Epworth Sleepiness Scale and sleep studies in patients with obstructive sleep apnea syndrome

Excessive daytime sleepiness (EDS) is the major symptom of patients with obstructive sleep apnea syndrome (OSAS). In this study, we examined the relationship between subjective EDS scored with the Epworth Sleepiness Scale (ESS), objective EDS measured with the multiple sleep latency test (MSLT) and sleep variables evaluated with polysomnography for patients with OSAS. Subjects were 10 patients (51.7+/-19.0 years old). The average ESS and MSLT scores were 10.6+/-5.6 and 7.7+/-5.6, respectively. There was no significant relationship between ESS and MSLT. The Multiple Sleep Latency Test had a significant negative relationship with the number of awakenings and the apnea/hypopnea index. No relationship was found between nocturnal hypoxia and either ESS or MSLT. Our findings suggest that objective EDS in OSAS is related with fragmentation of sleep, and that several patients are not aware of their EDS.     

Comparison of Epworth Sleepiness Scale scores by patients with obstructive sleep apnea and their bed partners

OBJECTIVES: In some patients with obstructive sleep apnea (OSA), Epworth Sleepiness Scale scores (ESS) do not reflect the severity of disease. In many cases, bed partners (BPs) report more severe hypersomnia on the part of the patient than the patient him/herself. The purpose of this study was to assess the agreement between patients and BPs on ESS scores and to compare patients and BPs on the correlation between ESS and the severity of OSA. METHODS: ESS scores were estimated by patients and their BPs and their scores were compared. The correlation between the ESS and the apnea-hypopnea index, arousal index, minimum oxygen desaturation, and body mass index of the patient was estimated and compared between the patient and BP. RESULTS: ESS scores of the patient and BP were similar in their correlation with polysomnographic variables. BPs tended to give slightly higher ESS scores than the patient. CONCLUSIONS: ESS scores as estimated by BPs of patients with OSA did not correlate more positively with polysomnographic variables of OSA severity than scores estimated by affected patients.     

Confirmatory factor analysis of the Epworth Sleepiness Scale (ESS) in patients with obstructive sleep apnoea

BackgroundThe Epworth Sleepiness Scale (ESS [Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep 1991;14(6):540–5]) has been used frequently to assess daytime sleepiness, particularly in the context of clinical sleep disorders. Its psychometric properties are still unclear, particularly when used to evaluate sleep propensity in patients with obstructive sleep apnoea.MethodsThe present study used confirmatory factor analysis (CFA) to investigate a potential single-factor structure of the ESS in a sample of 759 Australian patients with a diagnosis of obstructive sleep apnoea by the treating physicians.ResultsCFA results from showed that the original single-factor structure proposed by Johns [Johns MW. Reliability and factor analysis of the Epworth Sleepiness Scale. Sleep 1992;15(4):376–81] did not adequately fit the data. A re-specified single-factor solution provided a good fit for data, and this improved fit was confirmed on a second CFA.ConclusionsThe findings suggest that standard scoring of the ESS should be interpreted cautiously for patients with obstructive sleep apnoea.     

Clinical utility of the Chinese version of the Pediatric Daytime Sleepiness Scale in children with obstructive sleep apnea syndrome and narcolepsy

Aim: The present study examined the psychometric properties of the Chinese version of the Pediatric Daytime Sleepiness Scale (PDSS) and the utility of the PDSS as a screening tool for pathological daytime sleepiness in teenagers with obstructive sleep apnea (OSA) and narcolepsy. Methods: The PDSS was first administered to 238 middle and high school students to assess the reliability of the scale, and then administered to 28 teenagers with OSA, 31 teenagers with narcolepsy, and 34 normal controls to evaluate its clinical utility. Results: Test–retest reliability and internal consistency were acceptable. The PDSS scores were significantly higher in narcoleptic subjects than in subjects with OSA, and higher in OSA syndrome (OSAS) subjects than normal controls. Furthermore, the scores decreased in narcoleptic subjects after medical treatment. Both reliability and validity were proven to be good. As a screening tool for narcolepsy, receiver operator characteristic (ROC) curve analysis showed that the PDSS, with a cut‐off score of 16/17, had good sensitivity (87.1%) and fair specificity (74.3%) for identifying individuals with narcolepsy. When used for screening OSA, however, the differentiating power was not as good. Conclusion: The PDSS is a reliable and valid tool for the measurement of sleepiness in clinical youth populations. When used as a screening tool, it is useful for sleep disorders involving more severe pathological sleepiness, as in narcolepsy.     

