Sleep Disorders
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Prevalence of Restless Legs Syndrome among Medical Students of Karachi: An Experience from a Developing Country

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Sleep Disorders publishes original research articles, review articles, and clinical studies related to all aspects of sleep disorders.

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Research Article

Daytime QT by Routine 12-Lead ECG Is Prolonged in Patients with Severe Obstructive Sleep Apnea

Background. Obstructive sleep apnea (OSA) has been linked to sudden cardiac death (SCD). Prolonged QT is a recognized electrocardiographic (ECG) marker of abnormal ventricular repolarization linked to increased risk of SCD. We hypothesized that individuals with OSA have more pronounced abnormality in daytime QT interval. Methods. We reviewed consecutive patients who underwent clinically indicated polysomnography with 12-lead ECG within 1 year at a single center. Heart rate-corrected QT interval (QTc) was compared by OSA severity class (normal/mild: (); moderate: 15-30 (); severe: >30 ()) adjusting for body mass index, age, sex, hypertension, and heart failure. Further evaluation was performed by dividing patients into severe () and nonsevere (<30) OSA. Logistic analysis was used to determine association of OSA severity and abnormal QTc (>450/>470 ms for men/women, respectively). Results. A total of 249 patients were included. QTc was similar between the normal/mild and moderate groups, and the overall QTc trend increased across OSA (normal/mild: 435.6 ms; moderate: 431.36; severe: 444.4; ). Abnormal QTc was found amongst 34% of male and 31% of female patients. Patients with severe OSA had longer QTc compared with normal/mild OSA (mean difference (95% CI): 10.0 ms (0.5, 19.0), ). When stratified dichotomously (as opposed to three groups), patients with severe OSA again had longer QTc (vs. nonsevere OSA) (444.4 ms vs. 433.48 ms, ). Severe OSA was also associated with abnormal QTc (OR (95% CI): 2.68 (1.34, 5.48), ). Conclusions. In a sleep clinic cohort, severe OSA was associated with higher QTc and clinically defined abnormal QTc compared with nonsevere OSA.

Research Article

An fMRI Study of the Effects of Vibroacoustic Stimulation on Functional Connectivity in Patients with Insomnia

Background. It is well known that vibratory and auditory stimuli from vehicles such as cars and trains can help induce sleep. More recent literature suggests that specific types of vibratory and acoustic stimulation might help promote sleep, but this has not been tested with neuroimaging. Thus, the purpose of this study was to observe the effects of vibroacoustic stimulation (providing both vibratory and auditory stimuli) on functional connectivity changes in the brain using resting state functional magnetic resonance imaging (rs-fMRI), and compare these changes to improvements in sleep in patients with insomnia. Methods. For this study, 30 patients with insomnia were randomly assigned to receive one month of a vibroacoustic stimulation or be placed in a waitlist control. Patients were evaluated pre- and postprogram with qualitative sleep questionnaires and measurement of sleep duration with an actigraphy watch. In addition, patients underwent rs-fMRI to assess functional connectivity. Results. The results demonstrated that those patients receiving the vibroacoustic stimulation had significant improvements in measured sleep minutes as well as in scores on the Insomnia Severity Index questionnaire. In addition, significant changes were noted in functional connectivity in association with the vermis, cerebellar hemispheres, thalamus, sensorimotor area, nucleus accumbens, and prefrontal cortex. Conclusions. The results of this study show that vibroacoustic stimulation alters the brain’s functional connectivity as well as improves sleep in patients with insomnia.

Research Article

Disparities in Sleep Health among Adolescents: The Role of Sex, Age, and Migration

Background. Disparities in sleep disturbances have been described in adults; nevertheless, among adolescents, data have yielded conflicting results. Therefore, analyses of our cohort study of 500 urban, normally developed Hispanic adolescents (10–18 years), aim to determine if rates of sleep debt differ between: (a) male and female adolescents, (b) US-born Hispanics and first-generation immigrant ethnic counterparts, and (c) specific activities that these teens trade for sleep. Participants’ weekday and weekend sleep patterns, along with the reasons for sleeping less than the recommended hours were recorded. Standardized surveys were used to gather information regarding sociodemographics, migration, acculturation, and medical history. Using the criteria set forth by the National Sleep Foundation, analyses indicated that sleep deprivation is a pervasive problem, with 75% in the preadolescents and 45% of the late adolescents exhibiting sleep problems. Females slept on average at least one hour less per day than their male counterparts (7 vs. 8 hours). The sleep problems were rooted in several overlapping causes, including use of technology, video games, studying, and employment. Nevertheless, reasons for sleep loss differed by gender and by immigrant status. Multivariable adjusted logistic regression analyses showed that females, US-born teens, and preadolescents had higher odds of being sleep deprived. Pediatricians and sleep experts should be aware of gender-specific causes and responses of sleep problems. Cultural ecological frameworks need to be considered, and clearly indicate that findings may not generalize to youth from other cultural backgrounds.

