Associations of nonrestorative sleep with insomnia, depression, and daytime function.
ABSTRACT Nonrestorative sleep (NRS) complaints are common but associations with insomnia, daytime function or depressive symptoms are not well-established. This study aims to (1) describe insomnia related symptoms and sleep quality in those with NRS compared to those with no NRS; (2) identify the independent associations between NRS, insomnia severity, and depression; and (3) identify the association between NRS and daytime function independent of insomnia severity and depression.
Cross sectional survey of enrollees at a health plan in the Midwestern United States.
Respondents were surveyed about the presence and frequency of NRS complaints, depression, insomnia severity and related symptoms. Multivariate regression was used to examine the study's three research aims.
Study sample consisted of 541 subjects with NRS and 717 who reported never experiencing any NRS symptoms.
We found a statistically significant interaction between NRS and total sleep duration such that the association between sleep duration and sleep quality was attenuated in those with NRS compared to those without NRS (b=-0.26, SE=0.07, p<0.0001). In multivariate analysis, subthreshold, moderate and severe insomnia were associated with NRS (OR [95%CI]=5.93 [4.24-8.31], 9.22 [6.15-13.83] and 6.10 [3.34-11.14], respectively). NRS was independently associated with daytime physical function, cognitive function and emotional function OR [95%CI]=2.21 [1.59-3.08], 1.90 [1.37-2.64] and 1.71 [1.23-2.36], respectively.
NRS is a complex concept that should be further defined and studied in the larger context of sleep quality, other insomnia related symptoms, daytime function and depression.
- SourceAvailable from: Kate Wilkinson[show abstract] [hide abstract]
ABSTRACT: Nonrestorative sleep (NRS) refers to the subjective experience of sleep as insufficiently refreshing, often despite the appearance of normal sleep according to traditionally assessed objective parameters. This has led researchers to pursue alternative physiological markers of nonrestorative or unrefreshing sleep, though much of this research remains controversial and inconclusive. This review summarizes the recent findings on NRS in the literature and discusses some of the issues inherent in current efforts to define and measure NRS. We offer a summary of recommended clinical approaches to NRS and discuss a new potential paradigm for the assessment of NRS-an approach modelled on current diagnosis of insomnia.Sleep Medicine 05/2012; 13(6):561-9. · 3.49 Impact Factor
Article: Maximin Adaptive Array Algorithm[show abstract] [hide abstract]
ABSTRACT: A new algorithm for adaptively steering antenna pattern nulls while maintaining a pattern maximum on a desired signal is described. The derivation is carried out by maximizing an estimate of the signal-power-to-interference-power ratio. The resulting algorithm employs double loops; one set maximizes the desired signal power and the other set minimizes the interference power. The MAXIMIN algorithm does not require detailed knowledge of the received signal. Rather, it requires only that the desired signal plus interference and noise be separated from interference and noise alone. A detailed simulation of a spread-spectrum (FH/PN) modem incorporating the MAXIMIN algorithm has been developed. The simulation incorporates all known hardware effects having a significant impact on the operation of the algorithm such as: differing group delays of critical filters, nonlinear effects in the cross-correlation multipliers, limited bit resolution in A/D and D/A converters, and mutual coupling between the array elements. Excellent performance in terms of convergence speed and final signal-to-noise ratio is obtained over a wide range of interference conditions. This approach appears to be well suited to frequency-hopping modems.01/1982;
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ABSTRACT: Objective: To examine the relationship between trajectories of cigarette smoking among a community sample of women (N=498) with insomnia in late mid-life. Methods: Participants were administered structured interviews at four time waves in adulthood, spanning approximately 25years (mean ages=40, 43, 48, and 65years). At each wave, data were collected on participants' cigarette smoking. At the most recent time wave, in late mid-life, participants reported on their insomnia (difficulty falling asleep, staying asleep, early morning wakening, and daytime consequences of these sleep problems). Results: Growth mixture modeling extracted four trajectory groups of cigarette smoking (from mean ages 40-65years): chronic heavy smokers, moderate smokers, late quitters, and non-smokers. Multivariate logistic regression analysis then examined the relationship between participants' probabilities of trajectory group membership and insomnia in late mid-life, with controls for age, educational level, marital status, depressive symptoms, body mass index, and the number of health conditions. Compared with the non-smokers group, members of the chronic heavy smoking trajectory group were more likely to report insomnia at mean age 65 (Adjusted Odds Ratio=2.76; 95% confidence interval=1.10-6.92; p<0.05). Conclusions: Smoking cessation programs and clinicians treating female patients in mid-life should be aware that chronic heavy smoking in adulthood is a significant risk factor for insomnia.Sleep Medicine 08/2012; 13(9):1130-7. · 3.49 Impact Factor
Joseph A Johnston