The Epworth sleepiness scale in the identification of obstructive sleep apnea

The Epworth sleepiness scale (ESS) is often used clinically to screen for the manifestations of the behavioral morbidity associated to obstructive sleep apnea (OSA). The purpose of this study was to assess the sensitivity of the ESS in the identification of OSA, as defined by an elevated apnea-hypopnea index. A retrospective chart review of 268 consecutive patients diagnosed with OSA at a multidisciplinary sleep medicine clinic was conducted. The ESS obtained a relatively low sensitivity (66%) in the identification of an apnea-hypopnea index of 5 and above at the suggested cutoff of 10 and increased to 76% at 8. The results of the study showed only fair discriminatory ability of the ESS as a screener for OSA. A score of 8 (instead of 10) is suggested as the cutoff among clinic populations being screened for a sleep disorder.     

The assessment of daytime sleep propensity: a comparison between the Epworth Sleepiness Scale and a newly developed Resistance to Sleepiness Scale.

INTRODUCTION: The Epworth sleepiness scale (ESS) is widely used as a way of measuring subjective sleep propensity in research and clinical practice. Psychometric studies do not rule out the presence of more than one latent dimension underlying the items. OBJECTIVE: Aims of the present study were to: (a) evaluate psychometric proprieties of the ESS by means of classic psychometric techniques; (b) compare them with those from a newly developed resistance to sleepiness scale (RSS); (c) evaluate, following the latent trait theory, whether the items of both ESS and RSS could be conceptualized as different levels of an interval variable representative of a single latent trait related to sleep propensity. METHODS: One hundred and forty-six inpatients suffering from different sleep disorders filled in both the RSS and ESS in a sleep disorder centre. RESULTS: Indexes of fit derived by the application of the extended logistic model are consistent with the idea that each ESS item can be conceptualized as different levels of an interval variable representative of a single latent trait. However, most of the ESS items are found to be located at the opposite extremes of this continuum. CONCLUSIONS: The under representation of situations characterized by an intermediate soporific nature in the ESS could limit ESS sensitivity to detect intermediate variations of sleep propensity.     

Craniofacial abnormalities in Chinese patients with obstructive and positional sleep apnea

BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent episodes of a complete or partial collapse of the upper airway during sleep. Traditionally, the disease is diagnosed by overnight polysomnography. Studies have shown correlation between parameters of cephalometry and severity of sleep apnea. We wish to determine the variable of craniofacial dimensions in the upper airway that contribute to OSA, and to investigate the significance of craniofacial measurements in positional and non-positional sleep apnea patients. METHODS: From July 2002 to June 2006, we studied 84 males and 15 females who came to the sleep center because of daytime sleepiness. All the participants underwent overnight polysomnography and lateral cephalograms, performed by an experienced technician. RESULTS: Craniofacial measurements of gnathion-gonion, anterior superior hyoid to mandibular plane (MP-H), posterior nasal spine (PNS) to the velum tip (SPL), widest point of the soft palate (SPW), and the product of PNS to the velum tip and widest point of the soft palate (product of soft palate (SPP)=SPL x SPW) were positively related to the apnea/hypopnea index (AHI). The velum tip to the pharyngeal wall parallel to the Frankfurt horizontal (PAS) was negatively related to the AHI. We further divided the study subjects into 4 groups according to AHI value (group 1, AHI<5; group 2, 5 or=30). Age, body mass index (BMI), neck circumference (NC), distances of PAS, SPL, SPW, SPP and angle of sella-nasion-infradentale (SNB) were significantly different depending on the degree of severity of sleep-disordered breathing (SDB). Patients who were older, with a high BMI and longer MP-H distance, had more daytime sleepiness (Epworth sleepiness scale, ESS). Furthermore, lower AHI values and longer PAS measurements were found in the positional sleep apnea group when compared to the non-positional sleep apnea group. After adjusting for confounding factors of age, BMI and NC, we found that BMI, MP-H distance and PAS measurement were correlated with severity of OSA. CONCLUSIONS: Cephalometry could be a useful and inexpensive clinical tool to evaluate Chinese patients with OSA. MP-H and PAS should be measured in Chinese patients with OSA. MP-H was correlated with ESS. The PAS measurement was narrower in non-positional OSA patients compared to positional OSA patients.     

