[1] Karl Franzens Univ Graz, Dept Physiol, Graz, Austria
[2] Univ Hosp, Dept Paediat, Div Neonatol, Modena, Italy
[3] Univ Pisa, Inst Dev Neurol Psychiat & Educ Pyschol, I-56100 Pisa, Italy
[4] Stella Maris Fdn, Pisa, Italy
[5] Univ Groningen Hosp, Beatrix Childrens Hosp, Dept Paediat, Div Neonatol, Groningen, Netherlands