Glossary of Terms

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Action and Postural Tremor 

Tremor observed in the arm or hand with action or posture. This is different than rest tremor noted in PD with the arm or leg at rest. See also Essential or familial tremor. 



A neurochemical or neurotransmitter in the brain. In the basal ganglia or motor area of the brain impacted by PD, acetylcholine works in balance with dopamine to control some movements. Anticholinergic medications or agents that block and reduce the effect of acetylcholine are helpful for tremor and dystonia. Acetylcholine is also a neurotransmitter important for memory and cognitive functions.  


Acetyl cholinesterase inhibitor 

A medication used for Alzheimer’s and Parkinson’s dementia. This medicine blocks the metabolism or breakdown of acetylcholine effectively increasing levels of this important neurotransmitter. 


Advanced Directive 

These legal documents are designed to aid you during times that you are not competent or able to make decisions for yourself, for instance during time of severe injury, disease or end of life. Examples include a living will, that outlines your health care wishes at end of life, medical power of attorney, a document that designates who will make healthcare decisions for you in the event you are not able to do so and durable power of attorney, a legal document designating a person authority to make legal and financially decisions in your behalf in the event you are unable to do so. 



Difficulty and slowness with initiating and starting movements. 


Anti-anxiety medications 

Medications used to treat anxiety. These are most commonly benzodiazepines and select antidepressants called select serotonin reuptake inhibitors, SSRIs. 


Anti-cholinergic medications 

Medications that block and reduce the effect of acetylcholine in the brain and sometimes used for tremor and dystonia. Unfortunately, these medicines can have significant side effects including memory problems, constipation, dry eyes and mouth. 



A medication used to treat depression. Select antidepressants can sometimes be used to treat other conditions such as pain and anxiety.



Excessive worry, anxiousness and or panic in excess of that expected in the situation experienced. Anxiety can be generalized, associated with a phobia or fear, an abrupt sense of fear or be present as an end of medication dosing as a nonmotor fluctuation.  Physical symptoms of anxiety include rapid heart rate, erratic breathing, palpitations, chest pain, sweating, nausea, fatigue, concentration difficulties, and insomnia. 



Difficulty or trouble with initiating or engaging in activities. Sometimes an associated symptom of depression, Parkinson’s or dementia 



Food, saliva, liquids or stomach contents entering or partially penetrating the vocal cord area or lungs. Aspiration risk is increased in people that have swallowing problems and can lead to pneumonia. Aspiration can be silent and without symptoms or associated with sensation of food or liquid ‘getting caught’, cough, weight loss, change in dietary preference for softer moister foods. 


Aspiration Pneumonia 

Infection in the lungs caused by aspiration (food, saliva or stomach acid entering the lungs). Fever, chills, cough, breathing difficulties, confusion, hallucination and worsening PD movement are common symptoms. 


Atypical Parkinsonism (also called parkinsonism, or parkinson-plus)         

Brain conditions that share features of Parkinson’s such as bradykinesia, rigidity, shuffling gait and balance problems. Unlike PD, these conditions have early walking and balance problems, which are less responsive to medical therapy.  


Autonomic Nervous System 

A branch of the nervous system that controls and regulates organ function, and regulatory functions. The sympathetic nervous system is often referred to the fight or flight system, activated at times of stress. The parasympathetic nervous system is associated with relaxation and recovery. Examples of autonomic problems associated with PD include orthostatic hypotension sexual dysfunction constipation and bladder control. 



Involuntary spasm of eye muscles leading to unwanted eye closure. See also Eye opening apraxia. 


Botulinum toxin 

A neurotoxin (botulism) injected directly into muscle to reduce excessive spasm and contraction. Most commonly used for blepharospasm, facial spasm dystonia (torticollis) and spasticity from conditions like stroke and MS.   



Slowness of all movements also described as decreased speed, power, amplitude and fatiguing of movement. 


Cogwheel Rigidity (see rigidity) 



Delayed transit or movement of stool in the intestine leading to discomfort associated with infrequent bowel movements. Constipation is a common problem in PD caused by the disease, diet, limited exercise, dehydration and some medicines (anticholinergics).   


COMT Inhibitor (catechol-o-methyldopa transferase inhibitor) 

Medication that blocks metabolism or break down of dopamine or it precursor levodopa leading to enhanced duration of activity. Used in mid stage PD to treat motor offs or end of dose wearing off. 



A nuclear medicine imaging technique (SPECT scan) used to differentiate Parkinson’s tremor from essential tremor. An agent that binds to brain dopamine cells is injected prior to brain imaging allowing visualization of dopamine cells. DaTSCAN cannot differentiate Parkinson’s disease from other forms of atypical parkinsonism. 


