Changes in the way the brain functions, such as processing information more slowly or showing occasional forgetfulness, are a normal part of the aging process. However, about 10 percent of people older than age 65 develop difficulty with memory, language, thinking, and judgment that’s greater than average age-related changes. This condition is known as mild cognitive impairment (MCI), also simply called memory loss.
People with mild cognitive impairment may notice that their minds aren’t as sharp as they used to be, and family and friends may see a change as well. However, people with MCI do not meet the diagnostic criteria for dementia, which means symptoms are not severe enough to limit their ability to engage in usual activities.
Mild cognitive impairment is categorized by doctors as amnestic or nonamnestic. Amnestic mild cognitive impairment primarily affects memory. For example, a person may forget appointments, recent conversations, or the name of a family member. Nonamnestic mild cognitive impairment affects thought processes. For example, a person may have a hard time performing a complex task, like balancing a checkbook or exercising good judgment in risky situations, such as when driving.
Having mild cognitive impairment increases a person’s risk of developing Alzheimer's disease or other forms of dementia, such as Lewy body dementia. Unlike these conditions, however, memory loss doesn’t always get worse—and rarely, it may eventually get better.
Unlike Alzheimer’s disease, in which cognitive abilities gradually decline, the memory deficits in MCI may remain stable for years. However, some individuals with MCI develop cognitive deficits and functional impairment consistent with Alzheimer’s. It is still a topic of ongoing scientific investigation whether MCI is a disorder distinct from Alzheimer’s disease or a very early phase of Alzheimer’s.
Some causes of memory loss, such as normal pressure hydrocephalus, thyroid disease, Lyme disease, and nutritional deficiencies, are reversible with treatment. That’s why ruling out other possible causes of cognitive changes is essential in developing a treatment plan.
To make a diagnosis, NYU Langone doctors obtain a complete picture of your health by asking about symptoms, performing a physical exam, asking about your medical and family histories, and talking with family members or friends.
Doctors may also use other tools and tests as part of a diagnostic evaluation.
In a neurological evaluation, doctors assess a person’s speech, vision and other senses, spatial skills, and reflexes. People may be asked to name objects, follow verbal and written commands, write a sentence, or draw a complex shape. Doctors may ask you to walk a short distance, because problems with gait can signal other conditions involving memory loss, such as normal pressure hydrocephalus.
The doctor also checks cognitive skills—such as memory, ability to concentrate, and sense of time and place—by asking simple questions or talking with a family member or caregiver about how the person’s changing abilities affect everyday life.
Our physicians may perform a neuropsychological evaluation to assess memory, concentration, and orientation in regards to time, place, and people. Specialists determine how changes in these areas affect daily activities by asking questions about behavior and mood. Depression, for example, can contribute to or worsen memory problems.
Psychometric tests measure the accuracy, speed, and quality of mental processes such as decision making, paying attention, using language, planning, organizing, remembering details, and problem solving. A person may be asked to complete a written exercise to help the doctor determine if memory loss may be due to dementia or another cause of cognitive impairment.
An MRI scan is a noninvasive medical test that helps physicians diagnose and treat medical conditions. MRI uses a powerful magnetic field, radio frequency pulses, and a computer to produce detailed pictures of organs, soft tissues, bones, and virtually all other internal body structures. Doctors may order an MRI scan of the head to rule out other conditions that can cause memory loss, such as tumors or infections.
A positron emission tomography, or PET, scan is a unique imaging test that helps doctors see how the organs and tissues inside your body are functioning. The scan uses small amounts of a radioactive material, called a radiotracer, that are injected into a vein and collect in organs and other tissues. This allows doctors to see blood flow, brain cell activity, and how well the brain metabolizes sugar.
This information helps in determining how well the brain is working and whether memory loss is due to mild cognitive impairment or a type of dementia, such as Alzheimer’s disease.
NYU Langone doctors use the results of these diagnostic tests to design a treatment plan for a person experiencing memory loss. The results of the diagnostic evaluation can also provide “baseline” information for an older person who is not experiencing memory loss but is concerned about the possibility of future cognitive decline. This baseline information can be used for comparison with results of future examinations.
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