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Apnea, sleep, obstructive [keywords]
- The Consolidation of Implicit Sequence Memory in Obstructive Sleep Apnea. [JOURNAL ARTICLE]
- PLoS One 2014; 9(10):e109010.
Obstructive Sleep Apnea (OSA) Syndrome is a relatively frequent sleep disorder characterized by disrupted sleep patterns. It is a well-established fact that sleep has beneficial effect on memory consolidation by enhancing neural plasticity. Implicit sequence learning is a prominent component of skill learning. However, the formation and consolidation of this fundamental learning mechanism remains poorly understood in OSA. In the present study we examined the consolidation of different aspects of implicit sequence learning in patients with OSA. We used the Alternating Serial Reaction Time task to measure general skill learning and sequence-specific learning. There were two sessions: a learning phase and a testing phase, separated by a 10-hour offline period with sleep. Our data showed differences in offline changes of general skill learning between the OSA and control group. The control group demonstrated offline improvement from evening to morning, while the OSA group did not. In contrast, we did not observe differences between the groups in offline changes in sequence-specific learning. Our findings suggest that disrupted sleep in OSA differently affects neural circuits involved in the consolidation of sequence learning.
- Adiponectin Alleviates Genioglossal Mitochondrial Dysfunction in Rats Exposed to Intermittent Hypoxia. [JOURNAL ARTICLE]
- PLoS One 2014; 9(10):e109284.
Genioglossal dysfunction is involved in the pathophysiology of obstructive sleep apnea hypoxia syndrome (OSAHS) characterized by nocturnal chronic intermittent hypoxia (CIH). The pathophysiology of genioglossal dysfunction and possible targeted pharmacotherapy for alleviation of genioglossal injury in CIH require further investigation.Rats in the control group were exposed to normal air, while rats in the CIH group and CIH+adiponectin (AD) group were exposed to the same CIH condition (CIH 8 hr/day for 5 successive weeks). Furthermore, rats in CIH+AD group were administrated intravenous AD supplementation at the dosage of 10 µg, twice a week for 5 consecutive weeks. We found that CIH-induced genioglossus (GG) injury was correlated with mitochondrial dysfunction, reduction in the numbers of mitochondrias, impaired mitochondrial ultrastructure, and a reduction in type I fibers. Compared with the CIH group, impaired mitochondrial structure and function was significantly improved and a percentage of type I fiber was elevated in the CIH+AD group. Moreover, compared with the control group, the rats' GG in the CIH group showed a significant decrease in phosphorylation of LKB1, AMPK, and PGC1-α, whereas there was significant rescue of such reduction in phosphorylation within the CIH+AD group.CIH exposure reduces mitochondrial biogenesis and impairs mitochondrial function in GG, while AD supplementation increases mitochondrial contents and alleviates CIH-induced mitochondrial dysfunction possibly through the AMPK pathway.
- Prospective assessment of the risk of obstructive sleep apnea in patients attending a tertiary health facility in Sub-Saharan Africa. [Journal Article]
- Pan Afr Med J 2014.:302.
The impact of Obstructive sleep apnea (OSA) in worsening outcomes is profound, especially in the presence of comorbid conditions. This study aimed to describe the proportion of patients at a high risk of OSA in our practice setting.The STOP BANG questionnaire and the Epworth Sleepiness scale were used to assess for OSA risk and excessive daytime sleepiness respectively. Hospitalized patients and out-patients were recruited. Intergroup differences in continuous variables were compared using the analysis of variance. The proportion of patients with high risk of OSA and excessive daytime sleepiness was presented as frequencies and group differences compared with the Pearson χ(2) test. Independent risk predictors for OSA were assessed in multivariate logistic regression analysis.A total of 1100 patients (53.4% females) participated in the study. Three hundred and ninety nine (36.3%) had a high risk of OSA, and 268 (24.4%) had excessive daytime sleepiness. Of the participants with high OSA risk, 138 (34.6%) had excessive daytime sleepiness compared to 130 (18.5%) of those with low OSA risk (p).A significant proportion of patients attending our tertiary care center are at high risk of OSA.
- [Multisystemic involvement in obstructive sleep apnea]. [English Abstract, Journal Article]
- Rev Med Chil 2014 Jun; 142(6):748-57.
Obstructive Sleep Apnea (OSA) is characterized by repetitive upper airway collapse with apnea/hypopnea and recurrent hypoxia during sleep, which results in fragmented sleep and intermittent drops in arterial blood oxygen saturation (hypoxemia). Several dysfunctions of neurocognitive, endocrine, cardiovascular, and metabolic systems are recognized in patients with OSA. The most commonly reported associations are with obesity, increased cardiovascular risk, dyslipidemia, diabetes mellitus 2 and liver damage. However, there is a proven relationship between OSA and other diseases, such as polycystic ovary syndrome, gastroesophageal reflux, and chronic kidney disease. The aim of this review is to analyze clinical and experimental evidence linking OSA with other diseases.
- Sleep Architecture Following a Weight Loss Intervention in Overweight and Obese Patients with Obstructive Sleep Apnea and Type 2 Diabetes: Relationship to Apnea-Hypopnea Index. [JOURNAL ARTICLE]
- J Clin Sleep Med 2014 Oct 17.
