Changes in cognitive function associated with sleep disordered breathing in older people

OBJECTIVES: Sleep disordered breathing (SDB) is very common in older people and is known to be associated with complaints of impaired daily functioning, including excessive daytime sleepiness and cognitive impairments. As part of a larger study on SDB and aging, it became possible to examine the relationship between SDB and cognition in older men and women. DESIGN: A population-based longitudinal study. SETTING: In-home interviews and home sleep recordings in the greater San Diego area. PARTICIPANTS: Community-dwelling people age 65 and older with high risk for SDB were originally studied from 1981 through 1985 and then followed every 2 years. Data from the 46 subjects who completed Visit 3 and Visit 4 are presented. MEASUREMENTS: Subjects were interviewed in the home about their sleep and medical condition before each visit. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Daytime sleepiness was based on self-report. Objective sleep was recorded in the home and scored for sleep, apneas and hypopneas, and oximetry variables. RESULTS: Increases in respiratory disturbance index (RDI) (P= .036) and increases in daytime sleepiness (P= .002) were associated with decreases in cognitive performance (i.e., increases in cognitive impairment). Increases in RDI were also associated with increases in daytime sleepiness (P= .012). Change in MMSE scores was therefore regressed onto changes in RDI, daytime sleepiness, age, and education, resulting in decreases in MMSE scores being associated with increases in daytime sleepiness (P= .019) but not with changes in RDI (P= .515). There was no significant relationship between changes in oxygen saturation levels and changes in MMSE. CONCLUSIONS: The results of this study suggest that declining cognitive function is associated primarily with increases in daytime sleepiness. Although cognitive decline was also associated with increases in RDI, this association did not hold in the more inclusive model which also included variable of SDB, oximetry, sleep and subjective report. One theoretical model could suggest that any relationship between SDB and cognitive function may be mediated by the effect of SDB on daytime sleepiness. These results suggest that older patients suffering from mild to moderate SDB may benefit from the treatment of SDB, even if they are not markedly hypoxemic.     

Prevalence of snoring and sleep-disordered breathing in a student population

INTRODUCTION: The prevalence of snoring and sleep-disordered breathing (SDB) in young adults in Southeast Asian countries is unknown. We aim to determine the symptoms and prevalence of SDB in a university student population using a questionnaire survey followed by home sleep monitoring. METHODS: The Sleep and Health Questionnaire (a modified version of the Specialized Centers of Research Sleep Questionnaire, translated into Chinese) was distributed to all first-year students (1,306 male and 1,757 female) enrolled in the Chinese University of Hong Kong. Subsequently, those students who returned the questionnaires were randomly chosen to undergo portable home sleep monitoring using the MESAM IV device (Madaus Medizin-Elektronik; Freiburg, Germany). RESULTS: A total of 1,910 replies were obtained from 3,063 questionnaires sent by mail (response rate, 62.4%). The female to male ratio was 1.8:1, with mean age of 19.4 years (SD, 1.3 years) and mean body mass index (BMI) of 20.0 (SD, 2.5). Overall, 25.7% of subjects reported snoring; 10.7% and 42.1% reported impaired performance ability and daytime sleepiness, respectively. Of the 88 subjects who underwent overnight sleep monitoring, 66 subjects (75%) were snorers and 8 subjects (9%) snored > 10% of the night. Male subjects had a higher BMI (p < 0.001) and tended to snore more often than female subjects (p = 0.06). Subjects with an oxygen desaturation index (ODI) > or = 3 had a BMI > 22 (p < 0.05). On sleep study, nine subjects (10.2%) and two subjects (2.3%) had a respiratory disturbance index (RDI) > or = 3 and an RDI > or = 5, respectively, associated with self-reported sleepiness, giving a minimum estimated prevalence of SDB as 0.1% (RDI > or = 5) in the study population. There was no correlation between recorded snoring with either RDI or self-reported sleepiness. Questionnaire responses, neck circumference, and alcohol consumption did not predict the occurrence of SDB. CONCLUSION: Snoring was prevalent, while SDB was uncommon in this student population. However, snoring and self-reported symptoms by questionnaire were poor predictors for SDB. Male gender showed a trend as an independent predictor for snoring, but not for SDB.     

