Characteristics of apneas and hypopneas during sleep and relation to excessive daytime sleepiness

STUDY OBJECTIVES: One of the most important symptoms in patients evaluated for possible obstructive sleep apnea syndrome is excessive daytime sleepiness, but the measures of apnea severity and of sleepiness used most commonly have not generally shown strong associations. We explored whether information recorded during standard polysomnography, other than the overall rate of apneas and hypopneas per hour of sleep (AHI), might help explain the measured severity of sleepiness. DESIGN: Observational SETTING: A clinical sleep laboratory in a university hospital PATIENTS: N = 1,146 patients evaluated for suspected sleep-disordered breathing with nocturnal polysomnograms and multiple sleep latency tests. RESULTS: The AHI during supine sleep (recorded in a subgroup of n = 169 subjects), the rate of apneas (n = 1,146), and the rate of obstructive apneas (n = 1,146) were particularly useful in explaining variation in measured levels sleepiness; rates of hypopneas and central apneas were less useful (n = 1,146). In addition, the minimum recorded oxygen saturation (n = 1,097) was as important as the AHI to the level of sleepiness. CONCLUSIONS: In an attempt to explain excessive daytime sleepiness among patients evaluated for sleep-disordered breathing, additional insight is provided by observation of supine sleep during polysomnography, by emphasis on apneas rather than hypopneas, by emphasis on obstructive rather than central events, and by consideration of the minimum oxygen saturation.     

Elevation of plasma cytokines in disorders of excessive daytime sleepiness: role of sleep disturbance and obesity

Excessive daytime sleepiness (EDS) and fatigue are frequent symptoms in the general population and the chief complaint of the majority of patients at Sleep Disorders Centers. There is evidence that the inflammatory cytokines tumor necrosis factor-alpha (TNF alpha), interleukin-1beta (IL-1beta), and IL-6 are involved in physiological sleep regulation and that their administration to humans is associated with sleepiness and fatigue. To explore whether plasma levels of TNF alpha, IL-1beta, and IL-6 are elevated in patients with EDS, we measured morning plasma levels of TNF alpha, IL-1beta, and IL-6 in 12 sleep apneics, 11 narcoleptics, 8 idiopathic hypersomniacs, and 10 normal controls. TNF alpha was significantly elevated in sleep apneics and narcoleptics compared to that in normal controls (P < 0.001 and P = 0.001, respectively). Plasma IL-1beta concentrations were not different between sleep disorder patients and controls, whereas IL-6 was markedly and significantly elevated in sleep apneics compared to that in normal controls (P = 0.028). The primary factor influencing TNF alpha values was the degree of nocturnal sleep disturbance, whereas the primary determinant for IL-6 levels was the body mass index. Our findings suggest that TNF alpha and IL-6 might play a significant role in mediating sleepiness and fatigue in disorders of EDS in humans.     

Prevalence of daytime sleepiness in a population of drivers

Adult Ixodes ricinus (Acari: Ixodidae) ticks collected near Ljubljana, Slovenia, were tested for the agent of human granulocytic ehrlichiosis (HGE) by using PCR assays based on the 16S rRNA gene. Three (3.2%) of 93 ticks were found to contain granulocytic ehrlichiae. Nucleotide sequences of portions of the bacterial groESL heat shock operon amplified from these ticks were identical or nearly (99.8%) identical to those previously determined for human patients with HGE from Slovenia, providing additional evidence that the ticks were infected with the HGE agent. This study identified I. ricinus as the likely vector for these ehrlichial pathogens of humans in this part of Europe.     

Child sleep disorders: Associations with parental sleep duration and daytime sleepiness.

