Dreaming Characteristics in Non-Rapid Eye Movement Parasomnia and Idiopathic Rapid Eye Movement Sleep Behaviour Disorder: Similarities and Differences

Qi Rui See,1,* Kausar Raheel,1,* Iain Duncan,1,* Nazanin Biabani,1,* Irene Di Giulio,2 Andrea Romigi,3 Veena Kumari,1,4 David O’Regan,1,2,5 Scott Cairney,6 Daniele Urso,7,8 K Ray Chaudhuri,8 Valentina Gnoni,1,7 Panagis Drakatos,1,2,5,* Ivana Rosenzweig1,5,* 1Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, U.K; 2School of Basic and Medical Biosciences, Faculty of Life Science and Medicine, King’s College London, London, U.K; 3IRCCS Neuromed Istituto Neurologico Mediterraneo Pozzilli (IS), Pozzilli, Italy; 4Centre for Cognitive Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, U.K; 5Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, U.K; 6Department of Psychology, University of York and York Biomedical Research Institute, University of York, York, U.K; 7Center for Neurodegenerative Diseases and the Aging Brain, Department of Clinical Research in Neurology, University of Bari ‘Aldo Moro’, “Pia Fondazione Cardinale G. Panico”, Tricase, Lecce, Italy; 8Movement Disorders Unit, King’s College Hospital and Department of Clinical and Basic Neurosciences, Institute of Psychiatry, Psychology & Neuroscience and Parkinson Foundation Centre of Excellence, King’s College London, London, U.K*These authors contributed equally to this workCorrespondence: Ivana Rosenzweig, Sleep and Brain Plasticity Centre, Department of Neuroimaging, Box 089, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, De Crespigny Park, London, SE5 8AF, UK, Email ivana.1.rosenzweig@kcl.ac.ukBackground: Speech graph analysis (SGA) of dreams has recently shown promise as an objective and language-invariant diagnostic tool that can aid neuropsychiatric diagnosis. Whilst the notion that dreaming mentations reflect distinct physio