1 Sleep Medicine Center, University of Parma, Parma, Italy.
2 Neurology Unit, Parma University Hospital, Parma, Italy.
3 Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.
4 Sleep Disorders Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK.