Cross-cultural adaptation and measurement properties of the Brazilian Version of the Michigan Neuropathy Screening Instrument.

BACKGROUND The Michigan Neuropathy Screening Instrument is an easy-to-use questionnaire aimed at screening and detecting diabetic polyneuropathy. OBJECTIVE To translate and cross-culturally adapt the MNSI to Brazilian Portuguese and evaluate its measurement properties. METHODS Two bilingual translators translated from English into Brazilian Portuguese and made a synthetic version. The synthetic version was back translated into English. A committee of specialists and the translator checked the cultural adaptations and developed a pre-final questionnaire in Brazilian Portuguese (prefinal version). In pretesting, the prefinal version was applied to a sample of 34 subjects in which each subject was interviewed to determine whether they understood each item. For the later assessment of measurement properties, 84 subjects were assessed. RESULTS A final Brazilian Portuguese version of the instrument was produced after obtaining 80% agreement (SEM<0.01%) among diabetic patients and specialists. We obtained excellent intra-rater reliability (ICC3,1=0.90), inter-rater reliability (ICC2,1=0.90) and within-subject reliability ICC3,1=0.80, excellent internal consistency (Cronbach's alpha>0.92), reasonable construct validity for the association between the MNSI and Neuropathy Symptom Score (r=0.46, p<0.05) and excellent association between the MNSI and Neuropathy Disability Score (r=0.79, p<0.05). We did not detect floor and ceiling effects (<9.5% of patients with maximum scores). CONCLUSIONS The Brazilian Portuguese version of the MNSI is suitable for application in the Brazilian diabetic population and is a reliable tool for the screening and detection of DPN. The MNSI can be used both in clinical practice and also for research purposes.