Differences in physical functioning between relatively active and passive patients with Chronic Fatigue Syndrome

Multidisciplinary rehabilitation treatment versus cognitive behavioural therapy for patients with chronic fatigue syndrome: a randomized controlled trial

“…To analyse physical activity, data were processed from the two accelerometers of the activity monitor using matlab software (The Math Works Inc., Natick, MA, USA). The procedure has been described previously by Vos‐Vromans and colleagues .…”

An exploratory study of discrepancies between objective and subjective measurement of the physical activity level in female patients with chronic fatigue syndrome

“…Additionally, large individual differences have been identified and suggested to be the result of two different coping strategies applied by patients with CFS, the pervasively passive and relatively active strategy, respectively [7]. The pervasively passive patients show avoidance behavior towards physical activity (PA) and become inactive, while the relatively active patients try to perform at pre-illness levels despite their complaints, which leads to an irregular activity pattern with an imbalance between activity and rest [7,8]. Because both subgroups show such different activity patterns, activity management programs that aim at improving patients' PAL need to be tailored to their individual coping strategy [7][8][9] by accurately estimating patients' PAL and pattern.…”

“…Use of objective activity monitor systems (i.e. accelerometers) is recommended [7,8], but their psychometric properties depend on the device, how it is used, the studied population and type of activity [10][11][12][13]. Also, different calibration methods and cut-points for defining and categorizing physical activity intensities are often used [11,[13][14][15].…”

“…Moreover, measures using general subjective interpretations about PA in CFS seem to reflect a patients' view about PA and may be biased by their cognitions about illness and disability causing them to estimate their own activity level inaccurately [7,18]. Unrealistic thoughts about their premorbid activity level and misjudgment of the activity level of healthy controls contribute to these incorrect cognitions and patients' tendency to report being inactive most of the time [7,8]. Results of previous studies [18,20] also suggested fatigue to be related to discrepancies between self-report and objective measures.…”

“…Because subjective activity measures are relevant for clinical practice, identification of a format that is capable of measuring the PAL similar to an objective activity monitor would be a significant asset. Because the relationship between self-report measures consisting of subjective and general interpretations of PA and relying on recall and objective activity measures are low, self-report measures encompassing detailed information about a patient's daily activities including the type, amount and intensity of the activity are recommended [8,23]. According to Terwee et al (2010), the total activity counts generated by an accelerometer as outcome measure is the most optimal comparison to validate a measurement instrument that aims to measure total PA, due to lack of a 'gold' standard for PA [24].…”