[1] Univ Utrecht, Fac Social & Behav Sci, Utrecht, Netherlands
[2] Univ Med Ctr Utrecht, Utrecht Univ, Wilhelmina Childrens Hosp, Dept Pediat, Utrecht, Netherlands
[3] Univ Med Ctr Utrecht, Utrecht Univ, Wilhelmina Childrens Hosp, Dept Pediat Pulmonol, Utrecht, Netherlands
[4] Univ Med Ctr Utrecht, Dept Anesthesiol, Utrecht, Netherlands
[5] Univ Zurich, Dept Psychol, Zurich, Switzerland
[6] Martinus J Langeveldgebouw, Room H1-15,POB 80-140, NL-3584 TC Utrecht, Netherlands