Reliability and factor analysis of the Epworth Sleepiness Scale.

The Epworth Sleepiness Scale (ESS) is a self-administered eight-item questionnaire that has been proposed as a simple method for measuring daytime sleepiness in adults. This investigation was concerned with the reliability and internal consistency of the ESS. When 87 healthy medical students were tested and retested 5 months later, their paired ESS scores did not change significantly and were highly correlated (r = 0.82). By contrast, ESS scores that were initially high in 54 patients suffering from obstructive sleep apnea syndrome returned to more normal levels, as expected, after 3-9 months' treatment with nasal continuous positive airway pressure. The questionnaire had a high level of internal consistency as measured by Cronbach's alpha (0.88). Factor analysis of item scores showed that the ESS had only one factor for 104 medical students and for 150 patients with various sleep disorders. The ESS is a simple and reliable method for measuring persistent daytime sleepiness in adults.     

The Epworth Sleepiness Scale: influence of age, ethnicity, and socioeconomic deprivation. Epworth Sleepiness scores of adults in New Zealand

STUDY OBJECTIVES: To examine possible relationships between excessive sleepiness (Epworth Sleepiness Scale score >10), and age, sex, ethnicity, socioeconomic deprivation, usual sleep, and self-reported symptoms of obstructive sleep apnea. DESIGN: Mail-out survey to a stratified random sample of 10,000 people aged 30 to 60 years, selected from the electoral roll. Setting: Nationwide survey of adults in New Zealand (71% response rate). PARTICIPANTS: The sample design aimed for equal numbers of M?ori and non-M?ori participants, men and women, and participants in each age decade. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Two-page questionnaire. M?ori participants had higher mean Epworth Sleepiness Scale scores than non-M?ori (7.5 versus 6.0) and were more likely to have an Epworth Sleepiness Scale score of more than 10. Logistic multiple regression modeling identified the following significant independent risk factors for having an Epworth Sleepiness Scale score >10: being M?ori, male, older, reporting more or less than 7.5 to 8.0 hours usual sleep, never or rarely getting enough sleep, never or rarely waking refreshed, larger neck circumference, observed apneas, and not drinking alcohol (compared with moderate alcohol consumption). CONCLUSIONS: The relationships between an Epworth Sleepiness Scale score >10 and sleep habits and risk factors for obstructive sleep apnea are as expected. The relationships between an ESS score > 10 and being M?ori, a man, older, or more socioeconomically deprived could be related to a higher prevalence of sleep disorders in these groups. However, more research is needed to understand possible differences not only in pathophysiologic processes, but also in the wider societal trends and pressures that may impact differentially on sleep and sleepiness.     

Measurement properties and hierarchical item structure of the Epworth Sleepiness Scale in Parkinson's disease

The aim of this work was to evaluate the measurement properties and hierarchical item structure of the Epworth Sleepiness Scale (ESS) in patients with Parkinson's disease (PD). Data were taken from a cross-sectional study regarding fatigue and sleep-related aspects of PD. One hundred and eighteen consecutive patients with neurologist-diagnosed PD without significant co-morbidities (54% men; mean age, 64 years; mean PD duration, 8.4 years) from four Swedish neurological outpatient clinics participated. The ESS displayed good data quality with few missing items (0-2.5%): good reliability (Cronbach's alpha, 0.84), marginal floor and no ceiling effects (1.7% and 0% respectively), and differentiated between those reporting problems staying awake during the past month and those who did not. Item-total correlations, factor and Rasch analyses indicated that items tap a single underlying construct. Rasch analysis supported basic rating scale assumptions and demonstrated an item hierarchy similar to that previously found in patients with other sleep disorders. Gaps in the levels of sleep propensity covered by ESS items and their response options were identified at the higher and lower ends of the underlying sleepiness continuum. This study provides an evidence base for using the ESS in PD by demonstrating good psychometric properties and a stable hierarchical item structure. However, addition of new items and use of Rasch scoring has potential to further enhance the clinical usefulness of the ESS.     

