Sleep Quality Perception in the Chronic Fatigue Syndrome: Correlations with Sleep Efficiency, Affective Symptoms and Intensity of Fatigue

Sleep Laboratory, Department of Psychiatry, University Hospital Brugmann, Brussels, Belgium.
Neuropsychobiology (Impact Factor: 2.26). 02/2007; 56(1):40-6. DOI: 10.1159/000110727
Source: PubMed


One of the core symptoms of the chronic fatigue syndrome (CFS) is unrefreshing sleep and a subjective sensation of poor sleep quality. Whether this perception can be expressed, in a standardized questionnaire as the Pittsburgh Sleep Quality Index (PSQI), has to our knowledge never been documented in CFS. Furthermore, correlations of subjective fatigue, PSQI, affective symptoms and objective parameters such as sleep efficiency are poorly described in the literature.
Using a cross-sectional paradigm, we studied subjective measures like PSQI, Fatigue Severity Scale scores and intensity of affective symptoms rated by the Hamilton Depression and Anxiety scales as well as objective sleep quality parameters measured by polysomnography of 28 'pure' (no primary sleep and no psychiatric disorders) CFS patients compared to age- and gender-matched healthy controls.
The PSQI showed significantly poorer subjective sleep quality in CFS patients than in healthy controls. In contrast, objective sleep quality parameters, like the Sleep Efficiency Index (SEI) or the amount of slow-wave sleep did not differ significantly. Subjective sleep quality showed a correlation trend with severity of fatigue and was not correlated with the intensity of affective symptoms in CFS.
Our findings indicate that a sleep quality misperception exists in CFS or that potential nocturnal neurophysiological disturbances involved in the nonrecovering sensation in CFS are not expressed by sleep variables such as the SEI or sleep stage distributions and proportions.

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    • "The meta-analytic component of this review was performed in accordance with the Cochrane Handbook for Systematic Reviews[32]with the purpose of identifying possible differences in PSQI global and subscale scores between clinical and non-clinical samples (Tables S2a and S2b for raw data). Seven studies[22,46,49,51,56,68,79], six of fair quality[22,46,49,51,56,79]and one of good quality[68], provided global scores for both groups. The clinical samples combined equated to 801 individuals, and the non-clinical samples comprised 3433 persons. "

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    • "The PSQI has been used in several psychometric studies, including in patients with bone marrow transplant, renal transplant, breast cancer, benign breast problems, and primary insomnia[15,16]. Moreover, the PSQI is also used as a surrogate of perception of sleep quality in patients of chronic fatigue syndrome, myasthenia gravis, dementia , healthy women, and even in patients with OSA1718192021. Therefore, this retrospective study was conducted to investigate factors that are associated with the perception of sleep quality by analyzing the PSQI, focusing on the role of hypoxemia, in OSA patients. "
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    ABSTRACT: Background Perceived sleep quality may play an important role in diagnosis and therapy for obstructive sleep apnea (OSA). However, few studies have assessed factors that are associated with perceived sleep quality in OSA patients. Hypoxemia depresses the central nervous system and attenuates the perceived respiratory load in asthmatic patients. This study aimed to investigate the factors related to perceived sleep quality, focusing on the role of hypoxemia. Methods Polysomnography studies of 156 OSA patients were reviewed. Traditional polysomnographic parameters, including parameters of oxy-hemoglobin saturation (SpO2), were calculated, and the sleep questionnaire and scales were used. Considering the possible pitfalls of absolute values of SpO2 and individualized responses to hypoxemia, the amplitude of desaturation was further computed as “median SpO2 minus lowest 5 % SpO2 “and “highest 5 % SpO2 minus median 5 % SpO2”. Correlations between these parameters and perceived sleep quality, represented as the Pittsburgh sleep quality index (PSQI), were performed. Multiple linear regression analysis was also conducted to investigate the factors associated with the PSQI. Results Although the PSQI was not correlated with the apnea-hypopnea index (r = −0.113, p = 0.162) and oxygen desaturation index (r = −0.085, p = 0.291), the PSQI was negatively correlated with “median SpO2 minus lowest 5 % SpO2” (r = −0.161, p = 0.045). After adjusting for age, total sleep time, the periodic limb movements index, tendency of depression, and the lowest 5 % SpO2, the “median SpO2 minus lowest SpO2” was still a significant predictor for a lower PSQI (β = −0.357, p = 0.015). Conclusions More severe hypoxemia is associated with better perceived sleep quality among OSA patients. This paradox may be associated with hypoxemia-related impairment of perception. The effect of hypoxemia did not appear to be significant in relatively mild hypoxemia but become significant in severe hypoxemia.” Median SpO2 minus lowest 5 % SpO2” may also be a better predictor of perceived sleep quality than the apnea-hypopnea index because of the disproportionate effects of hypoxemia. Additionally, further studies are necessary to confirm the role of hypoxemia on perceived sleep quality and identify the possible threshold of hypoxemia in OSA patients.
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    • "Studies that examined differences in PSQI global score between healthy subjects and patients suffering from a variety of disorders known to be associated with poor sleep, showed significant differences between groups [9] [22] [45] [49] [51] [56] [60] [68] [71] [79]. Studies that examined differences within groups of people (i.e., race, age, sex, different symptom clusters within the same population, etc.) showed non-significant differences [49] [50] [53] [58] [61] [64] [67] [73]. "
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    ABSTRACT: This review appraises the process of development and the measurement properties of the Pittsburgh sleep quality index (PSQI), gauging its potential as a screening tool for sleep dysfunction in non-clinical and clinical samples; it also compares non-clinical and clinical populations in terms of PSQI scores. MEDLINE, Embase, PsycINFO, and HAPI databases were searched. Critical appraisal of studies of measurement properties was performed using COSMIN. Of 37 reviewed studies, 22 examined construct validity, 19 - known-group validity, 15 - internal consistency, and three - test-retest reliability. Study quality ranged from poor to excellent, with the majority designated fair. Internal consistency, based on Cronbach's alpha, was good. Discrepancies were observed in factor analytic studies. In non-clinical and clinical samples with known differences in sleep quality, the PSQI global scores and all subscale scores, with the exception of sleep disturbance, differed significantly. The best evidence synthesis for the PSQI showed strong reliability and validity, and moderate structural validity in a variety of samples, suggesting the tool fulfills its intended utility. A taxonometric analysis can contribute to better understanding of sleep dysfunction as either a dichotomous or continuous construct. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Feb 2015 · Sleep Medicine Reviews
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