Transcranial Photobiomodulation for Alzheimer's Disease (TRAP-AD)

This multi-site study will be the first to evaluate the dose-dependent effects of t-PBM in amnestic Mild Cognitive Impairment (aMCI) and early Alzheimer's Disease (AD) (CDR of 0.5-1, FAST 1-4; age 65-85) in a randomized clinical trial of 8 weeks of t-PBM vs. sham. At baseline, all subjects will complete initial neuropsychological testing. To elucidate mechanisms of action of t-PBM, prior to treatment, subjects will undergo neuroimaging related to critical features of AD: tau 18F MK-6240 load (PET), measures of brain bioenergetics (31P-MRS), and functional connectivity (rs-fMRI). After undergoing target engagement testing (t-PBM session performed during fMRI to detect BOLD changes with active t-PBM), subjects will then be randomized to t-PBM/sham and complete 24 t-PBM/sham treatments, \~11 min per day, 3 days per week, for 8 weeks. t-PBM will be administered via continuous, 808 nm wavelength laser delivery to the forehead bilaterally (at standard EEG electrode positions F4, F3).