Psychometric evaluation of the Epworth Sleepiness Scale in an obstetric population

BackgroundThe Epworth Sleepiness Scale (ESS) was initially developed to measure daytime sleep propensity in patients affected by a variety of sleep disorders. Obstetrical research has measured sleepiness in pregnant women with the ESS, although psychometric analyses and dimensionality evaluations have never been conducted with this population.ObjectiveThe objective was to perform a psychometric evaluation of the ESS in an obstetric population. The design was a secondary data analysis of the subjects enrolled in the Prenatal Exposures and Preeclampsia Prevention III (PEPP) study. The setting for the subjects who received prenatal care was at Magee-Women’s Hospital UPMC in Pittsburgh, Pennsylvania and included 337 pregnant women in their first trimester that completed the ESS.MethodsPrincipal components analysis and confirmatory factor analysis were performed using SPSS and M-Plus. Additionally, reliability was assessed and construct validity was measured using the Life Orientation Test (LOT). Lastly, a relationship between daytime sleepiness and snoring was investigated using item 5e from the Pittsburgh Sleep Quality Index (PSQI).ResultsPCA with varimax rotation yielded two factors that explained approximately 50% of the variance and CFA results verified this two-factor solution. An overall Cronbach’s alpha (0.751) revealed moderate reliability (Factor 1α = .754; Factor 2α = .524). Both convergent and discriminant validity were established.ConclusionThe ESS is appropriate for use in an obstetric population to measure daytime sleepiness. Future work should include additional evaluations of the ESS in a diverse group of pregnant women.     

Hypercoagulability in patients with obstructive sleep apnea

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to cardiovascular complications such as stroke and myocardial infarction. Previous studies demonstrate that OSA patients show elevated fibrinogen levels and increased platelet aggregation that are reversed with 1 night of nasal continuous positive airway pressure treatment (NCPAP). Questioning overall coagulability in OSA, we examined whole blood coagulability in 11 chronically NCPAP treated OSA subjects, 22 previously untreated OSA subjects, and in 16 of these after 1 night of NCPAP treatment. PATIENTS AND METHODS: During full polysomnography, subjects from each group had blood drawn prior to bedtime (21:00 h) and upon waking in the morning (07:00 h). RESULTS: Untreated OSA patients had faster P.M. clotting times than chronically treated OSA patients (3.33+/-0.31 versus 6.12+/- 0.66 min, P<0.05 by ANOVA). A.M. values showed similar results (4.31+/- 0.34 min versus 7.08+/-0.52 min, P<0.05 by ANOVA) for the respective groups. One overnight treatment with nasal CPAP did not produce a significant change in A.M. whole blood coagulability (4.35 +/-0.43 to 5.31+/-0.53 min; n=16; P=0.1) in 16 treated subjects. CONCLUSIONS: These data indicate a relationship between obstructive sleep apnea and blood hypercoagulability status that appears to be reversed by chronic NCPAP treatment. These data suggest that NCPAP might protect against the development of cardiovascular complications in OSA patients.     

Criterion validity of the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale for the diagnosis of sleep disorders

Objectives(1) To examine criterion validity of the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) using obstructive sleep apnea (OSA), periodic limb movement disorder (PLMD), rapid eye movement sleep behavior disorder (RBD), and narcolepsy as criterion standard. (2) To summarize the evidence for criterion validity of the ESS for the diagnosis of OSA by a meta-analysis that combines the current and previous studies. (3) To investigate the determinants of the PSQI and ESS scores.MethodsThe PSQI and ESS as well as the Hospital Anxiety and Depression Scale (HADS), which measures anxiety and depression levels, were administered to 367 patients consecutively referred to a sleep clinic. They underwent overnight polysomnography (PSG) and the multiple sleep latency test if narcolepsy was suspected.ResultsThe area under the receiver operating characteristic curves for the ESS and PSQI (and its subscale) were <0.9, meaning that these questionnaires were not highly accurate for predicting the four sleep disorders. The meta-analysis found that the ESS had no value in identifying OSA. The variable that most strongly influenced PSQI or ESS scores was the HADS score.ConclusionThe PSQI and ESS should no longer be used as a screening or diagnostic instrument for the four PSG-defined sleep disorders, especially in a low-risk population.     

