It is hard to tell from this article, but looking at the paper the key thing they were focusing on is the mechanism for the previously observed diurnal variatio

It is hard to tell from this article, but looking at the paper the key thing they were focusing on is the mechanism for the previously observed diurnal variation in amyloid beta. They do some modeling that they say suggests that the main factor allowing levels to decrease at night is reduced production rather than increased clearance. One implication of this is "Given that there are many approved therapies targeting sleep, the effect of sleep-inducing drugs on CSF Aβ should be tested in individuals with sleep disruption and promising candidates investigated in AD prevention trials."