Nocturnal hypoxemia biomarker predicts sleepiness in patients with severe obstructive sleep apnea

Purpose

This study aims to assess the association between excessive daytime sleepiness (EDS) and variables extracted from the pulse-oximetry signal obtained during overnight polysomnography.

Methods

A cross-sectional design was used to study the relation between four hypoxemia variables and EDS as determined by Epworth Sleepiness Scale scores (ESSS) in 200 consecutive patients, newly diagnosed with obstructive sleep apnea (OSA), as defined by an apnea–hypopnea index (AHI)?≥?15. Hypoxemia measurements were compared between sleepy (ESSS?≥?10) and nonsleepy (ESSS?<?10) patients before and after dichotomizing the cohort for each hypoxemia variable (and for AHI) such that there were 35 (165) patients in each of the corresponding higher (lower) subcohorts. The hypoxemia variables were combined into a biomarker, and its accuracy for predicting sleepiness in individual patients was evaluated. We planned to interpret prediction accuracy above 80 % as evidence that hypoxemia predicted EDS.

Results

Hypoxemia was unassociated with sleepiness in OSA patients with AHI in the range of 15 to 50. In patients with AHI?>?50, the hypoxemia biomarker (but not individual hypoxemia variables) predicted sleepiness with 82 % accuracy.

Conclusion

Nocturnal hypoxemia as determined by a polyvariable biomarker reliably predicted EDS in patients with severe OSA (AHI?>?50), indicating that oxygen fluctuation had a direct role in the development of EDS in patients with severe OSA.     

The effect of race and sleep-disordered breathing on nocturnal BP "dipping": analysis in an older population

STUDY OBJECTIVES: BP normally drops (or "dips") by approximately 10% at nighttime; however, in a number of illnesses there is an increased amount of "nondipping" of nocturnal BP. This study examined whether nondipping in older African Americans and older white subjects is related to the presence of sleep-disordered breathing (SDB) and hypertension. DESIGN: Prospective study with a convenience sample. SETTING: All data were collected in the subjects' homes. PARTICIPANTS: Seventy self-defined African Americans with complaints of snoring or excessive daytime sleepiness, and 70 age-matched and gender-matched white subjects. Measurements and results: Sleep was recorded for 2 nights, with 1 night of oximetry. BP was recorded on a separate 24-h period. African Americans had higher dipping ratios than white subjects even after accounting for covariates such as respiratory disturbance index (RDI), oxygen desaturation index (ODI), body mass index, and average 24-h mean arterial pressure (p = 0.025). Higher values of RDI (R(2) = 0.0686, p = 0.021) and ODI (R(2) = 0.042, p < 0.03) were correlated with higher dipping ratios in both African Americans and white subjects. However, there was a three-way interaction such that higher RDIs were correlated primarily with nondipping in African Americans receiving antihypertensive medication (R(2) = 0.0373, p = 0.022). CONCLUSIONS: These results demonstrated that African Americans tend to be "nondippers," while white subjects tended to be "dippers." This nondipping was not a result of weight, gender, or of having SDB. The analyses also confirmed that, in both races, the dipping ratio was greatest in those with SDB and hypertension. The third hypothesis, that RDI would be greatest in the nondipping hypertensive subjects, was true only for the African Americans.     

Relationship between 24-H blood pressure and sleep disordered breathing in a normotensive community sample

