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NAPS 2012-04-14

Posted by admin on April 14, 2012

  New Articles and Papers in Sleep for Apr 14 2012.

  Contents:
      Books / Reviews
      Physiology / Pharmacology
      Development / Aging / Evolution
      Dreaming / Behavior
      Biological Rhythms
      Sleep Deprivation
      Sleep Apnea / COPD / Snoring
      Other Disorders
      Methodology / Miscellaneous

Books / Reviews
Behr M, Hahnel S, Faltermeier A, Bürgers R, Kolbeck C, Handel G and Proff P (2012), "The two main theories on dental bruxism.", Ann Anat., Mar, 2012. Vol. 194(2), pp. 216-219.
Abstract: Bruxism is characterized by non-functional contact of mandibular and maxillary teeth resulting in clenching or grating of teeth. Theories on factors causing bruxism are a matter of controversy in current literature. The dental profession has predominantly viewed peripheral local morphological disorders, such as malocclusion, as the cause of clenching and gnashing. This etiological model is based on the theory that occlusal maladjustment results in reduced masticatory muscle tone. In the absence of occlusal equilibration, motor neuron activity of masticatory muscles is triggered by periodontal receptors. The second theory assumes that central disturbances in the area of the basal ganglia are the main cause of bruxism. An imbalance in the circuit processing of the basal ganglia is supposed to be responsible for muscle hyperactivity during nocturnal dyskinesia such as bruxism. Some authors assume that bruxism constitutes sleep-related parafunctional activity (parasomnia). A recent model, which may explain the potential imbalance of the basal ganglia, is neuroplasticity. Neural plasticity is based on the ability of synapses to change the way they work. Activation of neural plasticity can change the relationship between inhibitory and excitatory neurons. It seems obvious that bruxism is not a symptom specific to just one disease. Many forms (and causes) of bruxism may exist simultaneously, as, for example, peripheral or central forms.
Churchill SS, Kieckhefer GM, Landis CA and Ward TM (2012), "Sleep measurement and monitoring in children with Down syndrome: A review of the literature, 1960-2010.", Sleep Med Rev., Mar, 2012.
Diederich NJ and McIntyre DJ (2012), "Sleep disorders in Parkinson's disease: many causes, few therapeutic options.", J Neurol Sci., Mar, 2012. Vol. 314(1-2), pp. 12-19.
Abstract: Sleep symptoms in Parkinson's disease (PD) are frequent and have multifactorial and multilayered causes. Primary involvement of sleep/wake regulating centers in the brainstem, sleep problems caused by the nocturnal manifestation of motor and dysautonomic signs and medication-induced sleep problems are often impossible to disentangle in the individual patient. Two syndromes, hypersomnia and REM sleep behavior disorder (RBD), are increasingly recognized as harbingers of the core PD motor syndrome. RBD, associated with a panoply of other nonmotor symptoms, may predispose to a specific PD phenotype. Long-acting dopaminergic stimulation, when abating nocturnal akinesia, also improves subjective sleep quantity. While this strategy is backed up by several randomized controlled trials (RCT), other treatment recommendations are mostly based on case series or expert opinion. Thus we identified only two other RCT, one treating insomnia with eszopiclone, the other nocturnal behavioral abnormalities in demented PD patients with memantine. While the causal complexity of sleep problems in PD certainly hampers the design of therapeutic studies, multiple general treatment strategies against sleep disorders can however be applied efficiently in PD patients as well.
Diederich NJ and Parent A (2012), "Parkinson's disease: acquired frailty of archaic neural networks?", J Neurol Sci., Mar, 2012. Vol. 314(1-2), pp. 143-151.
Abstract: In Parkinson's disease (PD) many motor and non-motor symptoms are difficult to explain in terms of a purely ascending degeneration process as described by Braak. This essay proposes phylogenetic considerations for consolidating the multidimensional elements of PD. Subtle clinical analysis paired with ethological comparisons as well as patho-anatomical data suggests that disrupted automatic gait control, olfactory deficits, selected visual deficits, impaired emotional face recognition, and REM sleep behavior disorder could be due to dysfunction of phylogenetically ancient networks. Neuroanatomical and behavioral findings lead to a reconsideration of the basal ganglia, to be viewed as the nuclear core of a widely distributed neural network that arborizes throughout the primordial core of the neuraxis, including the brainstem. Fragility of the resulting multiple, closed, ancillary loops that link brainstem and forebrain components of the basal ganglia may be a nodal point, pivotal to the pathogenesis of PD. Other primitive neural networks, such as those located at cardiac or gastro-intestinal levels, may share the same vulnerability. Such a network-based hypothesis overrides the need of a fixed temporal ordering of symptoms based on putative caudal-cephalic propagation patterns of pathological lesions. It also creates testable, secondary hypotheses such as differential gene expression in different neural networks, potential early epigenetic influences, concepts of "overuse" or maladaptation of primitive networks to the constraints of adult life, and system frailty due to irreparable mitochondrial "exhaustion" in highly energy consuming postmitotic cells.
Fotuhi M, Do D and Jack C (2012), "Modifiable factors that alter the size of the hippocampus with ageing.", Nat Rev Neurol., Mar, 2012.
Abstract: The hippocampus is particularly vulnerable to the neurotoxic effects of obesity, diabetes mellitus, hypertension, hypoxic brain injury, obstructive sleep apnoea, bipolar disorder, clinical depression and head trauma. Patients with these conditions often have smaller hippocampi and experience a greater degree of cognitive decline than individuals without these comorbidities. Moreover, hippocampal atrophy is an established indicator for conversion from the normal ageing process to developing mild cognitive impairment and dementia. As such, an important aim is to ascertain which modifiable factors can have a positive effect on the size of the hippocampus throughout life. Observational studies and preliminary clinical trials have raised the possibility that physical exercise, cognitive stimulation and treatment of general medical conditions can reverse age-related atrophy in the hippocampus, or even expand its size. An emerging concept-the dynamic polygon hypothesis-suggests that treatment of modifiable risk factors can increase the volume or prevent atrophy of the hippocampus. According to this hypothesis, a multidisciplinary approach, which involves strategies to both reduce neurotoxicity and increase neurogenesis, is likely to be successful in delaying the onset of cognitive impairment with ageing. Further research on the constellation of interventions that could be most effective is needed before recommendations can be made for implementing preventive and therapeutic strategies.
Gulia KK (2012), "Dynamism in Activity of the Neural Networks in Brain is the Basis of Sleep-Wakefulness Oscillations.", Front Neurol. Vol. 3, pp. 38.
Jecmenica-Lukic M, Poewe W, Tolosa E and Wenning GK (2012), "Premotor signs and symptoms of multiple system atrophy.", Lancet Neurol., Apr, 2012. Vol. 11(4), pp. 361-368.
Abstract: Diagnostic criteria for multiple system atrophy are focused on motor manifestations of the disease, in particular ataxia and parkinsonism, but these criteria often cannot detect the early stages. Non-motor symptoms and signs of multiple system atrophy often precede the onset of classic motor manifestations, and this prodromal phase is estimated to last from several months to years. Autonomic failure, sleep problems, and respiratory disturbances are well known symptoms of established multiple system atrophy and, when presenting early and preceding ataxia or parkinsonism, should be regarded as evidence of premotor multiple system atrophy. An early and accurate diagnosis is becoming increasingly important as new neuroprotective agents are developed.
Lautenbacher S (2012), "Pain, sleeping problems and their many relatives.", Pain., Mar, 2012.
Meltzer LJ, Montgomery-Downs HE, Insana SP and Walsh CM (2012), "Use of actigraphy for assessment in pediatric sleep research.", Sleep Med Rev., Mar, 2012.
Abstract: The use of actigraphs, or ambulatory devices that estimate sleep-wake patterns from activity levels, has become common in pediatric research. Actigraphy provides a more objective measure than parent-report, and has gained popularity due to its ability to measure sleep-wake patterns for extended periods of time in the child's natural environment. The purpose of this review is: 1) to provide comprehensive information on the historic and current uses of actigraphy in pediatric sleep research; 2) to review how actigraphy has been validated among pediatric populations; and 3) offer recommendations for methodological areas that should be included in all studies that utilize actigraphy, including the definition and scoring of variables commonly reported. The poor specificity to detect wake after sleep onset was consistently noted across devices and age groups, thus raising concerns about what is an "acceptable" level of specificity for actigraphy. Other notable findings from this review include the lack of standard scoring rules or variable definitions. Suggestions for the use and reporting of actigraphy in pediatric research are provided.
Pang KP, Siow JK and Tseng P (2012), "Safety of Multilevel Surgery in Obstructive Sleep Apnea: A Review of 487 Cases.", Arch Otolaryngol Head Neck Surg., Mar, 2012.
Abstract: OBJECTIVE: To review the safety of multilevel surgery in patients with obstructive sleep apnea (OSA). DESIGN: Retrospective review. PATIENTS: A total of 487 consecutive patients with OSA and 1698 surgical procedures from January 2007 to May 2010. INTERVENTIONS: Multilevel OSA surgery comprising nasal surgery (endoscopic sinus surgery, septoplasty, and inferior turbinate reduction), palate surgery (traditional uvulopalatopharyngoplasty, expansion sphincter pharyngoplasty and anterior palatoplasty), and tongue surgery (hyoid suspension, radiofrequency tongue base, and tongue suspension suture). MAIN OUTCOME MEASURES: Surgical complications. RESULTS: The overall complication rate was 7.1 with 1 patient having an upper airway obstruction. Complications were as follows: (1) 6 patients had postoperative oxygen desaturation within 3 hours after extubation (these patients had severe OSA [apnea-hypopnea index > 60 and lowest oxygen saturation level <80), (2) 15 patients had persistent hypertension (these patients had a history of hypertension), (3) 15 patients had secondary hemorrhage (7-12 days postoperatively), (4) there were 2 cases of negative pressure pulmonary edema, (5) 9 patients had tongue edema (following tongue surgery), and (6) 1 patient had upper airway obstruction requiring reintubation. Patients who had undergone tongue surgery were admitted routinely to the high-dependency unit (step-down care from the intensive care unit) overnight. CONCLUSIONS: Routine postoperative admission to the intensive care unit for all patients with OSA is unnecessary. These patients should be closely monitored in the postanesthesia care unit area after surgery, and based on the outcome of this period, they can be observed overnight in either the high-dependency unit or the general ward.