To determine if weight loss and/ or changes in apnea-hypopnea index (AHI) improve sleep architecture in overweight/ obese adults with type 2 diabetes (T2D) and obstructive sleep apnea (OSA).This was a randomized controlled trial including 264 overweight/ obese adults with T2D and OSA. Participants were randomized to an intensive lifestyle intervention (ILI) or a diabetes and support education (DSE) control group. Measures included anthropometry, AHI, and sleep at baseline and year-1, year-2, and year-4 follow-ups.Changes in sleep duration (total sleep time [TST]), continuity [wake after sleep onset (WASO)], and architecture stage 1, stage 2, slow wave sleep, and REM sleep) from baseline to year 1, 2, and 4 did not differ between ILI and DSE. Repeated-measure mixed-model analyses including data from baseline through year-4 for all participants demonstrated a significant positive association between AHI and stage 1 sleep (p < 0.001), and a significant negative association between AHI and stage 2 (p = 0.01) and REM sleep (p < 0.001), whereas changes in body weight had no relation to any sleep stages or TST. WASO had a significant positive association with change in body weight (p = 0.009).Compared to control, the ILI did not induce significant changes in sleep across the 4-year follow-up. In participants overall, reduced AHI in overweight/ obese adults with T2D and OSA was associated with decreased stage 1, and increased stage 2 and REM sleep. These sleep architecture changes are more strongly related to reductions in AHI than body weight, whereas WASO may be more influenced by weight than AHI.NCT00194259.
- Sleep Disorders Associated with Primary Mitochondrial Diseases. [JOURNAL ARTICLE]
- J Clin Sleep Med 2014 Oct 17.
Primary mitochondrial diseases are caused by heritable or spontaneous mutations in nuclear DNA or mitochondrial DNA. Such pathological mutations are relatively common in humans and may lead to neurological and neuromuscular complication that could compromise normal sleep behavior. To gain insight into the potential impact of primary mitochondrial disease and sleep pathology, we reviewed the relevant English language literature in which abnormal sleep was reported in association with a mitochondrial disease.We examined publication reported in Web of Science and PubMed from February 1976 through January 2014, and identified 54 patients with a proven or suspected primary mitochondrial disorder who were evaluated for sleep disturbances.Both nuclear DNA and mitochondrial DNA mutations were associated with abnormal sleep patterns. Most subjects who underwent polysomnography had central sleep apnea, and only 5 patients had obstructive sleep apnea. Twenty-four patients showed decreased ventilatory drive in response to hypoxia and/ or hyperapnea that was not considered due to weakness of the intrinsic muscles of respiration.Sleep pathology may be an underreported complication of primary mitochondrial diseases. The probable underlying mechanism is cellular energy failure causing both central neurological and peripheral neuromuscular degenerative changes that commonly present as central sleep apnea and poor ventilatory response to hyperapnea. Increased recognition of the genetics and clinical manifestations of mitochondrial diseases by sleep researchers and clinicians is important in the evaluation and treatment of all patients with sleep disturbances. Prospective population-based studies are required to determine the true prevalence of mitochondrial energy failure in subjects with sleep disorders, and conversely, of individuals with primary mitochondrial diseases and sleep pathology.
- Does Neck-to-Waist Ratio Predict Obstructive Sleep Apnea in Children? [JOURNAL ARTICLE]
- J Clin Sleep Med 2014 Oct 17.
Central adiposity and large neck circumference are associated with obstructive sleep apnea (OSA) in adults but have not been evaluated in children as predictors of OSA. Study objectives were to determine whether (1) anthropometric measures including neck-to-waist ratio are associated with OSA in older children; (2) body fat distribution, measured by neck-to-waist ratio, is predictive of OSA in overweight/ obese children.Cross-sectional study involving children 7-18 years scheduled to undergo polysomnography at a tertiary care children's hospital. OSA was defined as total apnea-hypopnea index >5 events/h and/ or obstructive apnea index >1 event/h. Recursive partitioning was used to select candidate predictors of OSA from: age, sex, height and weight percentile, body mass index (BMI) z-score, neck-to-waist ratio, tonsil size, and Mallampati score. These were then evaluated using log binomial models and receiver operator characteristic analysis.Two hundred twenty-two participants were included; 133 (60%) were overweight/ obese, 121 (55%) male,47 (21%) had OSA. Neck-to-waist ratio (relative risk [RR] 1.97 per 0.1 units, 95% CI 1.48 to 2.84) and BMI z-score (RR 1.63 per unit, 95% CI 1.30 to 2.05) were identified as independent predictors of OSA. Considering only overweight/ obese children, neck-to-waist ratio (RR 2.16 per 0.1 units, 95% CI 1.79 to 2.59) and BMI z-score (RR 2.02 per unit, 95% CI 1.25 to 3.26) also independently predicted OSA. However, in children not overweight/ obese, these variables were not predictive of OSA.Neck-to-waist ratio, an index of body fat distribution, predicts OSA in older children and youth, especially in those who were overweight/ obese.
