Cross-cultural adaptation and validation of the Spanish-language version of the Allodynia Symptom Checklist (ASC-12) in patients with primary headaches.

INTRODUCTION: Cutaneous allodynia has been described in primary headaches. The 12-item Allodynia Symptom Checklist (ASC-12) is a valid, reliable scale for assessment in the population with migraine. No Spanish-language version of the ASC-12 is currently available, so we performed the cross-cultural adaptation and validation of a Spanish-language version of the ASC-12 in patients with primary headaches.

METHODS: This validation study included 131 patients who attended a single consultation at the headache unit and completed 3 self-administered scales: the ASC-12, the self-reported version of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale, and the ID Pain questionnaire. Patients' diagnosis was confirmed by a neurologist specialized in headache management, according to the diagnostic criteria of the third edition of the International Classification of Headache Disorders. A linguistic adaptation and a psychometric analysis were performed, assessing discriminative, convergent, and construct validity, as well as reliability and floor and ceiling effects.

RESULTS: The scale presented high diagnostic accuracy (receiver operating characteristic curve value of 0.91; 95% confidence interval, 0.86-0.97; P<.001). Pearson correlations indicated moderate to strong correlations between scales. The Kaiser-Meyer-Olkin test yielded a value of 0.72. The Bartlett test was significant (Chi-square value of 440.887; P<.001). The construct validity study identified 3 factors (thermal, mechanical static, and dynamic allodynia). Internal consistency was satisfactory (Cronbach alpha value of 0.78; 95% confidence interval, 0.72-0.83). No floor or ceiling effect was detected.

CONCLUSIONS: The Spanish-language version of the ASC-12 for patients with primary headaches is a valid, reliable tool that can be implemented in the clinical and research settings.