80s children's science fiction

I believe the setting is in Utah. The main characters are two older children about 12 I believe and one young boy, none of which are siblings. I only remember smatterings of the plot. I believe there was some type of alien encounter had by the youngest boy's mother while she was pregnant. Now the youngest child is mute but can communicate using mental pictures or colors. I believe the word "lights" was in the title, and the cover may have had children on a carnival ride. I also think one of the main scenes in the book takes place at a carnival. The older children need the younger child to lead them somewhere or to do something. I would have read this some time in the 1980s. Any help would be great.

This is Into the Dream by William Sleator.

Looking for a book I read years ago. A woman who's a scholar... no personal life.. afraid of relationship. . Meets her long lost friend who's an aspiring writer. She invites our lead role to her home. This friend s family consists of husband and two children. When the friend gets a new writing job, she asks our lead role to come help with her family. She does cooking, gardening.. bonds with the family well.. helps with the girl child to lose weight.. husband falls in love with our lead.. friend knows about all this.. lead role goes back to her old life.. she falls jn love with an acquaintance she met from a country side or so.. friend calls her and asks her details of her new love... this is all I remember

Thank you so much! That's it!

>3 itspalluhere: you will probably do better if you start a new thread with in informative title - the top of page http://www.librarything.com/groups/namethatbook gives good hints