- Obstructive Sleep Apnea Is Associated with Impaired Exercise Capacity: A Cross-Sectional Study. [JOURNAL ARTICLE]
- J Clin Sleep Med 2014 Oct 17.
Obstructive sleep apnea (OSA) is associated with increased risk of adverse cardiovascular events. Because cardiopulmonary exercise testing (CPET) aids in prognostic assessment of heart disease, there is rising interest in its utility for cardiovascular risk stratification of patients with OSA. However, the relationship between OSA and exercise capacity is unclear. This study was conducted to test the hypothesis that OSA is associated with impaired exercise capacity.Fifteen subjects with moderate-to-severe OSA (apnea-hypopnea index [AHI] ≥15 events/h) and 19 controls with mild or no OSA (AHI <15 events/h) were enrolled. Subjects underwent standard polysomnography to determine AHI and exclude other sleep disorders. Resting metabolic rate was measured via indirect calorimetry, followed by maximum, symptom-limited CPET. Subjects completed a sleep diary and physical activity questionnaire characterizing behaviors in the week prior to testing.Percent predicted peak oxygen uptake (V˙O2) was significantly lower in OSA subjects than controls (70.1%±17.5% vs 83.8%±13.9%; p = 0.02). Each 1-unit increase in log-transformed AHI was associated with a decrease in percent predicted peak V˙O2 of 3.20 (95% CI 0.53-5.88; p = 0.02). After adjusting for baseline differences, this association remained significant (p < 0.01). AHI alone explained 16.1% of the variability observed in percent predicted peak V˙O2 (p = 0.02).OSA is associated with impaired exercise capacity. Further study is needed to evaluate the utility of CPET for prognostic assessment of patients with OSA.
- The Impact of Recent Changes to the Respiratory Scoring Rules in Pediatrics. [JOURNAL ARTICLE]
- J Clin Sleep Med 2014 Oct 17.
In 2007 the American Academy of Sleep Medicine (AASM) published polysomnography (PSG) scoring guidelines, which were updated in 2012. A key change in terms of scoring respiratory events in children was the threshold for reduction in airflow (50% vs 30%) for the definition of hypopnea. This study aimed to determine the impact of different scoring rules on the assessment of severity of obstructive sleep apnea (OSA) in children.Forty-two children (mean age 4.3 y, 16 F) underwent PSG. An obstructive apnea-hypopnea index (OAHI) was determined using three scoring rules: (1) ATS 1996 rules with minor modifications (modified ATS 1996); (2) AASM 2007 rules (AASM 2007); and (3) AASM 2007 rules with respiratory event related arousals included in the OAHI (AASM+RERA).The AASM 2007 OAHI (median 0.4 events/h, range 0, 14) was lower than the modified ATS 1996 OAHI (median 0.8 range 0, 26.1, p < 0.001), underestimating severity of disease in 24% of cases. The AASM+RERA OAHI (median 0.8, range 0, 19.1) was also lower than the modified ATS 1996 OAHI (p = 0.02), but the difference was not clinically significant except at very high OAHIs.The AASM 2007 rules lead to a lower OAHI and lesser OSA severity when compared to the previous standard. Inclusion of RERAs in the AASM 2007 OAHI leads to a comparable OAHI to the previous rules. Given that morbidity has been demonstrated even in mild OSA, these results support the inclusion of events with a reduction in airflow of less than 50% as included in the updated AASM rules in 2012.
- Overnight Pulse Oximetry for Evaluation of Sleep Apnea among Children with Trisomy 21. [JOURNAL ARTICLE]
- J Clin Sleep Med 2014 Oct 17.
For children with trisomy 21, polysomnography at age 4 to assess obstructive sleep- disordered breathing (OSDB) is the standard of care. Oximetry alone has been used to screen for disease among children without trisomy 21. This study evaluates the potential usefulness of oximetry scoring in diagnosing OSDB among children with trisomy 21.A McGill oximetry score from 1 to 4 was derived from a full overnight PSG done on 119 consecutive pediatric subjects with trisomy 21. Most were referred to the sleep laboratory because of suspicion for OSDB. Oximetry scorers were blinded to the child's full PSG and clinical course. Results of the complete PSG were then compared to oximetry scores.Obstructive apnea/hypopnea index (OAHI) was ≥2.5 for 50% of all subjects. Fifty-nine subjects (49.6%) had McGill Score 1 ("inconclusive"); median OAHI was 1.0 (IQR 0.4-3.3). McGill Score was 2 for 43 subjects (36.1%); median OAHI was 4.5 (IQR 1.3-8.8). Seventeen subjects (14.3%) had McGill Scores of 3 or 4; median OAHI was 16.1 (IQR 9.3-45.5, range 2.1 to 101.1). Ten percent of subjects had a considerable number of central events (≥2.5 respiratory events/h but OAHI <2.5), including 7 with McGill Score 2.In a retrospective cohort of children with trisomy 21, McGill oximetry scores of 3 or 4 reliably identified patients with marked OSDB. The possibility of central apneas causing hypoxemia must be considered in those with McGill Score 2. With these caveats, oximetry screening should be considered when developing streamlined protocols for early intervention to treat OSDB in this population.