Alzheimer’s disease is a progressive neurodegenerative disorder characterized by declining mental abilities that affect a person’s memory, cognition, and personality. It is the most common cause of dementia.
As a complex condition, Alzheimer’s lacks a simple diagnostic test. Rather, diagnosis consists of assessing an individual’s pertinent medical history, signs and symptoms, lab tests, and brain imaging.
Medical and family history
Many risk factors can contribute to the likelihood that a person develops Alzheimer’s. To assess these, a physician will want to know about an individual’s history of medical conditions, lifestyle variables such as smoking and alcohol consumption, and medications.
Family history also will be assessed for relatives with Alzheimer’s or other forms of dementia. Although Alzheimer’s does not yet have a known genetic cause, having relatives with the disorder raises one’s own likelihood of developing it, as certain genes are known to increase the risk of developing the disease.
Signs and symptoms
Forgetfulness, confusion, and personality changes often provide the first clues that a person should seek medical attention.
An individual in Alzheimer’s early stages often has trouble with short-term memory, particularly with regard to learning new information. Confusion and memory impairments typically lead to difficulties completing tasks, becoming disoriented, and struggling to maintain concentration.
Personality changes related to these obstacles tend to appear as depression, anxiety, aggression, and anti-social behavior.
Evaluating these symptoms to make a diagnosis involves a battery of cognitive tests, lab evidence, and brain imaging.
Cognitive and neuropsychological tests
Cognitive, neuropsychological, and personality tests use self-reported and physical evidence to measure how much a person’s cognitive functions, memory, and personality have changed over time.
Mental and cognitive status such as the mini-mental state exam (MMSE) and the mini-cog test seek a sense of whether a person is aware of their symptoms, oriented to date, time, and identity, and tests their short-term memory. Typical questions ask a person to remember the names of three common objects over a period of several minutes, and to draw the face of a clock showing a time specified by the examiner.
Neuropsychological tests also can be preformed, and include extensive tests to evaluate memory and cognitive skills. These can help determine if a person has dementia, and if they are able to safely conduct daily tasks, such as driving and managing finances.
Neurological exams tests add physical evidence of neurological dysfunction to the more subjective cognitive exams. These typically examine a person’s reflexes, coordination and muscle tone, eye movement, speech, and ability to perceive sensations.
Lab tests, generally performed on blood and urine samples, help a physician rule out other dementias, such as those caused by thyroid disorders or vitamin B12 deficiency, as well as the potential adverse side effects of medications or alcohol use.
Brain imaging exams aim to identify changes caused by disease or trauma. Although insufficient to make a diagnosis on their own, they help to rule out other sources of physical harm that can cause Alzheimer’s-like symptoms, such as bleeding in the brain, tumors, and strokes.
They also can distinguish between different types of brain disease and help establish a baseline, against which to measure future changes.
Brain-imaging technologies include magnetic resonance imaging (MRI), computerized tomography (CT), and positron emission tomography (PET).
Benefits of early diagnosis
Although Alzheimer’s lacks a cure, treatments often are more effective at improving symptoms and slowing their progression, the earlier the disorder is diagnosed. Strategies to minimize Alzheimer’s effects in one’s everyday life, such as establishing routines, planning activities, and adapting the living environment also have greater effect the sooner they are implemented.
Last updated: June 23, 2021
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