Reliability and validity of the German version of the DePaul Symptom Questionnaire Post-Exertional Malaise (DSQ-PEM).
Kuczyk, Charlotte, Nöhre, Mariel, Herrmann-Lingen, Christoph et al. · Frontiers in psychiatry · 2025 · DOI
Quick Summary
Researchers tested a German-language questionnaire designed to measure post-exertional malaise (PEM)—the worsening of symptoms that happens after physical or mental activity in ME/CFS and long COVID. They found the questionnaire is reliable and accurately distinguishes between people with and without long COVID, making it a useful tool for German-speaking patients and doctors.
Why It Matters
Having validated symptom measurement tools in multiple languages is essential for consistent diagnosis and research across countries. This study confirms the DSQ-PEM is a reliable German-language instrument for measuring PEM in both ME/CFS-related conditions and long COVID, enabling better clinical assessment and comparative research in German-speaking regions.
Observed Findings
The German DSQ-PEM showed excellent internal consistency in both the general population and PCC samples.
Higher DSQ-PEM scores correlated with increased anxiety and depression symptoms in both samples.
Higher DSQ-PEM scores associated with fatigue severity on the Chalder Fatigue Scale in the PCC sample.
The German DSQ-PEM effectively differentiated between general population and PCC groups, even after adjusting for sociodemographic factors.
In the general population, advanced age and female gender were associated with higher DSQ-PEM scores, but this pattern was not observed in the PCC sample.
Inferred Conclusions
The German version of the DSQ-PEM is a reliable and valid instrument for measuring post-exertional malaise in German-speaking populations.
The questionnaire has good convergent validity, correlating meaningfully with related symptom measures of fatigue, anxiety, and depression.
The DSQ-PEM can reliably distinguish individuals with post-COVID-19 condition from the general population, supporting its clinical utility.
Disease status may moderate the relationship between demographic variables and PEM symptom severity.
Remaining Questions
Does the DSQ-PEM perform equally well in diagnosed ME/CFS samples compared to post-COVID populations?
What This Study Does Not Prove
This study does not prove that the DSQ-PEM can diagnose ME/CFS or long COVID alone—it only validates that it reliably measures the specific symptom of post-exertional malaise. The study also does not explain why gender and age affected scores differently in the general population versus the PCC sample, nor does it establish what causes PEM itself.