Yeah, maybe not. It's not like they'd be looking for it. Also, "not getting Alzheimer's" doesn't feel like anything. If it's preventing dementia, then you can't really notice it. You would only notice if it didn't work. (Unless you were too demented to notice...)
NINER: I agree to a small portion of your comment. I help people who have obvious dementia; short term memory failure. It is hit and miss asking a person with any degree of notable dementia what they notice or do not, in context to your point. Some lie, some answer just to answer, most say "I don't know". If a substance "works" / improves short term memory, then everyone connected with the demented person will know and eventually the demented person also.
I would try 10mg/day for a few days then 15mg/day for a ten days, test, then 20mg for ten days, test, then 25 mg/day...observing improvements & contradictions. It would be well worthy if a natural substance could be found that operates the same as Montelukast. Now that I have come across this information I am going to go check out the herb market here, it's the largest in Northern Peru, and ask about anti inflammatory's. I have found many research studies available on Cat's Claw ( Uña de Gato - Uncaria tomentosa and Uncaria guianensis) and it's similar effects on Alzheimer's; as Montelukast. I have not dived in to read up on the exact mechanism to see if it is the same or not. But here Cat's Clay is recommended by the herbalists (shaman) for dementia when first noticed.
SEE: (2013) The Globalization of Traditional Medicine in Northern Peru: From Shamanism to Molecules
http://www.ncbi.nlm....les/PMC3888705/