Ravesloot MJL, van Maanen JP, Dun L and de Vries N (2012), "The undervalued potential of positional therapy in position-dependent snoring and obstructive sleep apnea-a review of the literature.", Sleep Breath., Mar, 2012.
Abstract: PURPOSE: Research during the past 10-20 years shows that positional therapy (PT) has a significant influence on the apnea-hypopnea index. These studies are predominantly performed as case series on a comparably small number of patients. Still, results have not found their way into the daily diagnostic and treatment routine. An average of 56?% of patients with obstructive sleep apnea (OSA) have position-dependent OSA (POSA), commonly defined as a difference of 50?% or more in apnea index between supine and non-supine positions. A great deal could be gained in treating patients with POSA with PT. The aim of this paper was to perform a thorough review of the literature on positional sleep apnea and its therapy. METHODS: A broad search strategy was run electronically in the MEDLINE and EMBASE databases using synonyms for position and sleep apnea. RESULTS: Sixteen studies were found which examined the effect of PT on OSA. In this literature review, we discuss the various techniques, results, and compliance rates. CONCLUSION: Long-term compliance for PT remains an issue, and although remarkable results have been shown using innovative treatment concepts for PT, there is room for both technical improvement of the devices and for further research.
Veggiotti P, Pera MC, Teutonico F, Brazzo D, Balottin U and Tassinari CA (2012), "Therapy of encephalopathy with status epilepticus during sleep (ESES/CSWS syndrome): an update.", Epileptic Disord., Mar, 2012.
Abstract: Electrical status epilepticus in sleep (ESES)/continuous spikes and waves during slow sleep (CSWS) is an age-related, self-limiting disorder characterised by epilepsy with different seizure types, global or selective neuropsychological regression, motor impairment, and a typical EEG pattern of continuous epileptiform activity for more than 85% of non-rapid eye movement (NREM) sleep. Although the first description of ESES/CSWS dates back to 1971, an agreement about the optimal treatment for this condition is still lacking. ESES/CSWS is rare (incidence is 0.2-0.5% of all childhood epilepsies) and no controlled clinical trials have been conducted to establish the efficacy of different antiepileptic drugs; only uncontrolled studies and case reports are reported in the literature. Treatment options for ESES/CSWS include some antiepileptic drugs (valproic acid, ethosuximide, levetiracetam, and benzodiazepines), steroids, immunoglobulins, the ketogenic diet, and surgery (multiple subpial transections). In this study, the comparative value of each of these treatments is reviewed and a personal therapeutic approach is proposed.
Yang D, Liu Z, Yang H and Luo Q (2012), "Effects of continuous positive airway pressure on glycemic control and insulin resistance in patients with obstructive sleep apnea: a meta-analysis.", Sleep Breath., Mar, 2012.
Abstract: BACKGROUND: Previous studies addressing the question of whether continuous positive airway pressure (CPAP) could improve the insulin resistance and glucose control in patients with obstructive sleep apnea (OSA) have led to conflicting results. Therefore, we conducted the meta-analysis to evaluate the effects of CPAP on glycemic control and insulin resistance in OSA patients. METHODS: We searched PubMed, HighWire Press, Ovid Medline (R), Cochrane library, and EMBASE before December 2011 on original English language studies. The meta-analysis was conducted using Review Manager Version 5. RESULTS: The summary estimate for mean difference of homeostasis model assessment insulin resistance (HOMA) from 12 non-diabetic studies was -0.55 (95 % CI, -0.91 to -0.20; P?=?0.002). When compared with fasting blood glucose at baseline, 3 to 24 weeks of CPAP treatment did not improve glycemic control in non-diabetic subjects (-0.12; 95 % CI, -0.3 to 0.06; P?=?0.20), as well as in diabetic subjects (-0.71; 95 % CI, -2.24 to 0.83; P?=?0.37). There were no intervention-related changes in body mass index. CONCLUSIONS: Our analysis showed that CPAP significantly improved insulin resistance in non-diabetic patients with moderate to severe OSA, while no significant change in body mass index was detected. Compared with fasting blood glucose at baseline, there was no change in glycemic control with CPAP. Further large-scale, randomized, and controlled studies are needed to evaluate the longer treatment and its possible effects on weight loss and glycemic homeostasis.
Yoshida M, Knauer B and Jochems A (2012), "Cholinergic modulation of the CAN current may adjust neural dynamics for active memory maintenance, spatial navigation and time-compressed replay.", Front Neural Circuits. Vol. 6, pp. 10.
Abstract: Suppression of cholinergic receptors and inactivation of the septum impair short-term memory, and disrupt place cell and grid cell activity in the medial temporal lobe (MTL). Location-dependent hippocampal place cell firing during active waking, when the acetylcholine level is high, switches to time-compressed replay activity during quiet waking and slow-wave-sleep (SWS), when the acetylcholine level is low. However, it remains largely unknown how acetylcholine supports short-term memory, spatial navigation, and the functional switch to replay mode in the MTL. In this paper, we focus on the role of the calcium-activated non-specific cationic (CAN) current which is activated by acetylcholine. The CAN current is known to underlie persistent firing, which could serve as a memory trace in many neurons in the MTL. Here, we review the CAN current and discuss possible roles of the CAN current in short-term memory and spatial navigation. We further propose a novel theoretical model where the CAN current switches the hippocampal place cell activity between real-time and time-compressed sequential activity during encoding and consolidation, respectively.
Physiology / Pharmacology
Bušková J, Vorlová T, Piško J and Sonka K (2012), "Severe sleep-related movement disorder induced by sertraline.", Sleep Med., Mar, 2012.
Hilton-Jones D, Bowler M, Lochmueller H, Longman C, Petty R, Roberts M, Rogers M, Turner C and Wilcox D (2012), "Modafinil for excessive daytime sleepiness in myotonic dystrophy type 1 - The patients' perspective.", Neuromuscul Disord., Mar, 2012.
Abstract: Excessive daytime sleepiness (EDS), of very similar pattern to that seen in narcolepsy syndrome, is extremely common in myotonic dystrophy type 1 (DM1). In a significant minority it has a profound disabling effect on employment, social functioning and activities of daily living. Limited published studies have shown inconsistent results from use of the psychostimulant drug modafinil. A recent European Medicines Agency (EMA) review concluded that on current evidence regarding safety and efficacy, modafinil's use should be restricted to the treatment of narcolepsy. In other conditions (although DM1 was not specifically considered) it was concluded that there was insufficient evidence of benefit to outweigh potentially serious side-effects, including severe skin reactions and cardiac arrhythmia. Clinicians with extensive experience in the management of DM1 have found modafinil to be extremely effective in appropriately selected patients with a very low incidence of serious side-effects. Given the recent EMA review, patients have expressed concern about the potential restriction of the use of modafinil in DM1. This brief review is an audit of the experience of a large group of patients and their clinicians concerning EDS and DM1 and concludes that despite the limited literature there is strong evidence to support the use of modafinil in carefully selected patients.
Koehler C, Ginzkey C, Kleinsasser NH, Hagen R, Reiners C and Verburg FA (2012), "Short-term severe thyroid hormone deficiency does not influence sleep parameters.", Sleep Breath., Mar, 2012.
Abstract: PURPOSE: The influence of short-term severe thyroid hormone deficiency on sleep is currently still unknown. Several studies have demonstrated an effect of long-term hypothyroidism on sleep disorders due to anatomical changes of the pharynx or body mass. The aim of this preliminary study, however, is to evaluate the changes in sleep patterns of patients with short-term hypothyroidism to elucidate the isolated effect of thyroid hormone withdrawal before anatomical changes can potentially occur. METHODS: Ten patients with differentiated thyroid carcinoma were enrolled in this study. Two patients discontinued the study and one patient was finally excluded due to obesity, so that the datasets of seven patients were available for study analysis. During the course of carcinoma treatment, each patient had previously undergone total thyroidectomy and I-131 remnant ablation. Polysomnographic measurements were performed twice: (1) over the course of two consecutive nights during severe thyroid hormone deficiency after levothyroxine withdrawal and prior to further diagnostics and therapy and (2) during euthyroidism after substitution with levothyroxine. RESULTS: Comparison of the Epworth Sleepiness Scale during hypo- and euthyroidism for each patient revealed no statistically significant difference. Furthermore, the comparison of polysomnographic parameters like (1) apnea-hypopnea index, (2) the duration of various sleep stages, (3) duration of rapid eye movement sleep, (4) latency until rapid eye movement sleep, (5) total sleep time, (6) periodic leg movements, and (7) arousal index showed no statistically significant differences between the hypothyroid or euthyroid state. CONCLUSIONS: We conclude that, in this preliminary experimental setting, short-term severe thyroid hormone deficiency per se does not cause sleep disturbances and a feeling of fatigue as described in other studies may be due to changes in perception or brain metabolism during hypothyroidism.
Lemoine P and Zisapel N (2012), "Prolonged-release formulation of melatonin (Circadin) for the treatment of insomnia.", Expert Opin Pharmacother., Apr, 2012. Vol. 13(6), pp. 895-905.
