Given her deafness, the auditory part of the brain, deprived of its usual input, had started to generate a spontaneous activity of its own, and this took the form of musical hallucinations, mostly musical memories from her earlier life. The brain needed to stay incessantly active, and if it was not getting its usual stimulation..., it would create its own stimulation in the form of hallucinations.
Oliver SacksMemory is dialogic and arises not only from direct experience but from the intercourse of many minds.
Oliver SacksThere is certainly a universal and unconscious propensity to impose a rhythm even when one hears a series of identical sounds at constant intervals... We tend to hear the sound of a digital clock, for example, as "tick-tock, tick-tock" - even though it is actually "tick tick, tick tick.
Oliver SacksWhen I was five, I am told, and asked what my favorite things in the world were, I answered, smoked salmon and Bach.
Oliver SacksAbout 10 percent of the hearing impaired get musical hallucinations, and about 10 percent of the visually impaired get visual hallucinations.
Oliver Sacks