Sleep disordered breathing (SDB) and hypertension are commonly associated. In this study, we assessed how longitudinal measures of SDB predict a 24-h ambulatory blood pressure monitoring (ABPM) profile. Participants (n = 82) were recruited from a community-based urban (26% African American) sample and included family members of patients with laboratory diagnosed SDB (cases) and family members of neighborhood control subjects evaluated at baseline and at 5 years. Nearly all participants were normotensive and were not receiving therapy for SDB. During both examinations, the respiratory distress index (RDI) was assessed with overnight in-home polysomnography. Seated blood pressure (BP) was assessed at a baseline examination (t₁) and after a 5-year follow-up period (t₅), when 24-h ABPM also was performed.The change in RDI (t₅−t₁) over 5 years was significantly associated with 24-h mean systolic blood pressure (SBP) (P = .04), 24-h maximum diastolic blood pressure (DBP) (P = .03), sleep mean SBP (P = .05), sleep mean DBP (P < .05), and sleep maximum SBP (P = .02). Regression analysis revealed that average 24-h mean arterial pressure (MAP) and mean 24-h DBP were each best predicted by change in RDI, explaining 5% of the variance in these 24-h BP readings, and by current smoking status. After accounting for these variables, BP was not predicted by any of the other potential confounders (all P > .10). Mean RDI (averaged between t₅ and t₁) was associated with mean MAP, mean SBP, and maximal SBP measured during sleep. This study documents for the first time the association between changes in sleep apnea activity and BP and in a community-based normotensive sample. Further long-term evaluation of the effects of these findings and the long-term consequences of hypertension are needed.     

Prevalence of snoring and sleep-disordered breathing in a group of commercial bus drivers in Hong Kong

Objectives: To assess the prevalence of sleep‐­disordered breathing (SDB) and its associated symptoms in a group of commercial bus drivers in Hong Kong. Methods: Two hundred and sixteen of 410 bus drivers from three different shifts were interviewed with the Sleep & Health Questionnaire (SHQ) and the Epworth sleepiness scale (ESS) at a Hong Kong bus depot. Seventeen subjects from each shift were then randomly selected for at‐home sleep study using the Mesam IV device (Madaus Medizin?Elektronik, Freiburg, Germany). Results: There were 207 men and nine women (mean age 42.4 ± 7.5 years; body mass index (BMI) 25.4 ± 4.5 kg/m²; ESS 5.3 ± 4.2). From the SHQ it was discovered that: (i) daytime sleepiness was reported by 87 subjects (40%), (ii) snoring ≥ 3 times per week was reported by 80 subjects (37%), (iii) witnessed apnoea was reported by 17 subjects (7.9%) and (iv) 29 subjects (13.4%) reported having fallen asleep during driving. Among the 51 subjects who underwent the at‐home sleep study: (i) 31 subjects (61%) had respiratory disturbance index (RDI) ≥ 5 per hour of sleep, (ii) 21 subjects (41%) had RDI ≥ 10 per hour of sleep, (iii) 12 subjects (24%) had RDI ≥ 15 per hour of sleep and (iv) 35 subjects (68.6%) snored objectively ≥ 10% of the night. Ten subjects (20%) had RDI ≥ 5 and sleepiness at work, while five subjects (9.8%) had RDI ≥ 5 and ESS > 10. No significant differences were noted in the SHQ responses, ESS, objective snoring or RDI among the three groups. Multiple regression analysis showed that BMI and witnessed apnoea were the only positive independent predictors of RDI. Conclusions: This study showed a high prevalence of objective snoring and SDB in a group of commercial bus drivers. Neither self‐reported sleepiness nor the ESS could identify subjects with SDB. (Intern Med J 2002; 32: 149?157)     

A 3-year longitudinal study of sleep disordered breathing in the elderly

Limited and controversial data exist on the natural evolution of sleep disordered breathing (SDB) in untreated individuals. This study examines the evolution of SDB over a 3-yr period in a community-based sample of elderly subjects. From the initial cohort of 854 healthy subjects aged mean±sd 68.4±0.8 yrs, 519 untreated subjects accepted clinical and instrumental follow-up 3.6±1.6 yrs later. SDB was defined as a respiratory disturbance index (RDI) >15 events·h(-1). At baseline, 202 (39%) subjects had an RDI ≤15 events·h(-1) and 317 (61%) had an RDI >15 events·h(-1). 3 yrs later, 280 (54%) subjects were non-SDB and 239 (46%) had SDB. Between evaluations, the RDI decreased from 22.3±16.2 to 16.4±13.0 events·h(-1), with a greater decrease in the number of cases with an RDI >30 events·h(-1) that in those with RDI ≥30 events·h(-1). In the non-SDB group, 81% had a stable RDI and 19% increased their RDI by a mean of 13.7 events·h(-1). In the SDB group, the RDI decreased to values ≤15 events·h(-1) in 36.6% of cases, 63.4% still having SDB. The RDI changes did not depend on weight changes. In healthy elderly subjects, the prevalence and severity of SDB did not show a tendency toward natural worsening, some cases having improvement or a remission independent of weight changes. These findings also suggest that in the elderly, natural SDB progression is still hypothetical.     

