Introduction
Daytime sleepiness | Fatigue | |
---|---|---|
Definition | Daytime sleepiness is the inability to stay awake and alert during the day with unintentional occurrence of sleep almost daily for at least 3 months. Excessive daytime sleepiness is defined by subjective complaints or interferences with function [1] | Fatigue is “a subjective lack of physical and/or mental energy that is perceived by the individual or the caregiver to interfere with usual and desired activities” [26] |
Symptoms | Reduced alertness or wakefulness | Feeling of tiredness, exhaustion, weariness, or persistent lack of energy |
Increased likelihood of falling asleep or dozing off unintentionally (especially in monotonous, sedentary situations) | Increased mental or physical fatigue | |
Increased sleep drive during breaks or when resting (e.g., lying down for a nap) | Not necessarily associated with increased sleep pressure during breaks or when resting (e.g., lying down to relax) | |
Semantics | Tiredness is often used as a synonym (e.g., by patients with hypersomnia) | Tiredness is often used as a synonym (e.g., by patients with insomnia) |
Common questionnaires | E.g., Epworth Sleepiness Scale (ESS) | E.g., Fatigue Severity Scale (FSS) |
Objective measurements | MSLT, MWT, EEG, pupillography, psychomotor vigilance task; sustained attention and vigilance tasks, driving simulators | No validated measurement methods |
Effective countermeasures | Sleep or short naps, but not rest per se | Relief and improvement with rest |
Stimulants temporarily effective | Limited efficacy of stimulants | |
Alertness management | – |
Materials and methods
Study design and participants
Assessments
Sociodemographic and biometric data
Daytime sleepiness
Fatigue
Insomnia
Sleep-related movement and breathing disorders
Statistical analysis
Results
Study population
Total patients | No sleepiness ESS < 10 | Increased sleepiness ESS > 10 | p-value | Patients without or treated (n = 7) sleep apnea | Patients with newly diagnosed sleep apnea | p-value | ||
---|---|---|---|---|---|---|---|---|
Patient characteristics | (n) | 192 | 139 | 47 | – | 164 | 28 | – |
Male sex (%) | 43.2 | 43.9 | 42.3 | 0.874a | 40.9 | 57.1 | 0.108a | |
Age (M ± SD) | 44 ± 14 | 44 ± 14 | 44 ± 13 | 0.892 | 43 ± 14 | 51 ± 9 | 0.002* | |
BMI (M ± SD) | 27.2 ± 6.5 | 26.9 ± 6.5 | 28.2 ± 6.9 | 0.230 | 26.4 ± 5.8 | 32.0 ± 7.9 | 0.001* | |
BDI (M ± SD) | 29.2 ± 9.8 | 28.8 ± 9.9 | 30.6 ± 9.8 | 0.402 | 29.3 ± 10.1 | 28.3 ± 8.3 | 0.571 | |
Recurrent depression (%) | 51.1 | 53.2 | 48.9 | 0.610a | 53.0 | 39.4 | 0.178a | |
Additional psychiatric disorder (%) | 32.2 | 33.1 | 31.9 | 0.882a | 32.9 | 28.6 | 0.649a | |
Additional somatic disorder (%) | 64.6 | 66.2 | 55.3 | 0.181a | 61.0 | 85.7 | 0.011a | |
Epworth Sleepiness Scale (ESS) | (n) | 186 | 139 | 47 | – | 158 | 28 | – |
(Mean score ± SD) | 7.6 ± 4.8 | 5.3 ± 2.8 | 14.2 ± 2.7 | n. a. | 7.4 ± 4.7 | 8.2 ± 5.2 | 0.527 | |
ESS > 10 (%) | 25.3 | 0 | 100 | n. a. | 22.2 | 42.9 | 0.020a* | |
ESS > 12 (%) | 16.7 | 0 | 65.9 | n. a. | 15.8 | 21.4 | 0.423a | |
Fatigue Severity Scale (FSS) | (n) | 171 | 124 | 41 | – | 148 | 23 | – |
(Mean score ± SD) | 4.8 ± 1.5 | 4.6 ± 1.6 | 5.3 ± 1.2 | 0.008* | 4.7 ± 1.5 | 5.1 ± 1.4 | 0.230 | |
FSS > 4 (%) | 66.7 | 61.3 | 82.9 | 0.011a* | 64.2 | 82.6 | 0.081a | |
Regensburg Insomnia Scale (RIS) | (n) | 169 | 124 | 42 | – | 141 | 28 | – |
(Mean score ± SD) | 18.7 ± 7.8 | 18.4 ± 8.0 | 20.0 ± 7.4 | 0.226 | 18.2 ± 7.8 | 21.2 ± 7.5 | 0.096 | |
RIS > 12 (%) | 75.7 | 74.2 | 81.0 | 0.376a | 73.8 | 85.7 | 0.571a |
Prevalence of daytime sleepiness and specific sleep disorders
Depression and daytime sleepiness
Depression and sleep apnea
Discussion
Conclusion
Conclusion for clinical practice
-
Daytime sleepiness, characterized by sleep propensity in daily activities, should be distinguished from more global clinical concepts of tiredness, fatigue, and lack of energy.
-
Patients with depression should be asked about sleep-related symptoms, especially sleepiness. Special attention should be given to patients at risk of sleep-disordered breathing disorders (SRBDs; see Fig. 1 for a diagnostic assessment flowchart).
-
An early and comprehensive evaluation of the patient’s sleep history should be supplemented with standardized questionnaires, such as the Epworth Sleepiness Scale (ESS), to screen for excessive daytime sleepiness. The ESS is a useful tool for quick and inexpensive assessment of daytime sleepiness and can be easily integrated into psychiatric routines.
-
Elevated ESS scores may indicate the presence of undiagnosed hypersomnolence-related sleep disorders, including SRBDs. However, the ESS is not intended to screen for sleep apnea syndrome itself. To diagnose SRBDs, it is necessary to evaluate typical signs of suspected SRBDs and perform objective assessments such as polygraphy or polysomnography, with the latter being the gold standard.