Psychometric properties of the Epworth Sleepiness Scale: A factor analysis and item-response theory approach

Prevalence, dimensions, and correlates of excessive daytime sleepiness in community-dwelling older adults: the Yilan study, Taiwan

BACKGROUND

Daytime sleepiness is an important health problem. However, the dimensionality of the Epworth Sleepiness Scale (ESS) in older adults remains unclear. This study aimed to determine the prevalence of ESS-defined excessive daytime sleepiness in older adults. Furthermore, the dimensionality of ESS and its respective correlates were also compared.

MATERIALS AND METHODS

This is a community-based survey in which community-dwelling older adults aged ≥ 65 years participated. Excessive daytime sleepiness was assessed using the ESS and was defined as an ESS score of > 10. Exploratory factor analysis was performed to identify the ESS factors. Multiple logistic regression analysis was used to examine the independent correlates of the ESS-defined and factor-specific correlates of excessive daytime sleepiness.

RESULTS

In total, 3978 older adults participated in this study. The mean age was 76.6 ± 6.7 years, with 53.8% ≥ 75 years, and 57.1% were female. The prevalence of ESS-defined excessive daytime sleepiness was 16.0%. An exploratory factor analysis revealed two factors in the ESS, which were designated as 'passive' and 'active' according to the soporific levels of ESS items loaded in each factor. Multiple logistic regression showed that male, illiteracy, depression, disability, short sleep duration and no exposure to hypnotics were risk indicators for ESS-defined excessive daytime sleepiness. However, the correlates for passive and active factor-defined excessive daytime sleepiness differ in pattern, especially in variables related to education, exercise, mental health, and sleep.

CONCLUSIONS

The prevalence of ESS-defined excessive daytime sleepiness is high, and its correlates vary among older adults. This study also suggests a dual ESS structure in community-dwelling older adults.

The differential pattern of associations between nighttime sleep disturbances with dimensions of daytime sleepiness in community-dwelling older adults, the Yilan study, Taiwan

BACKGROUND

The association between nighttime sleep disturbance and daytime sleepiness remains unclear. This study aimed to examine the relationships between various domains of nighttime sleep disturbance, daytime sleepiness, and their specific dimensions.

METHODS

This was a community-based cross-sectional study. The participants were adults aged 65 years and older from Yilan City, Taiwan. Daytime sleepiness (DS) was defined using the Epworth Sleepiness Scale (ESS) with scores ≥ 11. The ESS dimensions were further examined using exploratory factor analysis. The highest 15% factor scores for each factor were defined as factor-specific DS. Various domains of nighttime sleep disturbance were assessed using the Pittsburgh Sleep Quality Index. Logistic regression analysis was used to examine the independent relationships among various nighttime sleep disturbances, ESS, and its dimensions.

RESULTS

Of the 2585 participants, a total of 59.0% were women. Two factors were identified by exploratory factor analysis and were designated as 'passive factor' and 'active factor'. Multiple logistic regression analyses elucidated that short sleep duration was a common risk indicator for ESS-defined (odds ratio (OR): 2.01; 95% confidence interval (CI): 1.43-2.83), passive factor-defined (OR: 2.23, 95% CI: 1.65-3.00), and active factor-defined DS (OR: 1.47, 95% CI: 1.07-2.00). Hypnotic use was associated with a lower risk of both ESS-defined (OR: 0.66, 95% CI: 0.47-0.92) and passive factor-defined DS (OR:0.69, 95% CI: 0.52-0.92). Bathroom use (OR: 1.41, 95% CI: 1.04-1.91), coughing or snoring (OR: 2.14, 95% CI: 1.01-4.56), and sleep efficiency (OR: 0.42; 95% CI: 0.31-0.57) were uniquely associated with active factor-defined DS.

CONCLUSION

Two factors were identified in the ESS, revealing factor-specific correlates of DS. Specifically, ESS- and passive factor-defined DS shared similar correlates. In contrast, some correlates seem unique to active-factor-defined DS.

