The level at which certain actions and activities can be carried out.

A chemical in the brain (neurotransmitter) that appears to be involved in learning and memory – Acetylcholine is greatly diminished in the brains of people with Alzheimer’s disease.

Activities of daily living (ADLs)
Personal care activities necessary for everyday living, such as eating, bathing, grooming, dressing and using the toilet.

Adult day services
Programs that provide participants with opportunities to interact with others, usually in a community center or dedicated facility.

Advance directive (living will)
A document written when in "good" health that informs your family and health care providers of your wishes for extended medical treatment in times of emergency.

Adverse reaction
A clinical trial term that includes any unexpected health or behavioral changes in the person participating in the trial.

Hitting, pushing or threatening behavior that commonly occurs when a caregiver tries to help an Alzheimer’s disease patient with daily activities, such as grooming and dressing.

Vocal or motor behavior—such as screaming, shouting, complaining, moaning, cursing, pacing, fidgeting, wandering, etc.—that is disruptive, unsafe or interferes with the delivery of care in a particular environment.

One of two or more alternative forms of a gene. For example, one allele of the gene for eye color codes for blue eyes, while another allele codes for brown eyes.

Alternative and complementary therapies
The use of techniques other than drugs, surgery or other conventional therapies to treat disease and manage chronic pain. Some common alternative therapies, also called complementary therapies, include the use of herbs, meditation and exercise, magnets, reflexology, massage and acupuncture.

Alzheimer’s disease
A progressive and fatal disease in which nerve cells in the brain degenerate and brain matter shrinks, resulting in impaired thinking, behavior and memory.

The ability to walk and move about freely.

Amino acids
The basic building blocks of proteins. There are 20 amino acids necessary for human growth and function.

A protein deposited in plaques in Alzheimer’s disease brains.

Amyloid imaging
PET scan showing amyloid proteins in the brain.

Amyloid plaque
Abnormal clusters of dead and dying nerve cells, other brain cells, and amyloid protein fragments, characteristic of the brains of people with Alzheimer’s disease.

Medications used to treat depression. Antidepressants are not addictive; they do not make you "high," have a tranquilizing effect or produce a craving for more. They can cause drowsiness and other side effects.

Specialized proteins produced by the cells of the immune system that counteract specific foreign substances. Antibodies may also be produced outside the body and infused as a treatment for Alzheimer’s disease.

Anti-inflammatory drugs
Drugs that reduce inflammation by modifying the body’s immune response.

A feeling of apprehension, fear, nervousness or dread accompanied by restlessness or tension.

Lack of interest, concern or emotion.

Difficulty understanding the speech of others and/or expressing oneself verbally.

Art therapy
A form of therapy that allows people with dementia to express their feelings creatively through art.

The evaluation or testing of a substance for toxicity or impurities.

An evaluation, usually performed by a physician, of a person’s mental, emotional and social capabilities.

Assisted living facility
A residential care setting that combines housing, support services and health care for people in the early or middle stages of a disabling disease, such as Alzheimer’s disease.

Associated disorders
Conditions that are present at the same time.

When there are no symptoms or no clear sign that disease is present.

Shrinking in size; often used to describe the loss of brain tissue seen in Alzheimer’s disease during autopsy or on brain imaging.

A person’s ability to make independent choices.

The examination of a body’s tissues and organs after death.

The arm of a nerve cell that normally transmits outgoing signals from one cell to another.

Basal ganglia
Nerve cells in the brain’s grey matter that are involved in controlling aspects of movement, judgment, personality, and speech.

Behavioral neurologist
A doctor who specializes in the diagnosis and treatment of behavioral and memory disorders that are due to brain disease.

Behavioral symptoms
In Alzheimer’s disease, emotional symptoms, such as wandering, depression, anxiety, hostility and sleep disturbances.

An individual named in a will who is designated to receive all or part of an estate upon the death of the person who made the will.

Binswanger’s disease
A type of dementia associated with stroke-related changes in the brain.

Used to indicate or measure a biological process; for example, levels of a specific protein in blood or spinal fluid. Detecting biomarkers specific to a disease can aid in the identification, diagnosis and treatment of affected individuals, as well as people who may be at risk but who do not yet have symptoms.

The use of biology, or the study of living things, and biological processes to make goods or develop technologies for the benefit of humanity. Biotechnology is often used in the fields of food, drugs, and energy.

