Alzheimer’s disease is a progressive neurological disorder and the most common cause of dementia.

No single diagnostic test can determine whether a person has Alzheimer’s disease. The diagnostic process involves assessing the patient’s medical history, clinical signs and symptoms, and laboratory tests, and using brain imaging to rule out other conditions.

Medical history

Evaluating the patient’s medical history is one of the first steps in the diagnostic process. This includes gathering information about the patient’s current and past diseases and medications taken. The doctor will also ask about medical conditions in the family, including Alzheimer’s disease or other dementias.

Clinical signs and symptoms

The primary symptoms that lead a patient or their family to seek a diagnosis are usually associated with forgetfulness and confusion. The patient typically has difficulties with short-term memory, orientation, concentration, and task completion.

Alzheimer’s disease can also affect personality and cause depression, anxiety, aggression, and anti-social behavior.

The doctor will first communicate with the patient, and may also interview family members and friends to get a better idea of when symptoms occurred and how they compare to former levels of function.

To objectively assess the patient’s cognitive abilities, mental status tests are conducted to gather information about memory, problem-solving, and other thinking skills.

Laboratory tests

Another part of the diagnostic process is the exclusion of other conditions. Based on the patient’s medical history and symptoms, the doctor will decide which laboratory tests to conduct.

Depression, untreated sleep apnea, side effects of medications, excessive alcohol consumption, thyroid disorders, and vitamin deficiencies (e.g. vitamin B12) can lead to symptoms that resemble Alzheimer’s disease.

Brain imaging

While the loss (degeneration) of brain cells that occurs in Alzheimer’s disease can be seen in a brain scan, distinguishing it from normal aging-associated decline is difficult.

Brain imaging, therefore, is used to rule out other causes, such as a brain tumor or stroke. It may also help to distinguish between different kinds of degenerative brain diseases.

When used over time, brain imaging can monitor the degree and progression of degeneration in the brain. Common imaging techniques include computerized tomography, magnetic resonance imaging, and positron emission tomography.


Last updated: June 03, 2019


Alzheimer’s News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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Özge has a MSc. in Molecular Genetics from the University of Leicester and a PhD in Developmental Biology from Queen Mary University of London. She worked as a Post-doctoral Research Associate at the University of Leicester for six years in the field of Behavioural Neurology before moving into science communication. She worked as the Research Communication Officer at a London based charity for almost two years.