European Journal of Applied Physiology

, Volume 114, Issue 9, pp 1841–1851 | Cite as

Dimensions of pure chronic fatigue: psychophysical, cognitive and biological correlates in the chronic fatigue syndrome

  • Daniel Neu
  • Olivier Mairesse
  • Xavier Montana
  • Medhi Gilson
  • Francis Corazza
  • Nicolas Lefevre
  • Paul Linkowski
  • Olivier Le Bon
  • Paul Verbanck
Original Article



To investigate associated dimensions of fatigue regarding cognitive impairment, psychomotor performances, muscular effort power and circulating cytokine levels and their relations to symptom intensity in a sample of pure chronic fatigue syndrome (CFS) patients without overlapping objective sleepiness or sleep disorders.


16 CFS patients were compared to 14 matched controls. We assessed structured symptom-scales, polysomnography, multiple sleep latency tests, attention (Zazzo-Cancellation ZCT, digit-symbol-substitution DSST), psychomotor vigilance and speed (PVT, finger tapping test, FTT), dynamometer handgrip force (tonic and phasic trials) and circulating cytokines (IFN-γ, IL-1b, IL-6, IL-8, IL-10, TNF-α).


In addition to fatigue, CFS patients presented with higher affective symptom intensity and worse perceived sleep quality. Polysomnography showed more slow-wave sleep and microarousals in CFS but similar sleep time, efficiency and light-sleep durations than controls. Patients presented with impaired attention (DSST, ZCT), slower reaction times (PVT) but not with lower hit rates (FTT). Notwithstanding lower grip strength during tonic and phasic trials, CFS also presented with higher fatigability during phasic trials. Cytokine levels were increased for IL-1b, IL-8, IL-10 and TNF-α and fatigue intensity was correlated to grip strength and IL-8.


In contrast to sleepiness, chronic fatigue is a more complex phenomenon that cannot be reduced to one single measured dimension (i.e., sleep propensity). Showing its relations to different measurements, our study reflects this multidimensionality, in a psychosomatic disorder such as CFS. To obtain objective information, routine assessments of fatigue should rule out sleepiness, combine aspects of mental and physical fatigue and focus on fatigability.


Chronic fatigue Sleep Sleepiness Attention Vigilance Handgrip strength Cytokines 


Conflict of interest

On behalf of all co-authors, I hereby declare that all co-authors gave their consent to the present submitted manuscript and that no co-author presented with any conflict of interest for the present study.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Daniel Neu
    • 1
    • 2
  • Olivier Mairesse
    • 1
    • 2
    • 3
    • 9
  • Xavier Montana
    • 1
    • 4
  • Medhi Gilson
    • 1
    • 5
  • Francis Corazza
    • 6
  • Nicolas Lefevre
    • 6
    • 8
  • Paul Linkowski
    • 4
  • Olivier Le Bon
    • 2
    • 7
  • Paul Verbanck
    • 1
    • 2
  1. 1.Sleep Laboratory and Unit for Chronobiology U78, Department of Psychiatry, Brugmann University HospitalUniversité Libre de Bruxelles (U.L.B)BrusselsBelgium
  2. 2.Laboratory for Medical Psychology ULB312, Faculty of Medicine, Neuroscience InstituteUniversité Libre de Bruxelles (U.L.B.)BrusselsBelgium
  3. 3.Department of Experimental and Applied Psychology (EXTO)Vrije Universiteit Brussel (V.U.B.)BrusselsBelgium
  4. 4.Sleep Laboratory, Department of Psychiatry, Erasme HospitalUniversity Clinics of Brussels, U.L.BBrusselsBelgium
  5. 5.UR2NF-Neuropsychology and Functional Neuroimaging Research Group at CRCN-Center for Research in Cognition and Neurosciences, and UNI-ULB Neurosciences InstituteUniversité Libre de Bruxelles (U.L.B.)BrusselsBelgium
  6. 6.Laboratory of Immunology, Department of Clinical BiologyQueen Elisabeth Foundation, Brugmann University Hospital, U.L.BBrusselsBelgium
  7. 7.Department of PsychiatryTivoli University Hospital, U.L.BLa LouvièreBelgium
  8. 8.Department of Pulmonology, Allergology and Cystic FibrosisQueen Fabiola Childrens’ University Hospital (Hôpital Universitaire des Enfants Reine Fabiola, HUDERF), U.L.BBrusselsBelgium
  9. 9.Vital Signs and Performance-Department LIFERoyal Military AcademyBrusselsBelgium

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