[Brazilian version of the Non-communicative Patient's Pain Assessment Instrument (NOPPAIN): conceptual, item, and semantic equivalence].

The evaluation and measurement of pain in individuals with dementia and unable to communicate verbally has been a challenging experience. The Non-communicative Patient's Pain Assessment Instrument (NOPPAIN) is an instrument that evaluates this phenomenon by observing behaviors that express pain. Considering the lack of instruments for this purpose in Brazil, the current study was designed to translate the NOPPAIN instrument into Brazilian Portuguese and culturally adapt it to the Brazilian reality. This was a methodological study, with Guillemin et al. as the theoretical reference. The study included four steps: translation; obtaining a consensus version; back-translation; and evaluation of the translation and back-translation by an expert panel. In this initial approach, the NOPPAIN-Br showed semantic equivalence to the original instrument and is now available in Brazilian Portuguese for further validation.