Subjective fatigue and subjective sleepiness: two independent consequences of sleep disorders?

Sleep Research Unit and Department of Psychiatry, University of Toronto, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.
Journal of Sleep Research (Impact Factor: 2.95). 10/2005; 14(3):245-53. DOI: 10.1111/j.1365-2869.2005.00466.x
Source: PubMed

ABSTRACT The objective of this investigation was to evaluate subjective fatigue versus subjective sleepiness as independent consequences of sleep disorders. Furthermore, we tried to explore how these symptoms relate to alertness, depressive symptoms and illness intrusiveness. In a prospective observational study, 283 sleep-disordered patients referred to a hospital-based sleep laboratory for various indications over a 1-year period were evaluated vis-à-vis fatigue and sleepiness. All patients completed five subjective questionnaires, underwent objective sleep recording and attended a clinical interview with a sleep specialist. The subjective questionnaires included the Epworth Sleepiness Scale, the Fatigue Severity Scale, the Toronto Hospital Alertness Test, the Illness Intrusiveness Rating Scale and the Center for Epidemiologic Studies-Depression Scale. Only 4% of the total sample was referred to the sleep clinic due to a complaint of excessive fatigue compared with 17% for excessive daytime sleepiness. However, during the assessment, 64% of referred patients reported pathological fatigue without overlap of sleepiness and only 4% reported pathological sleepiness without overlap of fatigue. Pearson's correlation analysis indicated a weak association (r=0.18) between subjective fatigue and sleepiness in the total sample. Analysis of variance testing showed strong association between those patients with prominent fatigue and depressive symptoms (P<0.01) and illness intrusiveness (P<0.001). The findings support the notion that subjective fatigue and sleepiness can be independent manifestations of sleep disorders. Furthermore, predominantly fatigued individuals with sleep disorders seem vulnerable to additional negative consequences due to possible interplay between amplified fatigue and psychological distress.

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    ABSTRACT: Background and Objective: Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) remains a challenge for health care professionals because of its complex pathogenesis. Scales and questionnaires have been developed in order to assess the severity of syndrome. Fibromyalgia share similar clinical features with CFS/ME however have its own diagnostic criteria. Our study was performed to analyze impact of value of fatigue severity in patients with CFS/ME and fibromyalgia (FM). Materials and Methods: One hundred and three CFS/ME patients and 21 fibromyalgia patients were included in study. CFS/ME patients were diagnosed using the diagnostic criteria of Fukuda et al. 1994. The diagnosis of fibromyalgia was established using the American College of Rheumatology (ACR) 1990 diagnostic criteria. Fatigue Severity scale (FSS) and Fibro Fatigue scale (FFS) were used to assess the severity of fatigue. Factor analysis was performed in order to detect most common combinations of clinical signs in patients with CFS/ME. The data were calculated using SPSS version 16.0. Results: The most common clinical feature other than fatigue was un-refreshing sleep established in 71(68.9%) patients. The mean score of FSS within CFS/ME patients was 6.65±0.256. The highest mean scores–6.94±0.243 were observed within statements – “Exercise brings on my fatigue”, “Fatigue is among my three most disabling symptoms”. The total score of FSS within CFS/ME patients was 59.94±2.045 and 53.62±8.880 in FM patients, (p=0.008). Fatigue was the most severe indicator according to FFS in CFS/ME patients with means score 5.76±0.664. Conclusion: Most part of the CFS/ME patients suffered from un-refreshing sleep. CFS/ME patients had higher rates according to FSS than FM patients, which shows that fatigue in patients with CFS/ME is more intense, affecting their daily activities. Keywords : Chronic fatigue syndrome; fibromyalgia; symptoms; severity.
    08/2014; 4(36):5866-5877. DOI:10.9734/BJMMR/2014/12225
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    ABSTRACT: Sleep complaints are common among Iranian chemically-injured veterans. The growing body of research has investigated (in) equalities between such subjective complaints and objective sleep records. Moreover, sleep complaints are associated with depressive symptoms. Depressive symptoms, also, have been frequently reported in chemically-injured veterans. Therefore, the purpose of this pilot study was to investigate the relationship between perceived sleep quality, polysomnographic measures and depressive symptoms in Iranian veterans with chemical injuries. In this pilot study, 35 Iranian veterans with chemical injuries complaining of a sleep problem were selected. Initially, participants were evaluated via all-night polysomnography, then, they completed the research questionnaires. Collected data were analyzed using Pearson correlation coefficients. Data analyses showed that there was no significant correlation between many of self-reposted variables and polysomnogaphic recordings, however, remarkable relationships were found between the Pittsburgh Sleep Quality Index and the Beck Depression Inventory scores. The findings indicated that sleep complaints of chemically-injured veterans are not equivalent to objective sleep disturbances, however, these complaints are largely associated with level of depression. This study emphasizes the important role of mood in sleep evaluation. Further, the findings suggest using a combination of both subjective and objective measures for accurate assessment of sleep quality in Iranian veterans with chemical injuries (i.e., multimethod approach).


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