Sleep-disordered breathing is associated with depletion of circulating endothelial progenitor cells and elevation in pulmonary arterial pressure in patients with decompensated systolic heart failure

Background Sleep-disordered breathing (SDB) is known to occur frequently in and may predict worsening progression of patients with congestive heart failure (CHF). SDB is also known to play an important role in the development of idiopathic pulmonary arterial hyperten?sion (PAH) via inducing endothelial dysfunction and vascular remodeling, a pathological process that can be significantly influenced by factors such as osteoprotegerin (OPG) and endothelial progenitor cells (EPCs). The objective of this study is to determine if CHF with SDB is associated with changes in OPG, EPCs, and PAH. Methods EPCs were isolated, cultured, and quantified from CHF patients with SDB (n = 52), or without SDB (n = 68). OPG and N-terminal pro-brain natriuretic peptide (NT-proBNP) from each group was analyzed and correlated with EPCs and the mean pulmonary artery pressure (mPAP) measured by right heart catheterization. Results A significant decrease in circulating EPCs (29.30 ± 9.01 vs. 45.17 ± 10.51 EPCs/× 200 field; P < 0.05) was found in CHF patients with SDB compared to those without SDB. Both OPG (789.83 ± 89.38 vs. 551.29 ± 42.12 pg/mL; P < 0.05) and NT-proBNP (5946.50 ± 1434.50 vs. 3028.60 ± 811.90 ng/mL; P < 0.05) were also significantly elevated in SDB CHF patients who also had significantly elevated mPAP (50.2 ± 9.5 vs. 36.4 ± 4.1 mm Hg; P < 0.05). EPC numbers correlated inversely with the episodes of apnea and hypopnea per hour (RDI, r = –0.45, P = 0.037) and blood level of OPG (r = –0.53, P = 0.011). Although NT-proBNP was also increased significantly in patients with SDB, it had no correlation with either EPCs or RDI. Conclusions SDB due to hypoxemia from decompensated CHF is associated with (1) OPG elevation, (2) EPC depletion, and (3) mPAP elevation. The inverse relationship of circulating OPG with EPCs suggests a likely mechanism for hypoxemia and OPG in the development of pulmonary vascular dysfunction via depleting EPCs, thus worsening prognosis of CHF.     

Sleepiness and nocturnal hypoxemia in Peruvian men with obstructive sleep apnea

Purpose

To evaluate the intensity of nocturnal hypoxemia associated with sleepiness in Peruvian men with a diagnosis of obstructive sleep apnea (OSA).

Methods

We carried out a secondary data analysis based on a study which includes patients with OSA who were seen in a private hospital in Lima, Peru from 2006 to 2012. We included male adults who had polysomnographic recordings and who answered the Epworth sleepiness scale (ESE). The intensity of nocturnal hypoxemia (oxygen saturation ≤90 %) was classified in four new categories: 0, <1, 1 to 10 and >10 % total sleep time with nocturnal hypoxemia (NH). When the ESE score was higher than 10, we used the definitions presence or absence of sleepiness. We used Poisson regression models with robust variance to estimate crude and adjusted prevalence ratios (PR) for association between sleepiness and NH.

Results

518 male patients with OSA were evaluated. Four hundred and fifty-two (87 %) patients had NH and 262 (51 %) had sleepiness. Of the 142 (27.4 %) patients who had >10 % total sleep time with NH, 98 (69.0 %) showed sleepiness and had a greater probability of sleepiness prevalence, with a crude PR of 1.82 (95 % CI 1.31–2.53). This association persisted in the multivariate models.

Conclusions

We found an association between NH and sleepiness. Only patients with the major intensity of NH (over 10 % of the total sleep time) had a greater probability of sleepiness. This suggests that sleepiness probably occurs after a chronic process and after overwhelming compensatory mechanisms.     

