Have you ever bumped into someone you know at a movie theater or grocery store and been totally stumped when you try to come up with the person’s name? Or greeted someone by name and then seen that Oh, help! look flicker across his face as he tries in vain to remember who you are? Either way, it’s embarrassing.

Forgetting someone’s name is not that unusual, especially as we age, even for otherwise cognitively normal people. But: When forgetting names is more severe or when it’s accompanied by a lack of recognition—i.e., not even realizing that you are familiar with the person—it can be an early warning sign of a particular form of dementia that primarily affects verbal communication, new research shows. Now there’s a test that uses the faces of Bill Gates, Princess Diana and others to check for possible memory problems.

Why this matters: This type of dementia, which is called primary progressive aphasia (PPA), often goes unrecognized in the early stages. That’s because, unlike other forms of dementia, PPA tends not to noticeably affect daily activities or cognitive abilities unrelated to language…it also strikes early, typically in middle age, before the possibility of dementia generally is “on the radar,” so to speak.

Though PPA cannot be cured, speech therapy and instruction in alternative forms of communication can greatly improve patients’ quality of life. That’s why a delay in diagnosis is a problem.

Helpful new tool: Thanks to the likes of Bill Gates, Princess Diana and Martin Luther King, Jr.—and researchers at Northwestern University in Chicago— there’s a new face-naming/face-recognition test that helps identify people with PPA. (There are also similar tests available online. How well would you score on a “famous-face test”?)

NAME THAT STAR

For the study, the researchers chose black-and-white photographs of 20 public figures who generally would be well-known to people currently between the ages of 40 and 65, because PPA typically develops in that age group. The famous faces included Bill Clinton, Humphrey Bogart, Lucille Ball and Oprah Winfrey, among others. The photos were shown to 30 people with a diagnosis of PPA…and to a control group of 27 people without PPA.

The face test included two parts—a naming section and a recognition section—because these two skills are actually quite different and use different parts of the brain. For the naming part, participants earned two points if they provided the first and last names of the famous person or one point if they gave just the first or last name. For the recognition part, participants earned points by providing descriptive information about the famous person. For example, saying “a singer” or “the actress from Funny Girl” earned recognition points because the participant clearly recognized the famous face, whether or not he could come up with the name Barbra Streisand.

Results: For naming, people in the control group (without dementia) earned an average score of 93%…but those with PPA averaged just 46%. For recognition, those without dementia scored 97%, on average…while the average score in the dementia group was just 79%.

Intriguing: Participants also had MRI scans to look at cortical thickness in various parts of the brain. Areas of thinning (atrophy) represent a loss of nerve cells, which is a sign of dementia. The MRIs showed direct relationships between participants’ test scores and the degree of atrophy in specific brain regions. People who had the lowest ability to correctly name the famous public figures showed more advanced atrophy in the left anterior temporal lobe…those with poor face recognition showed atrophy on both sides of the anterior temporal lobe. Hopefully, this new information will increase experts’ understanding of PPA and help lead to improvements in treatment.

TEST YOURSELF

It’s not surprising that people known to have dementia would score worse on cognitive tests. What’s important about this study is that this particular test could help identify as-yet-undiagnosed patients who are suffering from this often-overlooked form of dementia.

You can check your own ability to recognize famous faces with a test from Harvard University and others. Similar to the test used in the new study, it takes about five minutes to complete. If you do well, you’ll have fun and feel reassured…if you’re disappointed with your score, talk with your doctor about whether you should see a neurologist for a cognitive evaluation. In addition to PPA, there are several other conditions that can cause facial-recognition impairments, the researchers said, so a complete clinical evaluation is important for a proper diagnosis.