The PEM/PESE Activity Questionnaire: a novel health-related quality of life measure for post-exertional disablement


Todd Davenport: 0000-0001-5772-7727


Physical Therapy


Purpose/Hypothesis: Physical therapy practice depends on valid and reliable patient reported outcomes measures (PROMs). Post exertional malaise (PEM) and post exertional symptom exacerbation (PESE) are features of myalgic encephalomyelitis, Long Covid, and related conditions. They comprise a constellation of symptoms and signs including profound physical fatigue. Existing fatigue-specific instruments often are inappropriate to measure functional effects of accompanying symptoms and signs and demonstrate substantial floor effects. The purpose of this study was to determine the psychometric properties of a novel PROM for people living with PEM/PESE, the PEM/PESE Activity Questionnaire (PAQ).

Number of Subjects: 981 people living with PEM/PESE who completed a web-based questionnaire.

Materials and Methods: Respondents chose a function from a dropdown menu, consisting of the International Classification of Function core set for myalgic encephalomyelitis, and rated it on two different 0-10 scales. Each scale was anchored at 0 being “Completely unable to perform,” and 10 being “Can perform at the same level as a time I have good energy” and “Can perform at the same level as before I became ill,” respectively. Respondents also provided an estimate of effort intensiveness on a 0-10 scale, anchored at 0 being the activity took “No time, effort, and resources at all” and 10 being “All of my time, effort, and resources.” Respondents took the PAQ twice; they completed a demographic questionnaire after the first PAQ and before the second PAQ. Backward navigation was disabled so respondents could not view the first PAQ while completing the second PAQ. Descriptive statistics were calculated for the participants who completed vs. did not complete the entire survey. Subgroup analyses by completion status and function were undertaken by chi-square analysis for binomial variables and one-way analysis of variance for continuous variables. Intraclass correlation coefficients were calculated for each scale to assess test-retest reliability. Floor effects were the proportion of participants reporting the lowest score.

Results: 981 surveys were available for analysis, including 675 complete surveys. All participants reported PEM/PESE. Respondents reported less frequent flu-like symptoms and pain, shorter recovery times after physical activity (i.e., less than 24 hours), and lower thresholds for physical and mental fatiguability than respondents who did not complete the survey (p<.001). Activities most frequently chosen for rating were “Carry out my normal routine,” “Prepare meals,” and “Maintain employment for financial reward.” Test-retest reliability was generally fair to excellent, depending on function and scale. Floor effects were noted in 9.2-24.7% of responses, also with notable variation based on function and scale.

Conclusions: The PAQ provides valid, reliable, and sensitive outcome measure for people living with PEM/PESE. Survey completion may be limited by severity of PEM/PESE.

Clinical Relevance: Physical therapists could use the PAQ to assess illness severity and intervention efficacy for people living with PEM/PESE.

Document Type

Conference Presentation

Publication Date


Publication Title

American Physical Therapy Association, Combined Sections Meeting

Conference Dates

February 23-25, 2023

Conference Location

San Diego, CA

This document is currently not available here.