Research abstract:
Sleep dysfunction is a prominent feature in the subjective experience of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).
Although studies using polysomonography have identified at least one abnormal sleep characteristic in individuals with ME/CFS, no standard abnormalities in sleep have been identified. At the time of writing, only one published study had compared actigraphic measures of sleep between ME/CFS and controls, with no differences found. The aim of this study was to compare sleep parameters in people with and without ME/CFS using self-report and actigraphy.
The sample consisted of 16 individuals with ME/CFS and 16 healthy controls matched for age and sex who were self-reported good sleepers. Participants wore a wrist actiwatch and kept a sleep diary for 7 days. Participants were asked to give subjective ratings sleep quality and feeling rested each morning.
Results showed that individuals with ME/CFS experienced objectively (as measured by actigraphy) longer sleep onset latency and duration of wake after sleep onset, more fragmented sleep, and lower sleep efficiency than controls, with no difference in total sleep time. They also reported longer subjective (as reported in sleep diaries) sleep onset latency and duration of wake after sleep onset, and lower sleep efficiency, with no difference in total sleep time.
The ME/CFS group also reported poorer sleep quality and feeling less rested after
sleep. Individuals with ME/CFS experienced greater variability over the seven day assessment period in objective (actigraphic) total sleep time, sleep efficiency and duration of wake after sleep onset, and greater variability of subjective sleep efficiency and feeling rested than controls.
These results provide objective evidence to support the subjective reports of poor sleep in ME/CFS and suggest possible bases of the nonrestorative sleep described in ME/CFS. From a clinical perspective this highlights the importance of including sleep assessment and the treatment of sleep problems in this population as part of a holistic management plan.
The original intention of this study was to include cardiopulmonary coupling (CPC) as an additional measure in the investigation of possible differences between the sleep of ME/CFS and control groups. However, technical difficulties with the SleepImage M1™ devices lead to CPC data only being available from a subgroup of participants, which included both ME/CFS and control participants.
The available CPC data (n = 17) offered an opportunity to assess the validity of the M1™ device against actigraphic and subjective assessments. Analyses found mainly weak and non-significant correlations between CPC measures and the other measures of sleep quality. Total sleep time as measured by CPC was also significantly greater than actigraphic sleep time. Further research is needed before the M1™ device may be considered a valid measure of sleep quality
Investigation of naturalistic sleep/wake behaviour in myalgic encephaloyelitis/chronic fatigue syndrome, by Catherine Stevens, Victoria University thesis, March 4, 2015
