Carole Littleton was portrayed by two different actresses.
Arlene Newman-Van Asperen portrayed "coma Carole" in the
Season 3 episode "Par Avion".
Susan Duerdan portrayed Claire's mother in post-coma episodes.
I have written to both Ms. Newman-Van Asperen and Ms. Duerdan,
requesting autographs. I'll update this post if/when I receive a response.
Update! Autograph Received 8/26/2011
I received Susan Duerdan's autograph in yesterday's mail.
It is black and white, 8"x10 autographed photo,
most likely an agency photo.