Acceptance and Commitment Therapy, Combined with Bedtime Restriction, versus Cognitive Behavioral Therapy for Insomnia: A Randomized Controlled Pilot Trial

INTRODUCTION

Cognitive behavioral therapy for insomnia (CBT-I) is the current first-line treatment for insomnia. However, rates of nonresponse and nonremission are high and effects on quality of life are only small to moderate, indicating a need for novel treatment developments. We propose that Acceptance and Commitment Therapy (ACT) addresses core pathophysiological pathways of insomnia. ACT therefore has the potential to improve treatment efficacy when combined with bedtime restriction, the most effective component of CBT-I. The aim of this study was to compare the efficacy of ACT for insomnia combined with bedtime restriction (ACT-I) and CBT-I in improving insomnia severity and sleep-related quality of life.

METHODS

Sixty-three patients with insomnia disorder (mean age 52 years, 65% female, 35% male) were randomly assigned to receive either ACT-I or CBT-I in a group format. The primary outcomes were insomnia severity (Insomnia Severity Index) and sleep-related quality of life (Glasgow Sleep Impact Index). Outcomes were assessed before randomization (T0), directly after treatment (T1), and at 6-month follow-up (T2).

RESULTS

The results indicated significant, large pre-to-post improvements in both groups, for both primary and secondary outcomes. Improvements were maintained at the 6-month follow-up. However, there was no significant group by time interactions in linear mixed models, indicating an absence of differential efficacy. On a subjective treatment satisfaction scale, patients in the ACT-I group indicated significantly greater satisfaction with their improvement of several aspects of health including their energy level and work productivity.

CONCLUSIONS

The results suggest that ACT-I is feasible and effective, but not more effective than CBT-I for the improvement of insomnia severity and sleep-related quality of life. Future studies are needed to assess whether ACT-I is noninferior to CBT-I and to shed light on mechanisms of change in both treatments.

An app-based training for adolescents with problematic digital-media use and their parents (Res@t digital): protocol for a cluster-randomized clinical trial

Background

Digital media-use disorders (DMUD) in adolescents are a rising phenomenon associated with psychological distress, comorbid mental disorders, and high burden on affected families. Since the ICD-11 introduced criteria for gaming disorder, these can now be transferred to describe additional DMUD associated with social media platforms and streaming services. Most evidence for effective treatments comes from cognitive-behavioral therapy (CBT). However, interventions based on theoretical models for adolescents and their parents are widely missing, leading to a significant clinical gap.

Methods

Res@t digital (Resource-Strengthening Training for Adolescents with Problematic Digital-Media Use and their Parents) is the app-based translation of the first model-based digital intervention for adolescents with DMUD and their parents based on CBT. It comprises separate but content-related modules for adolescents (Res@t-A) and parents (Res@t-P), applying multimodal techniques. The effectiveness of Res@t will be evaluated within a multicenter cluster-randomized controlled evaluator-blinded pre-post follow-up trial with the waitlist control group (CG). In addition to the Res@t program in the intervention group, both groups will receive treatment as usual within primary child and adolescent psychiatric/psychotherapeutic healthcare. The primary outcome addresses DMUD symptom reduction after 10 weeks. Secondary outcomes are related to a reduction in psychological and family-related problems and an increase in parental self-efficacy. All outcomes will be assessed using standardized self-report measures. A total of 1,334 participating adolescent-parent dyads from a large clinical network throughout Germany are planned to be included in the primary analyses based on an intention-to-treat approach, applying linear mixed models.

Discussion

Assuming superiority of Res@t over the control condition, the intervention has the potential to provide evidence-based treatment for a significant number of help-seeking families, supporting local healthcare structures and resources. It is a promising program for practicable implementation and flexible use in different settings.

Clinical trial registration

https://drks.de, DRKS00031043.

