Adriano Primadei is a music therapist from Florence, Italy who has some interesting mp3s with his on-line article detailing his work with a teenage boy named Stefano. "His diagnosis is not clear...His language is very limited, bizarre and non-communicative. He is unhealthily attached to his mother and becomes distressed when she is absent. He tends to favour relationships with mainly soft objects...He shows different types of stereotypy, such as flapping his hands and rocking, and vocal stereotypy...in the form of babbling or small obsessively repeated melodic cells."
Primadei plays guitar lying flat on a table so Stefano can join in. Stefono's haunting, otherworldly vocals can be heard here:
Adriano Primadei & Stefano: Example2