Objective and Subjective Components of the First-Night Effect in Young Nightmare Sufferers and Healthy Participants

The first-night effect—marked differences between the first- and the second-night sleep spent in a laboratory—is a widely known phenomenon that accounts for the common practice of excluding the first-night sleep from any polysomnographic analysis. The extent to which the first-night effect is present in a participant, as well as its duration (1 or more nights), might have diagnostic value and should account for different protocols used for distinct patient groups. This study investigated the first-night effect on nightmare sufferers (NM; N D 12) and healthy controls .N D 15/ using both objective (2-night-long polysomnography) and subjective (Groningen Sleep Quality Scale for the 2 nights spent in the laboratory and 1 regular night spent at home) methods. Differences were found in both the objective (sleep efficiency, wakefulness after sleep onset, sleep latency, Stage-1 duration, Stage-2 duration, slow-wave sleep duration, and REM duration) and subjective (self-rating) variables between the 2 nights and the 2 groups, with a more pronounced first-night effect in the case of the NM group. Furthermore, subjective sleep quality was strongly related to polysomnographic variables and did not differ among 1 regular night spent at home and the second night spent in the laboratory. The importance of these results is discussed from a diagnostic point of view

Gender differences on polysomnographic findings in Greek subjects with obstructive sleep apnea syndrome

Background and purpose: Studies from North American clinics have reported that females with obstructive sleep apnea syndrome (OSAS) are about the same age as males but are heavier, have less severe apnea and make up a much smaller proportion of cases. We examined polysomnographic differences between Greek men and women with OSAS in order to study the influence of gender on clinical presentation and laboratory findings. Patients and methods: This retrospective study included a cohort of 1010 Greek patients (844 males, 166 females) diagnosed with OSAS by overnight polysomnography (PSG), who were referred to the Sleep Disorders Center of Evangelismos Hospital, Athens Medical School, University of Athens. All patients were studied over a period of three consecutive years, during which time clinical and polysomnography (PSG) findings were compared. Results: Body mass index (BMI) was similar in men and women with OSAS (BMI=31.6 +/- 5.5 kg/m(2) in men versus BMI=32.5 +/- 8.1 (SD) kg/m(2) in women). Female patients were significantly older than male patients (56.9 +/- 10.6 versus 50.6 +/- 11.7 year, P=0.001). The mean apnea-hypopnea index (AHI) during total sleep time was higher in men than in women (42.4 +/- 28.2 versus 33.2 +/- 27.7 events/h, P < 0.001). The AHI in non-rapid eye movement (NREM) sleep was higher in men than in women (42.9 +/- 28.9 versus 32.6 +/- 28.7 events/h, P < 0.001), but in rapid eye movement (REM) sleep AHI was similar in men and women (36.0 +/- 23.3 versus 34.9 +/- 25.4 events/h). Forty percent of men had AHI-REM sleep > AHI-NREM compared to 62% of women, and the difference between REM and NREM-AHI was significantly less in men than in women (14.21 +/- 11.18 versus 19.76 +/- 13.43 events/h, P < 0.001)). Several aspects of sleep were worse in women versus men: sleep efficiency index was lower (79.4 +/- 16.1% versus 85.1 +/- 12.5%, P < 0.001); sleep onset latency (27.7 +/- 27.7 versus 17.9 +/- 18.1 min, P < 0.001), and REM onset latency (161.5 +/- 76.2 versus 145.7 +/- 71.4 min, P < 0.018) were longer; wake time after sleep onset (WASO) was also greater in women (42.6 +/- 46.5 versus 30.7 +/- 34.9 min, P < 0.003). Conclusions: In Greek subjects with OSAS, there was no difference in BMI, and female patients were significantly older than male patients. OSAS was diagnosed in men five times more often than in women. AHI was greater in men than in women, but women are more likely than men to have a higher AHI in REM than NREM. Sleep quality is worse in female than in male patients. (c) 2006 Elsevier B.V. All rights reserved