Diagnosing Dementia

Memory loss alone doesn’t mean a person has dementia. NYU Langone doctors diagnose dementia only if two or more brain functions, such as memory and judgment, are impaired enough to interfere with a person’s daily life. Our doctors can skillfully diagnose all forms of dementia and rule out conditions that can cause similar symptoms, such as Lyme disease. 

To diagnose dementia, a doctor asks about symptoms, performs a physical exam, obtains thorough medical and family histories, and talks with family members to get a complete picture of how symptoms are affecting daily life. Such an evaluation can provide a basis for comparison with future assessments in someone who has a family history of dementia. 

Other diagnostic tools may include the following.

Neurological Evaluation

A neurologist assesses use of language, vision, spatial orientation, ability to walk, reflexes, and senses. The doctor may ask the person to name objects, follow verbal and written commands, write a sentence, or draw a complex shape. The person may be asked to walk a short distance to determine if there are any gait problems, which can signal the Parkinson-like symptoms of Lewy body dementia or other conditions with similar symptoms, such as normal pressure hydrocephalus. 

Psychiatric Evaluation

In a psychiatric evaluation, a doctor checks cognitive function—such as memory, the ability to concentrate, and orientation to time and place—and asks about how it affects daily activities. A doctor may also ask questions about behavior and mood, as well as any medications the person is taking; these can also contribute to memory problems or confusion.

Psychometric Testing

Psychometric tests measure a person’s mental abilities and difficulties, including the accuracy and speed of processes such as making decisions, paying attention, using language, planning, organizing, remembering details, and solving problems. A neuropsychologist may administer a pencil-and-paper worksheet as part of this evaluation. 

MRI Scans

An MRI uses a magnetic field and radio waves to create two- or three-dimensional images of organs and tissues in the body. NYU Langone doctors may order this test to view the brain and rule out other causes of cognitive impairment, such as tumors. 

PET Scans

A PET scan uses small amounts of radioactive material combined with glucose (sugar), called a tracer, in creating a map of how well the brain is working. The tracer is injected into a vein, where it travels through the bloodstream and reaches the brain. Because the brain makes use of glucose as a fuel, a PET scan can create a detailed map showing areas of activity and inactivity—that is, where the brain is metabolizing the glucose and where it isn’t. This map gives the doctor a good idea of how well all parts of the brain are working. 

NYU Langone doctors use the results of these tests to customize a treatment plan, with the goal of slowing the progression of dementia symptoms and supporting families throughout the course of diagnosis and treatment.