DEAR DOCTOR K:

My husband’s doctor suspects that he has Alzheimer’s disease and wants him to have neuropsychological testing. What will these tests involve?

DEAR READER:

There is no single test that can diagnose Alzheimer’s disease. In fact, a doctor cannot make the diagnosis with absolute confidence without studying the brain under the microscope, which is rarely done except in an autopsy.

Alzheimer’s disease is diagnosed presumptively by a combination of different types of evidence. The disease typically has a slowly progressive onset. Sudden confusion or speech problems, for example, are not caused by Alzheimer’s.

Indeed, a very important part of making a presumptive diagnosis of Alzheimer’s is first ruling out many other causes of thinking problems. Other conditions, such as a brain tumor, can impair a person’s thinking. So can certain medicines.

When doctors suspect that a person may be developing Alzheimer’s disease, they often perform multiple tests to evaluate different aspects of thinking. The tests may involve paper and pencil, or may be administered by interacting with a computer:

• ATTENTION. A major reason people fail to remember new information is that they don’t really concentrate on it when the information is first presented to them. There are many tests to assess attention. For example, the doctor might read a sequence of numbers, then ask the person to repeat back as many as he can remember.

• MEMORY. Memory testing usually requires that a person listen to or look at some information and then answer questions about it. Or the person may be asked to repeat it back immediately, and then again 10 to 30 minutes later. The doctor might also test long-term memory, things that almost everyone knows that happened long ago. For example, your husband might be asked to name his birthplace, or who was the president of the United States during World War II.

• EXECUTIVE FUNCTION. This is an umbrella term for high-level thinking skills. These include reasoning, problem solving, planning, inhibiting impulses and resisting distraction in order to stay focused on a task. These abilities often become impaired in early Alzheimer’s disease.

• LANGUAGE. Language functions include being able to express yourself through speaking and writing. They also involve understanding what another person is saying or what you are reading. The doctor may ask the person to name common objects. For example, the doctor may hold up a pencil and ask your husband what it’s called. Problems with naming and word finding can be early symptoms of Alzheimer’s. Your husband may be asked to follow instructions or describe a picture in writing.

• SPATIAL ABILITY. This involves analyzing visual information — shapes, faces, and routes between locations on a map, for example. Tests may include drawing and copying designs, solving maze puzzles, and putting blocks together to construct a specific pattern.

Neuropsych testing cannot, alone, definitively diagnose Alzheimer’s disease. However, the testing results, along with the medical history, brain-imaging studies and other evidence, can give the doctor pretty strong evidence for or against Alzheimer’s. I hope the testing turns out in your husband’s favor.