Kari is a fan of heavy metal music. her mother is concerned because she knows that prolonged exposure to ear-splitting music can cause:

Prolonged exposure to loud music can induce hearing loss. In the ear, there are hair cells that move in response to fluid movement caused by vibrations transmitted by sound. These hairs strike microscopic hair-like projections in the ear, causing channels to open and creating a pathway for electrical signals to transmit to the brain. This allows us to perceive sound. When these hairs are broken, we lose our sense of hearing. Prolonged exposure to loud music (and other loud sounds!) can cause these hairs to break, therefore inducing hearing loss.