Background: Subjective cognitive decline (SCD) is gaining importance as a focus of investigation, but adequate tools are needed for its quantification.
Objective: To develop and validate a questionnaire to quantify SCD, termed the Subjective Cognitive Decline Questionnaire (SCD-Q).
Methods: 124 controls (CTR), 144 individuals with SCD, 83 mild cognitive impairment subjects, 46 Alzheimer's disease patients, and 397 informants were included.