Radiolab's latest podcast talks about some very interesting research underway at MIT. Mice in various stages of mouse-alzheimer's are being exposed to light, pulsating at the Gamma frequency--or the frequency of neuron firing that brains exhibit when performing high-level tasks. In Alz patients, this frequency of brain activity is found to be very low.
They've found that an hour/day of exposure not only clears 50% of the amyloid plaque away, but has enabled the recovery of memories assumed to be gone.
This is mice, and there's a relatively abysmal record of mouse studies translating to efficacy in humans, but this shows some intriguing promise.