Glossary

A handy list of definitions for key terms used throughout this course

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Acetylcholine

important neurotransmitter that communicates messages between brain cells. The most commonly prescribed dementia drugs act by boosting acetylcholine levels with the aim of helping memory and thinking symptoms.

Activities of daily living

day to day tasks fundamental to maintaining health and independent living. E.g., shopping, preparing meals, managing medications, driving or using public transport.

Alzheimer’s disease

a progressive brain disease where build-up of two toxic forms of misfolded proteins leads to the death of brain cells. Alzheimer’s disease is the most common cause of dementia

Alzheimer’s dementia

diagnosis given when the symptoms of Alzheimer’s disease become severe enough to impact on a person’s ability to perform everyday tasks independently

Amyloid β (beta)

a protein found abnormally clumped together to form “plaques” in the brains of people with Alzheimer’s disease

Amyloid-positive

when amyloid build-up in the brain passes a certain threshold. Amyloid positivity can aid in a person’s diagnosis of, or risk status for, Alzheimer’s disease

APOE

gene involved in transport of cholesterol in the brain. Certain versions of the APOE gene are known to modify risk of developing Alzheimer’s disease

Atrophy

a shrinkage in size of areas of the brain, caused by the death of brain cells

Autosomal dominant Alzheimer’s disease (also; Familial Alzheimer’s)

rare form of inherited Alzheimer’s disease, caused by a single faulty gene passed down through families

B

Biomarker

‘biological marker’, a characteristic that can be measured to indicate the state of health or disease of an individual

C

Central nervous system (CNS)

The structures of the brain and spinal cord

Cerebrospinal fluid (CSF)

liquid which surrounds the brain and spinal cord, plays a role in cushioning these structures as well as transport of substances between the brain tissue and bloodstream

Cerebrovascular disease

disease of the blood vessels that supply the brain, causing problems with blood flow to affected brain regions.

Cognition

mental thinking abilities including perception, knowledge, problem solving, judgment, language, and memory

Cognitive test

a series of set tasks designed to assess thinking and memory abilities

Clinical Trial

research study to evaluate new tests and treatments (often drugs) and measure their effects on improving particular health outcomes

D

Dementia

umbrella term for a group of brain symptoms associated with impairments in memory, thinking or behaviour which impact the ability to perform everyday activities independently

E

Early onset Alzheimer’s Dementia

when the onset of symptoms of Alzheimer’s dementia occurs before the age of 65

F

Familial Alzheimer’s disease

see ‘autosomal dominant Alzheimer’s disease’

G

Glia (also; ‘glial cells’)

the non-neuronal cells of the nervous system that together conduct many essential roles in maintaining homeostasis and supporting, protecting, and nourishing neurons

H

Hippocampus

brain area important for memory and sense of direction, known to be affected early in the course of Alzheimer’s disease

I

Incidence

the rate of new cases of a disease developing within a set timeframe (for example number of new diagnoses of Alzheimer’s disease in a year)

L

Lumbar puncture

medical investigation where a hollow needle is inserted into the lower back to collect a sample of cerebrospinal fluid

M

Mild cognitive impairment (MCI)

disorder of thinking and memory where a person has problems over and above those expected for their age but these problems do not interfere with their day to day living. MCI can, though does not always, progress to dementia

MRI scan

Magnetic resonance imaging. A type of medical scan which uses strong magnets to generate 3D images of structures inside of the body, e.g. the brain in investigations of neurodegenerative disease

N

Neurodegenerative disease

progressive diseases of the central nervous system that are caused by degradation, dysfunction and death of neurons

Neuron

a nerve cell that sends and receives signals across the brain or between the central nervous system and other parts of the body

Neurotransmitters

chemical messenger molecules released by neurons at the synapse to pass on signals to neighbouring cells

P

Preclinical disease

period of time during the natural course of a disease where disease is biologically present but symptoms are not yet apparent

Prevalence

the total number of people in a population who have a disease at any one point in time

Prodromal disease

period of time when the first early symptoms of disease appear, signalling the impending onset of a more severe disease state

PET scan

medical imaging procedure where a small amount of radioactive tracer, designed to bind to a particular molecule of interest, is injected into the bloodstream and a scanner is used to produce a detailed map of areas inside the body where the tracer accumulates

R

Risk factor

something that makes an individual more likely to develop a disease

S

Small vessel disease

damage to the small blood vessels that feed deeper areas of the brain, leading to reduced blood supply to the affected area

Synapse

a small gap between two connected neurons where signals are passed from one neuron to the other to spread information

T

Tau

protein that helps stabilise the internal scaffold of neurons. In Alzheimer’s disease abnormal tau forms toxic tangles that damage neurons

Y

Young onset Alzheimer’s Dementia

see ‘early onset Alzheimer’s Dementia’