Abstract: Introduction: Insomnia is common among the elderly. The use of hypnotic drugs in elderly patients is frequently criticized owing to dependency, cognitive impairments, falls and withdrawal effects. The production of melatonin, a physiological sleep and circadian rhythm regulator, declines with age. Prolonged-release melatonin (Circadin®) , designed to mimic the endogenous pattern of melatonin production, is licensed for insomnia in patients aged ? 55 years. Areas covered: This review summarizes published studies on Circadin's efficacy and safety (Summary of Product Characteristics and Medline search on 'Circadin' and 'insomnia'). Expert opinion: The main significant and clinically relevant benefits are improvements in sleep quality and latency, next-day morning alertness and quality of life. The responses may develop over several days. An oral 2-mg dose once daily, for 3 months, has generally been well tolerated with no rebound, withdrawal or 'hangover' effects and no safety concerns on concomitant therapy with antihypertensive, antidiabetic, lipid-lowering or anti-inflammatory drugs. Untoward effects of hypnotics on cognition, memory, postural stability and sleep structure are not seen with Circadin. Given as a first-line prescription, with 13 weeks' posology and the lack of rebound effects, Circadin has the potential to improve quality of life in insomnia patients aged 55 years and older and avoid long-term use of hypnotics.
Matishov GG, Voynov VB, Verbitsky EV and Mikhaylyuk AL (2012), "The cardiorespiratory function and electrical activity of the brain of the ringed seal during the transition from wakefulness to sleep.", Dokl Biol Sci. Vol. 442, pp. 1-6.
Randler C, Ebenhöh N, Fischer A, Höchel S, Schroff C, Stoll JC and Vollmer C (2012), "Chronotype but not sleep length is related to salivary testosterone in young adult men.", Psychoneuroendocrinology., Mar, 2012.
Abstract: Sex hormones, including testosterone, are hypothesized to have an influence on the human circadian system. We sampled male students in the period after adolescence. We used the Composite Scale of Morningness (CSM) to assess chronotype and saliva testosterone sampling in 106 University students (23.87±3.56 years; range 19-37) between 26.4.2011 and 6.5.2011, always between 0800h and 0900h. There was a significant negative relationship between CSM scores and saliva testosterone (r(s)=-0.220, p=0.023, two-tailed test) but not between testosterone and average sleep length. Age and testosterone did not correlate with each other nor did age and CSM scores. Our data suggest that chronotype in men might be influenced by testosterone and that high testosterone levels lead to a stronger evening-orientation. Sleep duration was uncorrelated with testosterone, suggesting that timing of sleep - rather than sleep length itself - is influenced by testosterone.
Thurston RC, Santoro N and Matthews KA (2012), "Are vasomotor symptoms associated with sleep characteristics among symptomatic midlife women? Comparisons of self-report and objective measures.", Menopause., Mar, 2012.
Abstract: OBJECTIVE: Many women report vasomotor symptoms (VMS) and sleep problems during the menopausal transition. Although reported VMS are consistently related to reported sleep disturbance, findings using physiologic measures of VMS or sleep have been more mixed. Our objective was to examine whether more VMS during sleep are associated with poorer sleep among midlife women with VMS using physiologic measures of both VMS and sleep. METHODS: A subcohort of participants (N = 52) with VMS, a uterus and both ovaries, and free of medications affecting VMS from the Pittsburgh site of the Study of Women's Health Across the Nation underwent four 24-hour periods of in-home ambulatory VMS and sleep measurement. Measures included sternal skin conductance for the measurement of VMS, actigraphy for assessing sleep, a VMS diary, and a sleep diary completed before bed and upon waking. Associations between VMS and sleep were evaluated using generalized estimating equations with covariates age, body mass index, medications affecting sleep, race, financial strain, and depressive symptoms. RESULTS: More VMS recalled upon waking were associated with significantly lower actigraphy-assessed sleep efficiency, significantly higher wakefulness after sleep onset, and somewhat longer sleep latency. Conversely, physiologically measured VMS and VMS reported during the night were largely unrelated to sleep characteristics. CONCLUSIONS: Associations between VMS and sleep may depend more on the awareness of and recall of VMS rather than solely on their physiologic occurrence.
Verrillo E, Bizzarri C, Bruni O, Ferri R, Pavone M, Cappa M and Cutrera R (2012), "Effects of replacement therapy on sleep architecture in children with growth hormone deficiency.", Sleep Med., Mar, 2012.
Abstract: OBJECTIVE: Children with GH deficiency (GHD) show a general decrease in electroencephalographic (EEG) arousability represented by a significant global decrease in Cyclic Alternating Pattern (CAP). The aim of the present study was to evaluate if sleep structure is influenced by GH substitutive therapy by analyzing the classical sleep architecture parameters and sleep microstructure by means of CAP. SUBJECTS AND METHODS: Laboratory polysomnographic sleep recordings were obtained from five children affected by GHD (two girls and three boys; mean age: 4.6±3.1years), at baseline and after GH therapy, and from 10 normal healthy children (four girls and six boys, mean age: 5.6±2.2years). RESULTS: Compared to controls, GHD subjects showed a reduced total sleep time with increased wakefulness and a consequent decrease in sleep efficiency; GH therapy was associated with an increase of the awakenings/hour and a large effect size was evident for sleep latency, sleep efficiency, and stage N3, which were decreased, and for stage W, which was increased. CAP appeared to be globally reduced and all phase A subtypes and CAP cycle showed a longer duration in GHD children vs. controls. GH substitutive treatment was followed by an increase in CAP rate (total, in N2, and in N3); additionally, A1 index was also significantly increased, especially during stage N3, with a very large effect size. On the other hand, A2 and A3 index and CAP cycle mean duration were reduced. CONCLUSION: Sleep stage architecture seems to be influenced by the GH status, but the analysis of sleep microstructure by means of CAP reveals an enhancement of EEG slow oscillations in GHD patients (demonstrated by an increase in CAP rate and A1 index during N3) after the start of GH replacement therapy. These findings deserve to be verified in a larger trial.
Development / Aging / Evolution
Iacovou M and Sevilla A (2012), "Infant feeding: the effects of scheduled vs. on-demand feeding on mothers' wellbeing and children's cognitive development.", Eur J Public Health., Mar, 2012.
Abstract: BACKGROUND: Many popular childcare books recommend feeding babies to a schedule, but no large-scale study has ever examined the effects of schedule-feeding. Here, we examine the relationship between feeding infants to a schedule and two sets of outcomes: mothers' wellbeing, and children's longer-term cognitive and academic development. METHODS: We used a sample of 10?419 children from the Avon Longitudinal Study of Parents and Children, a cohort study of children born in the 1990s in Bristol, UK. Outcomes were compared by whether babies were fed to a schedule at 4 weeks. Maternal wellbeing indicators include measures of sleep sufficiency, maternal confidence and depression, collected when babies were between 8 weeks and 33 months. Children's outcomes were measured by standardized tests at ages 5, 7, 11 and 14, and by IQ tests at age 8. RESULTS: Mothers who fed to a schedule scored more favourably on all wellbeing measures except depression. However, schedule-fed babies went on to do less well academically than their demand-fed counterparts. After controlling for a wide range of confounders, schedule-fed babies performed around 17% of a standard deviation below demand-fed babies in standardized tests at all ages, and 4 points lower in IQ tests at age 8 years. CONCLUSIONS: Feeding infants to a schedule is associated with higher levels of maternal wellbeing, but with poorer cognitive and academic outcomes for children.
Biological Rhythms
Eckel-Mahan KL, Patel VR, Mohney RP, Vignola KS, Baldi P and Sassone-Corsi P (2012), "Coordination of the transcriptome and metabolome by the circadian clock.", Proc Natl Acad Sci U S A., Mar, 2012.
Abstract: The circadian clock governs a large array of physiological functions through the transcriptional control of a significant fraction of the genome. Disruption of the clock leads to metabolic disorders, including obesity and diabetes. As food is a potent zeitgeber (ZT) for peripheral clocks, metabolites are implicated as cellular transducers of circadian time for tissues such as the liver. From a comprehensive dataset of over 500 metabolites identified by mass spectrometry, we reveal the coordinate clock-controlled oscillation of many metabolites, including those within the amino acid and carbohydrate metabolic pathways as well as the lipid, nucleotide, and xenobiotic metabolic pathways. Using computational modeling, we present evidence of synergistic nodes between the circadian transcriptome and specific metabolic pathways. Validation of these nodes reveals that diverse metabolic pathways, including the uracil salvage pathway, oscillate in a circadian fashion and in a CLOCK-dependent manner. This integrated map illustrates the coherence within the circadian metabolome, transcriptome, and proteome and how these are connected through specific nodes that operate in concert to achieve metabolic homeostasis.
Sleep Deprivation
Hajali V, Sheibani V, Esmaeili-Mahani S and Shabani M (2012), "Female rats are more susceptible to the deleterious effects of paradoxical sleep deprivation on cognitive performance.", Behav Brain Res., Mar, 2012. Vol. 228(2), pp. 311-318.
Abstract: Paradoxical sleep deprivation (PSD) may alter subsequent learning and memory capacity. There are differences in both the intensity and direction of responses of the male and female species to the same environmental stimuli and experimental conditions. In the present study, we examined the extent of the effects of PSD for 72h on spatial learning and memory, anxiety-like behavior, corticosterone levels, and the body weight in male as well as in intact and ovariectomized (OVX) female Wistar rats. Multiple platform method was used for PSD induction. Spatial learning and memory and anxiety-like behavior were determined using Morris water maze (MWM) task and open field test, respectively. The data showed that PSD could not significantly affect subsequent spatial learning and short-term memory in male rats, while it significantly impaired the performance of the intact and OVX female rats. The PSD-intact and -OVX female rats showed more memory impairment than the PSD-male animals. Those impairments do not appear to be due to elevated stress level, since the plasma corticosterone did not significantly change following PSD induction. The open field data showed that PSD significantly reduced anxiety-like behavior in all experimental groups. In addition, PSD had a reducing effect on the mean body weight of female groups. Such results suggest that the female rats are more vulnerable to the deleterious effects of sleep loss on cognitive performance.