Self-Reported Daytime Sleepiness and Sleep-Disordered Breathing in Patients With Atrial Fibrillation: SNOozE-AF

BackgroundAtrial fibrillation (AF) management guidelines recommend screening for symptoms of sleep-disordered breathing (SDB). We aimed to assess the role of self-reported daytime sleepiness in detection of patients with SDB and AF.MethodsA total of 442 consecutive ambulatory patients with AF who were considered candidates for rhythm control and underwent polysomnography comprised the study population. The utility of daytime sleepiness (quantified by the Epworth Sleepiness Scale [ESS]) to predict any (apnea-hypopnea index [AHI] ≥ 5), moderate-to-severe (AHI ≥ 15), and severe (AHI ≥ 30) SDB on polysomnography was tested.ResultsMean age was 60 ± 11 years and 69% patients were men. SDB was present in two-thirds of the population with 33% having moderate-to-severe SDB. Daytime sleepiness was low (median ESS = 8/24) and the ESS poorly predicted SDB, regardless of the degree of SDB tested (area under the curve: 0.48-0.56). Excessive daytime sleepiness (ESS ≥ 11) was present in 11.9% of the SDB population and had a negative predictive value of 43.1% and a positive predictive value of 67.5% to detect moderate-to-severe SDB. Male gender (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.4-3.8, P = 0.001), obesity (OR: 3.5, 95% CI: 2.3-5.5, P < 0.001), diabetes (OR: 2.3, 95% CI: 1.2-4.4, P = 0.08), and stroke (OR: 4.6, 95% CI: 1.7-12.3, P = 0.002) were independently associated with an increased likelihood of moderate-to-severe SDB.ConclusionsIn an ambulatory AF population, SDB was common but most patients reported low daytime sleepiness levels. Clinical features, rather than daytime sleepiness, were predictive of patients with moderate-to-severe SDB. Lack of excessive daytime sleepiness should not preclude patients from being investigated for the potential presence of concomitant SDB.     

Predictors of objective level of daytime sleepiness in patients with sleep-related breathing disorders

Excessive daytime sleepiness, the most prevalent symptom associated with the OSAS, is hypothesized to result from either fragmentation of sleep or hypoxemia during sleep. Measures of nocturnal sleep, respiration during sleep, and daytime sleepiness in 466 patients with apnea were collected to evaluate these two hypotheses. The various parameters were submitted to correlation and multiple regression analyses to predict daytime sleepiness as measured by the MSLT. The RAI, which measures the number of arousals from sleep associated with respiratory disturbances (best fragmentation correlation), produced a higher correlation with MSLT scores than did TMES (best hypoxemia correlation); however, the measures were highly intercorrelated, and multiple regression analyses to determine which parameters independently predicted MSLT showed the single best predictor to be the RAI. Additional independent variance in MSLT score was explained by TST and PSG1. Measures of hypoxemia provided little or no independent predictive information. These data support the hypothesis that sleep fragmentation is an important determinant of daytime sleepiness in patients with apnea.     

Echocardiographic features of the right heart in sleep-disordered breathing: the Framingham Heart Study

The effect of sleep-disordered breathing (SDB) on right heart structure and function is controversial. Studies of patients referred for evaluation of possible sleep apnea have yielded conflicting results, and the impact of SDB on the right heart has not been investigated in the general population. We examined the echocardiographic features of subjects with SDB at the Framingham Heart Study site of the Sleep Heart Health Study. Of 1,001 polysomnography subjects, 90 with SDB defined as a respiratory disturbance index (RDI) score > 90th percentile (mean RDI = 42) were compared with 90 low-RDI subjects (mean RDI = 5) matched for age, sex, and body mass index. Right heart measurements, made without knowledge of clinical status, were compared between groups. The majority of the subjects were male (74%). After multivariable adjustment, right ventricle (RV) wall thickness was significantly greater (p = 0.005) in subjects with SDB (0.78 +/- 0.02 cm) than in the low-RDI subjects (0.68 +/- 0.02 cm). Right atrial dimensions, RV dimensions, and RV systolic function were not found to be significantly different between subjects with SDB and the low-RDI subjects. We conclude that in this community-based study of SDB and right heart echocardiographic features, RV wall thickness was increased in subjects with SDB. Whether the RV hypertrophy observed in persons with SDB is associated with increased morbidity and mortality remains unknown.     

