Alzheimer's disease can't be diagnosed with one test. Instead, doctors rely on a detailed medical workup known as a clinical assessment to diagnose Alzheimer's and other causes of dementia. That's why seeing a doctor is one of the first things you should do if you suspect Alzheimer's in a loved one. A clinical assessment involves many different tests.
"People are often afraid to see their doctor because they think there's only one outcome, but there are reversible causes of cognitive decline, so it's important to start with a primary care doctor when you're concerned," says Paul J. Mattis, chief of adult neuropsychology at Northshore University Hospital in Manhasset, New York.
The doctor's three goals in a clinical assessment for dementia are to document evidence of cognitive impairment, rule out other common causes for impaired thinking, and determine if other changes noted are consistent with Alzheimer's or another cause of dementia.
An experienced clinician can make an accurate Alzheimer's disease diagnosis from a clinical assessment up to 90 to 95 percent of the time, says neuroscientist and physician Paul Aisen, director of the Alzheimer's Disease Cooperative Study, a consortium of 80 academic institutions conducting Alzheimer's clinical trials. "Less experienced doctors accurately diagnose Alzheimer's 80 to 95 percent of the time," he adds.
What happens at a clinical assessment in the clinic
When a physician sees a patient concerned about memory problems or other symptoms of dementia, he or she will usually gather the following information or arrange for these tests:
A history of the present illness. The doctor will ask questions about memory problems or other concerning symptoms and will ask about other signs and symptoms that may be related to dementia or delirium, a temporary condition that's often mistaken for dementia. The doctor will also ask questions that help screen for depression, anxiety, or other psychiatric issues.
A review of past medical history. The doctor will review past illnesses and treatments and may ask about family history. He or she will ask about medications being taken and may inquire as to the patient's health habits, including diet and exercise, and work and social status (such as whom the person lives with).
A physical exam. This includes taking vital signs (blood pressure, pulse, temperature, weight), listening to heart and lungs, looking for signs of neurological impairment, and making a visual inspection.
Lab work. Lab tests usually include a complete blood count, urine tests, liver function tests, glucose count, and other tests to look for clues to underlying problems, such as infection or thyroid imbalance.
A brief cognitive screening test. These short (5- to 15-minute) tests involve asking a series of questions, which are scored, to look for signs of problems with thinking skills. Memory, verbal ability, problem-solving ability, ability to follow directions, and other areas that make up cognition are evaluated. Scoring poorly on a cognitive-status test doesn't mean the subject has Alzheimer's, only that there are cognitive deficits going on for some reason.
Other parts of a clinical assessment
In addition, the doctor may refer the patient being seen for dementia symptoms to the following kinds of exams, some of which are administered by specialists:
A neuropsychological evaluation. A neurologist, psychologist, or psychiatrist can conduct more in-depth testing on which specific thinking skills are weak. He or she can also test physical coordination, reflexes, balance, and speech.
A brain scan. An MRI, CT scan, or PET scan may be ordered to look for evidence of tumor, trauma, or strokes that are causing impairment.
Other tests. Depending on what the doctor sees or suspects, additional testing may include chest X-ray, spinal tap, EEG (to evaluate brain activity), and -- in the rare cases of a family history of early-onset Alzheimer's (before age 60) -- genetic testing.
What else to know about a clinical assessment for dementia symptoms
Clinical assessments are often completed over the course of several office visits, because the 15 to 20 minutes of the typical primary care exam aren't enough. Specialty clinics, such as memory clinics, may offer longer appointments for a more complete assessment in one visit.
Ideally, someone who lives with the person having symptoms should be part of the exam. A family member is likely to recall history more accurately and present a more accurate picture of symptoms. Many doctors go so far as to call a family member the critical "third leg of the stool" in dementia assessment: patient, doctor, and caregiver.
If you're wary of insulting a loved one by speaking up during a checkup, or you feel otherwise unable to speak up about your concerns, express your worries to the doctor in writing, before the exam. Briefly list your observations, if possible with specific examples about what's been happening and when worrisome behaviors started.
Bring to the checkup all medications currently taken or recently completed. A list of drugs is good, but the actual containers are better. Include over-the-counter medications and supplements taken regularly.