Two year follow-up of sleep diaries and polysomnography in chronic fatigue syndrome: a cohort study

ABSTRACT

Background: Chronic fatigue syndrome (CFS) is a prevalent and debilitating symptom complex of unknown aetiology. Up to 96.8% of people with CFS report unrefreshing sleep and many describe, in qualitative interviews, changes in sleep over the course of their illness.

Purpose: To establish whether subjective and objective sleep parameters change over a two-year follow-up period in patients with CFS.

Methods: Twenty-two participants with CFS were recruited during routine consultations at a clinic in the North-East of England. All had their sleep characterised in a previously published cross-sectional study. Two were excluded from this analysis because they fulfilled criteria for a primary sleep disorder. The remaining 20 were contacted and 15 repeated fatigue- and sleep-quality questionnaires and sleep diaries, two years after their sleep was first characterised. Seven participants also repeated two consecutive nights of polysomnography. Paired statistical tests were used to compare follow-up with baseline measures.

Results: Subjective questionnaires and sleep dairies did not show differences over two years follow-up. However, polysomnography demonstrated a higher proportion of stage one sleep (P < .01) and more awakenings per hour (P = .04) at follow-up.

Conclusions: This study is the first to longitudinally assess sleep parameters in people with CFS. The results suggest that subjective perceptions of sleep remain stable, although objective measures indicated a tendency towards increased periods of lighter sleep. However, the small number of participants increases the likelihood that observed differences are Type I errors.

KEYWORDS:

• Chronic fatigue syndrome
• myalgic encephalomyelitis
• unrefreshing sleep
• nonrestorative sleep
• polysomnography
• sleep diaries

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Funding for the project was provided by the registered charity Action for M.E.

Notes on contributors

Sean L. Davidson

Sean L. Davidson is a Foundation Trainee doctor at Newcastle upon Tyne Hospitals NHS Foundation Trust. He graduated from Newcastle University with a Masters in Research in Neuroscience in 2015 and in 2016 completed his Bachelor of Medicine, Bachelor of Surgery degree. His academic interest is in clinical neurology.

Zoe M. Gotts

Zoe M. Gotts is a trainee clinical psychologist at Newcastle University, and was a post-doctoral researcher in the Institute for Ageing and the Institute for Health and Society at Newcastle University. Her mixed-methods research assesses non-pharmacological interventions for chronic and long-term conditions.

Jason G. Ellis

Jason G. Ellis is a Professor of Psychology at Northumbria University and Director of the Northumbria Centre for Sleep Research. His research ranges across many aspects of sleep and he is actively involved in a number of public and professional engagement projects.

Julia L. Newton

Julia L. Newton is Clinical Professor of Ageing and Medicine at the Institute of Cellular Medicine at Newcastle University and an Honorary Consultant Physician at the Newcastle upon Tyne Hospitals NHS Foundation Trust. Her work focuses on autonomic dysfunction and its role in the pathogenesis of fatigue.