Epworth嗜睡量表在阻塞性睡眠呼吸暂停低通气综合症诊断中的应用

目的 探讨Epwoyth嗜睡量表对阻塞性睡眠呼吸暂停低通气综合症（OSAHS）临床诊断意义。方法 对83例鼾症、279例OSAHS患者（轻度65例、中度97例、重度117例）分别进行Epworth问卷调查并判断嗜睡评分（EP），然后行多导睡眠监测（PSG）。依据PSG检查将EP与相关资料做统计学分析。结果 鼾症、OSAHS患者EP评分与睡眠呼吸暂停-低通气指数（AHI）、夜间睡眠呼吸紊乱时间（T）呈明显正相关；EP与最低氧饱和度（SaO2）呈负相关。即OSAHS病情越重，EP评分越高。诊断符合率分别为：鼾症90．36％（75／83），轻度OSAHS92．3％（60／65），中度0SAHS91．75％（89／97），重度OSAHS92．3％（108／117）。结论 EP评分基本与病情相符，诊断符合率较高。可以用Epworth嗜睡量表作为临床OSAHS患者的初筛检查，尤其是在基层医院。     

Correlations among Epworth Sleepiness Scale scores, multiple sleep latency tests and psychological symptoms

The aim of this study was to identify factors other than objective sleep tendency associated with scores on the Epworth Sleepiness Scale (ESS). There were 225 subjects, of whom 40% had obstructive sleep apnoea (OSA), 16% had simple snoring, and 4.9% had snoring with sleep disruption (upper airway resistance syndrome); 9.3% had narcolepsy and 7.5% had hypersomnolence without REM sleep abnormalities; 12% had chronic fatigue syndrome; 7.5% had periodic limb movement disorder and 3% had diurnal rhythm disorders. ESS, the results of overnight polysomnography and multiple sleep latency test (MSLT) and SCL-90 as a measure of psychological symptoms were recorded. The ESS score and the mean sleep latency (MSL) were correlated (Spearman ö =−0.30, P <0.0001). The MSL was correlated with total sleep time (TST) and with sleep efficiency but not with apnoea/hypopnoea index. There was no association between the MSL and any aspect of SCL-90 scores, except a borderline significant association with the somatisation subscale. The ESS was correlated with TST but not with sleep efficiency or apnoea/hypopnoea index. The ESS was correlated with all subscales of the SCL-90 except psychoticism. An ESS≥10 had poor sensitivity and specificity as a predictor of MSL <10 min or MSL <5 min. We conclude that the MSLT and the ESS are not interchangeable. The ESS was influenced by psychological factors by which the MSL was not affected. The ESS cannot be used to demonstrate or exclude sleepiness as it is measured by MSLT.     

Factors related to increased daytime sleepiness during the menopausal transition as evaluated by the Epworth Sleepiness Scale

Background

Sleep disorders and sleep-apnea/hypopnea syndromes are very frequent in women, being misdiagnosed in many cases. The menopause, regardless of age, is associated to poor sleep quality and daytime sleepiness that can lead to impaired quality of life, and reduced productivity and functioning.

Objective

To assess daytime sleepiness and related risk factors among middle aged Ecuadorian women using the Epworth Sleepiness Scale (ESS).

Methods

In this cross-sectional study 149 women aged 40–59 years were assessed for hot flush presence and intensity using the Menopause Rating Scale (MRS) and requested to fill out the ESS and a questionnaire containing personal and partner data.

Results

Mean age of surveyed women was 47.6 ± 5.5 years, with 67.8% having less than 12 years of schooling, 33.6% being postmenopausal, and 2.7% on hormone therapy. A 10.1% were current smokers and 20.8% were sedentary. According to the MRS (item 1) 51.7% presented hot flushes, which were graded as severe–very severe in 42.8% of cases. Regarding the partner (n = 132), erectile dysfunction was present in 10.6%, premature ejaculation 6.1% and 17.4% abused alcohol. Mean total ESS score was 8 ± 4.4 (median 8), with 33.6% considered having some degree of daytime sleepiness (ESS score ≥10). Logistic regression analysis determined that postmenopausal status (OR 6.58, CI 95% [2.51–17.23], p = 0.001), sedentarism (OR 3.43, CI 95% [1.14–10.26], p = 0.02) and hot flush presence (OR 2.61, CI 95% [1.02–6.65], p = 0.04) among women were risk factors for increased daytime sleepiness (ESS total score ≥10) whereas partner faithfulness decreased this risk (OR 0.47, CI 95% [0.24–0.90], p = 0.02).