Zielinski MR, Mark Davis J, Fadel JR and Youngstedt SD (2012), "Influence of chronic moderate sleep restriction and exercise on inflammation and carcinogenesis in mice.", Brain Behav Immun., Mar, 2012.
Abstract: The effects of chronic moderate sleep restriction and exercise training on carcinogenesis were examined in adenomatous polyposis coli multiple intestinal neoplasma (APC Min(+/-)) mice, a genetic strain which is predisposed to developing adenomatous polyposis. The mice were randomized to one of four 11week treatments in a 2×2 design involving sleep restriction (by 4h/day) vs. normal sleep and exercise training (1h/day) vs. sedentary control. Wild-type control mice underwent identical experimental treatments. Compared with the wild-type mice, APC Min(+/-) mice had disrupted hematology and enhanced pro-inflammatory cytokine production from peritoneal exudate cells. Among the APC Min(+/-) mice, consistent interactions of sleep loss and exercise were found for measures of polyp formation, inflammation, and hematology. Sleep loss had little effect on these variables under sedentary conditions, but sleep loss had clear detrimental effects under exercise conditions. Exercise training resulted in improvements in these measures under normal sleep conditions, but exercise tended to elicit no effect or to exacerbate the effects of sleep restriction. Significant correlations of inflammation with polyp burden were observed. Among wild-type mice, similar, but less consistent interactions of sleep restriction and exercise were found. These data suggest that the benefits of exercise on carcinogenesis and immune function were impaired by chronic moderate sleep restriction, and that harmful effects of sleep restriction were generally realized only in the presence of exercise.
Sleep Apnea / COPD / Snoring
de Silva S, Abeyratne UR and Hukins C (2012), "Impact of gender on snore-based obstructive sleep apnea screening.", Physiol Meas., Apr, 2012. Vol. 33(4), pp. 587-601.
Abstract: Obstructive sleep apnea syndrome (OSA) is a serious widespread disease in which upper airways (UA) are collapsed during sleep. OSA has marked male predominance in prevalence. Although women are less vulnerable to OSA, under-diagnosed OSA in women may associate with serious consequences. Snoring is commonly associated with OSA and one of the earliest symptoms. Snore sounds (SS) are generated due to vibration of the collapsing soft tissues of the UA. Structural and functional properties of the UA are gender dependent. SS capture these time varying gender attributed UA properties and those could be embedded in the acoustic properties of SS. In this paper, we investigate the gender-specific acoustic property differences of SS and try to exploit these differences to enhance the snore-based OSA detection performance. We developed a snore-based multi-feature vector for OSA screening and one time-measured neck circumference was augmented. Snore features were estimated from SS recorded in a sleep laboratory from 35 females and 51 males and multi-layer neural network-based pattern recognition algorithms were used for OSA/non-OSA classification. The results were K-fold cross-validated. Gender-dependent modeling resulted in an increase of around 7% in sensitivity and 6% in specificity at the decision threshold AHI = 15 against a gender-neutral model. These results established the importance of adopting gender-specific models for the snore-based OSA screening technique.
Amos LB and D'Andrea LA (2012), "Severe central sleep apnea in a child with leukemia on chronic methadone therapy.", Pediatr Pulmonol., Mar, 2012.
Abstract: We describe a child with acute myeloid leukemia (AML) who developed severe central sleep apnea (CSA) on methadone therapy for chronic pain management. His chemotherapy-related cerebral atrophy and renal insufficiency with impaired methadone clearance may have also contributed to the severity of his sleep-disordered breathing. Maintenance methadone treatment is not a common pediatric practice; therefore, the adverse effects of methadone therapy, including CSA, are rarely reported in children. Pediatr Pulmonol. © 2012 Wiley Periodicals, Inc.
Barnes ME, Gozal D and Molfese DL (2012), "Attention in children with obstructive sleep apnoea: An event-related potentials study.", Sleep Med., Mar, 2012.
Abstract: BACKGROUND: Obstructive sleep apnoea (OSA) in children has been causally implicated in neurobehavioural and cognitive dysfunction. Consequently, the American Academy of Paediatrics highlighted the need to study pertinent functional cognitive outcomes before and after treatment. However, neurocognitive function has thus far only been assessed by caregiver-completed questionnaires, which can be labour intensive and time consuming, such that the need for complementary and more objective measures has emerged. OBJECTIVE: The study aimed to identify electrophysiological correlates of neurocognitive alterations in children with OSA and investigate utility as a predictive tool. PATIENTS AND METHODS: Twenty-eight children (14 OSA and 14 matched controls) underwent overnight sleep studies and neurocognitive testing, as well as the oddball attention task while event-related potentials (ERPs) were recorded. ERPs were analysed using temporal principal components and source analyses that provided dependent variables for the subsequent repeated measures analysis of variance (ANOVA) and multiple regressions. Time-locked waveforms formed spatial models that localised electrical activity in the brain. ERP differences between groups were then correlated to neurocognitive outcomes. RESULTS: OSA children exhibited significantly altered ERP patterns of neural activation and impaired neurocognitive performance. Specific ERP variables exhibited accurate predictive ability regarding performance on neurobehavioural measures. CONCLUSION: Specific ERP events during a single attention task can reliably identify the presence of OSA-associated cognitive dysfunction. Electrophysiological approaches during specific cognitive tasks may serve as simple, complementary, and reliable reporters of cognitive dysfunction associated with OSA in children.
Ehrmann DA (2012), "metabolic dysfunction in pcos: Relationship to obstructive sleep apnea.", Steroids., Mar, 2012. Vol. 77(4), pp. 290-294.
Abstract: Polycystic ovary syndrome (PCOS) affects between 5% and 8% of women, making it one of the most common endocrinopathies in women. The disorder typically has its onset at puberty with evidence of excessive androgen production, obesity, and insulin resistance. Women with PCOS are more insulin resistant than weight-matched controls and have an exceptionally high prevalence of early-onset impaired glucose tolerance (30-40, and type 2 diabetes (up to 10. Over the past several years, chronic decreases in sleep duration and/or quality have been identified as a risk for the development of a number of metabolic derangements that are strikingly similar to those seen in PCOS. Specifically, decreased sleep quality due to obstructive sleep apnea (OSA) has been causally linked to insulin resistance, glucose intolerance, dyslipidemia and hypertension independent of body mass index (BMI). Until recently, however, it had not been recognized that OSA is present in a disproportionate number of women with PCOS: the risk for OSA is at least 5- to 10-fold higher compared to the risk in similarly obese women without PCOS. The causes and consequences of OSA in women with PCOS are addressed in this manuscript.
Friedman M, Samuelson CG, Hamilton C, Maley A, Taylor D, Kelley K, Pearson-Chauhan K, Hoehne C, Levay AJ and Venkatesan TK (2012), "Modified Adenotonsillectomy to Improve Cure Rates for Pediatric Obstructive Sleep Apnea: A Randomized Controlled Trial.", Otolaryngol Head Neck Surg., Mar, 2012.
Abstract: Objective. To compare the efficacy of adenotonsillectomy (T&A) with and without pharyngoplasty (tonsillar pillar closure) in the treatment of pediatric obstructive sleep apnea-hypopnea syndrome (OSAHS).Study Design. Randomized single-blind controlled study.Setting. Tertiary care center.Subjects and Methods. Sixty pediatric patients with a clinical diagnosis of OSAHS presenting between January 2009 and December 2010 were enrolled and randomized to undergo either standard T&A (n = 30) or T&A with pharyngoplasty (n = 30). Surgical cure was defined as apnea-hypopnea index (AHI) <5 plus OSA-18 health-related quality-of-life (HRQL) score <60. Other outcomes included postsurgical AHI and minimum oxygen saturation (SpO(2)) improvement, changes in OSA-18 scores at 1 month, and postsurgical days to resume normal diet and activity.Results. Three patients from each group did not undergo surgery. Of the 54 patients treated, 8 from the pharyngoplasty group and 2 from the standard group were lost to follow-up. Intention-to-treat analysis revealed no difference in cure rate between groups (standard 60 pharyngoplasty 56.6 P = .793). Limiting analysis to those patients with complete data, a higher, but not significantly increased, cure rate with pharyngoplasty was noted (72% vs 89.5 P = .155). Greater OSA-18 improvement (P = .036) and greater (although nonsignificant) AHI improvement and earlier return to normal function were noted with pharyngoplasty.Conclusion. The addition of pharyngoplasty to traditional adenotonsillectomy did not significantly improve OSAHS cure rates as measured by sleep testing and HRQL, although a nonsignificant increase in cure rate was observed in those who completed the study protocol. An unexpectedly high rate of patient dropout rendered the study statistically underpowered and therefore inconclusive.
Guo Q, Wang Y, Li QY, Li M and Wan HY (2012), "Levels of thioredoxin are related to the severity of obstructive sleep apnea: based on oxidative stress concept.", Sleep Breath., Mar, 2012.
Abstract: BACKGROUND: Oxidative stress is a typical feature of obstructive sleep apnea (OSA). Thioredoxin (TRX), as one of the oxidative stress biomarkers, is a potent protein disulfide reductase in antioxidant defense. Our study is designed to test whether thioredoxin could assess the severity of OSA. METHODS: Sixty-three adults suspected of having OSA were included in this study and were divided into four groups based on the results of polysomnography (PSG): control, mild, moderate, and severe. Subjects with chronic medical diseases (with the exception of essential hypertension) or taking any antioxidant medication were excluded. Blood samples were obtained within an hour after the overnight PSG test. Plasma TRX levels were detected by enzyme-linked immunosorbent assay. RESULTS: The plasma TRX level in severe group was obviously increased (8.62?±?2.14, 13.33?±?5.60, 14.71?±?5.53, and 16.10?±?7.34 ng/ml; p?
