Jumping the Scratch by Sarah Weeks 167 p.

Jamie and his mother have had to move to Wondrous Acres trailer park to care for his aunt. She is suffering from amnesia after a head injury at work. Jamie tries hard to "jump the scratch" on the record that is his Aunt Sapphy's memory, with sensory clues that might help her remember. Jamie, too, has an unhappy, deeply buried memory of being sexually abused; it keeps him wary and unable to concentrate or make friends at school. When Jamie has a nightmare, his aunt's memory returns, and together, they help each other remember and recover.