Blood-brain barrier
The selective barrier that controls the entry of substances from the blood into the brain.

Blood tests
A series of tests routinely done on blood to look for abnormalities associated with various diseases and disorders.

With the spinal cord, one of two parts making up the central nervous system. The brain is the center of thought and emotion. It is responsible for the coordination and control of bodily activities and the interpretation of information from the senses.

An element taken in through the diet that is essential for a variety of bodily functions, such as the transmission of nerve impulses, muscle contraction and proper heart function. Imbalances of calcium can lead to many health problems and can cause nerve cell death.

Calcium channel blocker
A drug that blocks the entry of calcium into cells, thereby reducing activities that require calcium, such as the transmission of nerve impulses. Calcium channel blockers are used primarily in the treatment of certain heart conditions, but are being studied as potential treatments for Alzheimer’s disease.

The primary person in charge of caring for an individual with a serious illness, such as Alzheimer’s disease; usually a family member or a designated health care professional.

Care planning
A written action plan containing strategies for delivering care that addresses an individual’s specific needs or problems.

Case management
A term used to describe formal services planned by care professionals.

The fundamental unit of all organisms; the smallest structural unit capable of independent functioning.

Cell body
In nerve cells, the central portion from which axons and dendrites sprout. The cell body controls the life-sustaining functions of a nerve cell.

Cell culture
Cells grown in a test tube or other laboratory device for experimental purposes.

Cell membrane
The outer boundary of the cell. The cell membrane helps control what substances enter or exit the cell.

Central nervous system (CNS)
One of the two major divisions—with the peripheral nervous system—of the nervous system. Composed of the brain and spinal cord, the CNS is the control network for the entire body.

Cerebral cortex
The outer layer of the brain, consisting of nerve cells and the pathways that connect them. The cerebral cortex is the part of the brain in which thought processes take place. In Alzheimer’s disease, nerve cells in the cerebral cortex degenerate and die.

Cerebrospinal fluid (CSF)
The fluid that fills the areas surrounding the brain and spinal cord.

Chest X-ray (CXR, chest film)
Using a very small amount of radiation to produce an image of the structures of the chest (heart, lungs and bones) on film.

A brain transmitter that allows cells to communicate with each other.

Choline acetyltransferase (CAT)
An enzyme that controls the production of acetylcholine. CAT is depleted in the brains of individuals with Alzheimer’s disease.

Cholinergic system
The system of nerve cells that uses acetylcholine as its neurotransmitter and is damaged in the brains of individual’s with Alzheimer’s disease.

An enzyme that breaks down acetylcholine into active parts that can be recycled. This enzyme is inhibited by drugs used to treat Alzheimer’s disease, such as donepezil, rivastigmine, and galantamine.

An X-shaped structure inside the cell nucleus made up of tightly coiled strands of genes. Each chromosome is numbered (in humans, 1-46). Genes on chromosome 1, 14, 19 and 21 are associated with Alzheimer’s disease.

Clinical psychologist
See psychologist.

Clinical social worker
An individual who has specialized training in identifying and accessing community resources—such as adult daycare, home care or nursing home services—as well as in individual and group counseling.

Clinical trial
An organized research program conducted with patients to evaluate a new medical treatment, drug or device.

Co-existing illness
A medical condition that exists simultaneously with another, such as arthritis and dementia.

Cognitive abilities
Mental abilities, such as judgment, memory, learning, comprehension and reasoning.

Cognitive symptoms
In Alzheimer’s disease, the symptoms that relate to loss of thought processes, such as learning, comprehension, memory, reasoning and judgment.

Incidents of aggression.

A person’s ability to make informed choices.

Computed axial tomography (CAT or CT scan)
A technique in which multiple X-rays of the body are taken from different angles in a very short period of time. These images are collected by a computer to give a series of cross-sectional "slices" of the body. In diagnosing dementia, CT scans can reveal tumors and small strokes in the brain.

In some states, the guardian who managers an individual’s assets.

Continuum of care
Care services available to assist individuals throughout the course of a disease.

A group of people or animals in a research trial that does not receive a treatment or other intervention or that is not affected by the disease being studied. This group is used as a standard to compare any changes in a group that receives treatment or has the disease. In Alzheimer’s research, patients often are compared with controls of the same age (age-matched) to rule out the effects of age on study results.

