Maria do Carmo Sfreddo Lenz

Diagnosis of Obstructive Sleep Apnea Syndrome and Its Outcomes With Home Portable Monitoring

BACKGROUND The use of portable respiratory monitoring (PM) has been proposed for the diagnosis of obstructive sleep apnea syndrome (OSAS), but most studies that validate PM accuracy have not followed the best standards for diagnostic test validation. The objective of the present study was to evaluate the accuracy of PM performed at home to diagnose OSAS and its outcomes after first validating PM in the laboratory setting by comparing it to polysomnography (PSG). METHODS Patients with suspected OSAS were submitted, in random order, to PM at the sleep laboratory concurrently with PSG (lab-PM) or at home-PM. The diagnostic performance was assessed by sensitivity, specificity, positive and negative predictive values, positive likelihood ratio (+LR), negative likelihood ratio (-LR), intraclass correlation coefficients, kappa statistic, and Bland-Altman plot. RESULTS One hundred fifty-seven subjects (73% men, mean age +/- SD, 45 +/- 12 yr) with an apnea-hypopnea index (AHI) of 31 (SD +/- 29) events/h were studied. Excluding inadequate recordings, 149 valid comparisons with lab-PM and 121 with unattended home-PM were obtained. Compared to PSG for detecting AHI > 5, the lab-PM demonstrated sensitivity of 95.3%, specificity of 75%, +LR of 3.8, and -LR of 0.11; the home-PM exhibited sensitivity of 96%, specificity of 64%, +LR of 2.7, and -LR of 0.05. Kappa statistics indicated substantial correlation between PSG and PM results. Bland-Altman plot showed smaller dispersion for lab-PM than for home-PM. Pearson product moment correlation coefficients among the three AHIs and clinical outcomes were similar, denoting comparable diagnostic ability. CONCLUSIONS This study used all available comparison methods to demonstrate accuracy of PM in-home recordings similar to that of repeated PSGs. PM increases the possibility of correctly diagnosing and effectively treating OSAS in populations worldwide.

Is sleep apnea a winter disease?: meteorologic and sleep laboratory evidence collected over 1 decade.

BACKGROUND The severity of obstructive sleep apnea increases by influence of conditions that are more frequent in winter. The hypothesis that the apnea-hypopnea index (AHI) of different patients undergoing polysomnography may be seasonally affected was tested. METHODS The retrospectively analyzed database included 7,523 patients of both sexes who underwent in-laboratory baseline polysomnography to investigate any complaint of disordered sleep, during 1 decade, between January 2000 and December 2009. Data on climate and air pollution were obtained from official organizations. AHI was the main outcome variable. Cosinor analysis, a statistical method for the investigation of time series, was used to detect seasonality. RESULTS The cosinor analysis confirmed the existence of a circannual pattern of AHI, with acrophase in winter and nadir during the summer. The seasonality is significant even after adjusting for sex, age, BMI, neck circumference, and relative air humidity. Median (25-75 interquartile range) AHI in the 6 months with colder weather was 17.8 (6.5-40.6/h), and in the warmer weather was 15.0 (5.7-33.2/h). The AHI correlated inversely with ambient temperature and directly with atmospheric pressure, relative air humidity, and carbon monoxide levels. Correlations with precipitation, particulate air matter < 10 μm, sulfur dioxide, and ozone were nonsignificant. CONCLUSIONS More sleep-disordered breathing events were recorded in winter than in other seasons. Cosinor analysis uncovered a significant seasonal pattern in the AHI of different patients undergoing polysomnography, independent of sex, age, BMI, neck circumference, and relative air humidity. This finding suggests that obstructive sleep apnea severity may be associated with other seasonal epidemiologic phenomena.

Diagnóstico dos transtornos do sono relacionados ao ritmo circadiano

Insomnia and excessive sleepiness are common in the investigation of sleep-disordered breathing. Circadian rhythm sleep disorders are perhaps the most often overlooked conditions in the differential diagnosis of these symptoms. Circadian rhythm sleep disorders manifest as misalignment between the sleep period and the physical/social 24-h environmental cycle. The two most prevalent circadian rhythm sleep disorders are delayed sleep phase (common in adolescents) and advanced sleep phase (common in the elderly), situations in which the sleep period is displaced to a later or earlier time, respectively. It is important to keep these two disorders in mind, since they can be confused with insomnia and excessive sleepiness. However, there are nine possible diagnoses, and all nine are of clinical interest. Since light is the principal cue used in synchronizing the biological clock, blind individuals and night-shift/swing-shift workers are more prone to develop circadian rhythm sleep disorders. In this article, the new international classification of circadian rhythm sleep disorders is reviewed.

