External additional trial
We additionally included 34 elderly volunteers (aged > 60 years) suspected of having declining cognitive function, with the same inclusion criteria for extra-validation, between July 22, 2022, and August 30, 2022. The trial was conducted by Kolab (Gwangju, South Korea), an International Organization for Standardization-certified International Contract Research Organization. All the same tests (fNIRS, PET, brain MRI, 