40 Hz Audio-Visual Stimulation Therapy for AD

This is a single-center, parallel-group, double-blind randomized controlled trial conducted at the First Affiliated Hospital of Xiamen University, enrolling 50 participants with Alzheimer's disease (AD)-derived mild cognitive impairment (MCI) or mild AD aged 50-80 years with ≥4 years of education. Subjects must meet diagnostic criteria per Chinese AD guidelines, show medial temporal lobe atrophy on baseline brain MRI, have a reliable caregiver, and be capable of completing all assessments. Exclusion criteria include severe visual/auditory impairment, non-AD dementia, recent neuromodulation therapy, uncontrolled severe systemic diseases, prominent psychiatric disorders, significant cerebral focal lesions on MRI, and other conditions precluding safe participation. Eligible participants will be randomly assigned to either the 40 Hz audio-visual stimulation group or the placebo group. The intervention lasts 1 hour once daily for 12 weeks, with a total subject follow-up period of 36 weeks (12-week treatment + 24-week observational follow-up). The primary efficacy outcome is the change from baseline in the 11-item Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) at the end of treatment. Secondary outcomes include changes in Mini-Mental State Examination (MMSE) and ADCS-Activities of Daily Living (ADCS-ADL) scores across all follow-up visits. Exploratory biomarkers cover plasma Aβ42, Aβ40, Tau-217, gamma wave power on electroencephalography (EEG), and repeat Aβ-PET imaging (if previously performed). Cognitive, functional, emotional, EEG, and blood biomarker assessments will be conducted at scheduled time points. Safety monitoring focuses on intervention-related adverse events such as headache and dizziness, with detailed recording of onset, duration and accompanying symptoms. Statistical analyses will use two-sided tests at α=0.05. Linear mixed models and repeated-measures ANOVA with ANCOVA adjustment for covariates will analyze the primary endpoint; appropriate parametric or nonparametric tests will be applied for secondary and exploratory outcomes. Baseline group balance will be compared via t-tests, Mann-Whitney U tests or chi-square tests. All data processing and statistical modeling will be performed using Python 3.11 and related analytical packages. The trial runs from July 2026 to December 2027.

Inclusion Criteria Subjects diagnosed with Alzheimer's disease-derived mild cognitive impairment (AD-MCI) or mild Alzheimer's dementia, diagnosed in accordance with Chinese Guidelines for the Diagnosis and Treatment of Alzheimer's Dementia (2020 Edition) and Chinese Expert Consensus on the Diagnosis and Treatment of AD-derived Mild Cognitive Impairment (2021). Clinical Dementia Rating sum of boxes (CDR-SB) score ranges from 0.5 to 1. Age between 50 and 80 years old, with education ≥ 4 years, any biological sex. Able to cooperate with 12-week intervention and all scheduled assessments including cognitive scales, EEG, blood tests and brain imaging. Subject or legal guardian provides written informed consent and agrees to comply with study procedures. Baseline brain MRI with coronal hippocampal sequence shows medial temporal lobe atrophy (MTA) grade ≥2, highly suggestive of AD pathology. Has a stable, reliable caregiver throughout the study period. Exclusion Criteria Severe visual impairment (uncorrected visual acuity \4. Baseline MRI shows significant focal cerebral lesions: ≥2 infarcts \>2 cm; infarcts in thalamus, hippocampus, entorhinal cortex or angular gyrus; Fazekas white matter hyperintensity grade ≥3. Active HIV, syphilis, hepatitis B/C or other severe chronic infectious diseases. Severe communication disorders or altered consciousness preventing completion of assessments or intervention. Refusal of informed consent by legal guardian. Any other clinical condition judged by investigators to make the subject unsuitable for participation.