title: Taking fatigue seriously: I. Variations in fatigue sampled repeatedly in healthy controls.
abstract: OBJECTIVE
  The four objectives of this study were to test the ability of a 1-item fatigue scale to correlate with the fatigue subscale of the Profile of Mood States (POMS), to test the acceptability of recording hourly fatigue ratings, to examine the chronobiological variation in self-reports of fatigue, and finally to examine the degree to which self-report of fatigue correlated with actigraphy findings.
  
  
  METHODS
  Ten healthy normal controls completed the POMS fatigue subscale hourly for three days. The same 10 healthy subjects wore an actigraph for 72 consecutive hours. The actigraph was modified to incorporate two event buttons which subjects were asked to push hourly to report their level of fatigue.
  
  
  RESULTS
  The 1-item fatigue rating correlated significantly (mean r = 0.61) with the rest of the POMS subscale for fatigue. Subjects had no difficulty using the event button on the actigraph in entering the 1-item fatigue ratings. Fatigue ratings revealed marked differences in how healthy subjects report fatigue. There was no consistent diurnal patterning of fatigue. The fatigue ratings in general were not correlated with actigraphic measures.
  
  
  CONCLUSIONS
  The study documents that fatigue can be repeatedly assessed with an ambulatory device and that self-reported fatigue levels vary enormously from hour to hour in a healthy normal sample.
authors.affiliation: Department of Psychiatry, University of California, San Diego 92093-0804, USA. jdimsdale@ucsd.edu
authors.forename: J E
authors.initials: JE
authors.lastname: Dimsdale
authors.forename: S
authors.initials: S
authors.lastname: Ancoli-Israel
authors.forename: T F
authors.initials: TF
authors.lastname: Elsmore
authors.forename: W
authors.initials: W
authors.lastname: Gruen
mesh_terms: D000203:Activities of Daily Living; D002909:Chronobiology Phenomena; D005221:Fatigue / Q000175:diagnosis* / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires