Translation, cross-cultural adaptation and measurement proprieties of the German version of the Allodynia Symptom Checklist (ASC-12)

Background: Cutaneous allodynia is highly prevalent among migraineurs and is associated with a poor prognosis. The Allodynia Symptom Checklist (ASC-12) is a comprehensive questionnaire to identify the presence and severity of allodynia. Our aim was to translate and adapt the ASC-12 to German and evaluate its measurement properties. Methods: Following the COSMIN guidelines, 80 migraine patients were enrolled in the study to evaluate the stages of translation (n=30) and measurement propriety assessment (n=50), respectively. After reaching a final version, the German ASC-12 was assessed for structural validity, internal consistency, test-retest reliability, construct validity and absolute agreement, using mechanical and thermal pain thresholds as reference method. Results: The German version of the ASC-12 presented an adequate structural validity compatible with the original version of the questionnaire. Its internal consistency ranged from 0.70 to 0.80 considering the total score and the thermic, static and dynamic mechanic subdomains. The total score presented excellent reliability (ICC: 0.85) with a standard error of measurement of 1.15 points and smallest detectable change of 3.40 points. ASC-12 total scores were correlated with headache intensity (r=0.38, p=0.004), headache disability (r=0.37, p=0.004) and cold pain thresholds (r=0.28, p=0.025). The thermic allodynia ASC-12 scores were correlated with cold (r=0.36, p=0.005) and heat (r=-0.30, p=0.010) pain thresholds, while the static mechanical allodynia ASC-12 scores correlated with mechanical pain threshold (r=0.29, p=0.019) and with mechanical pain sensitivity (r=0.24 to 0.28, p< 0.045). Despite no significant bias between methods, quantitative sensory testing (QST) results and ASC-12 scores tend to disagree. Conclusion: The German version of the ASC-12 is available for research and clinical settings and presented adequate measurement proprieties, as the original version. Despite the correlation between the ASC-12 and QST, one method cannot be replaced by the other.