Research Article

Sleep Quality of Hospitalized Patients, Contributing Factors, and Prevalence of Associated Disorders

Background. Data in the literature has shown poor sleep quality to be frequently observed in hospitalized patients and known to be associated with poor treatment outcome. Many factors may impact poor sleep quality, and there is currently limited available data. We aim to determine the prevalence of poor sleep quality and associated factors in patients admitted to internal medicine wards as well as the change of sleep quality over time after admission. Methods. An analytic observational study was conducted at the internal medicine wards at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Patients were personally interviewed to evaluate the history of sleep quality at home, sleep quality after the first and the third days of admission, and potential associated factors. The Pittsburgh Sleep Quality Index and screening questionnaires for the common diseases associated with poor sleep quality were also utilized. The logistic regression analysis was used to determine the independent factors which led to poor sleep quality. Results. Data were collected from 96 patients during the period of June 2015 to February 2016. The mean age of the patients was years, and 51% were male. Infectious disease was the most common principal diagnosis accounted for 29.2%. The results show high prevalence of poor sleep quality after the first night of admission compared to baseline sleep quality at home (50% vs. 18.8%; ). After 3 days of admission, the prevalence of poor sleep quality was reduced to the level close to baseline sleep quality at home (28.1% vs. 18.8%; ). Multivariate analysis demonstrated that light exposure and pain were the main independent factors for poor sleep quality on the first day (odds ratio 6.68; 95% CI 2.25-19.84) and on the third day (odds ratio 3.47; 95% CI 1.24-9.71), respectively. Conclusions. This is the first study conducted on the sleep quality of hospitalized patients that included the follow-up period during hospital admission. Our study demonstrated high prevalence of poor sleep quality in hospitalized patients on the first day. Interestingly, the sleep quality was partly improved during hospitalization. Light exposure and pain were demonstrated to be the factors associated with poor sleep quality.

Research Article

Can We Use Home Sleep Testing for the Evaluation of Sleep Apnea in Obese Pregnant Women?

Objective. To evaluate the performance of a type III home sleep testing (HST) monitor including its autoscoring algorithm, in a population of obese pregnant women. Methods. This was an ancillary study of an ongoing prospective study of obese (BMI of ≥30) pregnant women. For the primary study, women undergo serial in-lab polysomnograms (PSG) during pregnancy. Sleep apnea was defined as an apnea hypopnea index (AHI) of ≥ 5 events/hour. A subgroup of women were asked to wear an ApneaLink HST device for 1 night, within 2 weeks of a late pregnancy PSG (≥ 28 weeks’ gestation). The AHI obtained from PSG was compared to the AHI from the HST via autoscoring (HST-auto) as well as the AHI via technician scoring (HST-tech). We calculated Shrout Fleiss Fixed correlation coefficients (ICC) and looked at positive-positive and negative-negative agreement. Results. 43 women were recruited and we obtained 30 valid HST. The mean PSH AHI was 3.3 (±3.2, range 0.5-16.6). Six (20%) women had a positive PSG study. ICCs were 0.78 for HST-auto versus HST-tech, 0.76 for HST-auto versus PSG, and 0.70 for HST-tech versus PSG. Categorical agreement was also strong, with 24/30 (80.0%) for HST-auto versus HST-tech, 25/30 (83.3%) for HST-auto versus PSG, and 23/30 (76.7%) for HST-tech versus PSG. Conclusion. In obese women evaluated in late pregnancy, we found relatively high intraclass correlation and categorical agreement among HST-auto scores, HST-tech scores, and in-lab PSG results obtained within a two-week window. These results suggest that HST may be used to screen pregnant women for OSA.

Research Article

Neck Grasp Predicts Obstructive Sleep Apnea in Type 2 Diabetes Mellitus

Aims. Obstructive sleep apnea (OSA) is a common disorder with high morbidity, mortality, and an increasing prevalence in the general population. It has an even higher prevalence among individuals with type 2 diabetes mellitus (DM). The snoring, tiredness, observed apnea, high blood pressure, body-mass-index, age, neck circumference and male gender (STOP-BANG) questionnaire and Berlin Questionnaire can be cumbersome in clinical practice and require subjective data on sleepiness. We proposed prospectively studying a primary care population with type 2 DM comparing neck grasp, neck circumference, and common screening questionnaires to identify OSA. Methods. Persons with a diagnosis of type 2 DM were recruited from a primary care clinic. Participants were screened using Easy Sleep Apnea Predictor (ESAP), STOP-Bang questionnaire, and Berlin questionnaire. A positive ESAP was defined as a 1cm gap when a patient encircled their hands around the neck. All subjects underwent in-laboratory PSG testing. Results. Forty-three participants were enrolled and the prevalence of OSA was 90.7% (AHI ≥ 5). The median BMI was 38.0. The prevalence of mild OSA by PSG (AHI 5-14) was 27.9%, moderate OSA (AHI 15-29) was 25.6%, and severe OSA (AHI >30) was 37.2%. For mild OSA both ESAP and neck circumference showed 100% specificity. Conclusions. This study reinforces the need for screening diabetic persons for obstructive sleep apnea. ESAP and neck circumference are useful for identifying persons with type 2 DM who are at risk for OSA. Together these findings could improve recognition of OSA in persons at risk for cardiovascular disease. Trial Registration of “Neck grasp as a predictor of Sleep Apnea,” https://clinicaltrials.gov/ct2/show/NCT02474823, Clinical Trials.gov Identifier, is NCT02474823.

Sleep Disorders
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