Original ResearchSleep DisordersIs Sleep Apnea a Winter Disease?: Meteorologic and Sleep Laboratory Evidence Collected Over 1 Decade

BACKGROUND The severity of obstructive sleep apnea increases by influence of conditions that are more frequent in winter. The hypothesis that the apnea-hypopnea index (AHI) of different patients undergoing polysomnography may be seasonally affected was tested. METHODS The retrospectively analyzed database included 7,523 patients of both sexes who underwent in-laboratory baseline polysomnography to investigate any complaint of disordered sleep, during 1 decade, between January 2000 and December 2009. Data on climate and air pollution were obtained from official organizations. AHI was the main outcome variable. Cosinor analysis, a statistical method for the investigation of time series, was used to detect seasonality. RESULTS The cosinor analysis confirmed the existence of a circannual pattern of AHI, with acrophase in winter and nadir during the summer. The seasonality is significant even after adjusting for sex, age, BMI, neck circumference, and relative air humidity. Median (25-75 interquartile range) AHI in the 6 months with colder weather was 17.8 (6.5-40.6/h), and in the warmer weather was 15.0 (5.7-33.2/h). The AHI correlated inversely with ambient temperature and directly with atmospheric pressure, relative air humidity, and carbon monoxide levels. Correlations with precipitation, particulate air matter < 10 μm, sulfur dioxide, and ozone were nonsignificant. CONCLUSIONS More sleep-disordered breathing events were recorded in winter than in other seasons. Cosinor analysis uncovered a significant seasonal pattern in the AHI of different patients undergoing polysomnography, independent of sex, age, BMI, neck circumference, and relative air humidity. This finding suggests that obstructive sleep apnea severity may be associated with other seasonal epidemiologic phenomena.

Circadian rhythm sleep disorders

Circadian rhythm sleep disorders are common conditions manifested as misalignment between the sleep period and the physical/social 24-h environmental cycle. Delayed sleep phase (typical in adolescents) and advanced sleep phase (frequent in the elderly), situations in which the sleep period is displaced to a later or earlier time, respectively, are the two most prevalent circadian rhythm sleep disorders. There are, however, nine possible diagnoses of clinical interest. Since light is the main cue used in synchronizing the biological clock, blind individuals and night-shift/rotating-shift workers are more prone to develop circadian rhythm sleep disorders. In this article, the circadian rhythm syndromes included in the new International Classification of Sleep Disorders are reviewed as well as the most recent guidelines for diagnosis and treatment.

Repeating administration of Epworth Sleepiness Scale is clinically useful

PurposeWe aimed to verify whether it is clinically useful to repeat the Epworth Sleepiness Scale (ESS) in individuals with suspected sleep-disordered breathing (SDB).MethodsIn this cross-sectional, prospective study, results of the repeated administration of the ESS were analyzed. In 929 consecutive patients, ESS was obtained as usual in the laboratory routine, immediately before the sleep study (ESS1) and was repeated in the morning, after the polysomnography (ESS2). ROC curve, classical psychometry, and item response theory (IRT) Rasch analysis were used to assess measurement properties of ESS.ResultsThe ESS1 score was (mean ± SD), 11 ± 5.1, and the ESS2, 13 ± 4.7 (p < 0.001). Change in ESS score is explained in multivariate analysis by age, but not by gender, educational level, change in Stanford Sleepiness Scale, symptoms of sleep disorder, or polysomnography results. Accuracy of an ESS score >10 to predict apnea–hypopnea index ≥5 increased from 56% (ESS1) to 72% (ESS2). IRT psychometric properties (unidimensionality, invariance, local independence) were maintained in ESS2.ConclusionsRepeating the administration of the Epworth Sleepiness Scale in a clinical setting increases its score and diagnostic accuracy and correlation with SDB variables, without changing the psychometric properties of the scale. This experiment indicates the clinical usefulness of repeating the ESS. The scale can be repeated at a negligible cost, before dismissing individual patients on the basis of a low ESS score, discontinuing a potentially lifesaving diagnostic and therapeutic process.

Light sleep and sleep time misperception – Relationship to alpha–delta sleep

OBJECTIVE We investigated the association of alpha-delta sleep (A-DS) with: (1) perception of light sleep and (2) discrepancy between subjective and objective sleep duration. METHODS We analyzed data from 5764 individuals who underwent polysomnography (PSG) and replied questions about quantity and quality of sleep, including sleep depth. The difference between objectively recorded sleep time and subjectively estimated sleep time was calculated. Alpha-delta sleep (A-DS) was visually scored in a scale from 1 to 4, based on the density and overnight duration of alpha activity and confirmed using spectral array of the electroencephalographic activity. RESULTS A-DS scores 1-4 occurred in, respectively, 37.9%; 31.3%; 20.5%; and 6.2% of the cases. ANOVA showed significant difference of light sleep sensation (p<0.001) and sleep time underestimation (p<0.001) among the four A-DS categories. Regression to explain both light sleep and sleep time underestimation, controlling for confounders, confirmed A-DS as a significant regressor. CONCLUSIONS This study of a large prospective sample provides evidence for the association of alpha-delta sleep with subjective sensation of light sleep and with sleep time underestimation. SIGNIFICANCE Alpha-delta sleep may be a marker of the physiological disorder underlying light sleep and sleep state misperception.