High prevalence of previously unknown subclinical hypothyroidism in obese patients referred to a sleep clinic for sleep disordered breathing

BACKGROUND AND AIM: To evaluate the prevalence of previously unknown hypothyroidism in adult male and female patients with a wide range of body mass index (BMI) values, referred to a Sleep Clinic because of sleep disordered breathing (SDB). METHODS AND RESULTS: Serum concentrations of thyroid stimulating hormone (TSH) and free thyroxin (fT4), as well as forced vital capacity (FVC), PaO2, PaCO2, the Epworth sleepiness scale (ESS), respiratory disturbance index (RDI), loud snoring, and the percentage of total sleep time (TST) with <90% oxyhemoglobin saturation (TST(saO2<90%)) were measured in 78 overweight and obese adult subjects with no previous diagnosis of hypothyroidism (age: 18-72 years). The prevalence of previously undiagnosed subclinical hypothyroidism in the population as a whole was 11.5%. BMI, TSH and ESS were significantly higher in the hypothyroid than the euthyroid subjects, but there was no significant between-group difference in RDI, TST(saO2<90%) or the other investigated variables, including the prevalence of obstructive sleep apnea (OSA). Among the hypothyroid individuals, BMI, neck circumference, ESS, RDI and TST(Sao2<90%) were significantly higher in those with than in those without OSA. Furthermore, there was a clear trend towards a lower FVC% and higher snoring score in the OSA patients. CONCLUSIONS: Our results demonstrate a higher prevalence of hypothyroidism than that commonly reported in overweight and obese individuals referred to a Sleep Clinic for polysomnography because of SDB, thus suggesting that thyroid function should be evaluated in all obese patients suffering from SDB despite economic concerns.     

Detection of postoperative sleep-disordered breathing using a portable monitoring device

Purpose

Adverse surgical outcomes may occur more frequently in patients with sleep-disordered breathing (SDB). Despite this concern, there have been no prospective studies using objective measures of postoperative SDB to determine the scope of the problem. We designed a prospective study to determine the feasibility of identifying SDB in elective postoperative patients by the use of a type IV portable monitor (PM).

Methods

Patients >18?years old who presented for elective surgery with at least one postoperative hospital night on a non-monitored unit were enrolled and wore a type IV device that measured nasal flow, heart rate, and oxygen saturation on their first postoperative night. Respiratory disturbance index (RDI) and oxygen desaturation index (ODI) were generated for each patient.

Results

Data sufficient for interpretation were collected on 100/116 patients enrolled. SDB (RDI ??5) was observed in 51% of the study group, and 17% had a RDI >15. An elevated ODI ??5 was seen in 42%, while 17% had an ODI ??15. Device malfunction occurred in 16% of the study participants.

Conclusion

A type IV PM can be employed in the postoperative setting to detect and gauge the severity of SDB.     

A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong

BACKGROUND: Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong. METHODS: Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned. Subsequently, full polysomnographic (PSG) examinations were conducted in 153 questionnaire respondents. Subjects with an apnea-hypopnea index (AHI) > or =5 were recalled for clinical assessment. RESULTS: Questionnaire respondents were similar in age and body mass index (BMI) to the general community in the target age range and gender. Habitual snoring was reported by 23% of this cohort and was associated with excessive daytime sleepiness (EDS), hypertension, witnessed abnormal breathing pattern, BMI, and leg movements during sleep. Allowing for subject bias in undergoing PSG, the estimated prevalence of SDB and obstructive sleep apnea syndrome (OSAS) (defined as SDB in the presence of EDS) at various AHI cutoff threshold values was 8.8% and 4.1% (AHI > or =5), 6.3% and 3.2% (AHI > or =10), and 5.3% and 3.1% (AHI > or =15). Multiple stepwise logistic regression analysis identified BMI, habitual snoring, time taken to fall asleep, and age as predictors of SDB at AHI > or =5. Analysis of anthropometric parameters indicated that the relative risk of OSAS attributable to obesity was less than in white subjects. CONCLUSION: This community-based study of sleep apnea among middle-aged men in Hong Kong using full PSG demonstrated an estimated prevalence of OSAS (AHI > or =5 and EDS) at 4.1%. Increasing BMI and age were associated with SDB, although factors other than adiposity may also have an important pathogenic role in OSA in Chinese subjects.     