Emergence of different dimensions of sleepiness in a general population sample: An EPISONO study

INTRODUCTION

Recent evidence supports the idea that sleepiness has several dimensions, comprising psychophysiological phenomena, such as sleep propensity and sleepiness perception. The Epworth Sleepiness Scale (ESS) is among one of the most used sleepiness assessment tools, but recent data suggest that it might not detect problematic impairments in sleep health. More research is warranted investigating sleepiness dimensions with large sample sizes, using both objective and subjective methods of analyzing sleep.

METHODS

We used data from the Epidemiological Sleep Study (EPISONO), a major study carried out in Brazil using a representative sample of 1042 participants of the general population of Sao Paulo city, who completed questionnaires and underwent type I polysomnography. Sleepiness was measured by the ESS (sleep propensity) and the UNIFESP Sleep Questionnaire, which asked about the frequency of feeling sleepy during the day (sleepiness perception). The participants were distributed into 4 groups in respect of excessive daytime sleepiness (EDS) according to the following criteria: 1) having an ESS score >10 (ESS group). 2) feeling sleepy ≥3 times per week (Frequent EDS group). 3) the combined criteria (Combined EDS group). 4) having no evidence of EDS (no EDS group). The UNIFESP Sleep Questionnaire was used to obtain self-reported sleep duration, sleep debt, and sleep duration variability. Participants also completed the Pittsburgh Sleep Quality Index, the Insomnia Severity Index, and a pre-polysomnography sleep questionnaire.

RESULTS

After removing participants with missing data, there were 620 participants with no EDS, 255 individuals in the ESS group, 68 in the Frequent EDS group, and 73 in the Combined EDS group. Compared to the no EDS group, the ESS and Combined EDS groups had significantly increased sleep efficiency, diminished sleep latency, wake after sleep onset, and self-reported weekly sleep duration. The Frequent and Combined EDS groups had significantly higher scores in the Insomnia Severity Index and Pittsburgh Sleep Quality Index. All EDS groups had an increased likelihood of nonrestorative sleep. EDS frequency and the ESS scores were significantly correlated.

CONCLUSIONS

Participants with a high sleep propensity had a profile suggesting prior sleep deprivation, while high sleepiness perception was associated with impaired sleep quality. These findings indicated that, in the general population, these instruments evaluated separate sleepiness dimensions with different associations, highlighting that screening using a combination of instruments might be more effective in detecting impairments in sleep health.

Daytime sleepiness and sleep quality in Charcot-Marie-Tooth disease

BACKGROUND

Sleep abnormalities have been reported in Charcot-Marie-Tooth disease (CMT), but data are scanty. We investigated their presence and correlation in a large CMT patients' series.

METHODS

Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI) were administered to CMT patients of the Italian registry and controls. ESS score > 10 indicated abnormal daytime somnolence, PSQI score > 5 bad sleep quality. We analyzed correlation with disease severity and characteristics, Hospital Anxiety and Depression Scale (HADS), Modified Fatigue Impact Scale (MFIS), Body Mass Index, drug use.

RESULTS

ESS and PSQI questionnaires were filled by 257 and 253 CMT patients, respectively, and 58 controls. Median PSQI score was higher in CMT patients than controls (6 vs 4, p = 0.006), with no difference for ESS score. Abnormal somnolence and poor sleep quality occurred in 23% and 56% of patients; such patients had more frequently anxiety/depression, abnormal fatigue, and positive sensory symptoms than those with normal ESS/PSQI. Moreover, patients with PSQI score > 5 had more severe disease (median CMT Examination Score, CMTES, 8 vs 6, p = 0.006) and more frequent use of anxiolytic/antidepressant drugs (29% vs 7%, p < 0.001).

CONCLUSIONS

Bad sleep quality and daytime sleepiness are frequent in CMT and correlated with anxiety, depression and fatigue, confirming that different components affect sleep. Sleep disorders, such as sleep apnea and restless leg syndrome, not specifically investigated here, are other factors known to impact on sleep quality and somnolence. CMT patients' management must include sleep behavior assessment and evaluation of its correlated factors, including general distress and fatigue.

