WASHINGTON (AP) – A mysterious brain disorder can be confused with early Alzheimer’s disease. It isn’t robbing patients of their memories, but rather their ability to talk about them.

It’s called primary progressive aphasia, and researchers said Sunday they’re finding better ways to diagnose the rare syndrome so that people whose thoughts are lucid but who are verbally locked in get the right kind of care.

One patient communicates using a phone-sized speech device, playing the recorded message: “I have trouble speaking but I can understand you.”

Researchers say special brain scans can identify the degenerative disorder, and a study is underway to see if brain-stimulating technology might help treat it.

The work was presented at a meeting of the American Association for the Advancement of Science.