Efficacy and Safety of Photobiomodulation Therapy in Patients With Mild Cognitive Impairment and Mild Alzheimer's Disease

The goal of this clinical trial is to learn if photobiomodulation therapy (PBMT) can help treat mild cognitive impairment and mild Alzheimer's disease in adults aged 50 to 85 years. It will also learn about the safety of PBMT. The main questions it aims to answer are: Does PBMT improve cognitive function in adults with mild cognitive impairment or mild Alzheimer's disease? What medical problems do participants have when using PBMT? Researchers will compare an active PBMT device to a sham (look-alike) device that delivers no active light therapy to see if PBMT improves cognitive function. Participants will: Use a transcranial near-infrared light therapy device (or a matching sham device) once a day for 20 minutes, 5 days a week, for 6 months Visit the clinic for cognitive, mood, sleep, and daily-function assessments at the start of the study, at Month 3, and at Month 6 Have brain MRI scans at the start of the study, at Month 3, and at Month 6