Assessment of the Brazilian Version of the Epworth Sleepiness Scale Using Item Response Theory: A Psychometric Study

There seems to be a consensus that adolescents worldwide are not getting enough sleep. This study aimed to evaluate the psychometric properties of the Epworth Sleepiness Scale (ESS) in adolescents using the item response theory. A psychometric study was conducted with 2206 adolescents aged 18 and 19 years in the city of São Luís, Maranhão, Brazil. The dimensionality of the ESS was assessed by principal component analysis. A Samejima's graded response model (SGRM) was fitted to it. The findings of this study showed a good internal consistency and the unidimensionality of the ESS. Considering the latent trait continuum, we obtained three levels, with anchor items. For the item 'Sitting still in a public place', the adolescents presented a small possibility of dozing in level 1, and a medium and great possibility in level 2. The item 'Sitting around talking to someone' presented small, medium, and great possibilities of dozing in level 3. The ESS with five items showed satisfactory psychometric properties. In addition, the results from the SGRM showed that adolescents with high levels of sleepiness are likely to nod off or sleep sitting up while talking to someone. This study allows us to understand excessive daytime sleepiness in adolescents.

Epworth sleepiness scale: A meta-analytic study on the internal consistency

OBJECTIVE/BACKGROUND

The Epworth Sleepiness Scale (ESS) is one of the most used self-reported instruments to assess sleepiness. Thus, several adaptations into different Languages have been performed worldwide over the years. The scale has produced disparate psychometric properties when applied in different settings. In the current study, our aim was to perform a Reliability Generalization meta-analysis of the Cronbach᾽s alphas of all published studies on ESS, specifically with a psychometric focus.

PATIENTS/METHODS

Three reference databases (Scopus, PubMed and Web of Science) were searched since 1991 to October 2022 and all the records on psychometric or validation studies that reported Cronbach's alphas, from clinical and nonclinical groups, were included. In total, data from 46 publications (63 estimates) were extracted, comprising 92,503 participants.

RESULTS

Using a Random-Effects Model, the cumulative Cronbach's alpha for the 63 estimates was about 0.82 (CI: 0.798, 0.832) which can be considered as a good measure. However, and as expected, it was observed a high level of heterogeneity (I2 = 98.96%). Moderation analyses considering setting, date, continent, risk of bias, sex, age and language were performed in order to account for the heterogeneity. Even so, only the variables study setting and continent were significant, and had little importance in explaining the heterogeneity.

CONCLUSIONS

The ESS is a reliable tool to measure sleepiness; however, further studies are needed to investigate what variables might explain the observed variability. Moreover, it will be important to include empirical studies beyond psychometric ones.

Validierung des Fragebogens zum Schlafverhalten von Sportlerinnen und Sportlern (FSVS)

Zusammenfassung. Der Athlete Sleep Behavior Questionnaire ist ein englischsprachiger Fragebogen zur Erhebung des individuellen Schlafverhaltens von Sportler_innen. Ziel dieser Studie war die Übersetzung des Athlete Sleep Behavior Questionnaire ins Deutsche sowie die wissenschaftliche Validierung dieser deutschen 18-Item-Version, dem Fragebogen zum Schlafverhalten von Sportlerinnen und Sportlern (FSVS). Die Validierungsstichprobe umfasste 450 Teilnehmende. Mittels eines dichotomen Items zur regelmäßigen Wettkampfteilnahme (ja/nein) wurde in Wettkampfsportler_innen ( n = 209) und Kontrollgruppe ( n = 241) unterteilt. Cronbach-α des FSVS-Gesamtwerts ergab .66. Die Pearson-Produkt-Moment-Korrelationsanalysen ergaben moderate Korrelationen zwischen FSVS-Gesamtwert, der Epworth-Sleepiness-Scale ( r = .33) und dem Pittsburgh-Sleep-Quality-Index ( r = .30). Es wurden signifikante Gruppenunterschiede für den FSVS-Gesamtwert gefunden, t‍(448) = 4.47, p < .001, d = 0.42, bei deskriptiv höheren Werten der Gruppe der Wettkampfsportler_innen. In einer separaten Stichprobe, die 13 Ruderer_innen der deutschen Junioren-Nationalmannschaft umfasste, wurden die Fragebogenwerte anschließend mit objektiven Schlafparametern korreliert. Dabei ließ sich eine hohe Korrelation zwischen FSVS-Gesamtwert und Einschlaflatenz ( rs = .68, p = .011) erkennen. Zusammenfassend ist der FSVS ein schnelles und valides Werkzeug, um dysfunktionale Schlafverhaltensweisen bei Wettkampfsportler_innen zu identifizieren. In Anlehnung an die Originalversion wird die Ableitung von Interventionen anhand einzelner Items empfohlen.

