The number of people with Alzheimer's disease is increasing every year, but the available drugs are not effective. Both transcranial alternating current stimulation (tACS) and sound stimulation are non-invasive methods to modulate Central Nervous System excitability. tACS has been shown to modulate cognitive processes by affecting intrinsic oscillatory manipulation and entrainment in the brain. And 40 Hz sound stimulation reduces Aβ amyloid deposition in the hippocampus of AD mice.~Sixty patients with mild-to-moderate AD will be recruited in this randomized, double-blind, controlled study. The researchers will evaluate whether tACS (40Hz) to the DLPFC region or 40Hz sound stimulation to both ears improves cognition in patients with mild to moderate AD. The study will also investigate which stimulation method has a more pronounced and sustained improvement in cognition in the following three groups of patients.~Subjects will be randomized into three groups, with the first group receiving tACS combined with sound stimulation, the second group receiving tACS alone, and the third group receiving sound stimulation alone. All will receive three weeks (15 sessions) of treatment. Patients will be assessed by neuropsychological testing at baseline, post-treatment (21 days) and at the 3-month follow-up. Subjects will be compared by functional MRI at baseline and post-treatment for brain network connectivity before and after treatment.
Alzheimer's disease is characterized by progressive cognitive decline, and cognition is associated with cerebral concussion. Previous studies have found reduced gamma energy in the brain of AD patients. Therefore, modulation of gamma activity in AD patients may help improve cognitive function.~The purpose of this study was to investigate the safety and tolerability of transcranial alternating current stimulation (tACS) combined with 40Hz sound stimulation in patients with mild to moderate Alzheimer's disease (AD); to compare the effects of tACS combined with sound stimulation, tACS, and 40Hz sound stimulation on cognition in AD patients; and the effects of tACS combined with sound stimulation, tACS, and 40Hz sound stimulation on brain network connectivity in AD patients before and after tACS.