The impact of ageing and sex on the association between sleepiness and sleep disordered breathing

The aim of our study was to investigate age-related changes in sleepiness symptoms associated with sleep disordered breathing (SDB). Wisconsin Sleep Cohort participants were assessed using polysomnography, the Epworth Sleepiness Scale (ESS) and the multiple sleep latency test (MSLT). SDB was defined as an apnoea/hypopnoea index ≥15 events·h(-1), and sleepiness as ESS ≥10 and MSLT ≤5 min. Odds ratios were calculated using generalised estimating equations associating sleepiness with SDB, and conditional logistic regression examining changes in longitudinal sleepiness status (ESS only). Models were a priori stratified by sex. ESS was measured in 1,281 participants and MSLT in 998 at multiple time-points (ESS n=3,695; MSLT n=1,846). Significant interactions were found between SDB and age in males, but not females. The odds ratios modelled for sleepiness in a 40-yr-old male with SDB were significant compared to a male without SDB (ESS 2.1 and MSLT 2.9); however, these associations were not significant at 60 yrs of age. The within-subject odds ratio for sleepiness was also significant at 40 yrs of age (OR 3.4), but not at 60 yrs of age. The age-related reductions in the association between sleepiness and SDB may have clinical implications for the diagnosis and treatment of SDB in older people as sleepiness is often used as a therapeutic target.     

Sleep apnea syndrome in patients with cardiac pacemaker

BACKGROUND: Heart rhythm disturbances are cardiac side effects in patients with sleep-disordered breathing (SDB), which in itself is considered to be a risk factor for bradycardic rhythm disturbances. OBJECTIVE: We analyzed the prevalence and degree of SDB in patients who received a cardiac pacemaker due to bradycardic rhythm disturbances and investigated the relationship between the severity of an underlying SDB and the type of heart rhythm disturbance. METHODS AND RESULTS: 192 patients (100 males, 92 females, mean age 62.2 +/-12.2 years) were studied using the portable screening device MESAM IV. The respiratory disturbance index (RDI) was calculated visually. The mean RDI in all patients was 9.13+/-11. 09/h, 11.7+/-13.15/h in males and 6.33+/-7.42/h in females. The prevalence ratio of SDB between men and women was 1.7:1, with significant differences in the respective severity (p<0.05). The screening showed a prevalence of SDB (RDI >10/h) of 32.3%. The highest prevalence was found in the group of patients with atrial fibrillation and bradycardia. However, there were no significant differences compared to other types of rhythm disturbances. The RDI in the population studied depended on age and body mass index, but not on the existence or type of rhythm disturbance and not on concomitant diseases. CONCLUSION: The prevalence of SDB in cardiac pacemaker patients is similar to that in patients of comparable age without a pacemaker. A heart rhythm disturbance does not seem to be an independent risk factor for development of SDB. Nevertheless, the differential diagnosis of bradycardic rhythm disturbances in this age group should include a screening for sleep apnea.     

Sleep-Disordered Breathing in Adults with Precapillary Pulmonary Hypertension: Prevalence and Predictors of Nocturnal Hypoxemia

Purpose

To evaluate the frequency of sleep-disordered breathing (SDB) and predictors of the presence of nocturnal desaturation in adults with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension.

Methods

Outpatients with a hemodynamic diagnosis of precapillary pulmonary hypertension who underwent portable polysomnography were evaluated. Diagnosis and severity of SDB were assessed using three well-established respiratory disturbance index (RDI) thresholds: 5.0/h, 15.0/h, and 30.0/h, while nocturnal hypoxemia was defined by the average oxygen saturation (SpO₂)?<?90%. Multiple linear regression analysis evaluated the potential relationships among explanatory variables with the dependent variable (average SpO₂ values), with comparisons based on the standardized regression coefficient (β). The R-squared (R²; coefficient of determination) was used to evaluate the goodness-of-fit measure for the linear regression model.