Patterns and predictors of dyspnoea following left ventricular assist device implantation

AIMS

Dyspnoea is a common symptom of heart failure (HF) that often prompts patients to seek treatment. Implantation of a left ventricular assist device (LVAD) has been associated with reduced dyspnoea but it is unclear if all patients experience similar improvements in dyspnoea over time following LVAD implantation. Our aim was to identify distinct trajectories of dyspnoea symptoms over time following LVAD implantation and predictors of dyspnoea trajectory. We hypothesized that at least two, distinct trajectories of dyspnoea would be observed following LVAD implantation.

METHODS AND RESULTS

This was a secondary analysis of data from the Profiling Biobehavioral Responses to Mechanical Support in Advanced Heart Failure study. In the parent study, sociodemographic and clinical data were collected prior to LVAD implantation and at 1, 3, and 6 months following LVAD implantation from a sample (n = 101) of patients with advanced HF. Latent growth mixture modelling was performed to identify distinct trajectories of dyspnoea symptoms. Backwards stepwise logistic regression was used to identify predictors of dyspnoea trajectory. Two, distinct trajectories of dyspnoea symptoms were identified: sustained improvement and unsustained improvement. Participants who experienced sustained improvement (86.7% of sample) demonstrated large, significant improvement in dyspnoea from pre-implantation to 3 months post-implant followed by smaller, non-significant improvement from 3 to 6 months. Participants who experienced unsustained improvement (13.3% of sample) demonstrated initial improvement from pre-implantation to 3 months post-implantation followed by worsening of dyspnoea from 3 to 6 months. Greater depressive symptoms at baseline and living alone were significant predictors of unsustained improvement.

CONCLUSION

Patients experience different patterns of dyspnoea over time following LVAD implantation. Clinicians should inquire about living arrangements and depressive symptoms at each visit to determine risk of unsustained improvement in dyspnoea.

Current Management of Residual Excessive Daytime Sleepiness Due to Obstructive Sleep Apnea: Insights for Optimizing Patient Outcomes

Although excessive daytime sleepiness (EDS) attributable to obstructive sleep apnea (OSA) can be resolved by consistent usage of and effective treatment (often with the use of continuous positive airway pressure therapy), 12–58% of patients report residual EDS (REDS). While REDS is difficult to treat, a proportion of cases are possibly due to reversible issues, and wake-promoting medications can prove useful for the remaining cases. Given the challenges associated with effective management of REDS and its relationship to multiple comorbidities, multidisciplinary management of patients with REDS is often recommended. Here we aim to bridge the knowledge gap on the burden, risk factors, prevalence, and potential pathophysiologic mechanisms of REDS in patients with OSA after first-line treatment. The roles of primary care physicians and sleep specialists, as well as the importance of the use of objective assessment tools for the evaluation of REDS and the effective management of comorbidities, are discussed. An update of approved treatments and emerging candidate treatments is also presented.

Nature-Based Therapies for Sleep Disorders in People Living with Human Immunodeficiency Virus

Following diagnosis of human immunodeficiency virus (HIV), getting adequate sleep may be the farthest thing from the mind of patients or providers. Even further from mind are the potential benefits on both sleep and HIV from nature-based therapy. In developing and developed countries, access to high-quality natural spaces has the potential to support physical and mental health. This article provides a review of sleep disorders, conventional and nature-based therapies, and the potential of nature-based therapy to support the health of people living with HIV through increased restorative sleep and immune function.