Conclusion

Increased daytime sleepiness in this middle aged series was related to female (hormonal status and sedentarism) and partner factors; several which are susceptible of intervention.     

Psychomotor vigilance performance predicted by Epworth Sleepiness Scale scores in an operational setting with the United States Navy

It is critical in operational environments to identify individuals who are at higher risk of psychomotor performance impairments. This study assesses the utility of the Epworth Sleepiness Scale for predicting degraded psychomotor vigilance performance in an operational environment. Active duty crewmembers of a USA Navy destroyer (N = 69, age 21–54 years) completed the Epworth Sleepiness Scale at the beginning of the data collection period. Participants wore actigraphs and completed sleep diaries for 11 days. Psychomotor vigilance tests were administered throughout the data collection period using a 3‐min version of the psychomotor vigilance test on the actigraphs. Crewmembers with elevated scores on the Epworth Sleepiness Scale (i.e. Epworth Sleepiness Scale >10) had 60% slower reaction times on average, and experienced at least 60% more lapses and false starts compared with individuals with normal Epworth Sleepiness Scale scores (i.e. Epworth Sleepiness Scale ≤10). Epworth Sleepiness Scale scores were correlated with daily time in bed (P < 0.01), sleep (P < 0.05), mean reaction time (P < 0.001), response speed 1/reaction time (P < 0.05), slowest 10% of response speed (P < 0.001), lapses (P < 0.01), and the sum of lapses and false starts (P < 0.001). In this chronically sleep‐deprived population, elevated Epworth Sleepiness Scale scores identified that subset of the population who experienced degraded psychomotor vigilance performance. We theorize that Epworth Sleepiness Scale scores are an indication of personal sleep debt that varies depending on one's individual sleep requirement. In the absence of direct performance metrics, we also advocate that the Epworth Sleepiness Scale can be used to determine the prevalence of excessive sleepiness (and thereby assess the risk of performance decrements).     

The reliability of the Epworth Sleepiness Score in a sleep clinic population

Despite the Epworth Sleepiness Score being widely used, there are limited studies of its reliability in clinical practice. The aim of this study was to assess the reliability of the Epworth Sleepiness Score in a clinical population. The study included patients referred to Middlemore Hospital sleep service between October and November 2014, aged over 17 years, with at least two Epworth Sleepiness Score measurements at up to three different points on the diagnostic pathway: on General Practitioner referral (GP Epworth Sleepiness Score); at overnight oximetry assessment (Oximetry Epworth Sleepiness Score); and at a specialist clinic (Specialist Epworth Sleepiness Score). No treatment was administered between scores. One‐hundred and thirty‐three patients were included in the study. There was a median of 91 days from GP Epworth Sleepiness Score to Oximetry Epworth Sleepiness Score, and 11 days from Oximetry Epworth Sleepiness Score to Specialist Epworth Sleepiness Score. There was poor test–retest reliability between GP Epworth Sleepiness Score and Specialist Epworth Sleepiness Score; 72.4% and 17.8% of patients had an absolute difference of more than 2 and 8 Epworth Sleepiness Score points, respectively. A Bland–Altman plot of mean Epworth Sleepiness Score versus the difference between GP Epworth Sleepiness Score and Specialist Epworth Sleepiness Score demonstrated a wide scatter of data and 95% confidence interval for the difference in Epworth Sleepiness Score for an individual patient of ?14 to +10. There was similar variability between GP Epworth Sleepiness Score and Oximetry Epworth Sleepiness Score. The reliability of the Epworth Sleepiness Score is unproven in clinical settings. This study shows poor test–retest reliability of Epworth Sleepiness Score, particularly between primary and secondary care, arguing against the use of Epworth Sleepiness Score for clinical decision‐making or prioritisation of services without first assessing the reliability of the Epworth Sleepiness Score in the relevant clinical population.     