Cortical dementia
Dementia associated with impairment of the part of the brain that affects memory, attention, reasoning and abstract thinking, and arising from disease of the cerebral cortex.

Creutzfeldt-Jakob disease
A rare disorder caused by prions that typically leads to rapid decline in memory and cognition. Most people with this disease die within one year of onset.

CT scan
See computed axial tomography.

The process of providing cues, prompts, hints and other meaningful information, direction or instruction—such as adding labels to drawers—to aid a person who is experiencing memory loss.

Physical and/or cognitive skills or abilities that a person has lost, has difficulty with, or can no longer perform because of his or her dementia.

A false idea that is firmly believed and strongly maintained in spite of proof or evidence to the contrary.

The loss of mental functions—such as thinking, memory and reasoning—severely enough to interfere with a person’s daily functioning. Dementia is not a disease itself, but rather a group of symptoms that may accompany certain disease or conditions. Symptoms also may include changes in personality, mood and behavior. Dementia is irreversible when caused by disease or injury, but may be reversible when caused by drugs, alcohol, hormone or vitamin imbalances, or depression. Alzheimer’s disease is the most common cause of dementia.

Skilled in working with people with dementia and their caregivers, knowledgeable about the kinds of services that may help them, and aware of which agencies and individuals provide such services.

Services that are provided specifically for people with dementia.

Branched extensions of the nerve cell body that receive signals from other nerve cells. Each nerve cell usually has many dendrites.

A clinical mood disorder that prevents a person from leading a normal life. Types of depression include: major depression, bipolar depression, chronic low-grade depression (dysthymia) and seasonal depression (Seasonal Affective Disorder or SAD).

Developmental disability
Any mental or physical impairment that occurs before age 22, impedes normal growth and development, and which continues into old age.

The process by which a doctor determines what disease a patient has by studying the patient’s symptoms and medical history, and analyzing any tests performed (blood tests, urine tests, brain scans, etc.).

Differential diagnosis
The clinical evaluation of possible causes of dementia to rule out all other factors before settling on Alzheimer’s disease as a diagnosis.

A cognitive disability in which the senses of time, direction and recognition become difficult to distinguish.

DNA (Deoxyribonucleic acid)
The genetic material of each cell.

Double-blind, placebo-controlled study
A research procedure in which neither researchers nor patients know who is receiving the experimental substances or treatment and who is receiving a placebo.

Down syndrome
A syndrome that causes slowed growth, abnormal facial features and mental retardation. Down syndrome is caused by an extra copy of all or part of chromosome 21. Individuals with Down syndrome develop Alzheimer’s disease in adulthood.

Drug development
The phase of testing a drug and involving animal and human subjects.

Durable power of attorney
A legal document that allows an individual an opportunity to authorize another person, usually a trusted family member or friend, to make legal decisions when the person is no longer able to make legal decisions for himself or herself.

Durable power of attorney for health care
A legal document that allows an individual to appoint another person to make all decisions regarding health care, including choices regarding health care providers, medical treatment and, in later stages of the disease, end-of-life decisions.

The inability to find the right word or understand the meaning of a word.

Early-onset Alzheimer’s disease
An unusual form of Alzheimer’s disease in which individuals are diagnosed with the disease before age 65. Less than 10 percent of all Alzheimer’s disease patients have early-onset. Early-onset Alzheimer’s disease sometimes is associated with mutations in genes located on chromosomes 1, 14 and 21.

Early stage
The beginning stages of Alzheimer’s disease when an individual experiences very mild to moderate cognitive impairments.

Elder law attorney
An attorney who practices in the area of elder law, a specialized area of law focusing on issues that typically affect older adults.

Electrocardiogram (ECG)
A recording of the electrical activity of the heart.

Electroencephalogram (EEG)
A procedure that measures the amount and type of brain wave activity using electrodes placed on the surface of the scalp.

The physical and interpersonal surroundings that can affect mood and behavior in people with dementia.

A protein produced by living organisms that promotes or influences chemical reactions.

A hormone produced by the ovaries and testes. It stimulates the development of secondary sexual characteristics and induces menstruation on women. Estrogen is important for maintaining normal brain function and development of nerve cells.

The over-stimulation of nerve cells by nerve impulses. Excitotoxicity often leads to cell damage or cell death.

