[1] CNR, Inst Clin Physiol, Pisa, Italy
[2] Guys & St Thomas NHS Fdn Trust, Lane Fox Resp Unit, Sleep Disorders Ctr, London, England
[3] Univ Padua, Dept Med DIMED, Padua, Italy
[4] Univ Pisa, Pisa, Italy
[5] Kings Coll London, Inst Psychiat, Dept Clin Neurosci, London, England