Do idiot savants have bigger brains than normal humans or not?

Question

Do idiot savants have bigger brains than normal humans or not?

Answer 1

No.  A savant may be extremely proficient in one cognitive area because of a deficit in another area, but his brain's size will not tend to be skewed from the norm.

Answer 2

No.

"Savant-ism" is often due to autism, or sometimes, to brain injury.

Or, it might be unrelated to anything at all; for example, there's a woman who can remember every single detail of every day of her life from the age of 8 onward-- but other than that, she's totally normal.