Extract taken from the authoritative and very popular MEA Clinical and Research Guide 2020 (The Purple Book), section 5.12 (pp.42-43).
ME/CFS patients may complain of excessive sleep/hypersomnia in the early stages of their illness. This is often followed by a general decrease in sleep efficiency once the illness enters a more chronic stage.
Reported sleep disturbances include difficulty in initiating sleep, frequent waking during the night and vivid dreams. Periodic limb movements during sleep and ‘restless legs syndrome’ are also quite frequently reported.
Overall, the result is what many people with ME/CFS describe as unrefreshing sleep. A variety of abnormalities in normal sleep patterns, which may act as perpetuating factors, have been reported in ME/CFS patients.
These include changes in alpha nonrapid eye movement (Moldofsky 1989) and blunted slow-wave activity in a twin study in response to a sleep challenge (i.e., 4-hour sleep delay; Armitage et al 2007) – the latter results suggesting that a normal homeostatic response is impaired.
Another study (Morris et al 1997) found very little evidence to support the hypothesis that ME/CFS patients with a concurrent diagnosis of anxiety, depression or somatisation disorder have any more sleep disorders than those with no psychiatric disorder.
So, it appears that sleep disorder in ME/CFS is an integral part of the disease process.
The MEA leaflet on Sleep Disturbance (and Restless Legs Syndrome) provides more helpful advice on this key symptom.
A case control study, which measured diurnal salivary cortisol over five days, found no evidence of circadian rhythm disturbance in ME/CFS (Rahman et al 2011).
Daytime napping, particularly in the afternoon, is associated with poorer cognitive functioning and more daytime sleepiness in ME/CFS (Gotts et al 2015). The same research group has also carried out a qualitative study of patients’ experiences of sleep disturbance in ME/CFS (Gotts et al 2016b).
Sleep research that has been carried out by Gotts et al at the University of Northumbria was funded by The MEA Ramsay Research Fund (Gotts et al 2015, 2016a, 2016b).
Whatever the cause, sleep disturbance is one symptom that the physician should always aim to identify and manage (see also sections 7.5.12 and 7.6.2).
For a recent review of sleep disturbance in ME/CFS, see Jackson and Bruck (2012).
Are there sleep-specific phenotypes in patients with chronic fatigue syndrome? A cross-sectional polysomnography analysis. Gotts et al 2013.
Objectives: Despite sleep disturbances being a central complaint in patients with chronic fatigue syndrome (CFS), evidence of objective sleep abnormalities from over 30 studies is inconsistent.
The present study aimed to identify whether sleep-specific phenotypes exist in CFS and explore objective characteristics that could differentiate phenotypes, while also being relevant to routine clinical practice.
Design: A cross-sectional, single-site study.
Setting: A fatigue clinic in the Netherlands.
Participants: A consecutive series of 343 patients meeting the criteria for CFS, according to the Fukuda definition.
Measures: Patients underwent a single night of polysomnography (all-night recording of EEG, electromyography, electrooculography, ECG and respiration) that was hand-scored by a researcher blind to diagnosis and patient history.
Results: Of the 343 patients, 104 (30.3%) were identified with a Primary Sleep Disorder explaining their diagnosis. A hierarchical cluster analysis on the remaining 239 patients resulted in four sleep phenotypes being identified at saturation.
Of the 239 patients, 89.1% met quantitative criteria for at least one objective sleep problem. A one-way analysis of variance confirmed distinct sleep profiles for each sleep phenotype.
Relatively longer sleep onset latencies, longer Rapid Eye Movement (REM) latencies and smaller percentages of both stage 2 and REM characterised the first phenotype.
The second phenotype was characterised by more frequent arousals per hour. The third phenotype was characterised by a longer Total Sleep Time, shorter REM Latencies, and a higher percentage of REM and lower percentage of wake time.
The final phenotype had the shortest Total Sleep Time and the highest percentage of wake time and wake after sleep onset.
Conclusions: The results highlight the need to routinely screen for Primary Sleep Disorders in clinical practice and tailor sleep interventions, based on phenotype, to patients presenting with CFS. The results are discussed in terms of matching patients’ self-reported sleep to these phenotypes in clinical practice.