This study examined the associations between childhood sleep disorders and mothers' and fathers' sleep duration and daytime sleepiness. One hundred seven families of children (ages 2-12 years) presenting to a pediatric sleep disorders clinic completed questionnaires assessing the sleep symptoms of the mother, father, and child. Parents of children with more than 1 type of sleep disorder experienced more daytime sleepiness than parents of children with a single sleep disorder. The pattern of results suggested more associations between maternal and child sleep than between paternal and child sleep. Within families, mothers reported significantly more daytime sleepiness than fathers, although there were no parental differences in sleep duration. Results provide preliminary evidence for an association between child sleep problems and parental daytime sleepiness, which may, in turn, extend previous research linking young children's sleep problems and parental functioning. Implications for treatment of both children and adults with sleep problems are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of long-term therapy of obstructive sleep apnea syndrome with CPAP for symptoms of daytime sleepiness

The study was undertaken to investigate whether a long-term CPAP therapy improves the symptoms of daytime sleepiness in patients with the obstructive sleep apnoea syndrome. Seventy six patients (72 men and 4 women) with AHI = 53(+/- SE = 3), BMI 35 (+/- SE = 0.8), mean age 46.3 (+/- SE = 11.4) have undergone CPAP therapy for at least one year (mean: 2.48 +/- SE = 0.33). The aggravation of alterations of the daytime sleepiness was estimated using the questionnaire from Sleep Laboratory at the Marburg University and the Epworth Sleepiness Scale (ESS). After the CPAP therapy, we have observed the decrease of the symptoms of the excessive daytime sleepiness (p < 0.001). Negative correlation between CPAP compliance and ESS outcome was observed (r = 0.4; p < 0.001). There was not correlation between the term of using CPAP and the degree of the complaints decrease.     

A quantitative study of daytime sleepiness induced by carbamazepine and add-on vigabatrin in epileptic patients

Improvement in natural erections has been reported in approximately 9% of impotent men using intracavernous injections of vasoactive drugs for erection induction. The mechanisms which may account for this improvement are psychogenic, improved cavernous hemodynamics, prostaglandin-induced angiogenesis, improved cavernous oxygenation, cavernous smooth muscle hypertrophy and/or normal episodic fluctuations in erectile function. A review of the basic science literature on this subject reveals several theoretical explanations for this phenomenon but a review of the clinical literature reveals little convincing evidence that physiologic and/or pharmacologic factors are responsible for improvement in natural erections with intracavernous injection therapy. Furthermore, the prevalence of a placebo effect from impotence therapy exceeds the reported rate of improvement in natural or spontaneous erections. The most plausible explanations for spontaneous improvement in erections during or after intracavernous injection therapy are psychogenic and episodic variations in erectile function, rather than physiologic or pharmacologic factors. However, intracavernous injection therapy started soon after radical prostatectomy may have a protective effect in preserving normal cavernous physiology and erectile function in men being treated for prostate cancer.     

Secondary prevention of excessive alcohol use: assessing the prospects of implementation

BACKGROUND: Alcohol risk and harm reduction is a public health approach that goes beyond specialized treatments for alcoholism. The greatest potential for reducing alcohol risk and harm in a population depends on the extent to which health care practitioners use secondary prevention programmes. OBJECTIVE: We aim to assess the factors that affect the prospects of disseminating comprehensive, secondary prevention programmes into mainstream practice. METHOD: A decision balance was used to assess the prospects of practitioners implementing comprehensive programmes systematically. The stages-of-change model provides perspectives about behaviour change with regard to patients, practitioners and practice settings. RESULTS AND CONCLUSIONS: Programme implementation is extremely unlikely given the current organization of health care settings. To maintain the use of such programmes, we need to change the "unit of leverage" in the system: from the clinical encounter--that is, practitioners working with individual patients in a case-finding manner--to an organizational level--that is, the appropriate use of managerial and information systems supporting health care settings to identify at-risk patients systematically as they enter primary care and hospital settings. With appropriate infrastructure support, practitioners will be able to fulfil the potential for as well as maintain the use of comprehensive, secondary prevention programmes to reduce alcohol risk and harm in the population.     

The normal curve and the attenuation paradox in test theory.