The Epworth Sleepiness Scale in epilepsy: Internal consistency and disease-related associations

BACKGROUND

The Epworth Sleepiness Scale (ESS) is the most common instrument for measuring subjective sleep propensity in people with epilepsy but has not yet been validated in this population.

STUDY OBJECTIVES

We aimed to systematically assess the validity, performance, and internal consistency of the ESS, as well as correlations between the ESS and disease-specific variables and patient-reported outcome measures in a cohort of adults with epilepsy (AWE).

METHODS

Ninety-five AWE completed sleep and seizure diaries, in-laboratory polysomnography (PSG) and patient-reported outcome measures, including the ESS, Insomnia Severity Index (ISI), and the Beck Depression Inventory (BDI). Demographic information and data from 95 matched controls referred for PSG for suspected obstructive sleep apnea (OSA) was taken from the electronic medical record. Frequencies of high ESS item ratings (item score ≥2) were calculated for each group. Cronbach's α and factor analysis were performed to assess the internal consistency and validity of the ESS within cases and controls. Multivariable linear models were used to assess the association between ESS and predictors of interest, adjusting for demographic and disease-specific variables, including seizure type, frequency, and anti-seizure medication (ASM) therapy.

RESULTS

While suspected OSA controls had significantly greater mean ESS total scores (9.9 vs 7.9, p = 0.004) and proportion with ESS >10 (42% vs 25%, p = 0.014), there were no significant differences in the severity of item responses, with the exception of "lying down to rest in the afternoon when circumstances permit," for which more controls rated as likely/very likely (79% vs 64%), p = 0.024). AWE with ESS >10 had higher mean standardized ASM dose (2.5 vs 1.7, p = 0.026). All ESS items were significantly correlated with the total score within each group. Cronbach's α was 0.75 for cases and 0.85 for controls, indicating good internal consistency of the ESS for both groups. After adjusting for demographic and sleep characteristics, higher ESS scores were associated with greater insomnia scores on the ISI (p = 0.024) and depressive symptoms on the BDI (p = 0.018).

CONCLUSIONS

This study provides validity for the use of the ESS in adult populations with epilepsy.

Assessment of sleep quality and daytime sleepiness in German national ice hockey players preparing for the world championship

Objectives

Objectives were to examine subjective sleep quality and daytime sleepiness of the German ice hockey junior national team prior to the world championship to identify athletes of concern and areas of optimization with the intention of equally preventing injury and enhancing performance.

Methods

Twenty-one athletes (Mage = 18.5 ± 0.6 years, Mheight = 181.7 ± 4.3 cm, Mweight = 81.4 ± 7.1 kg), playing for national (n = 13) and international (n = 8) home clubs, answered the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) before training camp (T1, day 1) and prior to tournament (T2, day 11).

Results

Overall, 9 players at T1 and 7 at T2 were identified as bad sleepers (PSQI > 5), while high sleepiness (ESS > 10) was found for 6 athletes at each measurement time. Group means and standard deviations reduced descriptively for PSQI (T1 = 5.38 ± 2.31, T2 = 4.57 ± 2.36) and ESS (T1 = 9.24 ± 3.74, T2 = 8.48 ± 3.28). Tendential differences were visible for PSQI in international-based players (Z = −1.7, p = 0.09) and ESS in first-national-league players (Z = −1.73, p = 0.08) over time. Higher PSQI values for international-based players (6.25 ± 2.6) were found compared to first-national-league (5.83 ± 1.60) and lower-league players (4.00 ± 2.08), with large effect sizes for lower-league compared to international (d = 0.95) and national players (d = 0.98) at T1 and small effect sizes compared to first-league players (d = 0.24) at T2.

