Research abstract
Objectives
The precise relationship between sleep and physical and mental
functioning in chronic fatigue syndrome (CFS) has not been examined
directly, nor has the impact of daytime napping. This study aimed to
examine self-reported sleep in patients with CFS and explore whether
sleep quality and daytime napping, specific patient characteristics
(gender, illness length) and levels of anxiety and depression,
predicted daytime fatigue severity, levels of daytime sleepiness and
cognitive functioning, all key dimensions of the illness experience.
Methods
118 adults meeting the 1994 CDC case criteria for CFS completed a standardised sleep diary over 14 days. Momentary functional assessments of fatigue, sleepiness, cognition and mood were completed by patients as part of usual care. Levels of daytime functioning and disability were quantified using symptom assessment tools, measuring fatigue (Chalder Fatigue Scale), sleepiness (Epworth Sleepiness Scale), cognitive functioning (Trail Making Test, Cognitive Failures
Questionnaire), and mood (Hospital Anxiety and Depression Scale).
Results
Hierarchical Regressions demonstrated that a shorter time since diagnosis, higher depression and longer wake time after sleep onset predicted 23.4% of the variance in fatigue severity (p<.001). Being male, higher depression and more afternoon naps predicted 25.6% of the variance in objective cognitive dysfunction (p <.001). Higher anxiety and depression and morning napping predicted 32.2% of the variance in subjective cognitive dysfunction (p<.001). When patients were
classified into groups of mild and moderate sleepiness, those with longer daytime naps, those who mainly napped in the afternoon, and those with higher levels of anxiety, were more likely to be in the moderately sleepy group.
Conclusions
Napping, particularly in the afternoon is associated with poorer cognitive functioning and more daytime sleepiness in CFS. These findings have clinical implications for symptom management strategies.
The association between daytime napping and cognitive functioning in Chronic Fatigue Syndrome, by Zoe M. Gotts, Jason G. Ellis, Vincent Deary, Nicola Barclay, Julia L. Newton in PLoS One Vol. 10, January 9, 2015
From the conclusion:
Overall this study suggests that sleep is only one of the factors associated with daytime functioning in CFS… The other key predictors were scoring higher on the depression scale of the HADS and having a more recent diagnosis…
Overall the most parsimonious interpretation of these results would be that fatigue is influenced by multiple factors, and that this study has highlighted that sleep, adjustment to illness, and mood may be pieces in the complex biopsychosocial fatigue jigsaw. Again this would also suggest that helping people to adjust and adapt to illness, sleep management strategies, and mood management may impact positively on daytime fatigue…
As such, any intervention probably needs to consider each factor on an individual basis. Whilst one person may benefit from straight forward sleep management, another person relatively early post-diagnosis may also need help adjusting to the illness, whilst others still may need help with the emotional impact of being ill. As there is no one sleep phenotype, there is no one typical CFS patient. It is therefore recommended that at the minimum patients receive an individualised sleep assessment by an experienced clinician and a sleep and napping diary.
There are several limitations to this study…
