Measuring Functional Deficits in PEM/PESE: An In-Depth Look at the Development and Properties of a New Survey Tool
Are you, or someone you know, experiencing post-exertional malaise (PEM), also called post-exertional symptom exacerbation (PESE)? PEM/PESE refers to a delayed worsening of symptoms after physical, cognitive, or emotional stress. PEM/PESE is the hallmark feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and those with long COVID who meet the diagnostic criteria for ME/CFS.
Until recently, we lacked a tool for patients to self-report the effects of PEM/PESE on their ability to function. Quantifying the impacts of PEM/PESE can be helpful for assessing medical treatments, documenting disability, or simply tracking function over time.
The recently-published PEM/PESE Activity Survey (PAQ) by Workwell Foundation seeks to measure the impacts of PEM on a person’s ability to function.
Existing questionnaires, such as the DePaul Symptom Questionnaire, ask ME/CFS patients to rank symptoms based on frequency and severity during the previous six months. The focus is solely on symptoms, rather than how symptoms affect daily functions.
Other generic fatigue surveys suffer from “floor effects” when people with ME/CFS complete them. A floor effect occurs when a large percentage of respondents score near the lower limit on a survey or questionnaire. In other words, if a majority scores zero on a survey, it is not a very helpful tool.
The PAQ, in contrast, was created to fill a gap in the existing literature. Currently, existing questionnaires do not specifically assess functional deficits associated with PEM/PESE.
Functional deficits involve difficulty completing activities of daily living, such as dressing, grooming, getting in and out of bed, preparing meals, managing finances, and housework.
The PAQ can be administered electronically which makes it an ideal tool for patients tracking their function as well as medical providers who use telehealth applications.
Let’s take a closer look at the PESE/PEM activity questionnaire (PAQ).
Building on a Strong Foundation: the PAQ is based on the WHO ICF Core Set for ME to Maximize Validity
One of the unique aspects of the PAQ is that it uses an existing World Health Organization International Classification of Functioning, Disability and Health, commonly referred to as the WHO ICF. Specifically, the PAQ uses the WHO ICF Core Set for myalgic encephalomyelitis (ME) as the conceptual foundation for assessing functional deficits.
Use of the WHO ICF Core Set in the PAQ maximizes the validity of the survey and provides a standardized way to assess function. It also facilitates bioinformatics and software engineering efforts to integrate the PAQ into electronic health records and research databases.
The PAQ offers two anchors for self-rating:
- Compared to a good day
- Compared to before illness
These anchors provide two separate temporal frames of reference that are meaningful to patients.
According to the study, the PAQ and most of its options for self-rating function meet the following criteria:
- Good to excellent test-retest reliability
- Adequate responsiveness
- Negligible “floor and ceiling effects”
The Importance of Considering Burden of Function in Functional Assessment
Another important feature of the PAQ is its “Burden of Function” self-rating. This rating allows for an assessment of how easily the respondent can complete tasks. This may include the time, effort, and resources needed to attain the self-reported level of function.
This is important for functional assessment in PEM/PESE as basic daily tasks often require a significant investment in preparatory activities.
By considering the ease of functioning alongside the level of functioning, the PAQ may be better optimized to detect subtle changes in improving or worsening function than previous fatigue surveys.
Use Potential Directions for Additional Research on the PAQ
Overall, the PAQ has some promising applications and directions for additional research.
Future studies may stratify subjects by illness severity to determine whether there are important differences in function selected by patients at different illness levels.
For those living with PEM/PESE, the PAQ offers a much-needed tool for accurately measuring functional deficits and tracking changes over time.
Workwell: Leading the Way in ME/CFS and Long COVID Research
Workwell is an organization dedicated to research and understanding fatigue-related illnesses.
These illnesses include:
- Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
- Long COVID
Workwell aims to explore the biological basis for these illnesses through cutting-edge research and innovative testing services.
Workwell also provides resources to educate patients and providers about these conditions.