Hammerstingl C, Schueler R, Wiesen M, Momcilovic D, Pabst S, Nickenig G and Skowasch D (2012), "Effects of untreated obstructive sleep apnea on left and right ventricular myocardial function.", Int J Cardiol., Mar, 2012. Vol. 155(3), pp. 465-469.
Hrubos-Strøm H, Einvik G, Nordhus IH, Randby A, Pallesen S, Moum T, Omland T and Dammen T (2012), "Sleep apnoea, anxiety, depression and somatoform pain: A community-based high risk sample.", Eur Respir J., Mar, 2012.
Abstract: Community-based studies that measure both psychiatric diagnoses and obstructive sleep apnœa (OSA) are lacking. This study reports current psychiatric disorders in community-dwelling adults at high risk for OSA identified by the Berlin Questionnaire. Further, associations between OSA and current psychiatric disorders, unadjusted and adjusted for putative confounders, are reported.A subsample of the Akershus Sleep Apnœa Project (ASAP) consisting of 290 adults, aged 30-65 years, with positive Berlin Questionnaire screening, underwent the Structured Clinical Interview for DSM-IV and polysomnography. Auxiliary analyses of depression are provided.The median apnœa-hypopnœa index score in the sample was 7.7 (25(th )percentile 2.4, 75(th )percentile 22.2). Major depressive disorder, current anxiety and somatoform pain disorder were diagnosed in 12.4 14.8% and 19.3% of participants, respectively. At least one psychiatric disorder was diagnosed in 110 participants. The odds ratio of participants with OSA for having a psychiatric disorder compared with participants without was 0.54 (95% CI = 0.33-0.88). A negative association did not exist among Berlin Questionnaire low risk participants.In conclusion, more than one-third of participants in a community-based, Berlin Questionnaire high-risk sample were diagnosed with a psychiatric disorder. A negative association between OSA and psychiatric morbidity was found.
Karaca S, Fidan F, Erkan F, Nural S, Pinarc? T, Gunay E and Unlu M (2012), "Might psoriasis be a risk factor for obstructive sleep apnea syndrome?", Sleep Breath., Mar, 2012.
Abstract: BACKGROUND: It is believed that psoriasis is a chronic systemic inflammatory disease. Obstructive sleep apnea syndrome (OSAS) is a disease influencing all systems and characterized by intermittent partial or complete obstruction of the upper respiratory tract during sleep. In our study, we aimed to investigate the frequency of OSAS in patients previously diagnosed with psoriasis in order to investigate a potential association between chronic inflammation psoriasis and OSAS. METHODS: Thirty-three patients diagnosed with psoriasis by biopsy were enrolled into the study. Demographics of patients, Psoriasis Area Severity Index (PASI), Dermatology Life Quality Index (DLQI), and Epworth Sleepiness Scale were examined. All patients underwent polysomnography. RESULTS: OSAS was determined in 18 of 33 patients with psoriasis (54.5 . Eleven of the 18 patients had mild, 2 had moderate, and 5 had severe OSAS. Mean age was significantly higher in the OSAS group in comparison with non-OSAS group (54.4?±?15.5 vs 39.4?±?11.8, respectively, p??0.05). It is believed that this was caused by the small patient population. CONCLUSION: We detected that the frequency of OSAS in patients with psoriasis was much higher than that in the normal population. Though OSAS is not easy to diagnose without detailed testing, it should be investigated in psoriatic patients with long disease duration and high PASI score, and patients refractory to conventional systemic treatment. Physicians treating patients with psoriatic disease should incorporate this life-altering comorbidity into their assessment of disease and selection of treatment.
Kufoy E, Palma J-A, Lopez J, Alegre M, Urrestarazu E, Artieda J and Iriarte J (2012), "Changes in the Heart Rate Variability in Patients with Obstructive Sleep Apnea and Its Response to Acute CPAP Treatment.", PLoS One. Vol. 7(3), pp. e33769.
Abstract: Obstructive Sleep Apnea (OSA) is a major risk factor for cardiovascular disease. The goal of this study was to demonstrate whether the use of CPAP produces significant changes in the heart rate or in the heart rate variability of patients with OSA in the first night of treatment and whether gender and obesity play a role in these differences.Single-center transversal study including patients with severe OSA corrected with CPAP. Only patients with total correction after CPAP were included. Patients underwent two sleep studies on consecutive nights: the first night a basal study, and the second with CPAP. We also analyzed the heart rate changes and their relationship with CPAP treatment, sleep stages, sex and body mass index. Twenty-minute segments of the ECG were selected from the sleep periods of REM, no-REM and awake. Heart rate (HR) and heart rate variability (HRV) were studied by comparing the R-R interval in the different conditions. We also compared samples from the basal study and CPAP nights.39 patients (15 females, 24 males) were studied. The mean age was 50.67 years old, the mean AHI was 48.54, and mean body mass index was 33.41 kg/m(2) (31.83 males, 35.95 females). Our results showed that HRV (SDNN) decreased after the use of CPAP during the first night of treatment, especially in non-REM sleep. Gender and obesity did not have any influence on our results.These findings support that cardiac variability improves as an acute effect, independently of gender or weight, in the first night of CPAP use in severe OSA patients, supporting the idea of continuous use and emphasizing that noncompliance of CPAP treatment should be avoided even if it is just once.
Monneret D, Tamisier R, Ducros V, Garrel C, Levy P, Baguet JP, Faure P and Pépin JL (2012), "The impact of obstructive sleep apnea on homocysteine and carotid remodeling in metabolic syndrome.", Respir Physiol Neurobiol., Mar, 2012. Vol. 180(2-3), pp. 298-304.
Abstract: Obstructive sleep apnea (OSA) and metabolic syndrome (MetS) are associated with increased cardiovascular morbidity and mortality. Increased homocysteine is suggested as an independent risk factor for atherosclerosis and cardiovascular disease but remains disputed in OSA. We assessed polysomnography, carotid intima-media thickness (CIMT) and biology in 35 MetS patients, according to the presence (OSA+MetS; n=26) or the absence of OSA (MetS; n=9). In OSA+MetS patients, homocysteine levels were increased compared to MetS subjects (12.8 ± 3.8 vs. 9.5 ± 2.5 ?mol/L; P=0.026). In the whole population, homocysteine correlated with apnea-hypopnea index (AHI) (r=0.522; P=0.001) and CIMT (r=0.376; P=0.026). Homocysteine was negatively correlated with plasma thiols (r=-0.406; P=0.017) and positively with urinary 15-F2t-isoprostanes (r=0.347; P=0.044). Multivariate regression analysis revealed that AHI (?=0.559; P<0.001) and urinary 15-F2t-isoprostane (?=0.310; P=0.018) were independently associated with homocysteine level. We conclude that homocysteine level was higher in MetS when associated with OSA and proportional to OSA severity. In this context, vascular remodeling appeared more severe and mediated by oxidative stress.
Oliveira W, Poyares D, Cintra F, Vieira MLC, Fischer CH, Moises V, Tufik S, Carvalho A and Campos O (2012), "Impact of continuous positive airway pressure treatment on right ventricle performance in patients with obstructive sleep apnoea, assessed by three-dimensional echocardiography.", Sleep Med., Mar, 2012.
Abstract: BACKGROUND: Obstructive sleep apnoea (OSA) is a predictor of right ventricle (RV) impairment. However, there is scant information on the effect of OSA treatment on RV performance. We sought to evaluate the impact of OSA treatment with a continuous positive airway pressure (CPAP) device on RV volume and function, as well as on variables related to pulmonary vascular haemodynamics. METHODS: Fifty-six OSA patients and 50 controls were studied. All individuals underwent three-dimensional echocardiogram (3DE) to estimate RV volumes, function, pulmonary vascular resistance, and tricuspid regurgitation velocity. A total of 30 patients with apnoea-hypopnoea index greater than 20 were randomly selected to receive placebo (n=15) or effective CPAP (n=15) for 24weeks. They underwent 3DE examination on three different occasions: at baseline, after 12weeks, and after 24weeks of CPAP or placebo. RESULTS: Higher pulmonary vascular resistance (2.1 Wood's±0.5 vs. 1.8 Wood's±0.4), larger end-diastolic RV volume index (52.2mL/m(2)±7.3 vs. 49.9mL/m(2)±6.0), larger end-systolic RV volume index (18.7mL/m(2)±4.3 vs. 15.4mL/m(2)±3.6), and lower RV ejection fraction (64.36.8 vs. 68.45.9) were observed in the OSA group compared to non-OSA controls (P<0.05, all). In the effective CPAP group we observed the following changes from the baseline to the 24-week echo evaluation: (A) reduction in pulmonary vascular resistance (2.2 Wood's±0.3 to 1.8 Wood's±0.3); (B) reduction in the RV end-systolic volume index (20.3mL/m(2)±4.5 to 16mL/m(2)±2.1); and (C) increase in RV ejection fraction (63.07.2 to 70.80.9) (P<0.05 for all). CONCLUSION: Twenty-four-week treatment with CPAP improved RV performance but did not change RV structural variables.
Paramasivan VK, Arumugam SV and Kameswaran M (2012), "Randomised comparative study of adenotonsillectomy by conventional and coblation method for children with obstructive sleep apnoea.", Int J Pediatr Otorhinolaryngol., Mar, 2012.
