Translation, cross-cultural adaptation, and validity of the Brazilian version of the Cognitive Function Instrument

Subjective cognitive decline (SCD) is defined as a self-perception of a progressive cognitive impairment, which is not detected objectively through neuropsychological tests. The Alzheimer's Disease Cooperative Study developed the Cognitive Function Instrument (CFI) to evaluate individuals with SCD. The CFI consists of two versions, namely, a self-report and a partner report.

This study aimed to translate CFI into Brazilian Portuguese, perform a cross-cultural adaptation, and validate the Brazilian version.

The translation and transcultural adaptation process consisted of six stages, and the preliminary version was answered by a sample of individuals recruited among the patients' caregivers from a cognitive neurology outpatient clinic. Finally, the final Brazilian version of the CFI was applied to a sample of nondemented older adults to validate the instrument, which was divided into with and without SCD, according to the answer "yes" for the question: "Do you feel like your memory is becoming worse?".

The final version of CFI showed a high level of acceptability as an assessment tool in nondemented older adults. Participants with SCD had higher scores in the CFI self-report compared with those without complaints. In the receiver operating characteristic curve analysis, the area under the curve of the CFI self-report was 0.865 (95% confidence interval 0.779-0.951), and the cutoff score of 2.0 was the one that best distinguished the SCD group from the control group, with a sensitivity of 73.3% and a specificity of 81.5%.

CFI proved to be an instrument with good accuracy and easy applicability to identify older adults with SCD.