Conclusion

Findings emphasize great vulnerability and individuality and underline the importance of intraindividual sleep monitoring to meet the requirements needed to equally obtain health and enhance overall performance.

Obstructive sleep apnea screening in young people: Psychometric validation of a shortened version of the STOP-BANG questionnaire using categorical data methods

BACKGROUND:

The STOP-BANG is an easily administrable questionnaire for the screening of obstructive sleep apnea in adults, which may be adapted for use by young people. Here, we assessed the psychometric properties of the STOP-BN, a shortened version of the STOP-BANG questionnaire, using categorical data methods.

METHODS:

Four hundred and three young people (age 20.71 ± 1.93 years) were selected by random sampling to participate in this cross-sectional study. Participants completed the STOP-BN, a tool for recording social and demographic characteristics, and the Epworth Sleepiness Scale (ESS), a measure of daytime sleepiness. The obtained data were analyzed using categorical data methods.

RESULTS:

A two-factor model was identified for the STOP-BN, using the Kaiser's criteria (eigenvalue >1) and the screen test. However, the parallel analysis based on minimum rank, and the cumulative variance criteria (>40%) identified an one-factor model. Factor loadings ranged from 0.364 to 0.745. The identified two-factor model showed acceptable fit as the reported goodness of fit index and weighted root mean square residual were in the ideal range, and the comparative fit index was close to the ideal range. Greatest lower bound to reliability for two factors of the STOP-BN was 0.67 and 0.67, indicating an acceptable internal consistency. A weak to a nonsignificant correlation between the ESS and the STOP-BN score was demonstrated, favoring STOP-BN's divergent validity.

CONCLUSION:

Categorical methods support the psychometric validity of the STOP-BN in the study population.

Sleep and Organizational Behavior: Implications for Workplace Productivity and Safety

The interaction between sleep and work-related behaviors influence many aspects of employee performance, safety, and health as well as organizational-level success. Although it is well established that quantity and quality of sleep can affect different types of task performance and personal health, the interactions between sleep habits and organizational behaviors have received much less attention. It is important to examine how sleep habits and workplace behaviors relate and the role of the underlying circadian rhythm on the potential impact of sleep and sleepiness in the workplace. Developing a deeper understanding of how sleep habits and sleepiness impact workers and the organization can help provide the necessary background for human resource management to develop more progressive support networks for employees that benefit both the worker and the organization. Human resources and employees should emphasize the impact of good sleep and sleep habits on organizational and individual productivity and safety.

Psychometric properties of the Epworth sleepiness scale in Ethiopian university students

Background

Daytime sleepiness is highly prevalent across the globe. The Epworth sleepiness scale (ESS) is the most widely used tool for screening daytime sleepiness. The psychometric properties of the ESS have not been comprehensively examined in African populations.

Material and methods

A cross-sectional design with simple random sampling was used in the present study. The study recruited 600 students from Mizan-Tepi University, Ethiopia, of which 329 (age = 18–28 years and body mass index = 21.19 ± 3.17 kg/m²) completed the study. ESS, a semi-structured socio-demographics questionnaire and a clinical interview to diagnose insomnia according to the International Classification of Sleep Disorders were employed.

Results

All except one item of the ESS showed a floor effect, while only one item score showed ceiling effect. However, no ceiling/floor effect was observed in the ESS total score. The Cronbach’s alpha (0.75) and composite reliability (0.75), indicated good internal consistency, while a moderate item-total score correlation (r = 0.55–0.67) implied favorable internal homogeneity. The known-group validity was established by significantly higher scores for all the ESS item scores and the ESS total scores among those with symptoms of insomnia than among non-symptomatic students. Fit indices along with the consideration of inter-factor correlation coefficient, measures of item retention favored the unidimensional structure of the ESS.

Conclusion

The ESS has excellent psychometric validity for screening daytime sleepiness in Ethiopian university students.

Electronic supplementary material

The online version of this article (10.1186/s12955-019-1098-9) contains supplementary material, which is available to authorized users.