Cardiac arrhythmias during normal sleep and in obstructive sleep apnea syndrome

Normal sleep is associated with a slowing in heart rate due to a relative shift from sympathetic to parasympathetic neural dominance. Bradyarrhythmias consisting of sinus bradycardia, sinus arrest and second degree (Mobitz type 1) heart block are not uncommon in young adults. With aging, bradyarrhythmias decrease in frequency while atrial arrhythmias and ventricular ectopy increases. Patients with obstructive sleep apnea (OSA) have been demonstrated to have bradyarrhythmias and increased ventricular ectopy in association with apneas when oxyhemoglobin desaturations become severe. Although retrospective studies have suggested that cardiovascular mortality may be increased in patients with OSA, this remains to be proven in prospective clinical studies. Sudden death during sleep secondary to apnea related brady or ventricular tachyarrhythmias may occur. However, this is likely to be a very rare event that remains to be documented in the literature.     

Nocturnal cardiac arrhythmia in patients with obstructive sleep apnea

BACKGROUND AND PURPOSE: Nocturnal cardiac arrhythmias occur in patients with obstructive sleep apnea (OSA), reportedly as a consequence of the autonomic effects of recurrent apnea with subsequent oxygen desaturation. We have investigated whether different patterns of OSA are associated with specific arrhythmia during sleep. PATIENTS AND METHODS: Electrocardiographic (ECG) data recorded during polysomnography (PSG) were analysed in 257 consecutive OSA patients to determine the prevalence of cardiac rhythm disturbances, and to relate these to breathing pattern (normal, apnea/hypopnea, recovering ventilation, snoring) and oxygen saturation. RESULTS: Arrhythmias were found in 18.5% of patients. Patients with nocturnal bradyarrhythmia (BA) had higher values of ventilatory disturbance (apnea-hypopnea index [AHI] 58.8+/-36.8 vs 37.2+/-30.3, p=0.02), mean desaturation amplitude (8.9+/-4 vs 5.9+/-3.4%, p=0.03), and a lower SaO(2) nadir (69% vs 77%, p=0.003) than those without arrhythmia. The prevalence of BA in patients with AHI>or=30/h was significantly higher than that observed in those with AHI<30/h (7.8% vs 1.5%, respectively; chi(2)=5.61, p=0.01). In contrast, patients with tachyarrhythmia (TA) had no significant differences in AHI, mean desaturation amplitude or SaO(2) nadir than those without arrhythmia. No associations were found between arrhythmia and the presence of comorbidity or concomitant medical therapy, except for an association between tachyarrhythmia and chronic obstructive pulmonary disease (COPD) (odds ratio 2.53; 95% confidence intervals 1.1-5.8, p=0.03). CONCLUSIONS: We conclude that while BA during sleep is associated with OSA severity, concomitant COPD or beta(2)-treatment may play a role in the development of TA during sleep.     

Atherosclerosis and obstructive sleep apnea in patients with ischemic stroke

BACKGROUND: Of late, obstructive sleep apnea (OSA) has been suggested to be a risk factor for atherosclerotic artery disease. In the present study, we analyzed the prevalence of atherosclerosis in stroke patients with and without OSA. PATIENTS AND METHODS: Two hundred and fourteen consecutive patients with ischemic stroke were included in this study. Patients were screened for classical cerebrovascular risk factors. All patients received a cardiorespiratory polygraphy to determine the apnea-hypopnea index. Duplex ultrasonography was used to evaluate the carotid bulb and the internal carotid artery for the presence of atherosclerotic lesions, which were graded in 'none', 'plaques with <50% stenosis', 'stenosis > or =50% to subtotal', and 'occlusion'. RESULTS: Atherosclerotic lesions were identified in 42% of patients. These were significantly more prevalent in patients with OSA than in patients without. In multiple logistic regression analysis, this association was independent of other known vascular risk factors. Arterial hypertension, which was significantly related to atherosclerosis in univariate analysis, lost its statistical impact in multivariate analysis. CONCLUSION: This study confirms that OSA is an independent risk factor for atherosclerotic artery disease that may even outweigh the impact of arterial hypertension in selected patient collectives. To further elucidate this topic, treatment studies are needed that look for a possible improvement of markers and signs of atherosclerosis in patients with OSA.     

Pulmonary hypertension in patients with severe obstructive sleep apnea

Thirty-seven patients (35 men and two women) with obstructive sleep apnea-hypopnea syndrome (OSAHS) without any known cardiovascular and lung diseases were examined by Doppler echocardiography. Eight of the 37 (21.6%) patients experienced daytime pulmonary hypertension (PH), and all of them had severe OSAHS with an apnea-hypopnea index of > 30. The study suggested that one-third of patients with severe OSAHS had daytime PH.