Hearing is basically a specialized form of touch. Sound is simply vibrating air which the ear picks up and converts to electrical signals, which are then interpreted by the brain.
Read more from Evelyn Glennie.
Evelyn managed to distinguish the rough pitch of notes by associating where on her body she felt the sound with the sense of perfect pitch she had before losing her hearing. The low sounds she feels mainly in her legs and feet and high sounds might be particular places on her face, neck and chest.