Effects and Mechanisms of Temporal Interference Brain Stimulation on Memory Function in Preclinical Alzheimer's Disease

Participants receive active TIBS targeted at the bilateral hippocampus. Stimulation parameters include a 5 Hz (Theta band) low-frequency modulation envelope, generated by two high-frequency current pairs (e.g., f1=2000 Hz, f2=2005 Hz). Peak-to-peak current intensity for each pair will be 2 mA (or 1 mA per electrode). Stimulation is delivered daily for 40 minutes, 6 days/week, for a total of 2 weeks. Individualized targeting and initial intensity optimization are guided by baseline sMRI and DTI. Real-time high-density EEG monitoring during each daily session (D2-D11) provides feedback on brain activity

Participants receive sham stimulation designed to mimic the sensation of active TIBS without therapeutic output. This involves using a sham coil or a device mode with extremely low current intensity (e.g., 0.1-0.2 mA) or brief ramp-up/ramp-down sensations at the beginning and end of sessions, with no effective current delivery during the main stimulation period. The stimulation position and apparent parameters are identical to the active TIBS group to maintain blinding.