Deep Brain Stimulation (DBS) 

A brain surgery procedure in which electrical wires are implanted into specific brain regions (globus pallidus, subthalamic nucleus and thalamus) to treat motor symptoms of PD. DBS is used to treat tremor, dystonia and mid stage PD when motor fluctuations/off periods and dyskinesia are experienced. 



A brain condition affecting cognitive abilities to a significant degree that it impairs ability to perform daily living tasks.



Sustained feeling of sadness, blunted mood, loss of interest, hopelessness, irritability. Physical symptom of depression can include sleep problems, weight change, apathy, pain, fatigue and select cognitive difficulties.



A neurotransmitter that is decreased in Parkinson’s as dopamine nerve cells degenerate in the basal ganglia. This neurotransmitter controls and modulates movement. 



Uncontrolled involuntary movements. In PD dyskinesia are often experienced in mid stage as a peak dose effect. Dyskinesia in PD is s medicine induced side effect. 



Sustained, involuntary contraction of muscle causing twisting, bending at a joint or trunk. 

E - O

End of Dose Wearing-Off 

A decline in medicine benefit at end of dose or before the next dopamine medicine dose is due (levodopa) causing re-emergence of PD motor symptoms. Nonmotor symptoms such as pain, mood, anxiety, sweating can also be experienced as an end of dose problem. 


Essential or Familial Tremor 

A tremor condition with notable tremor of head, voice, arms and hands. Arm and hand tremor is worse with action and posture. 


Executive Dysfunction 

Cognitive difficulties usually attributed to brain frontal lobe activity (area in the front of the brain) and the most common cognitive problem associated with PD. Examples of executive dysfunction include problem with prioritizing activities and thoughts, abstract thinking, multitasking, word finding. 


Eye Opening Apraxia 

Difficulty voluntarily opening eyes. This is thought to be a problem with initiating movement and not forceful muscle contraction or spasm. See also blepharospasm.  


Forced Use 

Usually refers to physical therapy or exercise technique in which ‘activity’ is performed at an intense or repetitive fashion to enhance performance. 


Globus pallidus (GP) 

A collection of nerve cells or nuclei deep in the brain that is part of a larger circuit of neurons in the basal ganglia a group of cells and circuits controlling movement. The GP is a target for DBS stimulation in PD. 



Often described as visual illusion or visual hallucination, this is a sensory perception that is not real (seeing, hearing, smelling or feeling something that is not present). Hallucinations are more likely to be experienced in Lewy body disease, when is PD associated with cognitive problems or with high dose of dopaminergic medicines or other brain active medicines (narcotics, sedatives).  



Loss of spontaneous facial expression associated with PD, sometimes referred to as masked like face. 



Loss of normal speech volume leading to soft speech in PD. 


Lee Silverman Technique (LSVT) 

A specific speech therapy technique involving frequent and intensive therapy designed to increase speech volume and clarity in PD. 


Lewy Body 

An abnormal collection in nerve cells seen in Parkinson’s disease when brain tissue is stained and examined under the microscope in the laboratory.        


Lewy Body Disease 

A parkinsonian condition like PD but with early cognitive problems, hallucinations caused by medicine and fluctuating levels of alertness. By definition, these cognitive problems are noted within the first year (or two) of movement problems. This is different than Parkinson’s associated dementia in which these problems are experienced after years of the disease. See PD Dementia.   



Small, cramped handwriting often seen as an early motor sign of PD. 



An aggressive and malignant form of skin cancer usually seen as dark pigmented lesions on the skin. Skin checks and or dermatology evaluation is recommended for people with PD since there is an increased risk of melanoma.  


MRI (Magnetic Resonance Imaging) 

A non-X-ray imaging technique used to visualize brain structure in PD. Although not currently needed for diagnosis, brain MRI can determine causes of disease that can mimic PD such as stroke or normal pressure hydrocephalus. See Normal Pressure Hydrocephalus. 


Modified Barium Swallow 

A special x-ray technique called fluoroscopy that is used to image movement of food or liquid while swallowing. This test is a helpful measure of swallowing problems and aspiration. See aspiration pneumonia. 


Movement Disorders Specialist 

A neurologist that receives additional training (often called fellowship) in the area of movement disorders. a specialist in the diagnosis and non-medical treatment of speech and language disorders. 



Quick, fast jerking movements of the body often worse with sleep onset (called nocturnal myoclonus).  


Neurogenic Bladder 

Altered nerve control of the bladder leading to incontinence of bladder control problems. Examples include urinary frequency, Nocturia (increased urination at night) and urinary urgency. See also overactive bladder, urinary urgency.  



Change in nerve and brain activity as a result of the activities and experiences we have. 



