Clinical Research Directory

Inclusion Criteria * Adults aged ≥60 years under the care of Primary Care and/or the Geriatrics Service of the Hospital Universitario de Navarra; * Normal cognitive function as determined at baseline assessment (Mini-Mental State Examination \[MMSE\] score ≥23; ≥21 for individuals without formal education); * Fluent in speaking, reading, and understanding Spanish; * Adequate olfactory function; * Adequate visual and auditory acuity to complete neuropsychological and computerized assessments; * In good general health, with no condition expected to interfere with study participation; * Willing and able to comply with study procedures and to participate for the entire study duration; * Willing to refrain from the use of scented candles, essential oils, or air fresheners during study participation. Exclusion Criteria * Refusal or inability of the participant, primary caregiver, or legal representative to provide informed consent; * Diagnosis of a neurodegenerative disease or severe dementia (Global Deterioration Scale \[GDS\] stage 6-7); * Conditions affecting the olfactory system (e.g., nasal polyps); * Life expectancy \<3 months; * History of asthma, allergies, or olfactory-triggered responses producing allergy-like symptoms (e.g., rhinorrhea, lacrimation, sneezing, or skin rash); * History of neurological disorders such as Parkinson's disease, multiple sclerosis, brain cyst, tumor, or aneurysm; * Significant medical conditions, including uncontrolled diabetes mellitus, uncontrolled hypertension, nutritional deficiencies, or thyroid disorders; * History of major psychiatric disorders such as schizophrenia, bipolar disorder, anxiety disorders, or attention-deficit/hyperactivity disorder; * History of alcohol or substance abuse or dependence within the past 2 years (DSM-IV criteria), including use of cigarettes, e-cigarettes, cigars, marijuana, or any substance that may produce odors interfering with the study.