What cognitive tests can show -- and what they can't

Political opponents and nervous supporters are calling for Joe Biden to undergo a cognitive test. What can these tests tell us about cognitive health?

It’s the new chant in Washington politics: “Get a cognitive test!”

Political opponents, armchair pundits and even nervous supporters are demanding that U.S. President Joe Biden undergo such testing after his dismal debate performance – even though his physician says he gets, and passes, an annual neurologic exam.

Former President Donald Trump, who’s only a few years younger, makes his own gaffes. He recently bragged about passing a 2018 cognitive test – while calling the doctor who administered it by the wrong name.

With all the concern, what can cognitive testing actually tell about a person’s brain health – and what can’t they answer? And presidents aside, does the average older adult need one?

They’re brief screening tools, a 10-minute series of questions to assess different brain functions. Two of the most common are called the MMSE, Mini-Mental State Exam, and the MoCA, Montreal Cognitive Assessment.

Recalling a list of five unrelated nouns or seeing how many words beginning with F you can say in a minute can assess short-term memory and language. Counting backward by 7s tests attention and concentration. Drawing a clock with the correct time is a clue to spatial awareness.

They don’t diagnose health problems. A bad score is just a red flag that indicates a need for further testing to see if there is a health problem and uncover what kind, said Dr. James Galvin, a neurologist at the University of Miami.