A chemical, physiologic or nerve cell activity that results in protection of vulnerable nerve cells otherwise at risk for degeneration or cell death in PD. Specific medications and exercise are treatments being studied for potential neuroprotection in PD. 



A licensed psychologist with additional training in examining and measuring cognitive abilities and behavioral symptom associated with neurologic disease. A neuropsychologist can aid in the diagnosis of dementia or cognitive problems associated with PD. See executive dysfunction and dementia.  



A biochemical important to nerve cell activity and regulation. These chemicals modulate activity at nerve cell connections cause synapses.  Examples important to Parkinson’s disease include dopamine, serotonin, acetylcholine, glutamate and norepinephrine.  


Normal Pressure Hydrocephalus (NPH) 

A brain conditions associated with large ventricles visualized by brain imaging. Early shuffling, cognitive problems and bladder problems differentiate NPH from PD. 


Orthostatic Hypotension 

 drop in blood pressure with change in position against gravity such as lying to sitting or sitting to standing often associated with dizziness or lightheadedness.  This drop in blood pressure can also be associated with sedation, weakness, imbalance and cognitive change. 

P - Z


Altered sense of reality or sensory perception often experienced as delusional thoughts or hallucinations. 


Postural Instability 

Trouble with balance experienced in mid and later stage PD defined as a problem with keeping posture upright. Automatic posture reflexes needed to adjust to changes in movement and maintain balance are affected often leading to falls without warning. Postural instability is worse with turns, and pivots. 


REM Sleep Disorder 

Active vivid and physical dreaming (kicking, screaming, punching, and yelling) present during rapid eye movement (REM) stage or dream sleep. This problem can precede PD symptoms as an early symptom or risk factor for PD. 


Restless Legs Syndrome 

Uncomfortable or distressing sensations in legs, arms or other body part, worse with rest, especially before bed. Sensations are associated with the urge to move and improve with movement. 



The tendency to fall backwards. 



Increased muscle tone often felt as stiffness or tightness of muscles. Examined and identified by slowly moving the arm or leg and measuring resistance or difficulty to passive movement. Superimposed ‘ratcheting’ or cog wheeling can sometimes be felt. 


Occupational therapist 

A rehabilitation specialist trained in the functional treatment of difficulties performing daily activities, chores and occupational activities. 


Overactive bladder (see Urinary Problems) 


Parkinson’s Dementia 

Cognitive difficulties associated with PD severe enough to affect daily activities and independence. Risk of PD dementia increased with age and years of disease (unlike Lewy Body Disease characterized by early cognitive problems. Medicine (dopamine) induced hallucinations can be a problem in PD dementia. See also executive dysfunction, hallucinations and Lewy body disease. 


Physical therapist 

A rehabilitation specialist trained in treating physical and neurologic problems of joints, muscle, movement, and pain. 


Rest Tremor 

Characteristic of Parkinson’s tremor to increase or be present with hand, arm or leg in resting position and improvement with action. See action and postural tremor. 



A skin problem seen as any oily flaking of the skin often located on the face and scalp of people with PD. 


Serotonin Reuptake Inhibitors (SSRIs) 

Medications that enhance serotonin activity often used to treat depression and anxiety. 


Sleep Apnea 

A sleep problem defined by prolonged pauses in breathing associated with a drop in measured blood oxygen levels. Snoring and halted breathing problems are symptoms of sleep apnea. Polysomnography or a sleep study is needed to diagnose sleep apnea. Oxygen delivered under pressure (CPAP, BiPAP masks) and weight loss (in obesity) are common treatments. Other symptoms associated with sleep apnea are confusion, depression, hypertension and heart disease. 


Speech and Swallowing Pathologist 

A rehabilitation specialist trained in treatment of problems associated with speaking, language, communication and swallowing. 


Subthalamic Nucleus (STN) 

A collection of nerve cells or nuclei deep in the brain that is part of a larger circuit of neurons in the basal ganglia a group of cells and circuits controlling movement. The STN is a target for DBS stimulation in PD. 



A collection of nerve cells or nuclei deep in the brain that is part of a larger circuit of neurons in the basal ganglia a group of cells and circuits controlling movement. The thalamus is a target for DBS stimulation sometimes used for PD tremor. 



Involuntary and rhythmic shaking. In PD this can be experienced in the hand, arm, leg, jaw or tongue and is noted at or worse at rest (when resting rather than using the arm). 


Urinary Urgency 

Sense of urgency of urination sometimes leading to incontinence. This problem is also called overactive bladder and one of the problems associated with neurogenic bladder (bladder problems caused by altered nerve control) seen with PD. See also neurogenic bladder. 


Young onset Parkinson’s Disease (YOPD) 

Parkinson’s symptoms or diagnosis on or before the age of 50 years old.