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.
There are, of course, inherent tendencies to repetition in music itself. Our poetry, our ballads, our songs are full of repetition; nursery rhymes and the little chants and songs we use to teach young children have choruses and refrains. We are attracted to repetition, even as adults; we want the stimulus and the reward again and again, and in music we get it. Perhaps, therefore, we should not be surprised, should not complain if the balance sometimes shifts too far and our musical sensitivity becomes a vulnerability.
But the saddest difference between them was that Zazetsky, as Luria said, 'fought to regain his lost faculties with the indomitable tenacity of the damned,' whereas Dr P. was not fighting, did not know what was lost. But who was more tragic, or who was more damned -- the man who knew it, or the man who did not?