DIFFERENCES IN EFFICACY OF CONTINUOUS POS ITIVE PRESSURE (CPP) IN DIURNAL SOMNOLENCE OF PATIENTS SUFFERING FROM THE SLEEP-APNEA (HYPOPNEA) SYNDROME (SAHS)

Diurnal hypersomnia was studied in sixteen patients suffering from the sleep apnoea/hypopnoea syndrome (SHAS) Group I, and seventeen snorers Group II. The groups were studied in their basal state then after 51/-14 days of continuous positive pressure (CPP) in Group I with the ai d of clinical scores and of multiple latency rests of sleeping episode s (TIME). The patients in Group I presented with increased and patholo gical diurnal somnolence (TIME = 3.9+/-2.45 min) associated with distu rbances of oxygen saturation during the course of sleep (a significant reduction of the mean SaO(2)) and of the pattern of sleep (significan t reduction in light slow sleeep at the;expense of deep slow sleep, wi th a significant increase in the index of brief arousals). We have fou nd a positive correlation between the initial TIME and the mean SaO, d uring the course of sleep (p<0.05; R = 0.51) without any correlation w ith other polysomnographic parameters. At the time of the final assess ment, the improvement in TIME in the patients of Group I was significa nt (p<0.001). However, in a sub-group of patients (BR: n = 7) the TIME were returned to normal using CPP (16.4+/-2.21 min) while those in pa tients in the second sub-group (MR: n = 9) the TIME remained below ten minutes on CPP (6.18+/-1.88 min). In the BR subgroup which presented with the most elevated mean initial TIME levels the amplitude of the t he rise of TIME between the two groups was significantly larger No ini tial polysomnographic difference existed between the two sub-groups. O n the other hand, only those patients of the MR sub-group presented wi th a positive correlation between TLME and the mean SaO(2) from the in itial assessment (p<0.05; r = 0.68). The results seem to favour a role for nocturnal hypoxaemia in the severity of day-time wakening problem s during the course of SAHS in relation to a probable alteration of ce rebral function with a hypoxic origin, whose outcome was initially lit tle changed under treatment with CPP.