Differences in efficiency of continuous positive pressure respiration on the diurnal somnolence of patients with sleep apnea/hypoapnea syndrome]

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 aid of clinical scores and of multiple latency tests of sleeping episodes (TLME). The patients in Group I presented with increased and pathological diurnal somnolence (TLME = 3.9 +/- 2.45 min) associated with disturbances of oxygen saturation during the course of sleep (a significant reduction of the mean SaO2) and of the pattern of sleep (significant reduction in light slow sleep at the expense of deep slow sleep, with a significant increase in the index of brief arousals). We have found a positive correlation between the initial TLME and the mean SaO2 during the course of sleep (p < 0.05; R = 0.51) without any correlation with other polysomnographic parameters. At the time of the final assessment, the improvement in TLME in the patients of Group I was significant (p < 0.001). However, in a sub-group of patients (BR: n = 7) the TLME were returned to normal using CPP (16.4 +/- 2.21 min) while those in patients in the second sub-group (MR: n = 9) the TLME remained below ten minutes on CPP (6.18 +/- 1.88 min). In the BR subgroup which presented with the most elevated mean initial TLME levels the amplitude of the rise of TLME between the two groups was significantly larger. No initial polysomnographic difference existed between the two sub-groups.(ABSTRACT TRUNCATED AT 250 WORDS)