Abstract: INTRODUCTION: Adenotonsillectomy is one of the most common surgical procedures throughout the world for children in otolaryngology. One of the current indications for adenotonsillectomy is adenotonsillar hypertrophy causing Obstructive Sleep Apnoea (OSA). The choice of surgical tools and technique affects the outcome and morbidity due to adenotonsillectomy. AIM OF THE STUDY: To assess the efficacy and safety of coblation adenotonsillectomy as compared to dissection method. To evaluate the morbidity and to study complications associated with each procedure. MATERIALS AND METHODS: This prospective and comparative study of dissection and coblation method of adenotonsillectomy was conducted in our institute, Madras ENT Research Foundation, Chennai over a period of 6 months. 50 cases of children with OSA age group between 5 and 12 years were randomly selected for each group and studied. Duration of surgical procedure, blood loss, post operative pain, post operative reactionary and secondary bleeding was noted and compared. OBSERVATION AND RESULTS: Operative time was more in dissection method compared to coblation technique. Blunt dissection tonsillectomy was associated with greater blood loss than coblation tonsillectomy. Post operative pain was more in dissection method and it was less in coblation technique. Post operative bleeding in both the techniques were found to be minimal. CONCLUSION: We conclude that the use of coblation for adenotonsillectomy may have several advantages over standard methods for the treatment of children with Obstructive Sleep Apnoea. It is highly efficacious, practical and safe with less morbidity and less complications.
Simon R, Chirakalwasan N, Teerapraipruk B, Hirunwiwatkul P, Jaimchariyatam N, Desudchit T, Charakorn N and Wanlapakorn C (2012), "Severity of Obstructive Sleep Apnea in Patients with and without Cardiovascular_Related Diseases.", Respir Care., Mar, 2012.
Abstract: Study objectives: Previous studies often investigated the association of obstructive sleep apnea (OSA) with cardiovascular morbidity and mortality but the possibility of reverse causation was not clearly defined. Our aim is to examine if the presence of any of the cardiovascular_related diseases including hypertension, diabetes mellitus, coronary artery disease and/or cerebrovascular disease correlates with more severe OSA. METHODS: This is a retrospective study where all patients aged ? 18 years referred to sleep laboratory for suspected OSA were included. The data from the full_night baseline and split night polysomnographic reports were reviewed. Data was then evaluated by logistic regression analysis to compare between two groups, the severity of OSA (RDI < 15 vs RDI ? 15 and RDI <5 vs RDI?5), other polysomnographic variables and daytime sleepiness score (ESS <10 and ? 10). RESULTS: 190 patients were analyzed. The patients with any of the cardiovascular_related diseases were noted to have more severe sleep apnea (RDI?15) with adjusted odds ratio (OR) of 3.24. Sleep efficiency ? 90% and mean oxygen saturation ? 95% were observed less commonly in the patients with any of the cardiovascular_related diseases (adjusted OR of 0.45 and 0.36, respectively). There was no statistically significant difference in ESS score. CONCLUSION: Patients with any of the cardiovascular_related diseases are at a higher risk of having moderate to severe OSA without significant increase in daytime sleepiness. Therefore, we suggest that patients with any of the cardiovascular_related diseases should be screened for OSA even if they are asymptomatic.
Weber SAT, Santos VJBD, Semenzati GdO and Martin LC (2012), "Ambulatory blood pressure monitoring in children with obstructive sleep apnea and primary snoring.", Int J Pediatr Otorhinolaryngol., Mar, 2012.
Abstract: OBJECTIVE: To evaluate the systemic blood pressure (BP) during daytime and nighttime in children with sleep breathing disorders (SBD) and compare parameters of BP in children with diagnosis of obstructive sleep apnea syndrome (OSA) to those one with primary snoring (PS). METHODS: Children, both genders, aged from 8 to 12 years, with symptoms of SBD realized an overnight polysomnography followed by a 24h recording of ambulatory BP. RESULTS: All subjects presented with a history of snoring 7 nights per week. Children who have apnea/hipoapnea index ? four or a apnea index ? one presented a mean BP of 93±7mmHg and 85±9mmHg diurnal and nocturnal respectively whereas children who have a apnea/hipoapnea < four or a apnea index < one presented 90±7mmHg and 77±2mmHg. Eight children out of fourteen, from OSA group, lost the physiologic nocturnal dipping of the blood pressure. Among OSA children 57% were considered non-dippers. Two (16 have presented absence of nocturnal dipping among children with primary snoring. The possibility of OSA children loosing physiologic blood pressure dipping was 6.66 higher than the possibilities of patients from PS group. DISCUSSION: Our results indicate that children with sleep apnea syndrome exhibit a higher 24h blood pressure when compared with those of primary snoring in form of decreased degree of nocturnal dipping and increased levels of diastolic and mean blood pressure, according to previous studies in literature. OSA in children seems to be associated to the development of hypertension or other cardiovascular disease.
Yu C-C, Hsiao H-D, Tseng T-I, Lee L-C, Yao C-M, Chen N-H, Wang C-J and Chen Y-R (2012), "Computational Fluid Dynamics Study of the Inspiratory Upper Airway and Clinical Severity of Obstructive Sleep Apnea.", J Craniofac Surg., Mar, 2012.
Abstract: ABSTRACT: The apnea-hypopnea index (AHI) is a widely accepted measure for the severity of obstructive sleep apnea (OSA). Current methods to determine AHI fail to provide anatomic information for treatment decisions. In this report, we studied three-dimensional models of upper airways acquired by computed tomographic scanning with geometric measurements and computational fluid dynamics (CFD) analysis and evaluated the correlations with AHI.Participants had CT scans of their upper airways after standard polysomnography studies. Three-dimensional surface models of upper airways were generated for cross-sectional area measurements of the choanae (ACH) and the smallest cross-sectional area (Amin). Computational fluid dynamic analysis was then performed by using this three-dimensional model. Pressure differences required to set tidal volume during inspiration (?Pmin-INSP) and expiration (?Pmax-EXP) and minimum negative pressure produced in the level of ACH (Pmin-INSP at ACH) and Amin (Pmin-INSP at Amin) were calculated. Correlations of these parameters and the body mass index with AHI were analyzed. Statistical differences between groups of different AHI ranges were also compared.The pressure distribution simulated by CFD demonstrated abrupt pressure drops in Amin level, and this phenomenon was more significant in severe OSA. All parameters except ACH and Pmin-INSP at Amin significantly correlated with the AHI, and there were significant statistical differences between the OSA groups and the normal group. The results indicate that, in our study group, the geometry of pharyngeal airway and its CFD simulation correlate well with AHI. This model may be further applied for clinical evaluation.
Other Disorders
Beaulieu-Bonneau S and Morin CM (2012), "Sleepiness and fatigue following traumatic brain injury.", Sleep Med., Mar, 2012.
Abstract: OBJECTIVES: To compare individuals with traumatic brain injury (TBI) to healthy controls (CTLs) on measures of sleepiness, fatigue, and sleep, and explore correlates of sleepiness and fatigue separately for each group. METHODS: Participants were 22 adults with moderate/severe TBI (time since injury ?1 year; mean=53.0±37.1months) and 22 matched healthy CTLs. They underwent one night of polysomnographic (PSG) recording of their sleep followed the next day by the Maintenance of Wakefulness Test (MWT). They also completed a 14-day sleep diary, the Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire (FOSQ), and the Multidimensional Fatigue Inventory (MFI). RESULTS: There were no significant group differences on measures of objective (MWT) or subjective (ESS) sleepiness, both groups being quite alert. However, TBI participants reported greater consequences of sleepiness on their general productivity (FOSQ), spent more time in bed at night, and napped more frequently and for a longer time during the day. Subjective fatigue was significantly higher in TBI participants on the general, physical, and mental fatigue MFI subscales. There were no between-group differences on any sleep parameters derived either from PSG or sleep diary. CONCLUSIONS: Fatigue appeared to be a more prominent symptom than sleepiness when assessed between 1 and 11 years after TBI. Participants with TBI used compensatory strategies such as increasing time spent in bed and daytime napping in this sample. Future research should document the time course of sleepiness and fatigue after TBI and investigate treatment options.
Buenaver LF, Quartana PJ, Grace EG, Sarlani E, Simango M, Edwards RR, Haythornthwaite JA and Smith MT (2012), "Evidence for indirect effects of pain catastrophizing on clinical pain among myofascial temporomandibular disorder participants: The mediating role of sleep disturbance.", Pain., Mar, 2012.
Abstract: Sleep disturbance and pain catastrophizing are important mediators of the chronic pain experience. To date, these factors have not been considered concurrently despite compelling theoretical rationale to do so. In the present study, we examined whether pain catastrophizing not only has direct effects on clinical pain and pain-related interference, but also indirect effects through its association with sleep disturbance. We evaluated this hypothesis using a cohort (n=214) of myofascial temporomandibular disorder participants using a statistical bootstrapping technique recommended for tests of indirect effects. Results suggested that pain catastrophizing was associated with greater sleep disturbance, and that a significant portion of variance in clinical pain severity and pain-related interference attributable to pain catastrophizing was mediated by sleep disturbance. Supplementary analyses revealed that the rumination component of catastrophizing seemed to be indirectly related to clinical outcomes through sleep disturbance. No evidence for indirect effects was observed for helplessness and magnification components. These results suggest that rumination about pain may contribute to clinical pain indirectly through alterations in sleep. Prospective studies are needed to examine lagged associations between these constructs. These findings have important theoretical and clinical implications. Critically, interventions that reduce pain catastrophizing may concurrently improve sleep and clinical pain.
Drabovicz PVSM, Salles V, Drabovicz PEM and Fontes MJF (2012), "Assessment of sleep quality in adolescents with temporomandibular disorders.", J Pediatr (Rio J)., Mar, 2012.
Abstract: OBJECTIVES: To determine the frequency of temporomandibular disorders and investigate their relationship with sleep quality in 18 and 19-year-old adolescents. METHODS: Cross-sectional design; dysfunctions were diagnosed using the Research Diagnostic Criteria for Temporomandibular Disorders and sleep was assessed using the Pittsburgh Sleep Quality Index in 200 students. Data were analyzed by frequency distribution and using the chi-square test and Student's t test. RESULTS: 35.5% dos adolescents had dysfunctions. The mean total score of adolescents with dysfunctions was 7.34 and 4.76 for adolescents without dysfunctions (p < 0.001). 82% of the participants free from dysfunctions. 17% of those with dysfunctions had good sleep quality. CONCLUSIONS: The frequency of dysfunctions was elevated and dysfunctions were associated with poor sleep quality. The study design does not allow it to be determined whether poor sleep quality is a cause or a consequence of TMDs, which can be elucidated in future studies.
