Associations of nonrestorative sleep with insomnia, depression, and daytime function.

Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
Sleep Medicine (Impact Factor: 3.49). 12/2010; 11(10):965-72. DOI: 10.1016/j.sleep.2010.08.007
Source: PubMed

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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Nonrestorative sleep (NRS) is defined as the subjective feeling that sleep has been insufficiently refreshing, often despite the appearance of physiologically normal sleep. While NRS has been shown to be associated with a variety of cognitive, affective, and medical complaints, there is currently no valid, reliable instrument available in the public domain for its assessment. The purpose of this study was to develop and validate the Nonrestorative Sleep Scale (NRSS). The scale was administered to a sample of 226 (age: 46.7 ± 14.9 years; gender: 48% female) consecutive sleep clinic patients and to 30 control participants (age: 36.9 ± 12.5; gender: 53% female). Data screening led to a final instrument of 12 items, and factor analysis resulted in 4 factors accounting for 73.2% of total variance. The scale demonstrated excellent internal reliability (α = 0.88) and good test-retest reliability (r = 0.72). Preliminary evaluations of construct validity found that certain subscales correlated reasonably well with previously validated sleep, alertness, and affective scales. Comparisons between global NRSS scores and objective polysomnographic variables revealed a few very small but significant correlations. Based on these findings, the NRSS was confirmed to be a valid and reliable tool for the assessment of nonrestorative sleep. Wilkinson K; Shapiro C. Development and validation of the Nonrestorative Sleep Scale (NRSS). J Clin Sleep Med 2013;9(9):929-937.
    Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 09/2013; 9(9):929-37. · 2.93 Impact Factor
  • [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.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sleep disorders (somnipathies) are conditions characterized by disruptions of sleep quality or of sleep pattern. They can involve difficulty falling asleep (prolonged sleep onset latency), difficulty staying asleep (disturbance of sleep maintenance), sleep of poor quality (unrefreshing), or combinations of these and can lead to poor health and quality of life problems. A subtype of sleep-maintenance insomnia is middle-of-the-night wakefulness, a relatively common occurrence. Zolpidem, a nonbenzodiazepine benzodiazepine receptor agonist, allosterically modulates an ion channel and increases the influx of Cl(-), thereby dampening the effect of excitatory (sleep disrupting) input. Recently, product label changes to some zolpidem containing products have been implemented by the FDA in order to reduce the risk associated with their morning after residual side effects. A new formulation of zolpidem tartrate (Intermezzo) sublingual tablet, an approved product indicated exclusively for the treatment of middle-of-the-night wakefulness and difficulty returning to sleep, did not have its label changed. We present a short summary of its basic science and clinical attributes in light of the recent regulatory changes for zolpidem products.
    Sleep disorders. 01/2014; 2014:527109.