4 – Clinical aspects and consequences of sleep disordered breathing 4.1 Obstructive sleep apnoea 74 Sophia E. Schiza, Izolde Bouloukaki and Athanasia Pataka 4.2 Central sleep apnoea 84 Dimitrios Papadopoulos, Bertien Buyse and Dries Testelmans 5 – Clinical assessment 5.1 Sleep history 90 Silke Ryan 5.2 Questionnaires in respiratory sleep medicine 95 Sarah Cullivan, Barry Kennedy and Brian D. Kent 5.3 Clinical examination 101 Louise Byrne, Brian D. Kent and Barry Kennedy 5.4 Comorbidities 106 Silke Ryan 5.5 Identification of high-risk patients 112 Walter T. McNicholas 6 – Monitoring sleep and wakefulness 6.1 Methods of different sleep tests 117 Renata L. Riha 6.2 Limitations of oximetry and respiratory polygraphy in 133 comparison with hospital-based PSG studies Renata L. Riha 6.3 Nocturnal capnography 136 Francesco Fanfulla 6.4 Assessment of excessive daytime sleepiness 141 Francesco Fanfulla 7 – Other diagnostic aspects of obstructive sleep apnoea and central sleep apnoea 7.1 Diagnostic algorithms based on an individualised patient 147 approach Sophia E. Schiza, Winfried Randerath and Özen K. Basoglu