Samenvatting
Introduction: Although that semiological, semantic and physiological confusion about fatigue and sleepiness still often persists in clinical practice, the necessary improvement of the distinction of both concepts has been repeatedly mentioned. Despite that a relatively clear linking of sleepiness and sleep drives to sleep has been achieved, the relationships of fatigue to sleepiness and to sleep quality still remain rather incomplete and less described.
In the present study we propose to use Rasch-analysis based methods to investigate the interrelations of fatigue, sleepiness and perceived sleep quality.
Methods: During a ten-month period we recruited 51 patients (mean age 47 +/- 13 years, 23 females) within a cross-sectional study protocol, presenting either with fatigue, sleepiness or with a non-restorative sleep complaint. We assessed fatigue and sleepiness with the Fatigue Severity (FSS) and Epworth Sleepiness (ESS) scales respectively. Sleep quality percepetion was measured by the Pittsburgh Sleep Quality Index (PSQI). Clinically significant alteration of sleep quality was defined as a PSQI score > 5 ("bad sleepers"). All patients underwent two consecutive nights of polysomnographic recording in our sleep lab. After Rasch-based rating scale diagnostics we investigated dimensionality, differential item functioning of measurement invariance and common person equating to study the relations of fatigue and sleepiness to sleep quality.
Results: "Bad sleepers" showed a significantly higher level of fatigue but not of sleepiness (p=0.001). Rasch analyses showed both the ESS and the FSS to measure uni-dimensional concepts of sleepiness and fatigue respectively. Both the FSS and the ESS globally showed relative invariance to sleep quality as measured by the PSQI. Common person equating suggested that, despite similar Rasch-derived agreeability scores, fatigue and sleepiness designate distinct constructs. However, about 50% of "bad sleepers" showed a far higher discrimination level of fatigue but not of sleepiness than "good sleepers".
Conclusion: In contrast to numerous reports about sleepiness and sleep quality, the more indirect nature of the relations between daytime fatigue and sleep quality is still lacking a defined description. Contributions to the disentangling of both concepts (fatigue and sleepiness) remain certainly useful to increase our knowledge in this field. In our sample good and bad sleepers differed essentially regarding their fatigue rather then their sleepiness levels. Interestingly Rasch-based common person equating showed bad sleepers also with a very different discriminative ability for fatigue alone.
In the present study we propose to use Rasch-analysis based methods to investigate the interrelations of fatigue, sleepiness and perceived sleep quality.
Methods: During a ten-month period we recruited 51 patients (mean age 47 +/- 13 years, 23 females) within a cross-sectional study protocol, presenting either with fatigue, sleepiness or with a non-restorative sleep complaint. We assessed fatigue and sleepiness with the Fatigue Severity (FSS) and Epworth Sleepiness (ESS) scales respectively. Sleep quality percepetion was measured by the Pittsburgh Sleep Quality Index (PSQI). Clinically significant alteration of sleep quality was defined as a PSQI score > 5 ("bad sleepers"). All patients underwent two consecutive nights of polysomnographic recording in our sleep lab. After Rasch-based rating scale diagnostics we investigated dimensionality, differential item functioning of measurement invariance and common person equating to study the relations of fatigue and sleepiness to sleep quality.
Results: "Bad sleepers" showed a significantly higher level of fatigue but not of sleepiness (p=0.001). Rasch analyses showed both the ESS and the FSS to measure uni-dimensional concepts of sleepiness and fatigue respectively. Both the FSS and the ESS globally showed relative invariance to sleep quality as measured by the PSQI. Common person equating suggested that, despite similar Rasch-derived agreeability scores, fatigue and sleepiness designate distinct constructs. However, about 50% of "bad sleepers" showed a far higher discrimination level of fatigue but not of sleepiness than "good sleepers".
Conclusion: In contrast to numerous reports about sleepiness and sleep quality, the more indirect nature of the relations between daytime fatigue and sleep quality is still lacking a defined description. Contributions to the disentangling of both concepts (fatigue and sleepiness) remain certainly useful to increase our knowledge in this field. In our sample good and bad sleepers differed essentially regarding their fatigue rather then their sleepiness levels. Interestingly Rasch-based common person equating showed bad sleepers also with a very different discriminative ability for fatigue alone.
Originele taal-2 | English |
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Titel | Journal of Sleep Research |
Pagina's | 179 |
Aantal pagina's | 1 |
Volume | 2 |
Status | Published - 2010 |
Evenement | Unknown - Duur: 1 jan 2010 → … |
Conference
Conference | Unknown |
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Periode | 1/01/10 → … |