What metaphors are used in Grace Notes by Bernard MacLaverty?

The musical theory of grace notes is evident throughout the book: a metaphor of Catherine's mental wellness. Catherine's thought processes run on a repeating rhythm of depression and happiness. In between these thoughts, there are small or major memories that act as grace notes to her internal symphony. An example would be when she gives birth to Anna. The process of labor is punctuated by Catherine's memories of childhood, music and breathing. These small things are not a part of the labor, but they are a product of the process of labor.