Possessed?

Greetings, I am a newcomer to the music of Zorn. Recently I purchased a copy of his 'Big Gundown' album. The music was fantastic, but a section in the liner notes caught my eye: "Other Downtown musicians (on the album) include...possessed vocalist Diamanda Galas..." Possessed? Can anyone tell me by what or whom this woman claims to be inhabited by, or if I have misinterpreted the whole thing and just made a complete dick of myself. Thanks John _________________________________________________________________ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus