Anxiety: Persistent and excessive worry about activities or events—even ordinary, routine issues

Dementia: Loss of brain function that worsens over time and affects memory, thinking, behavior, and language

Depression: Persistent feeling of sadness and loss of interest

Depth perception: Ability to understand one's body location with relation to objects in one's environment

Geriatrician: Physician specializing in multiple old age–related conditions

Impulsiveness: Behavior in which you do things suddenly without any planning and without considering the effects they may have

Irritability: Quality of becoming annoyed very easily

Mild Cognitive Impairment (MCI): A condition that causes changes in the way your brain works, affecting your memory and ability to think. MCI can be caused by many things, but it is most commonly due to Alzheimer's. MCI is the first stage in Alzheimer's where symptoms become noticeable

Neurologist: Physician specializing in conditions affecting the nervous system

PET scan: Positron emission tomography, a medical imaging test that uses a radioactive substance to assess organ and tissue function in the body and to look for disease

Plaques in the brain (also known as amyloid plaques): Protein clumps that appear in Alzheimer's disease and get in the way of a normal brain cell working properly

Short-term memory: Information the brain stores temporarily