Polysomnography

About: Polysomnography is a research topic. Over the lifetime, 19527 publications have been published within this topic receiving 858718 citations. The topic is also known as: PSG & polysomnogram.

Fibrinogen levels and obstructive sleep apnea in ischemic stroke.

Abstract: The plasma level of fibrinogen is felt to be an independent risk factor for vascular events. Obstructive sleep apnea (OSA) has a high prevalence in patients with stroke and may also be an independent risk factor. The aim of our study was to determine the association between OSA and plasma levels of fibrinogen in patients with stroke. Polysomnography was performed during neurological rehabilitation in 113 patients (82 men, 31 women, age 58 +/- 11.1 yr, mean +/- SD) with ischemic stroke. OSA was absent (RDI or = 20). Parameters of OSA (respiratory disturbance index [RDI], oxygen indices) were correlated to plasma levels of fibrinogen, measured in the morning after admission to rehabilitation. Fibrinogen was positively correlated with RDI (r = 0.24, p = 0.007), duration of the longest apnea (r = 0.18, p = 0.049), and negatively correlated with several oxygen indices including average minimal oxygen saturation (r = -0.41, p < 0.001). Correlation coefficients were slightly higher when excluding patients with stroke of presumed cardiac origin. Multiple linear regression identified minimal mean oxygen saturation and sex as independent predictors of fibrinogen level. The correlation between severity of coexisting OSA and fibrinogen level in patients with stroke suggests a possible pathophysiological mechanism for an increased risk of stroke in patients with OSA.

Subjective and objective sleep quality and aging in the sleep heart health study

Abstract: OBJECTIVES: To examine the extent to which subjective and objective sleep quality are related to age independent of chronic health conditions. DESIGN: Cross-sectional study. SETTING: The Sleep Heart Health Study (SHHS) is a multicenter study designed to determine the cardiovascular consequences and the natural history of sleep disordered breathing. PARTICIPANTS: Five thousand four hundred seven community-dwelling adults who participated in the SHHS (mean age 63, range 45–99; 52% women). MEASUREMENTS: Unattended home polysomnography (PSG) and sleep questionnaires. RESULTS: Older age was associated with shorter sleep time, diminished sleep efficiency, and more arousals in men and women. In men, age was independently associated with more Stage 1 and Stage 2 sleep and less slow-wave (Stage 3 to 4) and rapid eye movement sleep. In women, older age was less strongly associated according to linear trend with sleep stage. Conversely, poor subjective sleep quality was not associated with older age in men, but older women had more trouble falling asleep, and there was a trend toward older women having more problems with waking up during the night and waking up too early. Associations between self-report and directly measured sleep time and sleep latency were low to moderate across age groups (correlation coefficient=0.06–0.32). CONCLUSION: Older age was more strongly associated with poorer sleep according to PSG in men than women, yet the subjective report of poor sleep with older age was stronger in women. The higher prevalence of chronic health conditions, including sleep apnea, in older adults did not explain changes of sleep parameters with aging and age–sex differences in these relationships.

Partial sleep deprivation reduces natural killer cell activity in humans.

Abstract: Sleep disturbance, measured by either subjective report or electroencephalographic (EEG) assessment of sleep, correlates with a reduction of natural killer (NK) cell activity in major depression. To test whether sleep loss independent of mood disturbance alters daytime values of cellular immune function, the effect of late-night partial sleep deprivation on NK cell activity was studied in 23 medically and psychiatrically healthy male volunteers. After a night of sleep deprivation between 3 and 7 AM, NK cell activity was reduced in 18 of the 23 subjects with average lytic activity reduced significantly (p < .01) to a level 72% of the mean of three separate baseline values. After a night of resumed nocturnal sleep, NK cell activity had returned to baseline levels. These data implicate sleep in the modulation of natural immunity and demonstrate that even modest disturbances of sleep produce a reduction of NK cell activity.

The effect of sleep fragmentation on daytime function.

Abstract: It is clear from this literature that fragmented sleep is less restorative than consolidated sleep, and leads to sleepiness-related daytime impairment. The optimal approach to the quantification of sleep fragmentation continues to be debated. Modest and erratic correlations between measures of sleepiness and traditional measures of EEG arousals have pushed investigators to try and find more sensitive measures of sleep fragmentation. Simply correlating various measures of sleep fragmentation with a measure of sleepiness has significant limitations. Since sleep fragmentation is not the only factor affecting daytime sleepiness, these correlations can be misleading. For example, a subject with severely fragmented sleep will show elevated sleepiness during the day. However, the overall correlation may be reduced because lack of fragmented sleep does not guarantee that the level of sleepiness will be low. Multivariate statistical modeling is needed to account for sources of variance simultaneously in the prediction of daytime sleepiness. In this way it may be possible to identify the optimal definition of sleep fragmentation. More studies are needed that evaluate "sub-cortical" arousals, EEG arousals, and daytime function simultaneously. Ideally, clarification of these measurement issues will lead to an improved understanding of sleep structure and the mechanism through which sleep fragmentation impacts daytime function.