he says he had a photographic memory. >> when you can remember things that -- and you remember them well, it just becomes natural but all of a sudden when you can't remember things and remember them as well as you used to, then it becomes a concern. >> his wife, sandy, convinced him to see a doctor when she noticed him having some memory difficulty. he's been on medication for several years, which he says has helped slow down his loss. but more than anything, he's kept his mind and body active. >> i've always worked out. i just like it. it's just become a part of me. i do it every day. i try to walk my five miles. when i do, i normally stop each mile around and i do 25 pushups until i've done 150. >> what's become apparent in the last few years is that the development of alzheimer's disease need not be a passive process.