Figure 2 (A–D) Performance of the 4-odor discrimination score in differentiating participants of the various groups. NC – normal cognition; AD – Alzheimer disease; MCI-AD – mild cognitive impairment due to Alzheimer disease; MD-AD – mild dementia due to Alzheimer disease; AUC – receiver operating characteristic (ROC) area under the curve. Created using IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp.