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

1、Inclusion Criteria： 1. Age 50-85 years 2. Meet the 2011 NIA-AA diagnostic criteria for "MCI due to AD" or "probable AD dementia," or meet the 2018 NIA-AA "ATN" diagnostic framework for AD； 3. 0.5 ≤ CDR ≤ 2; for illiterate: MMSE ≤ 13; for primary school education: MMSE ≤ 19; for junior high school or above: MMSE ≤ 24; for MCI: ADL-20 ≤ 22; for mild AD: ADL-20 \> 22； 4. Able to understand instructions and cooperate with serological tests, scale assessments, and brain MRI； 5. Have a study partner who can participate throughout the study。 2、Exclusion Criteria： 1. Inability to complete serological tests, scale assessments, or brain MRI due to severe visual/auditory impairment, severe neuropsychiatric symptoms, contraindications to MRI, etc. 2. History of other central nervous system injuries causing cognitive decline (e.g., severe traumatic brain injury, severe CNS infection, carbon monoxide poisoning, alcohol abuse, primary CNS tumors) 3. Unstable or severe heart, lung, liver, kidney, or hematopoietic diseases, poor general health 4. Short life expectancy due to major diseases (e.g., end-stage metastatic cancer cachexia) 5. Large skin lesions or scars on the scalp, or poor heat dissipation that cannot tolerate PBMT 6. Patients with photosensitivity disorders 7. Abnormal nasal structure (deviated septum or large polyps); bacterial or viral infection; nasal dryness/bleeding; nasopharyngeal carcinoma unsuitable for intranasal device insertion.