[1] Queen Mary, University of London, Department of Psychiatry, Basic Med. Sci. Bldg., Mile End Rd., E1 4NS London, United Kingdom
[2] Stockholm University, 10691 Stockholm, Sweden
[3] Goteborg University, 405 30 Goteborg, Sweden
[4] The Natl. Inst. of Public Health, 3720 BA Bilthoven, Netherlands
[5] Instituto de Acustica (CSIC), 28006 Madrid, Spain