CDE Detailed Report

Post-exertional symptoms can start during, immediately after, or hours-days after exposure to a trigger and can last hours, days, weeks, or even months. Change in activity or function follows a similar time course. Timing of outcome measures need to reflect what is known about PEM timing. Most past research has concentrated primareily on the time period hours or up to 3 days after a PEM-inducing trigger. Outcomes should be measured at the very least at baseline (time point 0, before the stimulus is applied), immediately after, at 24 hours after, and at 7 days after the applied stimulus or after the study has started for participant-determined stimuli. We also suggest a time-point past 7 days to capture episodes of long-lasting PEM. Researchers are encouraged to include other time periods in additional to the suggested times.

There s an urgent need for studies where objective outcome measures for studies where objective outcome measures are studied in conjunction with post-exertional symptoms and change in function/level of activity. Without this type of study design, it is hard to interpret results within the context of a participant's condition. If some objectives outcome measures were correlated with subjective measures while others were not, please check "No" and provide an answer why this was not done.

Outcome measures may be study participant self-reported questionnaires, clinician/researcher assessments, biomarkers, or a combination of these. Researcher should list the names of standardized instruments use (e.g. Fatigue Severity Scale, DePaul Symptom Questionnaire), the type of biomarder (e.g. cytokine levels, functional MRI), and/or describe the outcome measure in a manner that other can replicate it.

Confounding activity is activity spontaneously engaged in by study participants and not intentionally meant to induce PEM. Because PEM can be delayed and prolonged, accounting for activity before, during and sometimes after the planned stimulus is important. In a study with researcher-applied stimuli, confounding activity is activity prior to and/or during the stimuli (e.g. for 2-day cardiopulmonary exercise testing (C{ET), activity conducted after the first CPET but before the second CPET is confounding activity). In a study with study-participant-determined stimuli, confounding activity is activity performed prior to when researchers start recording study-participant-determined activity or during times when activity is not being recorded (e.g. if activity is recorded for only 10 hours a day, activity performed during the remaining 14 hours is counfounding activity). In some cases, if there is a lag time between the stimuli and measurement of an outcome measure (e.g. blood draw 2 days after a treadmill test or after activity recording has stopped), intervening activity performed after the stimuli may also be confounding activity.

If a physical activity monitor was employed, please see the Exploratory Outcome Measures: Physical Activity table for more details/guidelines and consider completing items 7a, 7b, 7c. Objective measures of physical activity are impacted by the equipment used, the types of measurements taken, when activity is measured, and the duration of measurement. Consequently, researchers are encouaged to provide this information in the CRF.
If a physical activity monitor was employed, please see the Exploratory Outcome Measures: Physical Activity table for more details/guidelines and consider completing items 7a, 7b, and 7c. Objective measures of physical activity are impacted by the equipment used, the types of measurements taken, when activity is measure, and the duration of measurement. Consequently, researchers are encouraged to provide this information in the CRF.

For item 7c., "Start time" and "End time" refer to the first/last date and time that physical activity monitoring began and ended, respectively. For studies where physical activity monitors were used intermittently, researchers should also complete item 7c (iii), specifying the planned duration of monitoring (e.g. 10 hours a day for 3 days, before and for the 24 hours between 2 exercise tests).

"Researcher-applied stimuli" refers to stimuli that are not usually a part of a study participant's daily activities, e.g. treatdmill testing, neuropsychological batteries meant to induce cognitive fatigue, bicycle ergometers. "Study-participant-determined stimuli" refers to activities that participants usually engage in e.g. walking, driving, household chores, etc.