Translation, cross-cultural adaptation, reliability and validation of the German version
Pain is one of the most common human experiences, yet its neurophysiological mechanism remains a mystery to many. Understanding how pain arises is crucial for effective treatment. Chronic pain conditions affect millions of people worldwide and pose major challenges to healthcare systems. The International Association for the Study of Pain (IASP) even declared the "Global Year Against Pain" under the motto "Excellence in Pain Education" to raise awareness of the importance of pain education 1 .
Chronic pain affects approximately 20% of adults worldwide, with significant impacts on quality of life and healthcare systems.
In this context, the Neurophysiology of Pain Questionnaire (NPQ) was developed as an instrument to assess knowledge about the neurophysiology of pain. While the original English-language questionnaire found international distribution, a German-language adapted version was lacking for a long time. This article highlights the translation, cultural adaptation, and scientific validation of the German NPQ version and explains why this instrument represents a milestone in pain therapy.
The Neurophysiology of Pain Questionnaire is a scientific instrument developed to capture the understanding of patients and medical staff about the neurophysiological basis of pain. The questionnaire consists of 19 items with statements that can be answered as "true", "false" or "undecided" 5 7 .
The NPQ focuses on the biopsychosocial pain model, going beyond traditional biomedical understanding.
Patients' understanding of pain significantly influences their healing expectations and treatment success.
The particular strength of the NPQ lies in its focus on the biopsychosocial pain model, which goes beyond traditional biomedical understanding. While many people understand pain as a simple alarm signal for tissue damage, the NPQ considers the complex processing in the nervous system, in which psychosocial factors play a crucial role. This differentiation is highly clinically relevant, as patients' understanding of pain significantly influences their healing expectations and treatment success.
The development of the German NPQ version (NPQ-D) followed established translation guidelines for scientific instruments 1 . This process ensures that not only the literal translation but also the conceptual meaning of the original items is preserved.
Two independent translations from English to German by native-speaking translators with medical expertise.
Comparison and harmonization of the two versions by an expert panel.
Translation of the German version back into English by an uninvolved translator.
Checking whether the back-translated version matches the original.
Testing the preliminary version with patients to check comprehensibility and cultural appropriateness.
Special attention was required for the adaptation of technical terms. Technical terms such as "ion channels" had to be precisely translated as "Ionenkanäle", while colloquial formulations had to find a balance between scientific accuracy and patient-friendliness.
After translation, a comprehensive review of the psychometric properties followed - the scientific validation of whether the questionnaire reliably and correctly measures what it is supposed to measure 1 9 .
Patients with chronic nonspecific spinal pain
Physiotherapists
Patients for test-retest reliability
The comparison of these two groups served to verify the discriminant validity - the ability of the questionnaire to distinguish between different levels of knowledge 1 .
To determine the test-retest reliability (temporal stability), 55 patients completed the questionnaire again after 10 days. This method checks whether the measurements are consistent over time when the patients' actual knowledge has not changed 1 .
The psychometric review yielded promising results for the NPQ-D. The internal consistency, measured with Cronbach's Alpha, was α = 0.52 1 . This value appears moderate at first glance but corresponds to the values of other language versions and is quite acceptable for questionnaires that measure different aspects of knowledge.
Test-Retest Reliability (ICC)
Internal Consistency (Cronbach's Alpha)
Particularly impressive is the high test-retest reliability with an Intraclass Correlation Coefficient (ICC) of 0.88 1 . This means that the measurement results are stable and reproducible over time - an essential property for a measurement instrument to be used in therapy evaluation.
| Comparison | Result | Significance |
|---|---|---|
| Physiotherapists vs Patients | Physiotherapists scored significantly higher | p < 0.001 |
| Therapists with vs without pain neurophysiology training | Trained therapists performed better | p < 0.01 |
| Correlation with generic health questionnaires | No significant correlations found | Not significant |
The main study to validate the NPQ-D was conducted as a prospective cross-sectional study at the Back Center St. Georg in Hamburg 9 . Recruitment of participants took place between May and October 2018, with the planned sample size of 110 subjects exceeded with 122 actual participants 9 .
In addition to the NPQ-D, patients completed other standardized questionnaires, including the FABQ (Fear Avoidance Beliefs Questionnaire), QLIP (Quality of Life Impairment by Pain Inventory), DASS 21 (Depression, Anxiety and Stress Scale), FFbH (Funktionsfragebogen Hannover) and SF-12 (Health Questionnaire) 9 . This comprehensive test battery enabled the verification of construct validity by comparison with established instruments.
The successful development of the NPQ-D opens up new possibilities in pain therapy in the German-speaking region. Clinicians and researchers now have a scientifically tested instrument to capture patients' understanding of pain and to use educational measures in a targeted manner.
The particular strength of the NPQ-D lies in its differentiated recording of various aspects of pain knowledge. Factor analysis identified four different dimensions that the questionnaire maps 1 . This multidimensionality corresponds to the complex nature of the pain phenomenon and enables targeted identification of knowledge gaps.
An interesting comparison with other language versions: While the NPQ-D shows good measurement quality criteria in patients, the validation of the Danish version in health students showed poorer psychometric values 5 7 . This discrepancy emphasizes that the measurement quality of an instrument is population-specific and cannot simply be transferred between different groups.
| Methodological Tool | Function in NPQ-D Development |
|---|---|
| Exploratory Factor Analysis | Examined dimensionality - identified 4 factors in NPQ-D 1 |
| Intraclass Correlation Coefficient (ICC) | Measured test-retest reliability (0.88 for NPQ-D) 1 |
| Cronbach's Alpha | Assessed internal consistency (0.52 for NPQ-D) 1 |
| Construct Validity Analysis | Verified whether the questionnaire actually measures pain knowledge 1 |
| Cognitive Debriefing Interviews | Ensured cultural adaptation and comprehensibility 5 7 |
The development and validation of the German version of the Neurophysiology of Pain Questionnaire marks an important progress in pain therapy in the German-speaking region. The NPQ-D represents a reliable and valid instrument to capture the pain knowledge of patients and medical staff.
By using the NPQ-D, therapists can identify knowledge deficits and tailor their educational measures accordingly. The effectiveness of pain education can thus be scientifically verified - an essential step towards evidence-based and patient-centered pain therapy.
As research shows, pure biomedical understanding of pain is often insufficient. The NPQ-D helps to promote a more comprehensive understanding of pain - as a complex neurophysiological phenomenon in which biological, psychological and social factors interact. Thus, the questionnaire not only contributes to improved therapy but also to the destigmatization of chronic pain diseases.