmitter that regulates mood, body temperature, sleep, pain and appetite.

Serotonin-norepinephrine reuptake inhibitor, SNRI: A class of antidepressant medication that works by increasing levels of the neurotransmitter's serotonin and norepinephrine in the brain.

Shunt: A hole or passage that moves or allows movement of fluid from one part of the body to another.

Sialorrhea: Drooling or increased salivation.

Sleep apnea: A sleep disorder in which breathing repeatedly stops and starts. Snoring and daytime sleepiness are signs a person might have sleep apnea. Obstructive sleep apnea is the more common form.

Throat muscles collapse, preventing the person from breathing and resulting in the short episodes of breathing interruption (apnea).

Sleep study: A test, usually performed in a sleep laboratory, in which your sleep is recorded and monitored to diagnose sleep disorders.

SNCA gene: Provides instructions for making alpha synuclein. At least 30 mutations in this gene have been found to cause Parkinson’s. This gene is also known as PARK1, denoting its link to Parkinson’s disease and the order in which it was found to have a connection to PD (1st).

Social avoidance: Avoiding social situations due to feelings of anxiety, fear and/or embarrassment around others.

Speech-language pathologist: A specialist in the diagnosis and treatment of speech and language disorders. Can also assess and treat swallowing difficulties.

Striatum: The area of the brain that controls movement, balance and walking.

Stroke: The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain.

Substantia nigra: An area of the brain, part of the basal ganglia, where cells produce dopamine.

Subthalamic nucleus (STN): One of three potential targets for deep brain stimulation (DBS). The STN is a small, lens-shaped part of the basal ganglia system that sends signals affecting movement, thinking and mood. DBS of the subthalamic nucleus can reduce tremor, rigidity, bradykinesia, gait problems and dyskinesia.

Subthalamus: A region of the brain that sits below the thalamus and receives input connections from the substantia nigra and striatum.

Synapse: The space between two nerve cells where cellular communication occurs. Messages pass from one neuron to another via neurotransmitters.

Tai chi: An ancient Chinese martial art and exercise characterized by gentle, flowing movement couple with breathing. It has been shown to improve symptoms of PD.

Tapering: In reference to medication, the act of stopping a medication slowly, by gradually reducing the dose and/or frequency.

Thalamus: A brain structure consisting of two egg-shaped masses of nerve tissue, each about the size of a walnut, deep within the brain. The Thalamus is a key relay station for sensory information flowing into the brain and filters out information of particular importance from the mass of signals entering the brain. The ventralis intermediate nucleus (Vim) of the thalamus is one of three potential targets for deep brain stimulation (DBS). DBS to this site can reduce tremor but not the other symptoms of PD.

Tremor: Involuntary shaking of the hands, arms, legs, jaw or tongue. The typical Parkinson’s tremor is “pill-rolling” – it looks like holding a pill between thumb and forefinger and continuously rolling it around. Some people report an internal tremor, a shaking sensation inside the chest, abdomen or limbs that cannot be seen. Most Parkinson’s tremor is “resting tremor,” which lessens during sleep and when the body part is actively in use.

Tricyclic antidepressant: A class of older antidepressant medication named for its three-ring structure. It works by blocking reuptake of serotonin, norepinephrine and other brain chemicals, thereby making them more available in the brain.

Urinary retention: A lack of ability to urinate.

Visuospatial perception: The ability to perceive objects and the spatial relationships among objects.

Vivid dreaming: A dream state in which the dreams are very realistic, lifelike and disturbing at times.

Wearing off: The time period when levodopa begins to lose its effect and symptoms start to become more noticeable.