Memory and Aging Glossary

Atrophy: Wasting away or shrinking. Neuronal atrophy is wasting away of neurons, a decrease in neuronal density.

BSE: Bovine spongiform encephalopathy, also known as "mad cow disease."

Cellular inclusion: Any small entity found within a cell.

Central nervous system: A general term used to describe the brain and spinal cord.

Cerebellar ataxia: Shaky movements, wobbliness, unsteady walk and clumsiness usually caused by damage to the cerebellum, a part of the brain which controls movement.

Cerebellar signs: Pertaining to the cerebellum, the part of the brain in the back of the head between the cerebrum and the brain stem. The cerebellum controls balance for walking, standing and other complex motor functions.

Cerebrospinal fluid (CSF): A clear, watery liquid that bathes, cushions and protects the brain and spinal cord.

Cerebrum: The largest part of the brain, which is responsible for learning and other conscious mental functions.

Chorea: Irregular, spasmodic, involuntary movements of the limbs or facial muscles, often accompanied by hypotonia (decreased tone of skeletal muscles).

Chromosome: Strands of DNA compressed and organized into a double helix structure. Humans typically have 23 pairs of chromosomes.

Chromosome 17q21 (FTDP-17) : The chromosome that contains the gene for making the protein tau.

Codon 129: The human prion protein (PrP) has a common polymorphism at codon 129 of the gene PRNP; this polymorphism has a strong influence on genetic susceptibility to prion diseases.

Cortex: The outer portion of an organ. In the brain, the outer portion of the cerebrum is the cerebral cortex.

CT (computerized tomography): Pictures of structures within the body created by a computer that takes the data from multiple x-ray images and turns them into pictures. Compared to an x-ray, CT scan captures an entire slice of the body with about 100 times more clarity.

Dementia: A deterioration of intellectual faculties, such as memory, concentration and judgment, resulting from an organic disease or disorder of the brain. It is sometimes accompanied by emotional disturbance and personality changes.

DNA (deoxyribonucleic acid): The complex molecule that holds the "blueprint" for your body to make proteins.

Dysesthesia: A condition in which an unpleasant sensation — known as painful sensory symptoms such as distortion or impairment of any sense, especially the sense of touch — is produced by ordinary stimuli.

Dysphagia: Difficulty in swallowing due to problems in nerve or muscle control.

Dystonia: Involuntary, sustained muscle contractions that frequently cause twisting body motions, tremor and abnormal posture. These movements may involve the entire body, or only an isolated area.

Episodic memory: The memory of events, times, places, associated emotions and other conception-based knowledge in relation to an experience.

Electroencephalogram (EEG): A recording of the electrical activity of your brain. Flat metal discs (electrodes) placed on your scalp detect and record the patterns of electrical activity generated by your brain.

Encephalopathy: Any disease in which the functioning of the brain is affected.

Extrapyramidal signs: The extrapyramidal system regulates subconscious control of erratic motions, muscle tone and truncal stability through the basal ganglia. Injuries to this system can cause movement disorders, inability to initiate movement and/or inability to remain motionless.

Frontal lobe: The part of each hemisphere of the brain located behind the forehead that serves to regulate and mediate the higher intellectual functions. The frontal lobes have intricate connections to other areas of the brain. In the frontal lobes, we meld emotions, cognition, error detection, volition, a sense of self, and more to create our social brain.

Frontotemporal dementia (FTD): The umbrella term for the clinical syndromes of behavioral variant frontotemporal dementia (bvFTD), semantic dementia (SD) and progressive non-fluent aphasia (PNFA). These syndromes share involvement of the frontal and temporal lobes of the brain. This term is sometimes used to refer specifically to bvFTD.

Frontotemporal lobar degeneration (FTLD): The term that describes the specific pathological diseases that result in FTD syndromes. Sub-typing is based on the specific proteins found within neuronal inclusions.

Gait: How a person walks.

Gene: A specific subunit of DNA that codes for a specific protein.

Gliosis: A process leading to scars in the central nervous system that involves the production of a dense fibrous network of neuroglia (supporting cells) in areas of damage. Gliosis is a prominent feature of many diseases of the central nervous system, including frontotemporal dementia, Alzheimer's disease, multiple sclerosis and stroke. After a stroke, neurons die and disappear with replacement gliosis.

Gray matter: The cortex of the brain, which contains nerve cell bodies. The gray matter is in contrast to the white matter, the part of the brain that contains myelinated nerve fibers. The gray matter is so named because it appears gray.