A genetic analysis of the Epworth Sleepiness Scale in 1560 World War II male veteran twins in the NAS-NRC Twin Registry

Responses to the eight-item Epworth Sleepiness Scale (ESS) obtained from 1560 World War II male veteran twin pairs [818 monozygotic (MZ), 742 dizygotic (DZ)] were analysed to determine the extent to which genetic influences are involved in self-reported daytime sleepiness in the elderly. Average ESS score (+/- SD) in this sample was 7.1 +/- 3.9, range 0--24. More than half of the twins (65%--67%) reported a moderate to high chance of falling asleep while lying down to rest; fewer than 3% admitted that this would occur while sitting and talking to someone or while stopped in traffic. Daytime sleepiness was not associated with age but was significantly and positively associated with obesity. The intraclass twin correlation on ESS scores was 0.39 in MZ pairs and 0.21 in DZ pairs (both P < 0.001). Structural equation modeling of the observed variance-covariance matrices for MZ and DZ twins estimated the heritability of ESS to be 38% (95% confidence interval 33%--44%). Environmental influences not shared by twin brothers accounted for the remaining variance in daytime sleepiness. A reasonable interpretation of the heritability of ESS in this healthy cohort of elderly male twins is a genetic susceptibility for disordered breathing during sleep.     

Suitability of the Epworth Sleepiness Scale (ESS) for Economic Evaluation: An Assessment of Its Convergent and Discriminant Validity

Objective: To assess the suitability for use within economic evaluation of a widely used sleep-related instrument (the Epworth Sleepiness Scale [ESS]) by examining its convergent and discriminant validity with two widely used generic preference-based instruments (Short-Form 36 [SF-36] and the Assessment of Quality of Life 4 dimensions [AQoL-4D]). Methods: Data from a cross-section of 2,236 community-dwelling Australian men were analyzed. Convergent validity was investigated using Spearman’s correlation, intraclass correlation, and modified Bland-Altman plots, while discriminant validity was examined using Kruskal Wallis tests. Results: All instruments showed good discriminant validity. The ESS was weakly correlated to the Short Form 6 dimension, or SF-6D (derived from the SF-36) and AQoL-4D utilities (r = 0.20 and r = 0.19, respectively). Correlations between ESS and SF-36/AQoL-4D dimensions measuring the same construct were all in the hypothesized directions but also weak (range of absolute r = 0.00 to 0.18). The level of agreement between the ESS and AQoL-4D was the weakest, followed by that between the ESS and SF-6D. Moderate convergent validity was seen between the utilities. Conclusions: The lack of convergent validity between the ESS and the preference-based instruments shows that sleep-related constructs are not captured by the latter. The ESS has, however, demonstrated good discriminant validity comparable to that of the AQoL-4D and the SF-36/SF-6D and would therefore be equally useful for measuring subgroup differences within economic evaluation. We therefore recommend using the ESS within cost-effectiveness analysis as a complement to preference-based instruments in order to capture sleep-specific constructs not measured by the latter.     

Normative Data on the IOWA Conners Teacher Rating Scale

Obtained ratings on the IOWA Conners Teacher Rating Scale for 608 boys and girls from kindergarten through fifth grade in two elementary schools. Means, standard deviations, and suggested cutoff scores are reported by grade and sex for this sample on the Inattention/Overactivity and the Aggression (Oppositional/Defiant) subscales. Significant grade and sex effects are discussed, and implications for differential diagnosis of attention deficit and conduct disorders are addressed.     

