The article ends with...

“We know that insulin has a role in terms of providing energy to the brain, but it also [works] as a brain growth factor in a way, helping nerves work together,” said Besser. “So, they tried this and they found … patients treated with a low dose of insulin had a decline in their loss of function and a slight improvement in their short-term memory.” But experts warn that the study, published in the journal Neurology, was small –only 104 total patients – and it is too soon to say whether the treatment is safe and effective. The study lasted four months, which researchers noted was way too soon to allow for any concrete proof of efficacy. To make these findings more than just hopeful, researchers plan to carry out larger and longer studies, scheduled to begin next summer. In the meantime, hit the gym. It may keep your brain healthy. “Every time you exercise, your insulin levels go up,” Besser told “GMA.” “So, there’s no reason to not go out and get a little more exercise, but it’s too soon to be treating [Alzheimer's] with insulin.”

I would interpret this not as the Alzheimer's brain is in need of some beneficial effect of insulin, but rather that the brain cells themselves have become insulin resistant. This would also tie into the beneficial effect of exercise, increasing insulin sensitivity rather than making "insulin levels go up," and that somehow making the brain function more optimally.

Obviously insulin has numerous important functions in the body, but the logic of treating Alzheimer's with insulin is just as ludicrous as treating diabetes as a "lack of insulin" disease (excepting type I diabetics who literally don't produce insulin.) God forbid we did something crazy like changing people's crappy diets.

It is scary to think of the the next 20, 30, and 40 years as the current diabetes epidemic becomes an Alzheimer's epidemic.