But what if the procedure somehow makes brain functionality worse? Wouldn’t a control group of Alzheimer’s patients falsely attribute that decline to the diseas

But what if the procedure somehow makes brain functionality worse? Wouldn’t a control group of Alzheimer’s patients falsely attribute that decline to the disease rather than the treatment? Though I suppose you run into the same issue the other way, too. If the treatment somehow improves everyone’s cognitive function it’s difficult to measure because your “baseline” has moved.