Hakkou J, Rostom S, Mengat M, Aissaoui N, Bahiri R and Hajjaj-Hassouni N (2012), "Sleep disturbance in Moroccan patients with ankylosing spondylitis: Prevalence and relationships with disease-specific variables, psychological status and quality of life.", Rheumatol Int., Mar, 2012.
Abstract: Sleep disturbance is often reported by the patients with ankylosing spondylitis (AS), with awakenings produced by inflammatory pain. There are limited studies about sleep disturbance on these patients, and especially its association with psychological state and quality of life to examine the prevalence of sleep disturbance and to assess its association with disease-specific variables, psychological status and quality of life. One hundred and ten patients were included in this cross-sectional study according to the modified New York criteria for AS. Clinical and biological parameters were evaluated. Sleep disturbance was assessed by the fourth item of Hamilton Anxiety Scale. Psychological status was assessed by The Hospital Anxiety and Depression Scale including depression subscale and anxiety subscale. The quality of life was evaluated by the short form-36 (SF-36). Sleep disturbance was found in 64.5  depression in 55.5 % and anxiety in 60.9 % amongst our patients. Significantly, worse pain, higher disease activity and functional disability were present in patients with sleep disturbance. Likewise, sleep problems were significantly higher in patients with depression, anxiety and in patients with low scores of the SF36. Multivariate logistic regression analysis revealed that the pain (OR = 1.019) and depression (OR = 1.304) were independent risk factors that influenced sleep disturbance. Sleep problems are prevalent amongst Moroccan patients with AS. Our findings suggest that pain and depression were the independent risk factors that influenced the sleep disturbance and hence, the need for evaluation and optimal management of pain and depression to improve sleep quality in AS patients.
Jansson-Fröjmark M, Harvey AG, Norell-Clarke A and Linton SJ (2012), "Associations Between Psychological Factors and Nighttime/Daytime Symptomatology in Insomnia.", Cogn Behav Ther., Mar, 2012.
Abstract: Purpose: The aim of this study was to examine psychological factors in insomnia and the association between psychological mechanisms and nighttime and daytime symptoms. Methods: A cross-sectional examination in the general population was used. The study sample consisted of 1890 participants from the general population. The participants completed a survey on nighttime and daytime symptoms, health outcomes, and psychological factors. Results: Relative to poor and normal sleepers (NSs), the insomnia group had higher scores on worry, beliefs, physiologic arousal, monitoring/attentional bias, and safety behaviors than the other two groups, and the poor sleepers exhibited a similar pattern relative to the NSs. High total wake time was associated with more worry, physiologic arousal, and safety behaviors (26.3% variance), low sleep restoration with more worry, unhelpful beliefs, and monitoring/attentional bias (28.2% variance), and low sleep quality with higher scores on all the psychological mechanisms (35.8% variance). Elevated daytime symptoms were related to more unhelpful beliefs and monitoring/attentional bias (44.3% variance). Conclusion: The findings indicate that psychological factors are linked to nighttime and daytime symptomatology in insomnia.
Kerr S, McKinon W and Bentley A (2012), "Descriptors of restless legs syndrome sensations.", Sleep Med., Mar, 2012.
Abstract: BACKGROUND: Restless legs syndrome (RLS) is characterised by an urge to move in response to unusual sensations in the legs. Patients experience difficulty describing their RLS sensations, resulting in a diverse range of descriptors which have not been fully categorised. The purpose of this study was to describe RLS sensations and to evaluate the accuracy of current diagnostic descriptors. METHODS: Forty-one RLS participants completed an interview which involved: providing spontaneous descriptions of RLS sensations, completing the McGill Pain Questionnaire (MPQ), and selecting descriptors from a list of previously published RLS terms (prompted descriptors). RESULTS: The most frequent spontaneous descriptors were: "irritating" (17, "painful" (17, and "urge to move" (24; prompted descriptors were: "restless" (88, "uncomfortable" (78, and "need to stretch" (76; and MPQ words were: "tingling" (56 and "jumping" (54. DISCUSSION: The most frequently cited descriptors in this study differ from the terminology used in the RLS diagnostic criteria. Inclusion of these frequently used descriptors may improve the diagnostic accuracy of RLS. Our data emphasise the need for an international, large scale, multicultural study to determine the most accurate diagnostic descriptors to define RLS more clearly.
Melamud L, Golan D, Luboshitzky R, Lavi I and Miller A (2012), "Melatonin dysregulation, sleep disturbances and fatigue in multiple sclerosis.", J Neurol Sci., Mar, 2012. Vol. 314(1-2), pp. 37-40.
Abstract: Sleep disruption and fatigue are common in Multiple Sclerosis (MS). Melatonin is one of the major regulators of sleep-wake cycle. The role of melatonin in MS-related sleep disturbances and fatigue as well as the interaction between melatonin and Interferon beta (IFN-?) treatment were the subject of this study.To assess the influence of IFN-? treatment on melatonin secretion, fatigue and sleep characteristics in patients with MS.13 MS patients and 12 healthy controls participated. Fatigue was evaluated using the Fatigue Impact Scale (FIS), sleep was assessed by actigraphy and day/night levels of 6-sulphatoxy-melatonin (6-SMT) in urine were determined using a highly specific ELISA assay.Naïve MS patients demonstrated significantly decreased levels of 6-SMT and disrupted circadian regulation of its secretion, which were increased with IFN-? treatment, in association with improved fatigue. Sleep Efficiency was significantly lower in the MS group compared to controls.Our findings suggest dysregulation of Melatonin secretion in MS, which may be influenced by IFN-? treatment. The results call for further characterization of the role of neuro-hormones such as melatonin in MS, and their cross-regulation with immune-mediators.
Ng MY and Wong WS (2012), "The Differential Effects of Gratitude and Sleep on Psychological Distress in Patients with Chronic Pain.", J Health Psychol., Mar, 2012.
Abstract: This study aimed to examine the possible cross-sectional mediating role of sleep in the relationship of gratitude with depression and anxiety in patients with chronic pain. A total of 224 patients with chronic pain completed structured questionnaires assessing chronic pain, depression and anxiety symptoms, gratitude, and sleep disturbances. Results of multiple regression analyses yielded a modest mediating effect for sleep on the gratitude-depression link whereas a stronger mediating effect was found for sleep on the gratitude-anxiety link. These data show much of the effect of gratitude on depression was direct whereas sleep exerted a stronger mediating effect on the gratitude-anxiety link.
Park S, Cho MJ, Seong S, Shin SY, Sohn J, Hahm B-J and Hong JP (2012), "Psychiatric morbidities, sleep disturbances, suicidality, and quality-of-life in a community population with medically unexplained pain in Korea.", Psychiatry Res., Mar, 2012.
Abstract: We examined the psychiatric morbidities, sleep disturbances, suicidality, quality-of-life, and psychological distress of community-dwelling subjects in Korea who had medically unexplained pain. A total of 6510 subjects (age 18-65years) participated in this study. A medically unexplained pain symptom (MUS-pain) was defined as pain lasting for 6months or longer that was sufficiently severe to cause significant distress or to materially interfere with normal activities in the previous year, and that could not be explained by a medical condition or substance use/abuse. Diagnostic assessments were based on responses to the Composite International Diagnostic Interview, which was administered by lay colleagues. The presence of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) disorders, sleep disturbances, suicidal tendency, quality-of-life issues, and psychological distress were determined in subjects with and without MUS-pain. There were significant positive associations between MUS-pain and nicotine dependence and withdrawal, alcohol dependence, major depressive disorder, dysthymic disorder, bipolar disorder, post-traumatic stress disorder, social phobia, generalized anxiety disorder, and psychotic disorder (p<0.05). In addition, subjects with MUS-pain reported more sleep disturbances, suicidality, psychological distress, and a poorer quality-of-life, than did subjects without MUS-pain. The results of this study suggest that clinicians should carefully evaluate and treat comorbid psychiatric problems in individuals with MUS-pain.
Pinard J-M, Azabou E, Essid N, Quijano-Roy S, Haddad S and Cheliout-Héraut F (2012), "Sleep-disordered breathing in children with congenital muscular dystrophies.", Eur J Paediatr Neurol., Mar, 2012.
Abstract: OBJECTIVE: Most types of neuromuscular diseases are known to be associated with a high risk of sleep-disordered breathing. We performed a prospective study in a well individualized group of muscular disorders, congenital muscular dystrophies (CMD), to characterize the frequency of sleep-disordered breathing and thereby to determine the potential usefulness of sleep studies in such patients. METHODS: Twenty CMD children (12 F, 8 M, aged 4-17 years) were included. Using overnight polysomnography, we determined the following parameters: sleep stages, sleep latency, sleep efficiency index, wake time duration, total sleep time (TST), apnea/hypopnea index (AHI), arterial blood oxygen saturation, and nocturnal paroxysmal EEG activity. RESULTS: As compared to healthy controls, we detected in our study group frequent awakenings, a decreased TST (mean 448 ± 44.4 min) and a decreased REM duration (mean 11.5 ± 3.5% of TST). Significant increase in wake time duration (28-90 min) and decrease in REM duration were observed in 12 patients. An apnea/hypopnea syndrome was detected in 13 patients (65 with central apneas in 8, obstructive apneas in 2 and 3 mixed apneas in 3 patients. AHI was >10 in 3 cases, <10> 5 in 4 cases and were concomitant with blood oxygen de-saturation in four cases. NPA were detected in 10 patients ranging from 10 to 40% of TST. INTERPRETATION: Our results confirm the high incidence of sleep disordered breathing in children with CMD, and thereby, the usefulness of overnight polysomnography recordings in such patients.