Hyperreflexia: An abnormal, increased action of the reflexes; a reaction of the autonomic (involuntary) nervous system to over-stimulation.

Iatrogenic: Disease acquired as the result of accidental transmission from one patient to another by medical or surgical procedures.

MRI (magnetic resonance imaging): A radiology technique that uses magnetism, radio waves and a computer to produce non-invasive, high-quality images of internal structures of the body. An MRI is painless, does not use x-ray radiation and is a powerful tool for delineating brain structure.

Microtubules: A key structural element of the scaffolding structure of a cell or cytoskeleton.

Mutation: A permanent change in the DNA or RNA, the molecular "blueprints" that direct the building of proteins. Mutations can be helpful, neutral or harmful, and can occur randomly or be caused by environmental factors.

Myoclonus: Sudden, involuntary jerking or twitching of a muscle or group of muscles.

Neurofibrillary tangle: Pathological clusters of the protein which are found within neurons.

Neuronal inclusion: Any small intracellular body found within a neuron (nerve or brain cell).

Pathology: The study and diagnosis of disease through examination of organs, tissues, bodily fluids or whole bodies.

PCR (polymerase chain reaction): A key technique in molecular genetics that rapidly copies a short section of DNA or RNA for analysis without having to clone it.

Pedigree: In medicine, a family health history diagrammed with a set of international symbols to indicate the individuals in the family, their relationships to one another, those with a disease, etc.

Phonemic paraphasias: Errors involving use of the incorrect phoneme ("ped" instead of "bed") or transposition of a phoneme ("efelant" for "elephant").

Pick bodies: A specific type of cellular inclusion made up of the protein tau and seen in some people with FTD.

Pick's disease: Another name for behavioral variant frontotemporal dementia (bvFTD), also called frontotemporal dementia (FTD).

Presenile degenerative dementia: Dementia that starts in people before 65 years of age.

Presenting symptom: The first change in a person's behavior noticed by the patient or caregiver which brings them into the doctor's office.

Prion: An infectious agent made up of abnormally folded protein and no genetic material. A disease-causing agent that is neither bacterial nor fungal nor viral and contains no genetic material. The prion protein occurs normally in a harmless form. By folding into an aberrant shape, the normal prion protein turns into a rogue agent. It then co-opts other normal prions to become rogue prions.

Prodromal symptoms: Any symptom affecting a system other than the nervous system preceding the first neurologic symptom or sign.

Pulvinar sign: Symmetrically increased signal intensity in the pulvinar region (posterior part of the thalamus) relative to the signal intensity in other deep and cortical gray matter areas on an MRI. The presence of this MRI feature may suggest a vCJD diagnosis in the appropriate clinical context.

Pyramidal signs: The pyramidal system controls all of our voluntary movements. It is made up of two systems: upper motor neurons in the primary motor cortex and lower motor neurons in the anterior horn of the spinal cord. The axons of the corticospinal tract condense to form the pyramids, giving the system its name. Injuries to this system can cause paralysis.

Rapidly progressive dementia: A form of dementia in which the time period from first symptom to dementia is less than two years and often less than one year.

Semantic memory: The memory of meanings, understandings and other concept-based knowledge. Remembering that a robin is a bird with a red breast is one example of semantic knowledge.

Semantic paraphasia: The substitution of a word that is closely related to the target word, as in "cat" for "dog."

Sign: An indication that something is not right in the body, defined as things that can be seen by a doctor, nurse or other health care professional. For example, fever, rapid breathing rate and abnormal breathing sounds heard through a stethoscope may be signs of pneumonia.

Symptom: An indication of disease, illness, injury or that something is not right in the body. Symptoms are felt or noticed by a person, but may not easily be noticed by anyone else.

Tau: A protein in the body that aids in the cellular structure (cytoskeleton) and cellular transportation.

Temporal lobe: The lobe of the cerebral hemisphere located down on the side of the brain near the ears. The temporal lobe contains the auditory cortex which is responsible for hearing, language comprehension and memory.

Vacuolation: A neuropathologic term that replaces the older terminology of "spongiform change." This term describes the fluid-filled vesicles (vacuoles) that are seen at dendrite terminals in the neuropil (the network of nerve fibers, neuroglial cells and synapses in the gray matter). Brain damage characterized by a spongy appearance of brain tissue seen under a microscope. This is considered to be a classic neuropathologic feature of prion diseases.

White matter: The part of the brain that contains myelinated nerve fibers. The white matter is white because it is the color of myelin, the insulation covering the nerve fibers.