An interesting study in Cell recently showed that both flashing light and playing a sound at 40 Hz can mitigate damage caused by tau-associated pathology and beta amyloid plaques in Alzheimer's disease.
I don't know exactly how this works except that this frequency stimulates glial (brain supporting cell) and vessel changes by the stimuli causing improvement in cognition while also clearing beta amyloid.
I know I have posted before on the effects of sleep on Alzheimer's but thought this would be an interesting post to share as well.
While no studies have been set in humans, some people are trying this out on themselves for an hour a day. If you are this dedicated, you can set it as background light and noise on a computer monitor.
While great sleep and possibly watching/listening to 40 Hz stimuli may be helpful, it does not cure Alzheimer's, a disease which regrettably has no cure to this date.