How to measure effectiveness of Lions Mane?

My mother just turned 75. She's in good shape for her age, eats healthy, alot of exercise but her mom, my grandmother, died from complications of Alzheimer's and her sister has it now. She does have "senior moments" so we're both a little worried.
She's a retired nurse and she asked me if I knew of anything that might help her memory. I was shocked! She's always bitched about the supplements we take. She's a retired nurse and normally would never take something not directed to by her doc.
Anyway after getting a bunch of hard no's listing racetams etc. we landed on Lions Mane. I've been taking it for 3 years & love it.
My mom & I are trying to come up with some cognitive tests to administer every 30 days for a year to track her progress or decline and would like some suggestions. Any dosage recommendations would also be helpful. She's 75, 5 foot 2, 120lbs. I would really love for her to eventually try some other adaptogens etc. but right now that's out of the question. If this works for her it could potentially open up a whole new world of nutrition for her. Thanks