Three-Minute Take-Home Test May Identify Symptoms Linked to Alzheimer's Disease

I am not understanding this: "It can’t directly predict who will develop Alzheimer’s, but it does identify who could be at a higher risk." I get the part that it can't "directly predict", but what does it mean to "identify who could be at a higher risk"? How was "higher risk" independently diagnosed in the study in order to show a correlation between higher risk according to this test, and higher risk according to some other test?

"Patients with amnestic MCI—who have memory loss as their main symptom and are more likely to develop Alzheimer’s compared to people with non-amnestic MCI—had lower responses to the test, reports the Guardian’s Ian Sample. It can’t directly predict who will develop Alzheimer’s, but it does identify who could be at a higher risk."

It's correlated eith amnestic MCI, ehich itself correlated with higher risk of alzheimers(edit0:typo) (that's what I'm reading from the begining of the paragraph you quoted)