Stability of the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Questionnaires over 1 year in early middle-aged adults: the CARDIA study

STUDY OBJECTIVES: To describe the stability of the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS) scores over 1 year among a population-based sample of black and white early middle-aged adults. PARTICIPANTS: More than 600 participants, aged 38 to 50 years, from the Chicago site of the Coronary Artery Risk Development in Young Adults (CARDIA) Study. METHODS: The PSQI and ESS were completed twice, approximately 1 year apart, between 2003 and 2005. Seven PSQI 4-level component scores, a global PSQI score, and the ESS scores were calculated. A PSQI global score greater than 5 was classified as poor quality sleep, and an ESS score greater than 10 was classified as high daytime sleepiness. RESULTS: The mean+/-SD PSQI score was 5.7+/-3.1 in Year 1 and 5.9+/-3.1 in Year 2. The mean ESS score was 7.4+/-4.3 in Year 1 and 7.2+/-4.2 in Year 2. The Pearson correlation coefficient for the PSQI score in both years in the full sample was .68 and ranged from .54 among black men to .72 among black women. The Pearson correlation coefficient for the ESS score in both years in the full sample was .76 and ranged from .70 among black men to .80 among white men. In the full sample, 76% had the same PSQI dichotomous classification, and 85% had the same ESS dichotomous classification in both years. CONCLUSIONS: These results suggest that the PSQI and ESS are stable measures of sleep quality and sleepiness over the past year in early middle-aged adults.     

Definition of excessive daytime sleepiness in the general population: Feeling sleepy relates better to sleep‐related symptoms and quality of life than the Epworth Sleepiness Scale score. Results from an epidemiological study

Many different subjective tools are being used to measure excessive daytime sleepiness (EDS) but the most widely used is the Epworth Sleepiness Scale (ESS). However, it is unclear if using the ESS is adequate on its own when assessing EDS. The aim of this study was to estimate the characteristics and prevalence of EDS using the ESS and the Basic Nordic Sleep Questionnaire (BNSQ) in general population samples. Participants aged 40 years and older answered questions about sleepiness, health, sleep‐related symptoms and quality of life. Two groups were defined as suffering from EDS: those who scored >10 on the ESS (with increased risk of dozing off) and those reporting feeling sleepy during the day ≥3 times per week on the BNSQ. In total, 1,338 subjects (53% male, 74.1% response rate) participated, 13.1% reported an increased risk of dozing off, 23.2% reported feeling sleepy and 6.4% reported both. The prevalence of restless leg syndrome, nocturnal gastroesophageal reflux, difficulties initiating and maintaining sleep and nocturnal sweating was higher among subjects reporting feeling sleepy compared to non‐sleepy subjects. Also, subjects reporting feeling sleepy had poorer quality of life and reported more often feeling unrested during the day than non‐sleepy subjects. However, subjects reporting increased risk of dozing off (ESS > 10) without feeling sleepy had a similar symptom profile as the non‐sleepy subjects. Therefore, reporting only risk of dozing off without feeling sleepy may not reflect problematic sleepiness and more instruments in addition to ESS are needed when evaluating daytime sleepiness.     

Normative values for high voltage electrical stimulation across the brachial plexus

OBJECTIVES: To obtain normative values for High Voltage Electrical Stimulation across the brachial plexus between Erb's point, C8 root and T1 root. A case study of probable true thoracic outlet syndrome is used to illustrate the usefulness of the method. METHODS: 22 patients were tested for use in normative date pool with complaints unrelated to the ulnar nerve, the majority of which were pure carpal tunnel syndrome. High voltage stimulation was performed at Erb's point, C8 root and T1 root. Recording was from the abductor digit minimi muscle. RESULTS: Upper limit for absolute latencies were 13.9 ms, 14.5 ms and 14.5 ms for Erb's point, C8 root and T1 root stimulation respectively. Corresponding lower limits of amplitude were 4.8 mV, 3.4 mV and 2.9 mV. Upper limits for interpeak latencies were 1.4 ms and 1.2 ms for C8 to Erb's point and T1 to Erb's point respectively. In a case of true thoracic outlet syndrome, the symptomatic side revealed prolonged interpeak and absolute latencies. The asymptomatic side remained within normal limits. CONCLUSION: Normative values for high voltage stimulation across the brachial plexus are useful in cases of suspected compression in this proximal location of the upper limb.