Validated translation to Spanish of the evaluation questionnaire of patients with restless legs syndrome

Introduction. Restless legs syndrome (RLS) is a common sensory-motor condition, characterised by the irresistible need to move the legs while sitting or lying down, usually presenting late in the day, from the end of the afternoon into the night. Objective. To describe the translation process to Spanish of three different research RLS tools: the diagnosis criteria, the Practitioner Screening Questionnaire and the Basic Set of Questions for Epidemiological Studies. A procedure is proposed for the translation of these tools into other languages. Methods. The back translation method was employed. Five translators took part: two translated into their mother tongue and two into their foreign tongue, and once the translations were completed, a fifth independent translator introduced the changes using his mother tongue. Two expert analysts determined the equivalence between the original questionnaire and the translation. The clarity of the translated questionnaires was evaluated in a sample of students, who completed these themselves, and in RLS patients, for whom the doctor(s) or another authorised person filled them out. Results. The procedure undertaken varied according as to how each instrument were to be used either by health care professionals (diagnosis criteria) or to obtain information front patients (the questionnaire being directly completed by the patient directly or indirectly by a health care professional). No significant differences between the original and the translation of the practitioner screening questionnaire and the basic set of questions for epidemiological studies were found. The translators aimed to maintain concept equivalence function and validity of the original instrument were preserved in the translation. The same terminology was employed in the different translations to make sure they were all consistent should they be used together. The Spanish version of the practitioner screening questionnaire has added terms to the first item by providing examples of serisations to ensure its understanding by patients from different parts of Spain. Conclusions. Spanish translated versions of three different questionnaires have been obtained to be used for RLS assessment in Spain, following appropriate psychometric validation. The instrument translated in the third place showed the closest equivalence with original.