Dimensions of sleepiness and their correlations with sleep-disordered breathing in mild sleep apnea

OBJECTIVE There are many ways of assessing sleepiness, which has many dimensions. In patients presenting a borderline apnea-hypopnea index (AHI, expressed as events/hour of sleep), the mechanisms of excessive daytime sleepiness (EDS) remain only partially understood. In the initial stages of sleep-disordered breathing, the AHI might be related to as-yet-unexplored EDS dimensions. METHODS We reviewed the polysomnography results of 331 patients (52% males). The mean age was 40 +/- 13 years, and the mean AHI was 4 +/- 2 (range, 0-9). We assessed ten potential dimensions of sleepiness based on polysomnography results and medical histories. RESULTS The AHI in non-rapid eye movement (NREM) stage 1 sleep (AHI-N1), in NREM stage 2 sleep (AHI-N2), and in REM sleep (AHI-REM) were, respectively, 6 +/- 7, 3 +/- 3 and 10 +/- 4. The AHI-N2 correlated significantly with the greatest number of EDS dimensions (5/10), including the Epworth sleepiness scale score (r = 0.216, p < 0.001). Factor analysis, using Cronbachs alpha, reduced the variables to three relevant factors: QUESTIONNAIRE (alpha = 0.7); POLYSOMNOGRAPHY (alpha = 0.68); and COMPLAINTS (alpha = 0.55). We used these factors as dependent variables in a stepwise multiple regression analysis, adjusting for age, gender, and body mass index. The AHI-N1 correlated significantly with POLYSOMNOGRAPHY (beta = -0.173, p = 0.003), and the AHI-N2 correlated significantly with COMPLAINTS (beta = -0.152, p = 0.017). The AHI-REM did not correlate with any factor. CONCLUSIONS Our results underscore the multidimensionality of EDS in mild sleep apnea.

Exercise, Occupational Activity, and Risk of Sleep Apnea: A Cross-Sectional Study.

STUDY OBJECTIVES To investigate whether structured exercise and occupational activity are associated with obstructive sleep apnea (OSA) severity. METHODS The International Physical Activity Questionnaire was answered by 5,453 individuals who underwent full-night polysomnography. Participants were classified as exercisers or non-exercisers and also as occupationally active or non-active. The apnea-hypopnea index (AHI), minimum oxygen saturation (SaO2min), and time with saturation below 90% (TB90%) during polysomnography were used as indicators of OSA severity. RESULTS The sample included mostly men (59%), non-exercisers (56%), and occupationally non-active individuals (75%). Mean age (± standard deviation) was 44 ± 14 years, and mean body mass index was 29.9 ± 7.3 kg/m2. Non-exercisers had higher AHI (median 14, 25-75% interquartile range 4-34) than exercisers (8 [2-24]), lower SaO2min (83 ± 9 vs. 86 ± 8%), and longer TB90% (2 [0-18] vs. 0 [0-7] minutes), with p < 0.001 for all comparisons. AHI was higher in active (16 [6-34]) vs. non-active occupations (10 [3-27]; p < 0.001). Multinomial logistic regression with control for age, sex, overweight, obesity, and occupational activity showed that structured exercise was significantly associated with a 23% lower odds ratio for moderate OSA and 34% lower odds ratio for severe OSA. Active occupation was not associated with OSA. CONCLUSIONS Structured physical exercise is associated with lower odds for OSA, independently of confounders. Occupational activity does not seem to replace the effects of regular exercise. Compensatory behaviors may be involved in these diverging outcomes. Our results warrant further research about the effect of occupational activity on OSA severity.

Diagnostic performance of cheeks appearance in sleep apnea

Abstract Objective: Obstructive sleep apnea (OSA) is a common, potentially life-threatening, but underdiagnosed condition. The study aimed to test the role of facial myofunctional alterations in OSA screening. Method: Sixty-one individuals with sleep complaints were evaluated by the Orofacial Myofunctional Evaluation with Scores (OMES) protocol before undergoing polysomnography. The performance of each of the protocol scores in OSA screening was tested. Results: The nonparametric correlation of the apnea-hypopnea index (AHI) was significant for 18 of the 41 variables of the OMES protocol. Cheeks appearance had the best performance, increasing five times the odds for AHI ≥ 15. Its sensitivity was 66%; specificity, 72%; the area under the ROC curve, 0.69; positive and negative likelihood ratios, respectively, 2.38 and 0.47. Discussion: Cheeks appearance may be an instantly visible surrogate of tongue and pharyngeal fat deposition and of muscle function in OSA screening. Adding the item “cheeks appearance” to OSA screening tools and questionnaires may be useful for the identification of OSA risk.