Clinical studies testing the safety and efficacy of 40Hz sensory stimulation to treat Alzheimer's disease have found the therapy was well tolerated, produced no serious adverse effects and was associated with some significant neurological and behavioral benefits. Tsai's lab discovered exposing mice to light flickering or sound clicking at the gamma-band brain rhythm frequency of 40Hz produced improvements in learning and memory; reduced brain atrophy, neuron and synapse loss; and showed lower levels of hallmark Alzheimer's proteins amyloid beta and phosphorylated tau. In the Phase 1 study, volunteers filled out a questionnaire. Meanwhile, measurements taken with EEG scalp electrodes clustered...