Hi Tutor

It's very encouraging to have you on here looking for advice  like this; you obviously take the well being of your student very seriously.

My understanding would be that the mental capacity of your student would only be affected by any strokes that she might have suffered. The moyamoya itself wouldn't diminish the persons mental capacity, but depending on the stroke, it's possible to have some issues. You'll have to assess your student as an individual and not try to apply any rules because each person is affected differently.

Take care
Mark (Luca's Dad)

Welcome! I admire the dedication you have to your student. As a parent of a young lady(she's 13) with some significant dissabilities I know that not everyone  shares your dedication.
  My daughter was born with Down syndrome and was also diagnosed with moyamoya. She started life  with some mental and physical delays. She suffered several strokes. The strokes are what we feel has caused her most significant delays physically and accademically. She has an IEP (individualised education plan) at school and a 1-1 teaching assistant. Her IEP has her physical and academic goals, her personal needs, and what modifications she needs to be successful. Does the young lady your working with attend school? Is she diagnosed with specific delays? ie. speech,memory, attention difficulties or other physcial dissabilities. How old is the young lady? Does she attend school? If so you could check her IEP. If you have some more specific questions I may be able to offer more help. Feel free to e-mail me personally if you'de rather.
Mary Grace
mgrace5@nycap.rr.com