The person named in a will who manages the estate of the deceased individual.

Familial Alzheimer’s disease
A form of Alzheimer’s disease that runs in families.

Fatty acids
Acids within the body derived from the breakdown of fats.

Free radicals
Highly reactive molecules capable of causing damage in brain and other tissues. Free radicals are common by-products of normal chemical reactions occurring in cells. The body has several mechanisms to deactivate free radicals.

Free-standing, dementia-specific care center
A facility solely dedicated to the care of people with dementia. The facility can sometimes be part of a larger campus.

Frontotemporal dementia (FTD)
Originally called Pick’s disease, this condition is caused by the frontal and temporal anterior lobes of the brain becoming smaller. There are two major types of FTD: one is characterized by problems in speaking and/or understanding speech; the other is characterized by noticeable changes in the way the person acts.

Functional capabilities
What a person is able to do.

A person’s manner of walking. People in the later stages of Alzheimer’s disease often have a "magnetic gait," which means their ability to lift their feet as they walk has diminished.

The basic unit of heredity found in all cells. Each gene occupies a certain location on a chromosome (a linear thread in the nucleus of a cell that contains the DNA that transfers genetic information). Genes are self-producing, minuscule structures capable under certain circumstances of giving rise to a new character, also known as a mutation. Hereditary traits are controlled by pairs of genes in the same position on a pair of chromosomes.

Gene linkage
A group of genes located close together on a chromosome.

Gene regulation
Control of the rate or manner in which a gene is expressed.

Genetic counseling
A process in which a genetic counselor obtains a complete family and personal medical history in order to determine the probable existence of a genetic problem occurring and reoccurring within a family.

Genetic susceptibility
The state of being more likely than the average person to develop a disease as the result of genetics.

Genetic testing
Certain tests that are ordered by a physician specializing in genetics so that the presence of genetic abnormalities may be discovered. For patients and families suspected of having an inherited disease, it may be possible to find the mutation causing the disease through genetic testing of blood.

All the genes of an organism.

A doctor who specializes in the medical care and treatment of older adults.

A simple sugar that is a major energy source for all cellular and bodily functions. Glucose is obtained through the breakdown, or metabolism, of food in the digestive system.

An individual appointed by the courts who is authorized to make legal and financial decisions for another person.

A sensory experience in which a person can see, hear, smell, taste or feel something that is not there.

A part of the brain that is important for learning and memory.

Collecting and putting things away in a guarded manner.

The philosophy and approach to providing comfort and care at life’s end rather than heroic life-saving measures.

Huntington’s disease
An inherited, degenerative brain disease affecting the body that is characterized by mood changes, intellectual decline and involuntary movement of limbs.

Immune system
The body’s natural defense system against infection or disease; a system of cells that protects the body from bacteria, viruses, toxins and other foreign substances.

Loss of bladder and/or bowel control.

Inflammatory response
The immune system’s normal response to tissue injury or abnormal stimulation caused by a physical, chemical or biological substance.

Instrumental activities of daily living (IADLs)
Complex activities (different from basic ADLs, such as eating, dressing and bathing) important to daily living, such as cooking, writing and driving.

Late-onset Alzheimer’s disease
The most common form of Alzheimer’s disease, usually occurring after age 65. Late-onset Alzheimer’s disease affects almost half of all people over the age of 85 and may or may not be hereditary.

Late stage
Designation given when dementia symptoms have progressed to the extent that a person has little capacity for self-care.

Behavior that involves inappropriately changing or layering clothing on top of one another.

Lewy body dementia
A dementing illness associated with protein deposits called Lewy bodies in the cortex of the brain.

Living trust
A legal document that allows an individual (the grantor or trustor) to create a trust and appoint someone else as trustee (usually a trusted individual or financial institution) to carefully invest and manage his or her assets

Living will
A legal document that expresses an individual’s decision on the use of artificial life support systems.

Long-term care
A comprehensive range of medical, personal and social services coordinated to meet the physical, social and emotional needs of people who are chronically ill or disabled.

Magnetic resonance imaging (MRI)
A test that produces high-quality images of the body’s internal structures without the use of X-rays. MRI uses a large magnet, radio waves and a computer to produce these images.

A program sponsored by the federal government and administered by states that is intended to provide health care and health-related services to low-income individuals.