Results

Thirty-six adults were evaluated (69.4% females). The majority of the participants (75.0%) had SDB (26 with obstructive sleep apnea [OSA] and one with central sleep apnea [CSA]); while 50% of them had nocturnal hypoxemia. In the linear regression model (R²?=?0.391), the mean pulmonary artery pressure [mPAP] (β ? 0.668; p?=?0.030) emerged as the only independent parameter of the average SpO₂.

Conclusion

Our study found that the majority of the participants had some type of SDB with a marked predominance of OSA over CSA, while half of them had nocturnal desaturation. Neither clinical and hemodynamic parameters nor the RDI was a predictor of nocturnal desaturation, except for mPAP measured during a right heart catheterization, which emerged as the only independent and significant predictor of average SpO₂.

     

Obstructive sleep apnea

Purpose

Attempts to understand the causes of cognitive impairment in obstructive sleep apnea (OSA) are complicated by the overlap among clinical and demographic factors that may impact cognition. The goal of the current study was to isolate the contribution of hypoxemia to cognitive impairment in OSA.

Methods

Two groups of 20 patients with newly diagnosed OSA were compared. The groups differed on severity of hypoxemia but not other demographic (e.g., age, gender, education, estimated premorbid IQ) or clinical (e.g., sleep related respiratory disturbances, daytime sleepiness, depressive symptoms) variables. Participants completed polysonmography and cognitive assessment.

Results

We compared patients with high and low hypoxemia on measures of memory, attention, executive functioning, and motor coordination using independent sample t-tests. The high hypoxemia group performed significantly better on immediate recall (Hopkins Verbal Learning Test — Revised; t?=??2.50, p?<?0.02) than the low hypoxemia group. No group differences were observed on other neuropsychological measures.

Conclusions

This study is one of the first to compare the cognitive performance of patients with high and low hypoxemia after controlling for demographic factors and aspects of OSA severity that could confound the relationship. In our carefully matched sample, we observed an unexpected advantage of higher hypoxemia on memory. These preliminary findings are discussed in the context of basic science literature on the protective effects of adaptation to intermittent hypoxemia. Our data suggest that the association between hypoxemia and cognition may not straightforward. Future research targeting the effects of hypoxemia on cognition controlling for other clinical factors in large groups of patients with OSA will be important.     

Características clínicas y polisomnográficas del síndrome de apneas durante el sueño localizado en la fase REM

Objective

The aim of this study was to analyze the clinical and polysomnographic features of rapid eye movement (REM)–specific sleep disordered-breathing (SDB).

Patients and methods

All cases of sleep apnea-hypopnea syndrome (SAHS) (apnea-hypopnea index [AHI]?>10/h) diagnosed using overnight polysomnography during the period 2004 to 2006 were analyzed retrospectively. Those cases in which the ratio of AHI during REM sleep to AHI during non-REM sleep was more than 2 were classified as REM-specific SDB. We recorded the following data: clinical signs and symptoms related to SAHS, PSG results, cardiovascular risk factors, and previous cardiovascular events. Logistic regression analysis was used to identify predictors of REM-specific SDB and to analyze the possible interactions between variables.

Results

A total of 419 patients were analyzed, of whom 138 (32.9%) presented REM-specific SDB. This condition was more common in patients with mild to moderate SAHS than in those with more severe cases (odds ratio, 8.21; 95% confidence interval, 4.83–14.03). The variables independently associated with REM-specific SDB in the logistic regression analysis were female sex, lower AHI, and higher body mass index. No interactions between the main variables studied were found. There were no differences between patients with REM-specific SDB and those with non-REM-specific SDB with regard to signs and symptoms related to SAHS, excessive daytime sleepiness, sleep architecture, cardiovascular risk factors, or history of cardiovascular episodes.

Conclusions

REM-specific SDB could be considered an initial stage of SAHS that mainly affects obese women with mild to moderate sleep disorders, and that does not differ from non-REM-specific SDB in terms of clinical presentation, sleep architecture, or cardiovascular comorbidity.