Characterisation of Functional and Cognitive Responses Following Olfactory Stimulation and/or Functional Training in Older Adults.

Characterisation of Functional and Cognitive Responses Following Olfactory Stimulation and/or Functional Training in Older Adults: A Randomised Clinical Trial

This randomized controlled trial will evaluate the effects of olfactory stimulation and/or multicomponent physical training in adults aged 60 years and older. Eligible participants will be cognitively normal, community-dwelling outpatients recruited from Primary Care and Geriatrics services. After baseline assessment, participants will be randomized to one of four groups: usual care, olfactory training/stimulation, multicomponent physical exercise, or combined olfactory and exercise intervention.

Primary and secondary assessments will include olfactory function, cognition, physical function, quality of life, nutritional status, mood, frailty, multimorbidity, polypharmacy, blood-based molecular biomarkers, and exhaled-air biomarkers.

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.