therapy delivered via a nasal mask was a crucial development in the history of sleep-related breathing disorders, providing a highly effective but noninvasive modality of treatment for OSAS that revolutionised the whole field of sleep medicine. CPAP is now the mainstay of therapy, particularly in moderate and severe cases of OSAS. The high prevalence of OSAS has focused attention on simplified approaches to diagnosis, and there is an increasing trend towards diagnosis and therapy in the ambulatory setting. Although polysomnography remains the gold standard for diagnosis, such studies are resource-intensive since they generally require the facilities of a full sleep laboratory and a trained technician. Thus polysomnography is impractical in many sleep centres for routine assessment in the majority of patients with typical clinical presentations of OSAS. An increasing number of limited diagnostic systems are available to meet the high clinical demand, and ongoing research is directed at identifying novel signals in order to simplify and improve the diagnosis of OSAS in the home setting. Statement of Interest None declared. References 1. McNicholas WT. Ed. Respiratory disorders during Sleep. Eur Respir Mon 1998 10: 1–340. 2. Kiely JL, McNicholas WT. Overview and historical perspectives of sleep apnoea syndrome. Eur Respir Mon 1998 3: 1–8. 3. Broadbent WH. Cheyne–Stokes respiration in cerebral haemorrhage. Lancet 1877 1: 307–399. 4. Berger H. Ueber das Elektroenkephalogramm des Menschen. [Regarding the electroencephalogram in humans.] J Psychol Neurol 1930 40: 160–179. 5. Aserinsky E, Kleitman N. Regularly occurring periods of eye motility and concomitant phenomena during sleep. Science 1953 118: 273–274. 6. Jouvet M, Michel M, Courjon J. Sur un etude ´ d’activite ´ electrique cerebral ´ rapide au cours du sommeil physiologique. [On a stage of rapid cerebral electrical activity in the course of physiological sleep.] C R Seances Soc Biol Fil 1959 153: 1024–1028. 7. Gastaut H, Tassinari C, Duron B. Etude ´ polygraphique des manifestations episodiques (hypniques et respiratoires) du syndrome de Pickwick. [Polygraphic study of diurnal and nocturnal (hypnic and respiratory) episodal manifestations of Pickwick syndrome.] Rev Neurol (Paris) 1965 112: 568–579. 8. McNicholas WT, Bonsignore MR. Sleep apnoea as an independent risk factor for cardiovascular disease: current evidence, basic mechanisms and research priorities. Eur Respir J 2007 29: 156–178. 9. McNicholas WT. Sleep apnoea and driving risk. European Respiratory Society Task Force on ‘‘Public Health and Medicolegal Implications of Sleep Apnoea’’. Eur Respir J 1999 13: 1225–1227. 10. Ye L, Pien GW, Weaver TE. Gender differences in the clinical manifestation of obstructive sleep apnea. Sleep Med 2009 10: 1075–1084. 11. Bonsignore MR, McNicholas WT. Sleep-disordered breathing in the elderly. Eur Respir Mon 2009 43: 179–204. 12. Lugaresi E, Coccagna G, Mantovani M, et al. Effects de la tracheotomie ´ dans les hypersomnies avec respiration periodique. [Effects of tracheotomy in hypersomnia with periodic respiration.] Rev Neurol (Paris) 1970 123: 267–268. 13. Fujita S, Conway W, Zorick F, et al. Surgical correction of anatomic abnormalities in obstructive sleep apnea syndrome: uvulopalatopharyngoplasty. Otolaryngol Head Neck Surg 1981 89: 923–934. 14. Sullivan CE, Issa FG, Berthon-Jones M, et al. Reversal of obstructive sleep apnoea by continuous positive airway pressure applied through the nares. Lancet 1981 1: 862–865. ix W.T. MCNICHOLAS AND M.R. BONSIGNORE