Shahid A, Khairandish A, Gladanac B and Shapiro C (2012), "Peeking into the minds of troubled adolescents: The utility of polysomnography sleep studies in an inpatient psychiatric unit.", J Affect Disord., Mar, 2012.
Abstract: BACKGROUND: Sleep problems are commonly associated with the primary diagnostic criteria for many psychiatric disorders. Evidence suggests sleep disturbances may precede development of psychiatric disorders and the severity of psychopathology reflects the severity of sleep problems. Polysomnography (PSG) sleep studies in child and adolescent psychiatric populations, a particularly at risk group, has considerable value but has been more elusive requiring further investigation. METHODS: We performed a retrospective chart review of PSG sleep studies and psychiatrist evaluations of 106 adolescents aged 7-16 admitted to an involuntary adolescent psychiatric inpatient facility. RESULTS: Less than 5% of cases had mild/no sleep problems. Hyperarousal hallmarked this population, and severity of sleep disturbances trends with the severity of psychopathology. Inpatients with multiple psychiatric disorders had greater frequencies of insomnia, decreased sleep efficiency, and arousals from SWS (p<0.05). Inpatients with self-harm behavior more frequently had elevated sleep onset latency (SOL), reduced efficiency, reduced SWS (p<0.05), increased REM, and reduced REM latency compared to inpatients with dysthymia and/or depression. LIMITATIONS: Lacking an a priori hypothesis, this study was explorative and uncontrolled for factors such as medications. This notwithstanding however, analysis indicates the majority of inpatients were taking cocktails that "should" alleviate sleep symptoms suggesting greater associations may prevail in unmedicated populations. CONCLUSIONS: This study attests to the potential clinical utility of PSG sleep studies in the management of adolescent psychiatric disorders and contributes to the body of evidence reputing the intimate connection between sleep problems and the development and perpetuation of psychopathology with public health implications.
Skehan EB, Abdulrahim MMA, Parfrey NA and Hand CK (2012), "A novel locus for restless legs syndrome maps to chromosome 19p in an Irish pedigree.", Neurogenetics., Mar, 2012.
Abstract: Restless legs syndrome (RLS) is a common, sleep-related movement disorder. The symptoms follow a circadian pattern, worsening in the evening or night, leading to sleep disruption and daytime somnolence. Familial forms of RLS have been described and usually display an autosomal dominant pattern of inheritance. To date, linkage analysis has identified nine RLS loci, but no specific causative gene has been reported. Association mapping has highlighted a further four genomic areas of interest. We have conducted a genome-wide linkage analysis in an Irish autosomal dominant RLS pedigree with 11 affected members. Significant linkage was found on chromosome 19p for a series of microsatellite markers, with a maximum two-point LOD score of 3.59 at ??=?0.0 for marker D19S878. Recombination events, identified by haplotype analysis, define a genetic region of 6.57 cM on chromosome 19p13.3, corresponding to an interval of 2.5 Mb. This study provides evidence of a novel RLS locus and provides further evidence that RLS is a genetically heterogenous disorder.
Zhang J, Lam SP, Li SX, Yu MWM, Li AM, Ma RCW, Kong APS and Wing YK (2012), "Long-term outcomes and predictors of chronic insomnia: A prospective study in Hong Kong Chinese adults.", Sleep Med., Mar, 2012.
Abstract: OBJECTIVES: We aimed to determine the longitudinal course and outcome of chronic insomnia in a five-year prospective study in Hong Kong Chinese adults. METHODS: Two thousand three hundred and sixteen middle-aged adults (53.3% females, 46.3±5.1years old at follow-up) were recruited at baseline and follow-up. Participants were divided into three groups: non-insomnia, insomnia symptoms, and insomnia syndrome (insomnia symptoms plus daytime symptoms). Upper airway inflammatory diseases, mental problems, and medical problems were additionally assessed at follow up. RESULTS: The incidence of insomnia (symptoms and syndrome) was 5.9 The persistence rate of insomnia syndrome was 42.7% for insomnia syndrome and 28.2% for insomnia symptoms. New incidence of insomnia was associated with younger age, unemployment, and daytime symptoms, while persistence of insomnia was associated with female sex, lower education level, and daytime symptoms at the baseline (p<0.05). Baseline insomnia syndrome was significantly associated with upper airway inflammatory diseases (including asthma and laryngopharyngitis; adjusted OR=1.97-17.9), mental problems, and medical conditions (including arthritis, psychiatric disorders, chronic pain, and gastroesophageal reflux disease; AOR=2.29-3.77), whereas baseline insomnia symptoms were associated with poor mental health (AOR=2.43), psychiatric disorders (AOR=2.39), and chronic pain (AOR=2.95). CONCLUSIONS: Chronic insomnia is a common problem with considerable persistence and incidence rates among middle-aged Chinese adults. Insomnia syndrome has a higher persistence rate with more mental and medical comorbidities when compared with insomnia symptoms without daytime consequences.
Methodology / Miscellaneous
Liu D, Yang X, Wang G, Ma J, Liu Y, Peng C-K, Zhang J and Fang J (2012), "HHT based cardiopulmonary coupling analysis for sleep apnea detection.", Sleep Med., Mar, 2012.
Abstract: STUDY OBJECTIVES: To validate the feasibility of the Hilbert-Huang transform (HHT) based cardiopulmonary coupling (CPC) technique in respiratory events detection and estimation of the severity of apnea/hypopnea. METHODS: The HHT-CPC sleep spectrogram technique was applied to a total of 69 single-lead ECG signals downloaded from the Physionet Sleep Apnea Database. Sleep spectrograms generated by both the original and the improved CPC method were compared on the structure distribution and time-frequency resolution. The performance of respiratory events detection by using the power of low frequency coupling (pLFC) in the new method was estimated by receiver operating characteristic analysis. Furthermore, correlation between HHT-CPC index (temporal Variability of Dominant Frequency, TVDF) and conventional OSAHS scoring was computed. RESULTS: The HHT-CPC spectrum provides much finer temporal resolution and frequency resolution (8s and 0.001Hz) compared with the original CPC (8.5min and 0.004Hz). The area under the ROC curve of pLFC was 0.79 in distinguishing respiratory events from normal breathing. Significant differences were found in TVDF among groups with different severities of OSAHS (normal, mild, moderate, and severe, p<0.001). TVDF has a strong negative correlation with the apnea/hypopnea index (AHI, correlation coefficient -0.71). CONCLUSIONS: The HHT-CPC spectrum could exhibit more detailed temporal-frequency information about cardiopulmonary coupling during sleep. As two spectrographic markers, pLFC and TVDF can be used to identify respiratory events and represent the disruption extent of sleep architecture in patients with sleep apnea/hypopnea, respectively. The proposed technique might serve as a complementary approach to enhance diagnostic efforts.
Rajaraman S, Ramakrishnan S, Thorsley D, Wesensten NJ, Balkin TJ and Reifman J (2012), "A new metric for quantifying performance impairment on the psychomotor vigilance test.", J Sleep Res., Mar, 2012.
Abstract: We have developed a new psychomotor vigilance test (PVT) metric for quantifying the effects of sleep loss on performance impairment. The new metric quantifies performance impairment by estimating the probability density of response times (RTs) in a PVT session, and then considering deviations of the density relative to that of a baseline-session density. Results from a controlled laboratory study involving 12 healthy adults subjected to 85?h of extended wakefulness, followed by 12?h of recovery sleep, revealed that the group performance variability based on the new metric remained relatively uniform throughout wakefulness. In contrast, the variability of PVT lapses, mean RT, median RT and (to a lesser extent) mean speed showed strong time-of-day effects, with the PVT lapse variability changing with time of day depending on the selected threshold. Our analysis suggests that the new metric captures more effectively the homeostatic and circadian process underlying sleep regulation than the other metrics, both directly in terms of larger effect sizes (4-61% larger) and indirectly through improved fits to the two-process model (9-67% larger coefficient of determination). Although the trend of the mean speed results followed those of the new metric, we found that mean speed yields significantly smaller (?50 intersubject performance variance than the other metrics. Based on these findings, and that the new metric considers performance changes based on the entire set of responses relative to a baseline, we conclude that it provides a number of potential advantages over the traditional PVT metrics.
Truong MT, Woo VG and Koltai PJ (2012), "Sleep endoscopy as a diagnostic tool in pediatric obstructive sleep apnea.", Int J Pediatr Otorhinolaryngol., Mar, 2012.
Abstract: OBJECTIVES: Ten to twenty percent of children have persistent obstructive sleep apnea (OSA) after adenotonsillectomy (T&A). We hypothesize that sleep endoscopy, a flexible fiberoptic examination of the pharynx under anesthesia, is an effective tool for identifying sites of persistent obstruction. METHODS: In this retrospective cohort study, we reviewed records of children who had symptoms consistent with OSA and a positive polysomnogram (PSG) who underwent sleep endoscopy followed by sleep endoscopy directed surgery. Data collection included age, BMI and co-morbidities. Apnea-hypopnea index (AHI) was compared to pre and post surgery for each child using a paired t-test. RESULTS: Of the 80 children who underwent sleep endoscopy followed by directed surgery, 65% were male, mean age was 6years (SD 3.75years), average BMI was 19 (SD 0.43years) and 28% had co-morbidities. For the 51% of patients who had persistent OSA after T&A, the mean AHI after sleep endoscopy directed surgery was significantly lower then before surgery (7.9 vs. 15.7, p<.01). For the 49% of patients who had never undergone surgery for OSA, or who were surgically naïve, and underwent sleep endoscopy directed surgery, the mean AHI was significantly lower then before surgery (8.0 vs. 13.8, p<.01). CONCLUSIONS: Sleep endoscopy is a consistently reliable tool for identifying the sites of obstruction in both surgically naive children and those with persistent OSA after T&A.
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