A federal health insurance program for people age 65 and older, and for individuals with disabilities.

The ability to process information that requires attention, storage and retrieval.

The complex chemical and physical processes of living organisms that promote growth, sustain life and enable other bodily functions to take place.

Microglia (microglia cells)
A type of immune cell found in the brain. Microglia cells are scavengers, engulfing dead cells and other debris. In Alzheimer’s disease, microglia cells are found associated with dying nerve cells and amyloid plaques.

See multi-infarct dementia.

Mild cognitive impairment (MCI)
A memory problem that is noticeable to others. People with MCI may have other problems in brain function as well, but they are able to get through the day and do what they need to do without major difficulty. Some (not all) people with MCI progress to develop Alzheimer’s disease.

Mini-Mental State Examination
A mental status exam commonly used to measure a person’s basic cognitive skills, such as short-term memory, long-term memory, orientation, writing and language.

Components found in cells that serve as primary energy sources for cellular functions.

Model system
A system used to study processes that take place in humans or other living organisms.

Monoamine oxidase B (MAO-B)
An enzyme that breaks down certain neurotransmitters, including dopamine, serotonin and noradrenaline.

Monoamine oxidase inhibitor (MAOI)
A drug that interferes with the action of monoamine oxidase, slowing the breakdown of certain neurotransmitters; often used in treating depression.

See magnetic resonance imaging.

Multi-infarct dementia (MID)
A form of dementia, also known as vascular dementia, caused by a number of strokes in the brain. These strokes can affect some intellectual abilities, impair motor and walking skills, and cause an individual to experience hallucinations, delusions or depression. The onset of MID usually is abrupt and often progresses in a stepwise fashion. Individuals with MID are likely to have risk factors for strokes, such as high blood pressure, heart disease or diabetes. MID cannot be treated; once nerve cells die, they cannot be replaced. However, risk factors can be treated, which may help prevent further damage.

Music therapy
Use of music to improve physical, psychological, cognitive and social functioning.

Nerve cell (neuron)
The basic working unit of the nervous system. The nerve cell typically is composed of a cell body containing the nucleus, several short branches (dendrites), and one long arm (the axon) with short branches along its length and at its end. Nerve cells send signals that control the actions of other cells in the body, such as other nerve cells and muscle cells.

Nerve cell line
A group of nerve cells derived from a cell culture that can be used for experimental purposes.

Nerve cell transplantation
An experimental procedure in which normal brain cells are implanted into diseased areas of the brain to replace dying or damaged cells.

Nerve growth factor (NGF)
A protein that promotes nerve cell growth and may protect some types of nerve cells from damage.

Neuritic plaque
See amyloid plaque.

Neurodegenerative disease
A type of neurological disorder marked by the loss of nerve cells. (See Alzheimer’s disease and Parkinson’s disease.)

Neurofibrillary tangle
An accumulation of twisted protein (tau protein) fragments inside nerve cells. Neurofibrillary tangles are one of the characteristic structural abnormalities found in the brains of people with Alzheimer’s disease. Upon autopsy, the presence of amyloid plaques and neurofibrillary tangles is used to positively diagnose Alzheimer’s disease.

Neurological disorder
A disturbance in structure or function of the nervous system resulting from developmental abnormality, disease, injury or toxin.

A doctor who is specially trained to diagnose and treat disorders of the nervous system.

See nerve cell.

Changes in the brain produced by a disease.

Neuropsychological testing
The evaluation of brain function and an individual’s capabilities that utilizes tests to assess language, visual-perceptual skills, memory, attention, problem-solving and reasoning.

An individual who holds a doctoral degree (PhD) in clinical psychology or a related discipline and who specializes in the evaluation and management of brain dysfunction.

The passage of signals from one nerve cell to another via chemical substances or electrical signals.

A special chemical in the brain that is necessary for communication between nerve cells. Examples of neurotransmitters include acetylcholine, dopamine, norepinephrine and serotonin.

Neurotrophic factor
A protein, such as nerve growth factor, that promotes nerve cell growth and survival.

The central component of a cell containing all genetic material.

Occupational therapists
Health care professionals that teach people how to return to normal activities after injury or illness by therapy and rehabilitation.

Defines the time when a disease begins (early-onset, late-onset).

