It seems that the brain always has to be active, and if the auditory parts of the brain are not getting sufficient input, then they may start to create hallucinatory sounds on their own. Although it is curious that they do not usually create noises or voices; they create music.
Oliver SacksMusic can lift us out of depression or move us to tears - it is a remedy, a tonic, orange juice for the ear. But for many of my neurological patients, music is even more - it can provide access, even when no medication can, to movement, to speech, to life. For them, music is not a luxury, but a necessity.
Oliver Sacks