| The
objective of this study was to assess variability in symptoms and
physical capabilities in chronic fatigue syndrome (CFS) participants
both before and after a graded exercise intervention. Sixty-one CFS
subjects participated in a 12-week randomized controlled trial of
either graded exercise (n =32) or relaxation/stretching therapy (n
= 29). Specific physiological, psychological and cognitive variables
were assessed once weekly over a four-week period both prior to and
after the intervention period. All scores were assessed for reliability
using an intraclass correlation coefficient (ICC). Apart from mental
and physical fatigue, baseline ICC scores for all variables assessed
were moderately to highly reliable, indicating minimal variability.
Baseline scores for mental and physical fatigue were of questionable
reliability, indicating a fluctuating nature to these symptoms (R1
= 0.64 and 0.60, respectively). Variability in scores for mental fatigue
was reduced after graded exercise to an acceptable classification
(R1 = 0.76). Results from this study support a variable
nature to the symptoms of mental and physical fatigue only. Consequently,
in order to more accurately report the nature of mental and physical
fatigue in CFS, future studies should consider using repeated-measures
analysis when assessing these symptoms. Graded exercise resulted in
the reclassification of scores for mental fatigue from questionable
to acceptable reliability.
KEY
WORDS: Fluctuating symptoms, repeated measures, single session
measures, repeatability.
|