Aimless wandering or walking back and forth, often triggered by an internal stimulus—such as pain, hunger or boredom—or by some distraction in the environment—such as noise, smell or temperature.

Suspicion of others that is not based on fact.

Parkinson’s disease
A progressive, neurodegenerative disease with an unknown cause characterized by the death of nerve cells in a specific area of the brain. People with Parkinson’s disease lack the neurotransmitter dopamine and have symptoms such as tremors, speech impediments, movement difficulties and often dementia later in the course of the disease.

Peripheral nervous system (PNS)
One of the two major divisions of the nervous system. Nerves in the PNS connect the central nervous system with sensory organs, other organs, muscles, blood vessels and glands.

The persistent repetition of an activity, word, phrase or movement, such as tapping, wiping and picking.

Personal care
See activities of daily living.

PET scan
See positron emission tomography scan.

The study of drugs, including their composition, production, uses and effects in the body.

A word composed of root words that mean love of mankind. The word now refers to concern for social/community situations—such as health, education, welfare. Philanthropy is now linked to "doing good," such as donating money or property for a cause.

The chemical addition of a phosphate group (phosphate and oxygen) to a protein or other compound.

Pick’s disease
A type of dementia in which frontotemporal dementia causes dramatic alterations in personality and social behavior but typically does not affect memory until later in the disease. It is caused by an accumulation of tau proteins in nerve cells.

An inactive material in the same form as an active drug; for example, a sugar pill (See double-blind, placebo-controlled study).

Plaques and tangles
See amyloid plaque and neurofibrillary tangle.

Positron emission tomography (PET) scan
An imaging scan that measures the activity of the functional level of the brain by measuring its use of glucose, or reveals molecular abnormalities such as the amyloid protein.

Possible Alzheimer’s disease
A level of diagnosis that is supported, but with a degree of uncertainty, by the patient’s medical history, and by neurologic, psychiatric and clinical exams, neuropsychological tests and laboratory studies.

Premature aging
Physical changes related to aging that occur ahead of what would be expected for a person’s chronological age.

Genes, mutations of which are linked to early-onset Alzheimer’s disease.

The individual signing the power of attorney to authorize another person to legally make decisions for him or her.

Self-replicating proteins that may cause infection and may lead to some forms of dementia, such as Creutzfeldt-Jakob disease.

Probable Alzheimer’s disease
A level of diagnosis that is supported with relative certainty by the progressive deterioration of specific cognitive functions, motor skills and perception, impaired activities of daily living and altered patterns of behavior, as well as laboratory findings and brain scanning.

Prodromal Alzheimer’s disease
A condition in which a person has memory impairment and a biomarker (PET, MRI, CSF changes) of Alzheimer’s disease.

The probable outcome or course of a disease; the chance of recovery.

Progressive disorder
A disorder that gets worse over time.

Enzymes that break down proteins in the body.

Protein metabolism
The breakdown of proteins into amino acids, a process essential to human growth and metabolism.

A severe form of depression resulting from a progressive brain disorder in which cognitive changes mimic those of dementia.

Doctors who specialize in treating mental, emotional or behavioral disorders. They are doctors who can prescribe medications.

Specialists who concentrate on the science of the mind and behavior. Psychologists usually have advanced degrees and receive additional training to work with patients. Psychologists are not medical doctors and cannot prescribe medication, but do perform evaluations and use psychotherapy. They also are referred to as clinical psychologists.

A general term for a state of mind in which thinking becomes irrational and/or disturbed. Psychosis refers primarily to delusions, hallucinations and other severe thought disturbances.

A variety of techniques used to treat depression. Psychotherapy involves talking to a licensed professional who helps the depressed person. Psychotherapy has proven to be effective in treating mild and moderate forms of depression, and can be combined with drug therapy to treat all degrees of depression.

Quality of care
A term used to describe care and services that allow the recipients to attain and maintain their highest level of mental, physical and psychological function in a dignified and caring way.

Encouragement intended to relieve tension, fear and confusion that can result from dementia.

A site on a nerve cell that receives a specific neurotransmitter; the message receiver.

Receptor agonist
A substance that mimics a specific neurotransmitter, is able to attach to that neurotransmitter’s receptor and thereby produces the same action the neurotransmitter usually produces. Drug often are designed as receptor agonists to treat a variety of diseases and disorders in which the original chemical substance is missing or depleted.

