It sounds like people simply have different definitions of "a picture in her head." Her mental processing sounds entirely normal on all counts.
I guess I must have the condition. I closed my eyes and tried to see a red apple, which the article uses as the diagnostic test. Nope, all I saw was black. Could I think of what a red apple looks like? Of course. If the test is to actually, truly see an apple while your eyes are closed, my guess is everyone would fail.
I suspect the 3.9% estimation is wildly inaccurate but that the condition / spectrum is true.
In the 1-5 guide, I'd probabably rate myself a 99 or something silly. I feel like the equipment is capable of visualising, but I just don't know how to operate it.
However, I do have involuntary visualizations. My dreams are images, very unlike thought. And in the last 5 or so years I can recall 2 occasions where I was in a relaxed state and pictured things without really trying, so I know it's possible to have dream like images when awake.
My wife says she can just perfect recall stuff. I entirly believe she can visualise, but I believe she confuses what happened with what she can see. She also states she can visualise the apple, or pretty much anything else she wants.
I guess I must have the condition. I closed my eyes and tried to see a red apple, which the article uses as the diagnostic test. Nope, all I saw was black. Could I think of what a red apple looks like? Of course. If the test is to actually, truly see an apple while your eyes are closed, my guess is everyone would fail.