The attenuation paradox (lack of a monotonic relationship between reliability and validity) becomes more meaningful if the usual assumption of a normal continuous distribution in the criteria variable is dropped. On the basis of present day tests these assumptions are highly questionable. The author concludes that "there is no paradox if the criterion distributions can assume any shape." A sequence of issues to be considered in the construction of tests is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased prevalence of sleep disturbances and daytime sleepiness in subjects with bronchial asthma: a population study of young adults in three European countries

The aim of this study was to investigate whether asthma is associated with decreased quality of sleep and increased daytime sleepiness. The study involved a random population of 2,202 subjects supplemented by 459 subjects with suspected asthma, aged 20-45 yrs. The subjects were from Reykjavik (Iceland), Uppsala and G?teborg (Sweden) and Antwerp (Belgium), and participated in the European Community Respiratory Health Survey. The investigation included a structured interview, methacholine challenge, skinprick tests and a questionnaire on sleep disturbances. Participants in Iceland and Sweden also estimated their sleep times and made peak expiratory flow (PEF) recordings during a period of 1 week. Asthma was defined as self-reported physician-diagnosed asthma with current asthma-related symptoms (n = 267). Difficulties inducing sleep (DIS) and early morning awakenings (EMA) were about twice as common, and daytime sleepiness 50% more common, in asthmatics compared with subjects without asthma. After adjusting for possible confounders, a positive association was found between asthma and: DIS (odds ratio (OR) = 1.8); EMA (OR = 2.0); daytime sleepiness (OR = 1.6); snoring (OR = 1.7); and self reported apnoeas (OR = 3.7). Allergic rhinitis, which was reported by 71% of subjects with asthma, was independently related to DIS (OR = 2.0) and daytime sleepiness (OR = 1.3). A significant correlation was found between the number of asthma-related symptoms and sleep disturbances (p < 0.001). Asthma is associated with decreased subjective quality of sleep and increased daytime sleepiness. Concurrent allergic rhinitis may be an important underlying cause of sleep impairment in asthmatic patients.     

A test object for assessing image quality in mammography

The problems inherent in the design and manufacture of mammographic test objects are discussed and a test object is described which may be used for assessing image quality. Some typical results from both good and bad mammographic machine/film combinations are presented.     

Some perspectives on "the attenuation paradox in test theory."

Clarification is given of the "paradox" posed by Loevinger (see 29: 3299), i.e., "validity" (the product-moment r of test score with the common factor of test items) decreases upon the increase beyond a certain point of item intercorrelations in a test whose items are of equal difficulty. Four points are made: (1) the "region of paradox" is reduced using a curvilinear r rather than the usual product-moment "validity"; (2) the paradox's incidence in aptitude and achievement tests is not as great as is frequently believed; (3) over-all "validity" for a group is inferior to the test's discriminating power for a specified decision problem for a specific examinee; and (4) the conception that "… for optimum results the percentage of correct answers to each item should equal the percentage of examinees to be selected" is correct only if the latter percentage is 50. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interpretive algorithms for the symptom-limited exercise test: assessing dyspnea in Persian Gulf war veterans

The mechanisms by which respiratory syncytial virus (RSV) infection induces bronchiolitis and airway disease are unclear. The presence of large numbers of polymorphonuclear leukocytes (PMN) in the airways of infants with RSV infection suggests a potential role of PMN in airway injury associated with RSV infection. To investigate the potential role of neutrophils in RSV bronchiolitis, human alveolar type II cells (A549 cells) were infected with different doses of RSV for 6-48 h. A 51Cr-releasing assay was used to measure PMN-induced damage and image analysis was used to determine PMN adhesion and detachment of epithelial cells. The results showed that RSV infection of epithelial cells enhanced PMN adherence in a dose- and time-dependent pattern, RSV infection alone could damage and detach epithelial cells to a limited extent and PMN significantly augmented RSV infection-induced damage and detachment of epithelial cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances neutrophil adhesion to the epithelium and that activated neutrophils augment the damage and detachment of epithelium infected with the virus. Polymorphonuclear leukocytes may contribute to the pathogenesis of respiratory syncytial virus airway disease by inducing epithelial damage and cell loss.