Recombinant DNA technology
The artificial rearrangement of DNA. Segments of DNA from one organism can be incorporated into the genetic makeup of another organism. Using these techniques, researchers can study the characteristics and actions of specific genes. Many modern genetic research methods are based on recombinant DNA technology.

The ability to function in a normal or near-normal manner after disease or injury; the use of various therapies to help improve a person’s level of function.

The use of praise, repetition and stimulation of the senses to influence a person’s behavior.

Related disorders
Conditions that are similar in nature to the main condition but occur for a different reason.

A life review activity aimed at surfacing and reviewing positive memories and experiences.

Repetitive behavior
Repeated questions, stories and outbursts or specific activities done over and over again, common in people with dementia.

A short break or time away.

Respite care
Services that provide people with temporary relief from the tasks associated with care giving. Examples of respite care include in-home assistance, short nursing home stays, and adult day care.

Devices used to ensure safety by restricting and controlling a person’s movement. Many facilities are "restrain-free" or use alternative methods to help modify behavior.

Risk factor
A factor that increases a person’s chance of developing a disease or predisposes a person to a certain condition.

Safe Return
The Alzheimer’s Association’s nationwide identification, support, and registration program that assists in the safe return of individuals with Alzheimer’s disease or other dementias who wander and become lost.

Senile plaque
See amyloid plaque.

A term meaning "old," once used to describe elderly diagnosed with dementia.

Aspects of sensation and movement.

Determination of the order of amino acids that make up a gene.

Following, mimicking and interrupting behaviors that people with dementia may exhibit.

Side effect
An undesired effect of a drug treatment that may range from barely noticeable to uncomfortable to dangerous. Side effects usually are predictable.

Single photon emission computed tomography (SPECT) scan
A procedure that measures blood flow in different areas of the brain, or is used to measure certain brain chemicals such as dopamine.

Skilled nursing care
A level of care that includes ongoing medical or nursing services.

Special care unit
A designated area of a residential care facility or nursing home that cares specifically for the needs of people with Alzheimer’s disease.

SPECT scan
See single photon emission computed tomography scan.

Spinal cord
One of the two components of the central nervous system. The spinal cord is the main relay for signals between the brain and the rest of the body.

The course of disease progression defined by levels or periods of severity: prodromal, early, mild, moderate, moderately severe, severe.

Subcortical dementia
Dementia associated with impairment of the lower part of the brain that affects the speed of motor and mental processes. It is associated with disease of the basal ganglia, such as Huntington’s disease.

Unsettled behavior evident in the late afternoon or early evening.

Support group
A facilitated gathering of patients, caregivers, family, friends or others affected by a disease or condition for the purpose of discussing issues related to the disease.

A mistrust common in Alzheimer patients as their memory becomes progressively worse. An example is when patients believe their belongings have been stolen.

The junction between cells where a signal is transmitted from one nerve cell to another, usually by a chemical called a neurotransmitter.

Synaptic vesicles
Small sacs located at the ends of nerve cell axons that contain neurotransmitters.

See neurofibrillary tangles.

Tau protein
The major protein that makes up neurofibrillary tangles found in degenerating nerve cells.

A group of similar cells that act together in the performance of a particular function.

A substance that can cause illness, injury or death. Toxins are produced by living organisms.

An environmental or personal stimulus that sets off a particular behavior.

The individual or financial institution managing the assets of a living trust.

A test in which a urine sample is evaluated to detect abnormalities.

Vascular cognitive impairment
Changes in cognitive functioning—thinking, decision-making, memory, etc.—due to vascular disease. These changes are often brought on by a series of small strokes.

Vascular dementia
See multi-infarct dementia or MID.

A small pouch or pouch-like sac. Vesicles in nerve cell axons contain neurotransmitters.

Various substances found in plants and animals that are required for life-sustaining processes.

Common behavior that causes people with dementia to stray and become lost in familiar surroundings.

A legal document created by an individual that names an executor (the person who will manage the estate) and beneficiaries (persons who will receive the estate at the time of the individual’s death).

High-energy radiation used in low doses to create images of the body to help diagnose diseases and determine the extent of injuries.

A mineral that is essential for proper nutrition.

Last reviewed by a Cleveland Clinic medical professional on 07/09/2014.

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